U.S. patent application number 12/630189 was filed with the patent office on 2010-07-01 for system and method for wastewater treatment.
Invention is credited to RAINER BAUDER, Richard Hsu Yeh.
Application Number | 20100163489 12/630189 |
Document ID | / |
Family ID | 42233608 |
Filed Date | 2010-07-01 |
United States Patent
Application |
20100163489 |
Kind Code |
A1 |
BAUDER; RAINER ; et
al. |
July 1, 2010 |
SYSTEM AND METHOD FOR WASTEWATER TREATMENT
Abstract
The present disclosure is directed towards systems and methods
for the treatment of wastewater. A system in accordance with one
particular embodiment may include at least one resin tank including
an ion exchange resin configured to target a particular metal. The
at least one resin tank may be configured to receive an output from
an oxidation reactor configured to receive a flow of wastewater
from a wastewater producing process. The system may further include
a vacuum filter band system configured to receive a saturated resin
tank and to apply a water rinse to the resin to generate a resin
slurry, the vacuum filter band system including a vacuum filter
band configured to receive the resin slurry. Numerous other
embodiments are also within the scope of the present
disclosure.
Inventors: |
BAUDER; RAINER; (Nahant,
MA) ; Yeh; Richard Hsu; (Taipei, TW) |
Correspondence
Address: |
HOLLAND & KNIGHT LLP
10 ST. JAMES AVENUE
BOSTON
MA
02116-3889
US
|
Family ID: |
42233608 |
Appl. No.: |
12/630189 |
Filed: |
December 3, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61119567 |
Dec 3, 2008 |
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Current U.S.
Class: |
210/652 ;
210/143; 210/189; 210/672; 210/673; 210/675 |
Current CPC
Class: |
C02F 9/00 20130101; C22B
3/02 20130101; C02F 1/20 20130101; C02F 2001/425 20130101; C02F
2209/005 20130101; C02F 2103/16 20130101; C02F 1/76 20130101; C02F
2209/06 20130101; C22B 7/006 20130101; C02F 2301/063 20130101; C02F
2303/16 20130101; C22B 3/42 20130101; C02F 2101/20 20130101; C22B
3/20 20130101; Y02P 10/234 20151101; C02F 2209/03 20130101; C02F
2209/40 20130101; Y02P 10/20 20151101; C02F 1/42 20130101; C02F
2209/008 20130101; C02F 2209/003 20130101; C02F 1/283 20130101 |
Class at
Publication: |
210/652 ;
210/189; 210/143; 210/675; 210/673; 210/672 |
International
Class: |
B01J 49/00 20060101
B01J049/00; C02F 1/44 20060101 C02F001/44; C02F 1/58 20060101
C02F001/58; C02F 1/42 20060101 C02F001/42; B01D 15/42 20060101
B01D015/42 |
Claims
1. A wastewater treatment system comprising: at least one resin
tank including an ion exchange resin configured to target a
particular metal, the at least one resin tank configured to receive
an output from an oxidation reactor configured to receive a flow of
wastewater from a wastewater producing process; and a vacuum filter
band system configured to receive a saturated resin tank and to
apply a water rinse to the resin to generate a resin slurry, the
vacuum filter band system including a vacuum filter band configured
to receive the resin slurry.
2. The wastewater treatment system of claim 1, wherein the vacuum
filter band system further includes at least one spray nozzle
configured to provide a resin rinse to the resin slurry.
3. The wastewater treatment system of claim 2, wherein the at least
one spray nozzle includes a plurality of spray nozzles configured
to provide a cascading resin rinse to the resin slurry.
4. The wastewater treatment system of claim 1, wherein vacuum
filter band is configured to apply a negative pressure to at least
partially dewater the resin slurry.
5. The wastewater treatment system of claim 1, wherein the
cascading resin rinse includes at least one of HCL, NaOH, H.sub.2O,
oxidants, and reducing agents.
6. The wastewater treatment system of claim 1, further comprising a
resin slurry pump configured to pump the resin slurry from a
holding vessel to the vacuum filter band.
7. The wastewater treatment system of claim 1, wherein the vacuum
filter band system includes a plurality of spraying zones, each of
the plurality of spraying zones including a spray nozzle configured
to apply a solution to the resin slurry.
8. The wastewater treatment system of claim 1, wherein the vacuum
filter band controllable via an associated programmable logic
controller (PLC), the PLC configured to control at least one of a
speed and a direction of the vacuum filter band.
9. The wastewater treatment system of claim 7, wherein each of the
spraying zones includes an associated collection chamber configured
to collect liquids from the resin slurry.
10. The wastewater treatment system of claim 1, further comprising
a reverse osmosis unit configured to receive liquid from at least
one of the collection chambers, the reverse osmosis unit further
configured to treat the liquid and to redistribute the treated
liquid to at least one of the spraying zones.
11. A method for treating wastewater comprising: providing at least
one resin tank including an ion exchange resin configured to target
a particular metal, the at least one resin tank configured to
receive an output from an oxidation reactor configured to receive a
flow of wastewater from a wastewater producing process; receiving a
saturated resin tank at a vacuum filter band system; applying a
water rinse to the saturated resin tank to generate a resin slurry;
and receiving the resin slurry at a vacuum filter band.
12. The method of claim 11, further comprising providing a resin
rinse to the resin slurry via at least one spray nozzle.
13. The method of claim 12, further comprising providing a
cascading resin rinse to the resin slurry via a plurality of spray
nozzles associated with the at least one spray nozzle.
14. The method of claim 11, further comprising applying a negative
pressure via the vacuum filter band to at least partially dewater
the resin slurry.
15. The method of claim 11, wherein the cascading resin rinse
includes at least one of HCL, NaOH, H.sub.2O, oxidants, and
reducing agents.
16. The method of claim 11, further comprising pumping, via a resin
slurry pump, the resin slurry from a holding vessel to the vacuum
filter band.
17. The method of claim 11, further comprising applying a solution
to the resin slurry at each of the plurality of spraying zones via
a spray nozzle.
18. The method of claim 11, further comprising controlling the
vacuum filter band via an associated programmable logic controller
(PLC), the PLC configured to control at least one of a speed and a
direction of the vacuum filter band.
19. The method of claim 17, further comprising collecting liquids
from the resin slurry at a collection chamber associated with each
of the spraying zones.
20. The method of claim 11, further comprising receiving liquid
from at least one of the collection chambers at a reverse osmosis
unit configured to treat the liquid and to redistribute the treated
liquid to at least one of the spraying zones.
Description
RELATED APPLICATIONS
[0001] This application claims the priority of the following
application, which is herein incorporated by reference: U.S.
Provisional Application No. 61/119,567; filed 3 Dec. 2008,
entitled: "Ion Exchange Based Metal Bearing Wastewater Treatment
and Recycling System Therefore".
TECHNICAL FIELD
[0002] This disclosure generally relates to the field of industrial
wastewater treatment of metal bearing wastes. More specifically,
the present disclosure relates to the equipment, operating
procedures, chemical processes, and physical processes employed to
remove regulated and non regulated contaminants from industrial
wastewater.
BACKGROUND
[0003] Many industrial manufacturing processes generate wastewater
containing metals and other contaminants; both organic and
non-organic. Due to their inherent toxicity, regulatory authorities
place strict limits on the maximum concentration of certain metals
that can be legally discharged into the environment. In order to
comply with these regulations, factories employ wastewater
treatment processes to remove regulated substances from the
wastewater. The two principal wastewater treatment methods are
chemical precipitation and ion exchange.
[0004] Chemical precipitation is the most commonly used method
today to remove dissolved (ionic) metals from wastewater. Chemical
precipitation typically requires process operations of
neutralization, precipitation, coagulation, flocculation,
sedimentation, settling/filtration, and dewatering. It uses a
series of tanks in which coagulants, precipitants and other
chemicals such as polymers, ferrous sulfate, sodium hydroxide,
lime, and poly aluminum chloride are added to convert metals into
an insoluble form. In conjunction with adjusting the pH of the
wastewater, this causes the metals to precipitate out of the water.
Using a clarifying tank, the precipitates are allowed to settle,
and then are collected as sludge; filtration can also be used to
remove the solids. Excess water in the sludge is removed using
filter presses and/or dryers. The sludge, which itself is a
regulated hazardous waste, is then sent offsite where it is
stabilized by mixing with cement or polymers, and then buried in a
hazardous material landfill. In this fashion the concentrations of
the regulated metals in the wastewater are reduced to a level in
compliance with regulatory limits, allowing the water to be
discharged from the facility. However, the need to handle,
transport, and dispose of the resulting hazardous sludges is one of
the most costly, labor intensive, resource demanding and difficult
problems with chemical precipitation as a wastewater treatment.
[0005] The inherent disadvantage of chemical precipitation is that
it is an active and additive process and, as such, requires that
chemicals be added to the wastewater in order to remove regulated
metals. The side effect of this is an increase in the
concentrations of many other substances, as well as a deterioration
in characteristics such as chemical oxygen demand (COD) and
conductivity; thus requiring additional treatments and rendering
the water unsuitable or uneconomical for recycling and reuse.
Furthermore, the metals removed are not only unrecoverable, they
are rendered into a regulated hazardous material requiring
specialized disposal. As an additive process, chemical
precipitation also increases, by orders of magnitude, the mass of
waste material which needs to be handled, transported and
landfilled.
[0006] As an active process, the effectiveness of chemical
precipitation is predicated on the proper operational procedures
and dosing of chemicals relative to fluctuating variables such as
the number of metals in solution and their concentrations, as well
as the presence and concentration of other substances. Underdosing
of chemicals results in incomplete precipitation and removal of
regulated metals, while overdosing wastes chemicals, generates
additional volumes of sludge, and increases cost. Currently, due to
the consequences of illegal discharges, most wastewater treatment
operations simply absorb the additional cost and overdose the
chemicals in their treatment operations. Also, as each metal
optimally precipitates at a different pH, in wastewaters containing
several metals, adjusting pH to precipitate one metal may actually
cause another metal to resolubilize into the wastewater. Lastly,
chemical precipitation processes require a large amount of floor
space and capital equipment.
[0007] In contrast, ion exchange is a stoichiometrical, reversible,
electrostatic chemical reaction in which an ion in solution is
exchanged for a similarly charged ion in a complex. These complexes
are typically chemically bound to a solid, insoluble, organic
polymer substrate creating a resin; the most common of which is
crosslinked polystyrene. Also inorganic substrates like silica gel
in various porosities and chemical modifications can be employed.
Polystyrene crosslinking is achieved by adding divinyl benzene to
the styrene which increases stability, but does slightly reduce
exchange capacity. With a macro porous structure, these ion
exchange resins are normally produced in the form of small (1 mm)
beads, thus providing a very high and accessible surface area for
the binding of the functional group complexes; the site where the
ion exchange reaction actually occurs. The exchange capacity of the
resin is defined by the total number of exchange sites, or more
specifically, of its total available functional groups.
[0008] In the actual ion exchange reaction, an ion such as sodium
(Na+) loosely attached to a functional group of the complex is
exchanged for an ion in solution such as copper (Cu2+); that is,
the sodium ions detach from the complex and go into solution while
the copper ion comes out of solution and takes the place of the
sodium ions on the complex. There are two types of ion exchange
resins, cation exchangers, which exchange their positively charged
ions (H+, Na+ etc.) for similarly charged ions (Cu2+, Ni2+, etc.)
in solution, and anion exchangers, which exchange their negatively
charged ions (OH-) for similarly charged ions in solution
(chlorides, sulfates, etc.)
[0009] Ion exchange resins can also be selective or nonselective,
based on the configuration and chemical structure of their
functional groups. Non selective resins exhibit very similar
affinities for all similarly charged ions, and consequently will
attract and exchange all species without significant preference.
Selective resins have specialized functional groups which exhibit
different affinities to different ions of similar charge, causing
them to attract and exchange ions with species in a well defined
order of preference. The ion that is originally attached to the
resin (e.g., H+, Na+, OH-) is of the lowest affinity, which is why
it will exchange places with any other ion the resin encounters.
Generally speaking, the relative affinity a resin exhibits for a
particular ion is directly correlated to the exchange efficiency
and capacity for that ion. However, as selective resins are based
on relative affinities, the actual selectivity is also relative and
not absolute.
[0010] Ion exchange resins can be regenerated once their capacity
to exchange ions has been exhausted; that is, all of the functional
groups have already exchanged their original ion for one which was
in the solution. This is also known as a resin which has been
"saturated" in that it cannot adsorb any additional ions. The
process of regeneration is simply the reverse reaction of the
original ion exchange. Clean water is first flushed through the
saturated resin to remove any particles, solids, or other
contaminations. A solution containing a high concentration of the
original ion (e.g., the H+ ions contained in an acid) is then
passed through the resin, causing the ion captured on the
functional group (e.g., Cu2+) to forcibly detach from the
functional group and solubilize into the solution and be replaced
by the H+ ions from the acid. Depending on the type of resin
(cation or anion, weak or strong) different chemicals are used to
regenerate resins. In the case of selective or chelating resins,
the strong affinities exhibited by these resins require greatly
increased chemical consumption for the regeneration process.
Regeneration results in a return of the resin to its original form
(suitable for reuse) and a solution, also known as the regenerant,
containing all of the metals or other ions stripped from the resin.
Depending on its composition and complexity, some regenerants can
be further processed by methods such as electrowinning to recover
metals. The chemical consumption for regeneration as well as the
difficulty and costs of treating or disposing of regenerants
containing metals is the principal reason why ion exchange is often
not a cost effective wastewater treatment option for metal bearing
wastes.
SUMMARY OF DISCLOSURE
[0011] In a first implementation of this disclosure, a system in
accordance with one particular embodiment may include at least one
resin tank including an ion exchange resin configured to target a
particular metal. The at least one resin tank may be configured to
receive an output from an oxidation reactor configured to receive a
flow of wastewater from a wastewater producing process. The system
may further include a vacuum filter band system configured to
receive a saturated resin tank and to apply a water rinse to the
resin to generate a resin slurry, the vacuum filter band system
including a vacuum filter band configured to receive the resin
slurry.
[0012] One or more of the following features may be included. The
vacuum filter band system may further include at least one spray
nozzle configured to provide a resin rinse to the resin slurry. The
at least one spray nozzle may further include a plurality of spray
nozzles configured to provide a cascading resin rinse to the resin
slurry. The vacuum filter band may be configured to apply a
negative pressure to at least partially dewater the resin slurry.
The cascading resin rinse may include at least one of HCL, NaOH,
H.sub.2O, oxidants, and reducing agents.
[0013] In some embodiments, the system may include a resin slurry
pump configured to pump the resin slurry from a holding vessel to
the vacuum filter band. The vacuum filter band system may include a
plurality of spraying zones, each of the plurality of spraying
zones including a spray nozzle configured to apply a solution to
the resin slurry. The vacuum filter band may be controllable via an
associated programmable logic controller (PLC), the PLC configured
to control at least one of a speed and a direction of the vacuum
filter band. Each of the spraying zones may include an associated
collection chamber configured to collect liquids from the resin
slurry. The system may further include a reverse osmosis unit
configured to receive liquid from at least one of the collection
chambers, the reverse osmosis unit further configured to treat the
liquid and to redistribute the treated liquid to at least one of
the spraying zones.
[0014] In another implementation of this disclosure, a method in
accordance with one particular embodiment may include providing at
least one resin tank including an ion exchange resin configured to
target a particular metal, the at least one resin tank configured
to receive an output from an oxidation reactor configured to
receive a flow of wastewater from a wastewater producing process.
The method may further include receiving a saturated resin tank at
a vacuum filter band system and applying a water rinse to the
saturated resin tank to generate a resin slurry. The method may
also include receiving the resin slurry at a vacuum filter
band.
[0015] One or more of the following features may be included. The
method may include providing a resin rinse to the resin slurry via
at least one spray nozzle. The method may also include providing a
cascading resin rinse to the resin slurry via a plurality of spray
nozzles associated with the at least one spray nozzle. The method
may further include applying a negative pressure via the vacuum
filter band to at least partially dewater the resin slurry. The
cascading resin rinse may include at least one of HCL, NaOH,
H.sub.2O, oxidants, and reducing agents.
[0016] In some embodiments, the method may also include pumping,
via a resin slurry pump, the resin slurry from a holding vessel to
the vacuum filter band. The method may further include applying a
solution to the resin slurry at each of the plurality of spraying
zones via a spray nozzle. The method may also include controlling
the vacuum filter band via an associated programmable logic
controller (PLC), the PLC configured to control at least one of a
speed and a direction of the vacuum filter band. The method may
additionally include collecting liquids from the resin slurry at a
collection chamber associated with each of the spraying zones. The
method may further include receiving liquid from at least one of
the collection chambers at a reverse osmosis unit configured to
treat the liquid and to redistribute the treated liquid to at least
one of the spraying zones.
[0017] The details of one or more embodiments are set forth in the
accompanying drawings and the description below. Features and
advantages will become apparent from the description, the drawings,
and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0019] FIG. 2 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0020] FIG. 3 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0021] FIG. 4 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0022] FIG. 5 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0023] FIG. 6 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0024] FIG. 7 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0025] FIG. 8 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0026] FIG. 9 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0027] FIG. 10 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0028] FIG. 11 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0029] FIG. 12 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0030] FIG. 13 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0031] FIG. 14 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure; and
[0032] FIG. 15 is an exemplary embodiment of a wastewater system in
accordance with the present disclosure;
[0033] Like reference symbols in the various drawings may indicate
like elements.
DETAILED DESCRIPTION
[0034] The present disclosure is directed towards an automated,
modular, ion exchange resin based system that may process metal
bearing wastewaters such that the treated water can be recycled, or
discharged in compliance with regulatory standards. Embodiments of
the present disclosure may capture the metals within the wastewater
and then separate, purify and concentrate each individual metal
into commercially salable end products such as metal sulfates.
[0035] The system may be comprised of a front end unit situated at
the site of wastewater generation, and a central processing
facility where the metal bearing ion exchange columns from numerous
front end units are collected and processed. Alternatively, where
treatment volumes, economic, and/or regulatory considerations so
merit, the central processing facility can be located together with
the front end system.
[0036] Embodiments of the present disclosure may be used to collect
environmentally regulated metals from the rinse water streams of
plating baths and similar operations. Rinse water may be generated
when various work pieces are cleaned to receive the final, surface
washed, product. Excess plating fluid may need to be removed prior
to drying, packing and shipping of the work pieces. The rinse water
quality or the abundance of metals which are carried into the rinse
water may be dependent upon the rinse process itself (e.g.,
spraying, dipping, stifling, etc.) and also the overall surface
properties and nature of the plated work piece. Thus, the
concentration of toxic metals such as copper, nickel, zinc and
chrome may vary at a particular shop.
[0037] Generally, the present disclosure may be used to provide
safe and efficient removal of environmentally regulated metal
contaminations on-site at various plating facilities. Embodiments
of the present disclosure may include replacement of exhausted
resin tanks with re-conditioned, full capacity tanks and transport
between the plating facility and an off-site central processing
facility. Embodiments of the present disclosure may be used to
recover industrially valuable metals including, but not limited to,
Cu, Zn, Ni and Cr as metal salt products in liquid or solid form.
Once these metals have been successfully recovered, they may be
re-distributed as high quality, recycled metal salts back to the
plating industry or other consumers. The systems and methods
described herein may be used to provide safe and efficient
treatment of residual toxic metals and reduction of the overall
waste volume by more than 80%.
[0038] In some embodiments, the present disclosure may apply to a
wide variety of processes where metals from a surface treatment are
carried into rinsing waters and waste streams. The teachings of the
present disclosure may be used to replace, in whole or in part,
conventional sludging and landfill technology, which has been
employed since the early days of wastewater treatment. While the
present disclosure may discuss industrial metals such as copper,
nickel, zinc and chromium, it is by no means intended to be limited
to these metals, as the teachings of the present disclosure may be
used to treat any numerous types of metals.
[0039] Ion exchange technology is based upon the electro static
interaction of ions dissolved in water with certain organic
functional groups. These groups may attract the positively or
negatively charged ions and exchange their proton or hydroxide ion
used to pre-condition the functional groups. Positively charged
ions are referred to as cations while the negatively charged ions
are referred to as anions. The organic functional groups may
include, but are not limited to, sulfonic acid, carboxylic acids,
tertiary amines, and quaternary amines. The organic groups are
typically bound chemically to styrene or acrylic copolymers. The
polymers may provide a water insoluble backbone with a high surface
area to filter the ions form a water stream pumped in an efficient
and controlled manner.
[0040] In some embodiments of the present disclosure, the ion
exchange polymers or resins may be filled, for example, into tanks
or columns (e.g., 80-100 L). This may allow for the easy
replacement of a saturated ion exchange resin. A saturated ion
exchange resin is a polymer where all, or the vast majority of,
available functional groups have been replaced with the target
ions. The resin at this point may require reconditioning which may
allow for the harvesting of the "loaded" ions.
[0041] In some embodiments, ion exchangers or resin tanks may be
immobilized and may act like an ion selective filter. This means
that much diluted metal ions in water streams are adsorbed and
concentrated on the ion exchange resin. Very large volumes of water
can be treated with relative small ion exchange tanks or
cartridges. The other contaminants in the water stream are not
attracted to the ion exchange resins. Wastewater treatment is
therefore very effective and feasible when employing ion exchange
technology. Also, there are ion exchange resins which support an
even more selective organic functional group. These ion exchange
resins may allow for an additional level of selectivity and
adsorption capabilities.
[0042] Embodiments of the present disclosure may utilize both
non-selective and metal selective ion exchange resins. One of the
strengths in employing the selective ion exchange resins is the
capability to attract specific metal ions stronger than other
metals. For example, copper is attracted almost selectively to ion
exchange resins of the imminodiacetic acid type. The transition
metals (i.e. Cu, Zn, Ni) form a well-defined hierarchy of
attraction to this organic functional group.
[0043] In contrast, a non-selective exchange resin may be able to
adsorb a wide range of ions and therefore remove potential
contaminations completely. In some embodiments of the present
disclosure these resins may be used for water demineralization
prior to recycle or as polishers.
[0044] Referring now to FIG. 1, a schematic 100 depicting an
embodiment of a wastewater process in accordance with the present
disclosure is provided. In some embodiments, the wastewater process
may include both a front end system 102, which may take place at a
customer site such as a plating facility, and a core process 104,
which may occur at a central facility.
[0045] In some embodiments, front end system 102 may consist of
several individual processes assembled linearly into a seamless
treatment system, which may be controlled by a programmable logic
controller linked to sensors, pumps, valves, and other hardware
associated with system 102. Each process may remove or treat a
particular contaminant in the wastewater either to meet, or exceed,
regulatory discharge criteria and/or to ensure proper operation of
the ion exchange tanks for metal removal. Non-regulated substances
may be disposed of on site, while regulated materials (primarily
transition metals) may be collected in columns and cartridges for
transport to a central processing facility.
[0046] In some embodiments, front end system 102 may be configured
to perform a passive removal of the metal contamination in the
rinse waters generated at the plating facility. The effluent out of
front end system 102 may be filtered to contain little or no
regulated or toxic metals and may either be discharged and/or
treated for its organic contamination (e.g., chemical oxygen demand
(COD) or total organic carbon (TOC) removal).
[0047] Once the loading capacity of the ion exchange resins in
front end system 102 is reached, the ion exchange resin tanks may
be exchanged with freshly reconditioned resin tanks. The exhausted
and metal loaded tanks may be transported back to core process 104
at the central processing facility. The central facility may
harvest the target metals from the loaded resins and re-conditions
the material for re-use at the plating sites.
[0048] In some embodiments, the harvested metals may be collected
as a liquid having a mixed metals concentrate. This solution may
then be used to isolate and purify the individual target metals,
copper, nickel and zinc. The metals may be collected as a very
highly concentrated metal sulfate solution.
[0049] In some embodiments, the product of core process 104 may be
provided to production phase 106, which may be configured to create
a crystallization of the metal liquors to generate metal sulfate
salts. The sulfates may be fed back into the market as resource for
plating facilities 102 or to related industries.
[0050] In some embodiments, some or all of the metals that are not
economically viable or are too toxic to be discharged untreated,
may undergo a conventional hydroxide precipitation. The sludges
received may be treated and disposed of via the existing waste
management facilities and companies. The sludge volume produced by
core process 104 at the central facility may be a tiny fraction of
the originally produced amount generated using existing
technologies. Core process 104 and production phase 106 may also
allow for improved detoxification to provide a safe and reliable
service to the public and environment.
Front End System
[0051] Referring now to FIG. 2, one exemplary embodiment of front
end system 200 is provided. System 200 may include one or more
resin tanks 202A-D, which may be configured to contain an ion
exchange resin. Numerous ion exchange resins may be used in
accordance with the present disclosure. For example, some ion
exchange resins may be strongly acidic, strongly basic, weakly
acidic, or weakly basic. The ion exchange resin may also be a
chelating resin, such as chelex 100, or any other suitable ion
exchange resin. The adsorption of ions or metal complexes is
however also possible with inorganic support materials like silica
gels or chemically modified silica gels. The adsorption mechanism
can be of hydrophobic interaction or hydrophilic interaction
mechanism or other nature.
[0052] In some embodiments, the efficiency of the filtering and
metal removal may be significantly improved by employing a
pre-selective ion exchange resin of the iminodiacetic acid type as
shown in further detail in FIG. 9. In this way, precious ion
exchange capacity may not be used up by the metal ions which are in
high natural abundance but are not regulated by the authorities
because of their non-toxic character (e.g., sodium, calcium,
magnesium, potassium, etc.). This way the first economic
pre-selective mechanism may be applied to preserve resources and
ion exchange capacity. Thus, embodiments of the present disclosure
may be used to remove transition metals such as copper, nickel, and
zinc with a preference over the monovalent base metals (Na, K,
etc.) or the divalent base metals (e.g., Ca and Mg). This
pre-selection may allow for enriching only the metals which are
valuable target metals and/or those that are regulated by the
environmental authorities.
[0053] In some embodiments, system 200 may further include a
control panel 204, which may be configured to control one or more
operations of system 200. Control panel 204 may include a
programmable logic controller (PLC) 205, or similar device, which
may be configured to monitor and/or govern the operating parameters
of front end system 200. Sensors may be placed throughout system
200 to provide operational system data including, but not limited
to, the volume in various tanks, system throughput, flow rates, pH
of the wastewater in each process step, volume of available
chemical reagents, oxidation/reduction potential, pressure, etc.
PLC 205 may be configured to process this incoming data on a real
time basis and then issue commands to pumps, valves, and other
system hardware according to the algorithms of its proprietary
software. A flowmeter, or similar device, may measure the total
throughput volume of the system, while several smaller flowmeters
may monitor the flow rate through individual components of system
200. In some embodiments, PLC 205 may be operatively connected to a
communications system whereby data may be transmitted wirelessly or
via the internet to a centralized control center. This may allow
for remote monitoring of the operations of system 200. This may
also provide for decreased personnel costs as well as for
optimizing the scheduling of resin tank changes and/or
replacement.
[0054] In some embodiments, control panel 204 and/or PLC 205 may
allow an operator to control the flow of influent wastewater using
influent pump 206. Influent pump 206 may be configured to provide
influent wastewater to one or more storage tanks within system 200,
e.g., oxidation tank 208. Oxidation tank 208, which will be
described in further detail hereinbelow, may provide an output to
relay tank 210. Relay tank 210 may be operatively connected to
cartridge filter 212 and activated carbon (AC) filter 214. One or
more filter pumps 216 may also be used to pump the wastewater
through various portions of system 200. System 200 may also include
acid tanks such as hydrochloric acid (HCL) tank 218 and sodium
hypochlorite (NaOCL) tank 220, which may be operatively connected
via pumps, valves, etc to portions of system 200. Additional
details of system 200 are described below with reference to FIG. 3.
Depending on the components recovered and the adsorption mechanism
used, other chemicals might be used.
[0055] Referring now to FIG. 3, an exemplary embodiment of system
300 showing resin tanks 302A-G arranged in a series arrangement is
provided. Initially, wastewater from the customer may be stored in
buffer tank 301, which may be configured to regulate the flow of
wastewater into system 300. In addition, the concentrations of the
varying contaminants may be modulated and normalized (if required).
Buffer tank 301 may also allow for the assaying of wastewater
characteristics including, but not limited to, metals present and
their respective concentrations, pH, suspended solids, chemical
oxygen demand, and oxidation/reduction potential.
[0056] In some embodiments, the initial resin columns (e.g., 302A
and 302B) may become saturated first. This design may allow for a
partially or entirely mobile system, which may provide for easy
transfer of the resin tanks to and from the central facility. Resin
tanks 302A-G may be of any suitable size, for example, in one
particular embodiment each of tanks 302A-G may be configured to
contain approximately 80-100 liters of ion exchange resin. Each
resin tank associated with tanks 302A-G may further include one or
more RFID tracking tags or similar devices, which may be configured
to provide monitoring capabilities, which are discussed in further
detail below.
[0057] In some embodiments, each resin tank may be configured to
continuously extract copper (Cu), zinc (Zn), and Nickel (Ni) from
the rinse water generated by the plating process. This may be
achieved by pumping the rinse water over the ion exchange resin
tanks 302A-G after intermediate storage in relay tank 310. The
actual trapping of the transition metals Cu, Ni, and Zn may occur
in a passive way. One or more pumps may supply the energy required
for the loading or filtering process. After the rinse water has
passed through resin tanks 302A-G, metals such as copper, nickel,
and zinc, for example, may be removed to a level below the local
discharge limits (e.g., 1-3 mg/L, depending on the metal). The
water may then either be treated further for its organic
contamination or, if complying already with the local regulation,
may be discharged into the municipal drains. As the loading
capacity of the ion exchange resin is known (i.e., volume of
resin), the filter capacity may be easily adjusted to the observed
levels of metal contamination (e.g., individually for each
workshop). For example, a standard usage time until replacement
with a fresh set of resin tanks may occur after approximately ten
working days (e.g., 2 operational weeks utilizing 40 m.sup.3 of
rinse water daily).
[0058] In some embodiments, each of resin tanks 302A-G may be
wholly or partially enclosed and may be fitted with appropriate
inlet and outlet openings for the flow of the water to be treated.
Resin tanks 302A-G may be configured to contain and support the
resin, thus creating a resin bed of defined height and depth. This
configuration may also provide the environment for the ion exchange
reaction to occur as the wastewater may be passed through each of
resin tanks 302A-G and evenly distributed throughout the resin bed.
There are several possible flow designs that may be used in order
to pass solutions through each of resin tanks 302A-G, including,
but not limited to, top in/bottom out, bottom in/top out, and top
in/top out. Resin tanks 302A-G may be connected to additional
equipment, such as pumps, valves, piping, etc., which may regulate
the inflow/outflow of wastewater, reagents for regeneration, and
backwash solutions. As ion exchange resins may undergo fouling and
congestion from organics and solids, only certain types of
wastewaters may be suitable for ion exchange treatment. In other
cases where the levels of inappropriate contaminants are within a
manageable range, pretreatment steps such as filtering and
oxidation may be taken prior to the wastewater entering resin tanks
302A-G in order to ensure proper operation.
[0059] In operation, during the loading phase, one or more of resin
tanks 302A-G may contain fresh resin and wastewater may be pumped
through the resin tanks at a rate designed to provide an adequate
amount of contact time between the wastewater and the resin for the
ion exchange reaction to occur. As wastewater flows through the
resin bed, the ion exchange reaction may occur and metals and other
ionic contaminants may be removed from the wastewater and trapped
on the resin. As the exchange capacity of the resin becomes
progressively exhausted, some metals may not be captured by the
resin and may begin to leak out of, or "breakthrough", one or more
of resin tanks 302A-G. Consequently, resin tanks 302A-G may be
configured in series, as shown in FIG. 3, so that each resin tank
may be able to capture any metals or ions which escape the tank
preceding it; thus ensuring a successful treatment of the
wastewater. Once a resin tank becomes saturated, it may be taken
offline (e.g., using control panel 204), or out of the series of
tanks 302A-G in service operation, and regenerated. The physical
handling and exposure to chemicals may cause degradation of the
resin's structure and exchange capacity over time. Therefore, this
loading/regeneration cycle may be performed repeatedly until the
operational life of the resin is reached, and it is no longer
economical or possible to continue use of the resin. At that point,
the exhausted resin may be discarded, and resin tanks 302A-G may be
filled with new resin.
[0060] System 300 may further include a control panel such as
control panel 204 shown in FIG. 2, which may be configured to
control the operation of various components throughout the system.
Control panel 204 may include a programmable logic controller or
similar device, which may be operatively connected to the valves,
pumps, sensors and control lines of system 300. Control panel 204
may include numerous types of circuitry, which may be in
communication with the components of system 300.
[0061] As used in any embodiment described herein, the term
"circuitry" may comprise, for example, singly or in any
combination, hardwired circuitry, programmable circuitry, state
machine circuitry, and/or firmware that stores instructions
executed by programmable circuitry. It should be understood at the
outset that any of the operations and/or operative components
described in any embodiment or embodiment herein may be implemented
in software, firmware, hardwired circuitry and/or any combination
thereof.
[0062] As discussed above, front end system 300 may use a
pre-selective ion exchange mechanism to pre-separate many regulated
metals from the non-toxic base metals. Sensors may be placed
throughout system 300 to monitor operational parameters and feed
data to programmable logic controller 205 associated with control
panel 204. Each process within system 300 may remove or treat a
particular wastewater contaminant to particular concentrations,
which at a minimum, satisfy recycling or regulatory discharge
standards.
[0063] In some embodiments, relay tanks, such as relay tank 310,
may regulate input flow rate and allow for the assaying of the
wastewater as well as pH adjustment (as required). Relay tank 310
may be configured to receive an output from numerous sources, such
as oxidation tank 308. Oxidation tank 308 may be configured to
destroy and/or reduce organic agents that could potentially
negatively impact the efficiency of the ion exchange resin tanks
302A-G that follow. The output from relay tank 310 may be sent to
one or more filters, including, but not limited to cartridge filter
312 and activated carbon filter 314.
[0064] In some embodiments, cartridge filter 312 or other
mechanical filters such as a mesh bag or sand filter, may remove
suspended solids and other particles. Cartridge filter 312 may
provide an output to activated carbon filter for additional
filtering operations. For example, activated carbon filter 314 may
polish the wastewater to remove any potentially remaining
interfering organics and/or suspended solids.
[0065] Once the filtering is complete, the wastewater may be sent
to resin tanks 302A-G, which may contain various types of ion
exchange resins. Resin tanks 302A-G may be housed in mobile tanks,
which may be taken off or put on line as necessary. Resin tanks
302A-G may be configured to capture target metals as well as other
cationic or anionic species. Individual resin tanks 302A-G may be
radio frequency identification (RFID) tagged and linked with a
central database mining and logistical software system.
[0066] In some embodiments, system 300 may further include one or
more acid tanks, which may be configured to provide an acid
solution to portions of system 300. For example, H.sub.2SO4 acid
tank 318 and NaOCL acid tank 320 may be connected to one or more
lines or tanks of system 300. These particular acids are merely
provided for exemplary purposes as various other types of acids and
solutions may be used as well.
[0067] Referring now to FIG. 4, an additional embodiment of front
end system 400 is depicted. System 400 may include buffer tank 401,
which may be configured to store wastewater in order to regulate
the flow rate into system 400. In addition, the concentrations of
the varying contaminants may be modulated and normalized (if
required). Buffer tank 401 may also allow for the assaying of
wastewater characteristics including, but not limited to, metals
present and their respective concentrations, pH, suspended solids,
chemical oxygen demand, and oxidation/reduction potential.
[0068] In some embodiments, wastewater may be pumped at a
designated flow rate from buffer tank 401 to inline oxidation
reactor 408. Oxidation reactor 408 may be configured to destroy
interfering organic agents such as cyanide and surfactants and is
discussed in further detail with reference to FIGS. 5-6. Oxidation
reactor 408 may receive NaOCL from acid tank 420 and HCL from acid
tank 418. Using oxidation chemicals such as sodium hypochlorite,
hydrogen peroxide, sodium hydroxide, or electrochemical techniques,
wastewater may be oxidized at low (e.g., 4-6) pH to prevent and/or
reduce precipitation of target metals, and under positive pressure
to keep the active oxidation agent in solution. The dual chamber
design of oxidation reactor 408 may create a two step oxidation of
organic, as well as inorganic interfering contaminants. Oxidation
reactor may include one or more outlet ports, which may be
configured to allow various gases to travel to scrubber 427 and/or
degassing chamber 428.
[0069] In some embodiments, the wastewater may be pumped from
oxidation reactor 408 to mechanical filter 412. Mechanical filter
412 may be any suitable filter including, but not limited to, sand
filters, bag filters, etc. Mechanical filter 412 may be configured
to remove suspended solids and other particles to prevent clogging
or fouling of ion exchange (i.e., resin) tanks 402 downstream in
system 400.
[0070] In some embodiments, the wastewater may exit mechanical
filter 412 and be pumped through activated carbon filter 414.
Activated carbon filter 414 may be configured to adsorb any
interfering organics that may still remain dissolved, as well as
any residual suspended solids. At this point, the wastewater may be
substantially free of any solids, particles, interfering organics,
chelating agents, or other contaminants that could adversely impact
the efficiency of the ion exchange process to follow.
[0071] In some embodiments, upon leaving activated carbon filter
414, the pH of the wastewater may now be adjusted and controlled
(if necessary, depending upon the metals present) in a relay tank
such as relay tank 310 depicted in FIG. 3. The wastewater may then
be pumped at a designated flow rate into ion exchange tanks 402A-B,
which may be placed in series and may contain selective ion
exchange resins. While only two pre-selective ion exchange tanks
are depicted in FIG. 4, it is envisioned that any number of ion
exchange tanks may be used without departing from the scope of the
present disclosure. Softening, base cation and anion
demineralization may occur in tank 402C.
[0072] In some embodiments, ion exchange tanks 402A-B may be
constructed out of an extreme pH (e.g., acid and alkaline)
resistant, pressure bearing and unreactive material such as
fiberglass reinforced plastic (FRP). Ion exchange tanks 402A-B may
be of a suitable height and diameter to create the proper resin bed
depth for the flow rate of system 400. The tanks may also need to
be sized to allow for sufficient room for fluidization and
expansion of the resin bed. The number of ion exchange tanks used
may be dependent on the desired daily volume capacity and time
involved between exchanging of tanks. Each ion exchange tank may be
fitted with a bypass valve, allowing for on-the-fly servicing of an
individual tank, or tanks, without the need for a shut down of the
entire front end system 400.
[0073] In some embodiments, each individual ion exchange tank may
be mobile and set in a frame or housing, which may provide
additional protection as well as simplified handling and
transportation. Each ion exchange tank may also be fitted with a
unique radio frequency identification (RFID) tag linked into a
logistical management system. Handheld, truck mounted, and central
processing facility mounted sensors may allow for the real time
tracking and management of all of the ion exchange tanks (e.g.,
402A-B), as well as for the creation of an operational history,
which may be managed by database software. In this manner, the
history of each ion exchange tank, including parameters such as,
but not limited to, service location, service time, metals
captured, exchange efficiency/capacity, regeneration results, and
operational life can be accumulated in the database. System 400 may
further include database mining software, which may be used to
analyze the data to identify operational trends and efficiencies;
which may then be used to optimize operating procedures and lower
costs.
[0074] In some embodiments, for example where large volumes of
wastewater must be treated, several sets or strings of ion exchange
tanks may be placed in parallel. Each individual set or string may
include an independent bypass valve. In this layout, an individual
set of ion exchange tanks may be taken offline for servicing while
the other set(s) of tanks may continue in operation. This may allow
for continuous operation of front end system 400 with minimal
downtime. Alternatively, larger ion exchange tanks may be mounted
directly on a mobile platform such as a flatbed trailers to process
high volume applications.
[0075] In some embodiments, each set of ion exchange tanks (e.g.,
402A-B) may include a sensor positioned between two ion exchange
tanks near the end of the series, which may be designed to detect
the presence of metals in the wastewater. A positive signal from
this sensor may indicate a malfunction or breakthrough from the ion
exchange tank preceding the sensor. This sensor may trigger an
alarm that signals the operator that an exchange of ion exchange
tanks may be necessary. Further, a visual indicator consisting of a
clear segment of piping containing ion exchange resin may be
located next to the sensor and also between the two ion exchange
tanks. Typically, the ion exchange resin may change color as they
adsorb metals. Consequently, a change in the color of the indicator
resin may allow for a visual backup alarm to the operator that
breakthrough has occurred and that an exchange of ion exchange
tanks is required. This change in color may be determined using
additional sensing equipment or via visual inspection by the
operator. This design may insure that metal bearing wastewater does
not escape system 400 as a whole, and that treated wastewater
leaving system 400 is in compliance with regulatory discharge
limits and/or recycling water quality standards. Additional sensors
and indicators may be placed throughout the series of ion exchange
tanks in order to monitor operational parameters.
[0076] In some embodiments, once the metals and other ionic species
have been captured by ion exchange tanks 402A-B, the effluent from
these tanks may be stored in a tank 402C prior to being sent to
polishers 422 and 424. Polishers 422 and 424 may be used to remove
any remaining suspended particles that were not removed previously.
Upon leaving polishers 422 and 424, the wastewater may be sent to
recycled water storage tank 426 for subsequent storage. The
resulting water in water storage tank 426, may be suitable for
discharge from the facility, or alternatively, for recycling and
reuse onsite. Additional acid tanks 430 and 432 may be operatively
connected to recycled water storage tank 426 and configured to
provide various acids and/or solutions to tank 426 through one or
more transmission lines. In cases where recycling may require
higher purity water, the treated water may be pumped through a
reverse osmosis system or treated with a traditional
demineralization system prior to reuse.
[0077] In some embodiments, once ion exchange tanks 402A-B have
captured the necessary metals and other contaminants ion exchange
tanks 402A-B may then be transported to the central processing
facility for regeneration and recycling. A positive air pressure
device may be used to purge each tank of excess water in order to
minimize weight and facilitate handling and transportation. Some
wastes that are free of regulated materials (i.e. metals), such as
backwash from a sand filter, may be disposed of onsite and may not
require transportation. Alternatively, in applications where
economic, regulatory or other considerations merit, (such as large
daily wastewater volumes or restrictions on the transport of
regulated materials), the central processing facility may be
located on the same site as front end system 400. This layout may
eliminate handling and transportation costs with no detrimental
effect on capabilities or effectiveness of the system.
[0078] Referring now to FIGS. 5-6, as discussed above, systems 300
and 400 may include oxidation tank 308, 408, 500, which may be
placed between the influent wastewater stream and resin tanks
302A-G. Occasionally, during the plating process, some metals may
be plated while they are stabilized with a chemical agent,
typically cyanide. However, cyanide is a strong chelating agent and
may interfere with the ion exchange chemistry. In this way, cyanide
may prevent the metal ion from being trapped or adsorbed by the
functional groups within resin tanks 302A-G. Thus, the process
could lose efficiency and toxic metals and cyanides could escape
the proper treatment. Cyanide may be destroyed with a strong
oxidation agent such as sodium hypochlorite or bleach (NaOCl in
NaOH solution, pH ca. 12). The reaction may occur in a stirred
reactor prior or parallel to the hydroxide precipitation.
[0079] In order to address this issue, in some embodiments, system
300 may include oxidation reactor 500, which may be configured as a
flow through reactor to allow for the destruction of cyanide and
other organic contamination in the rinse water. Oxidation reactor
500 may include oxidation vessel 502 having inlet port 504, air
inlet port 506, outlet port 508, exhaust port 510, and reaction
member 512. Oxidation reactor 500 may be used to oxidize cyanide at
a low pH (e.g., 4-6) while the reaction solution may be pressurized
in reaction member 512, which may take on the coiled configuration
depicted in FIG. 5. The low pH may prevent hydroxide precipitation
of the valuable target metals while the pressure maintains the
active chlorine in physical solution. In this way, the reduced
oxidation potential of the sodium hypochloride or other strong
oxidation agents may be compensated and even improved.
[0080] In some embodiments, inlet port 504 may be configured to
allow numerous liquids to enter oxidation vessel 502. For example,
rinse water from various plating operations may enter oxidation
vessel 502 through inlet port 504. Inlet port 504 may also allow
for the addition of water peroxide and various other agents such as
bleach. Air inlet port 506 may be configured to allow for the
addition of air or other gases to oxidation vessel 502, which may
result in the removal of chlorine gas through exhaust port 510.
Outlet port 508 may be associated with a carbon filter or similar
device, which may be configured to remove chlorine and/or
decomposed organics. Exhaust port 510 may act as a conduit to
receive cyanide and chlorine gas for removal. A low pH may result
in outgassing within oxidation vessel 502, however, a high pH may
result in the formation of metal hydroxides, as such pressurized
reaction coil 512 may be used to counteract a high pH.
[0081] In some embodiments, reaction coil 512 may be arranged using
piping in a stacked coil in order to create an enclosed and
elevated pressure environment while increasing the time the
wastewater remains in oxidation vessel 502. Reaction coil 512 may
be of any suitable length, in one embodiment, reaction coil 512 may
be a couple of meters in length. Dosing pumps may be operatively
connected to oxidation vessel 502 via piping in order to adjust pH
and for the introduction of the oxidizing agent to the wastewater.
Oxidation vessel 502 may further include at least one monitor
configured to measure the pH of the wastewater. The monitor may be
operatively connected to a control system, which may dynamically
alter the pH of the wastewater in the vessel.
[0082] In some embodiments, mixing may be achieved by the inclusion
of a static mixer in the reactor following inlet port 504.
Additionally or alternatively, mixing may also be conducted with
traditional stifling techniques prior to introduction into reaction
coil 512. The application of positive pressure in this first step
may enrich volatile oxidation agents in the liquid phase, and
prevent them from degassing. This may increase oxidation efficiency
while extending the contact time of the oxidizing agent with the
wastewater; even when in a chemically unfavorable, slightly acidic
pH environment.
[0083] In some embodiments, in an additional oxidation step, the
wastewater may exit reaction coil 512 and flow into a second
chamber within oxidation reactor 500. The chamber may be sealed to
prevent the escape of fumes or other oxidation by-products.
Extensive aeration of the wastewater may be achieved with the
introduction of air through air inlet port 504 into oxidation
vessel 502 via a pump. Potentially cracked contaminants may be
further oxidized by the oxygen in the air while a scrubber system,
operatively connected to oxidation vessel 502 via exhaust port 510,
is used to control degassing and remove toxic fumes and/or volatile
oxidation by-products. This step may also effectively strip out
excess oxidant from the now oxidized wastewater, cleansing the
wastewater and minimizing any fouling or other contamination of the
ion exchange resins later in the system.
[0084] In some embodiments, integrated with oxidation vessel 502
may be an excess chlorine removal chamber. With the air stripping
approach, excess chlorine may be removed from the now cyanide free
rinse water solution to avoid damage of the ion exchange resin. The
chlorine may be safely transferred through exhaust port 510 and
trapped in a caustic scrubber. The saturated scrubbing solution may
be potentially re-injected as an oxidation agent in oxidation tank
502.
[0085] In some embodiments, reaction coil 512 may be pressurized
and may further prevent early degassing of the reaction fluid.
Reaction coil 512 may allow extended reaction time at a pH below 8,
which may assist in preserving the target metals in solution while
destroying cyanide and organic additives.
[0086] Referring again to FIG. 6, an additional embodiment
depicting oxidation reactor 600 is provided. Oxidation reactor 600
may further include excess chlorine removal chamber 614. In this
embodiment, two discrete treatment chambers, namely oxidation
vessel 602 and excess chlorine removal chamber 614 are provided
adjacent one another. Reaction coil 612 is provided within
oxidation vessel 602 affixed to inlet port 604, which may be
configured to provide rinse water from the plating operations
and/or acid and hypochlorite. Oxidation vessel 602 may be
configured to provide an extended reaction with active chlorine at
a pH of approximately 4-6.5. Excess chlorine chamber 614 may be
configured to scrub excess chlorine from the treated solution using
aeration or similar techniques. In some cases, the low pH may be
necessary to maintain the solubility of the target metal salts.
[0087] Referring now to FIG. 7, a flowchart 700 depicting
operations associated with an oxidation reactor of the present
disclosure is provided. Operations may include storing and/or
receiving rinse water from the plating process at a buffer tank
(702). Operations may further include utilizing a positive pressure
reaction coil and static mixer associated with the oxidation
reactor (704). Here, an oxidation agent may be added and a pH
adjustment may occur. Degassing and aeration may be performed,
e.g., using an air blower or other suitable techniques (706). The
effluent may be received at the ion exchange tanks (708) and any
exhaust fumes from the oxidation reactor may be sent to a scrubber
for detoxification (710). This is merely one exemplary set of
operations as numerous other operations are also within the scope
of the present disclosure.
[0088] Referring now to FIG. 8, a flowchart 800 depicting
operations associated with systems and methods of the present
disclosure is provided. Operations may include receiving and
subsequently storing rinse water from plating baths (802).
Operations may further include oxidation operations such as those
described above with reference to FIG. 7 (804). Operations may
further include filtering (806), via an activated carbon filter
prior to providing wastewater to resin tanks (808). The remaining
water may undergo a pH adjustment (810) prior to undergoing reverse
osmosis for water recovery/recycle (812) or additionally or
alternatively, being recycled untreated for workpiece pre-treatment
(814). Upon exiting the front end system, the treated water may be
ready for recycling onsite, or to be discharged in compliance with
applicable regulatory discharge guidelines. While non-regulated
substances may be disposed of onsite, the metal bearing ion
exchange tanks may be sent to a central processing facility for
resin regeneration, as well as processing and recycling of the
metals. This is merely another exemplary set of operations as
numerous other operations are also within the scope of the present
disclosure.
Central Processing
[0089] Central processing facility may serve as the collection and
processing point for saturated or partly saturated ion exchange
(resin) tanks from the front end system. At the central processing
facility, the ion exchange tanks from the front end system may be
regenerated for reuse and the metals may be recovered in a process
consisting of multiple stages including, but not limited to, ion
exchange tank stripping and resin regeneration, metals separation
and purification, and final processing of recovered metals into end
products.
[0090] In some embodiments, the exhausted and loaded resin tanks,
e.g., resin tanks 302A-G, may arrive at the central processing
facility and are unloaded. The resin may be removed from the tanks
and acid treated in a batch process. The acid may remove the metals
collected on the resin and, combined with the rinse water, provide
the loading solution for the isolation and purification unit
described below. The acid may also return the ion exchange resin
into its proton form.
[0091] In some embodiments, it should be noted that iminodiacetic
ion exchange resins in their proton form may be used. This may
minimize the use of chemicals and rinsing water requirements. A
savings of approximately 20% chemical costs and 50% of rinse water
may be achieved using this approach. Use of the chelating ion
exchange resin in a proton form may assist in conserving tremendous
amounts of caustic, brine and especially rinse water. Moreover,
there is a significant benefit in preventing the resin from
swelling while washing and regenerating with caustic (e.g., high pH
values of approximately 10-14). The swelling may occur as a result
of a volumetric expansion of the cross linked poly styrene
backbone. This swelling and the subsequent contraction at a low pH
is one of the major reasons for resin attrition. Therefore,
avoiding high pH values in which the resin is operating may
increase the life time of the material.
[0092] In some embodiments, at the site where the front end system
is installed, saturated ion exchange tanks, e.g., 302A-G, may be
exchanged for freshly reconditioned ion exchange tanks and then
transported back to the central processing facility. Where
economic, regulatory, or other considerations so merit, the central
processing facility may be located at the same site as the front
end system, which may eliminate the need for handling and
transportation of the ion exchange tanks from the front end system.
Additionally and/or alternatively, the central processing facility
may also have a front end system installed such that the process
waters used in the various stages may also be treated and recycled
into the process, further reducing costs and chemical
consumption.
[0093] In some embodiments, and as discussed above with reference
to FIG. 3, portions of the front end system may include RFID
tracking. For example, upon arriving at the central processing
facility, the ion exchange tanks may be sorted and grouped based on
data received from their respective RFID tags. The grouping may
allow for the most efficient processing of ion exchange tanks, for
example, tanks exhibiting similar characteristics. More
specifically, regarding the metals they contain and their relative
concentrations. Database software may be configured to analyze the
operational histories of the incoming ion exchange tanks (based
upon their RFID identifications) and suggest optimal processing
parameters to the operators. This categorization and sorting
process may improve the efficiency of the facility by leveling out
the varying input variables from different front end collection
sites. This, in conjunction with the pooling of recovered metals
into homogeneous volume batches reduces the range and number of
variables of each batch, simplifying processing and reducing
costs.
[0094] Referring now to FIG. 10, one exemplary embodiment of a
conveyor belt vacuum filter band stripping and regeneration system
1000 is provided. System 1000 may be located at the central
processing facility, which may be located on or offsite from the
front end system. System 1000 may utilize a cascading arrangement,
which may reuse lesser contaminated rinsewater in a repetitive
manner to help minimize overall rinsewater consumption and provide
a high degree of control over the composition and characteristics
of the regenerant. This may also result in a more efficient use of
chemical inputs, thus lowering operational costs.
[0095] In some embodiments, system 1000 may be configured to
receive one or more saturated ion exchange tanks 1002 from the
front end system. System 1000 may perform a stripping and
regeneration process in order to recover the captured metals and
recondition the resins to their original state.
[0096] In some embodiments, a saturated ion exchange tank 1002 may
be received at system 1000. The ion exchange resin may be removed
from ion exchange tank 1002 and placed in resin holding vessel
1004. The resin may be extracted from each ion exchange tank 1002
using any suitable technique, for example, using high velocity
water jets. This procedure may effectively rinse the resin to
remove any trapped particulates or solids, and also fluidize the
resin to counteract any compaction of the resin beds which may have
occurred during the loading stage of the front end process.
[0097] In some embodiments, once the resin has been fluidized,
resin slurry pump 1005 may be used to transfer the resin from
holding vessel 1004 to vacuum filter band 1006. The operational
parameters of slurry pump 1005 may be controlled via a PLC
associated with a control panel, which may be similar to that shown
in FIG. 2. It should be noted that some or all of the components of
system 1000 may be controlled via a PLC similar to that described
above with reference to FIG. 2. The fluidized resin, in a slurry
form, may then be spread onto vacuum filter band 1006.
[0098] In some embodiments, vacuum filter band 1006 may be
constructed out of any suitable material. For example, filter band
1006 may be a porous material such as a mesh, which may be
configured to receive a negative pressure or vacuum in order to
dewaterize or partially dewaterize the resin on the band. Vacuum
filter band 1006 may be located as part of a controllable (e.g.,
manually or automatically using control systems known in the art)
conveyor belt type, or alternative, system, which may allow filter
band 1006 to pass through discrete process zones, which may include
but are not limited to, washing, rinsing, and stripping zones.
Vacuum filter band 1006 may include one or a plurality of bands,
which may pass through the process zones. For example, in some
embodiments, one vacuum filter band may pass through each
individual zone. The rate at which the resin slurry is pumped onto
vacuum filter band 1006, as well as the rate of movement of vacuum
filter band 1006 itself may be automatically or manually altered as
necessary.
[0099] In some embodiments, spray nozzles 1008A-C may be positioned
adjacent vacuum filter band 1006 and configured to distribute
water, acids, and other treatment agents. For example, spray nozzle
1008A may be positioned above vacuum filter band 1006 and may be
operatively connected to hypochloric (HCL) acid storage chamber
1012. Spray nozzle 1008A may be configured to dispense HCL to
vacuum filter band 1006. Similarly, spray nozzle 1008B may be
operatively connected to NaOH storage chamber 1014 and may be
configured to dispense NaOH to vacuum filter band 1006. Spray
nozzle 1008C may be operatively connected to rinse water storage
chamber 1016 and may be configured to dispense rinse water to
vacuum filter band 1006. Each spray nozzle may be connected to one
or more pumps, which may control the rate of flow out of spray
nozzles 1008A-C.
[0100] The embodiment shown in FIG. 10 may provide an extremely
high level of operational flexibility and control over each
individual treatment parameter. For example, the depth of the resin
cake may be determined by the loading speed of the resin slurry
onto moving vacuum filter band 1006. The treatment and/or exposure
time of the resin in a particular process zone may be determined by
the speed of a particular vacuum filter band. Further, the
extraction volume may be precisely controlled by varying the flow
rate of the agents (e.g., water, acids, etc.) sprayed by nozzles
1008A-C onto the resin cake on vacuum filter band 1006. Drying of
the resin and fluid recovery may be regulated by the level of the
vacuum (or negative air flow) applied. In addition, the drying of
the resin and the discrete separation of each process zone prevents
any uncontrolled overlapping of each treatment step. Vacuum filter
band 1006 may be operatively connected to a number of collection
chambers 1014A-D.
[0101] In some embodiments, collection chambers 1014A-D may be
configured to receive liquids and/or solid material from vacuum
filter band 1006. For example, each collection chamber may apply a
negative pressure to band 1006 to assist in dewatering the resin
slurry. In some embodiments, system 1000 may include collection
chamber 1014A configured to receive water extracted from the resin
slurry and provide that water to rinse water storage chamber 1016.
In some embodiments, rinse water storage chamber 1016 may include a
reverse osmosis unit, which may be used to manage the quality of
the polisher stage.
[0102] In some embodiments, spray nozzles 1008A-B may be configured
to spray diluted acid, or other metal removing chemicals, onto the
resin cake in order to mobilize and remove transition metals
trapped on the resin, the resulting acid may be collected in
collection chambers 1014B-C as a mixed metal regenerant. Collection
chambers 1014B-C may provide any remaining liquids to brine
collection tank 1018, which may provide an output to the system
shown in FIG. 14. Spray nozzle 1008C may be configured to reuse the
water recovered from collection tank 1014A, the resin may be rinsed
to remove any residual acid from the previous zones. The resin may
be given a final rinse using fresh water. The water collected in
this zone may then be recycled into one or more of the initial
stages (e.g., ion exchange tank 1002, holding vessel 1004, vacuum
filter band 1006) and used to extract, rinse, and fluidize the
resin.
[0103] Once the resin has received its final rinse, the resin may
now be stripped of transition metals, reconditioned in its acid
(proton) form, and after undergoing a quality control check, may be
ready for reloading into front end ion exchange tanks for reuse at
the front end site. Several variations of the embodiments described
herein may be employed based upon the characteristics of the resin
to be processed.
[0104] In some embodiments, after a certain number of reuses, the
process waters used in the initial stages for rinsing and
backwashing may be sent to an onsite front end system for treatment
and continued reuse, for example, system 102, 200, and/or 300. The
removal of any trace metals and/or other contaminants may allow the
process water to be recycled and reused repeatedly. This drastic
reduction in water consumption is a substantial improvement and may
significantly reduce the cost of the process.
[0105] Alternatively, the front end ion exchange tanks may be
stripped and regenerated in a more traditional process. In such a
process, the resins may be left inside the ion exchange tanks and
may be back flushed with water to remove any trapped particles and
solids. This may also fluidize the resin bed and counter any
compaction that may have occurred during the loading stage of the
front end system. The resins can also be extracted from each
individual front end ion exchange tank using pressurized water and
collected in a larger column for processing as a batch. Upon
completion of the first stage processing and reconditioning, batch
processed resins may be reloaded into individual front end ion
exchange tanks for reuse at the front end site.
[0106] In some embodiments, after rinsing, acids may then be used
to strip the captured metals from the ion exchange resins and to
recondition the resins to their original proton form. This
regeneration procedure may result in an acidic, mixed metal
solution while the stripped and reconditioned columns are quality
checked for proper reconditioning and then sent back for reuse in
the front end system.
[0107] Referring again to FIG. 10, in operation, the resin may be
removed and rinsed with high velocity water streams from the resin
tank and then consequently exposed to recycled rinse water and
reconditioning acids. The contamination or metal loading levels may
be configured to run in a gradient situation against the resin
stream. This may be achieved by loading the resin after the removal
from the tanks onto vacuum band filter 1006. Vacuum filter band
1006 may then forward the resin through various spraying zones
where the different agents and rinse waters are applied. In this
way, the resources may be utilized as efficient as possible with
great economic benefits to the operation of the plant.
[0108] Once the target metals and contaminants have been collected
in a concentrated surge tank, the metal of highest affinity to
iminodiacetic ion exchange resin may be removed in a multiple
(e.g., 4 or 6) column setup. Again, the present disclosure may use
the selectivity of a functional group to collect specifically
valuable transition metals. For example, as copper has the highest
affinity in this example, the first metal to be removed and
purified may be copper sulfate. This may be achieved by a
controlled overloading of the first resin tank in the setup.
Overloading the first resin tank may result in a pure or
substantially pure copper loading in that tank. The following resin
tanks may be linked in a serial fashion, so that the so called
primary column can now move out of the series and undergo the
copper sulfate harvesting with diluted sulphuric acid. The formerly
secondary column now may undergo the same loading process until it
has reached a pure or substantially pure copper loading. This
process is relatively easy to control as the loading time is a
simple function of copper concentration and volume pumped over the
resin.
[0109] Referring now to FIG. 11, a flowchart 1100 depicting
operations consistent with stripping and regeneration system 1000
of the present disclosure is provided. Flowchart 1100 may include
receiving the ion exchange (resin) tanks from front end system
(1102). Operations may further include removing the resin from the
ion exchange tanks and generating a resin/water slurry (1104).
Operations may further include providing the resin/water slurry to
a vacuum filter band having three distinct zones (1106, 1108,
1110). Resin may move from zone 1, to zone 2, to zone 3, and the
recovery acid may move in an opposing direction to the flow of the
resin, i.e., zone 3 to zone 2 to zone 1. Operations may further
include providing the resin back to the front end system and
providing the metal solution for enrichment (1112), which is
discussed in further detail below.
[0110] Referring now to FIG. 12, an embodiment of a metal specific
purification system 1200 is provided. Here, the mixed metal strip
solution, or regenerant, from the system of FIG. 10 may be adjusted
and controlled to the necessary pH levels (if required) and then
pumped into a series of chelating ion exchange resin purification
units, as shown in FIG. 12.
[0111] In some embodiments, system 1200 may include a plurality
(e.g. 4 or more) of purification units (e.g., resin tanks), which
may utilize selective, chelating ion exchange resin or silical
gels. The arrangement may be designed to achieve continuous flow of
the re-conditioning solution through system 1200. For each target
metal, one or more extractor units may be employed. In the
particular embodiment depicted in FIG. 12, three or more
purification units are loaded with the reconditioning solution in
series. This results in primary purification unit 1202, secondary
purification unit 1204, and tertiary purification unit 1206. Other
configurations and numbers of tanks are also within the scope of
the present disclosure. In addition to trapping and retaining a
preferred metal in each purification unit or resin tank, system
1200 may also successfully purify and isolate a particular target
metal. The enriched and purified target metal, as it is absorbed on
the resin in the purification units, may then be harvested as
described below with reference to FIGS. 13-14.
[0112] In operation, once a purification unit goes offline, the
previously secondary purification unit may be switched into the
flow path as the primary purification unit. Being already enriched
partly, it may experience oversaturation quickly and purify the
trapped metal accordingly. This may be an ongoing process where the
purification units are switched into the flow path upstream. This
may allow for the operation of a limited number of purification
units continuously.
[0113] Table 1, provided below, depicts one particular embodiment
of the operation of metal purification system 1200 of FIG. 12. Once
primary purification tank 1202 has been supersaturated, the vessel
may be rinsed or blown empty and switched to regeneration mode. The
former secondary purification tank 1204 may now be switched into
the primary position and the former tertiary tank 1206 may now go
into the secondary position and the regenerated tank 1208 may now
switch into the tertiary position. The supersaturation may ensure
the displacement of lower affinity metals (depending upon mixed
metals composition and ion-exchange ligand) by the highest affinity
metal. In this way, purities of approximately 99% of the target
metal may be achieved (e.g., S930, TP207, SIR-1000).
TABLE-US-00001 TABLE 1 Primary Secondary Tertiary Regeneration 1 A
B C D 2 D A B C 3 C D A B 4 B C D A 5 A B C D
[0114] In some embodiments, purification units 1202, 1204, 1206,
1208 may each contain selective ion exchange resins and the units
may be arranged in the rotating configuration described in Table 1.
This system may be configured to selectively target and capture an
individual metal by using supersaturation to leverage the inherent
relative affinity of the resin to different metals.
[0115] In some embodiments, during supersaturation, regenerant may
be continually introduced into first purification unit 1202 even
after the effective capacity of the resin has been exhausted. As
the target metal of a particular purification unit may have a
higher affinity to the resin, relative to the other metals in the
solution, continued exposure of the resin to the regenerant may
cause the higher affinity target metal ions to dislodge and replace
other non target metals which may have been captured on the resin.
After a designated volume of supersaturation, the resin of a
particular purification unit may contain only the metal targeted by
that module. Some or all other metals not targeted by that
purification unit may remain in the regenerant solution and
continue to the next purification unit, where the same process then
targets and captures another metal. Depending on the number of
metals in the regenerant from the front end resin tanks, a
corresponding number of purification units each targeting a
specific metal may be arranged in series such that all the metals
may be separated. In this manner, the individual metals of a mixed
metal regenerant may be identified, targeted, separated by capture
on the resin, and purified.
[0116] It should be noted that the ability to separate individual
metal fractions from a multi-metal regenerant represents a drastic
improvement over existing ion exchange processes as purified metals
can be directly manufactured into end products. Currently,
processes involving mixed metal solutions require additional and
costly processing before usable products can be recovered.
[0117] In some embodiments, the regenerant from FIG. 12 may now be
cleansed of metals and may effectively be an acid again, albeit at
lower strength and concentration, and with trace contaminants. The
ion exchange process of FIG. 12, in which metals in the regenerant
are exchanged for protons on the resin, also has the additional
effect of regenerating the regenerant (acid) itself by the addition
of free H+ ions (from the ion exchange resin). Upon exiting system
1200, the regenerant may be infused with a small volume of fresh,
highly concentrated acid in order to restore its strength and
concentration to near original levels. In this manner, the
regenerant can then be recycled back into other systems (e.g.,
system 1000) several times and used to strip and recondition
incoming front end columns. The ability to repeatedly reuse acid in
this fashion is a significant improvement over existing ion
exchange processes; in which acid consumption constitutes a large
percentage of operating costs and the need to discard large amounts
of waste acid creates a liability.
[0118] In some embodiments, once a primary purification unit (e.g.
primary purification unit 1202 in FIG. 12) has reached
supersaturation and is fully loaded with a target metal, it may be
taken offline and readied for stripping and regeneration. The
purification unit may be back flushed with water to remove any
interstitial fluid, residual loading solution, solids and
impurities, as well as to fluidize the resin bed and to counter any
compaction. The process waters from this stage may also be sent to
an onsite or offsite front end system for treatment and recycling.
The repeated reuse of this process water may constitute a
significant decrease in water consumption and operating costs when
compared to existing ion exchange processes.
[0119] Referring now to FIGS. 13-14, embodiments depicting a
repetitive stripping system 1300 are provided. As discussed above,
the ion exchange tanks from the front end system may be stripped
with vacuum filter band 1006 associated with system 1000. In
contrast, the metal filled purification units from FIG. 12 may be
stripped using repetitive stripping system 1300. System 1300 may
utilize a repetitive stripping protocol regulated by an automated
concentrate management system based on a programmable logic
controller.
[0120] In some embodiments, system 1300 may include a series of
acid tanks, for example, acid tank A 1302, acid tank B 1304, and
acid tank C 1306. A fully loaded purification tank or column 1310
may be provided from system 1200 shown in FIG. 12. Fully loaded
column 1310 may receive additional acid from make-up strip acid
tank 1312 and may provide an output to product surge tank 1308. In
one possible sequence, acid tank A 1302 may be pumped through fully
loaded column 1310, feeding into tank 1308 (final product, product
surge tank) (step 1). Acid tank B 1304 may then be pumped through
column 1310 (step 2), followed by acid tank C 1306 being pumped
through column 1310 (step 3). Fresh diluted acid may then be pumped
through column 1310 (step 4). After the acid treatment loaded
column 1310 may undergo rinsing with water for complete
regeneration. Step 1 may empty into product surge tank 1308, step 2
may empty into acid tank A 1302, step 3 may empty into acid tank B
1304, and step 4 may empty into acid tank C 1306.
[0121] In some embodiments, each batch of acid may be used to strip
several different purification units and each purification unit may
be stripped by a series of acid batches of decreasing metal and
increasing free proton concentration. Consequently, the first batch
of acid to be introduced into a saturated purification unit (e.g.
column 1310) may be that which has already been used the most times
relative to the other batches within a set of acid batches. Upon
exiting the purification unit, this acid batch may have its maximum
metal and minimum free proton concentrations respectively. At that
point, the acid batch may be removed from stripping system 1300 and
sent for final processing into end products.
[0122] In some embodiments, the stripping process may continue in
this fashion with each subsequent acid batch having been used one
fewer time than the batch preceding it. Other than the first batch,
which may be sent to for final processing into end products, all
other batches may be stored for use with the next saturated column.
The final batch of acid may be fresh acid, to insure that the resin
is adequately stripped of metals and properly regenerated and
reconditioned for reuse. For example, referring again to FIG. 13,
in a four batch set of acids, consisting of a three strip batch in
acid tank 1302, a two strip batch in acid tank 1304, a one strip
batch in acid tank 1306, and a fresh acid batch in tank 1312, the
three strip batch may be used first, and then sent for final
processing into end products as shown in FIG. 15. Then, the two
strip batch may be used, which may become the three strip batch for
the next column. The one strip batch may then be used, and may then
become the two strip batch for the next column. Finally, the fresh
acid may be used and may become the one strip batch for the next
column.
[0123] In some embodiments, this stripping protocol may markedly
decrease chemical consumption by maximizing the utilization of free
acid. This may provide a substantial advantage over existing ion
exchange processes that may generate large volumes of waste acids
requiring additional treatment and disposal. As a result, less acid
may be consumed, which may constitute a significant operational
cost.
[0124] In some embodiments, the high purity and concentration of
the metal may allow for the regenerant to be directly and
economically processed into a metal salt chemical end product, with
little or no byproducts or wastes. In this manner, the columns or
resin tanks may be stripped and regenerated for reuse and the
target metal may be rendered as a high purity, highly concentrated
metal salt solution. This process may be a significant improvement
over existing ion exchange processes in that the acid may not be
consumed and discarded as a waste, but rather becomes an ingredient
of a commercially salable end product. This may result in
substantially lower operating costs, as well as in eliminating the
costly requirement for handling and disposing of waste acids.
[0125] Referring now to FIG. 14, an exemplary embodiment of a
system 1400 incorporating some or all of systems 1200 and 1300 is
provided. System 1400 may include purification units 1402, 1404,
1406, and 1408, which may be configured similarly to those
described above with reference to FIG. 12. System 1400 may further
include acid tanks 1410, 1412, 1414, and 1416, which may be
configured similarly to those described above with reference to
FIG. 13. Alternative arrangements of purification units and acid
tanks are also within the scope of the present disclosure.
[0126] In some embodiments, system 1400 may be used to recover
metal sulfates from iminodiacetic ion exchange resins by utilizing
a repetitive stripping system such as that described above with
reference to FIG. 13. The application of a concentration gradient
in the stripping acid may allow for an efficient utilization of the
provided protons as well as in minimizing rinse water requirements
and complex process controlling.
[0127] In some embodiments, system 1400 may be used to apply the
acid used to recover the pure metal ions from the ion exchange
resin in a multiple and repetitive fashion. Further, it always
follows with an exposure of less used acid, which means the
reconditioning and cleaning may become more and more efficient in
the ongoing process. In addition, residual free protons may be
minimized in the final, highly concentrated metal sulfate solution.
This feeds perfectly into the crystallization process (discussed in
FIG. 15) following the metal sulfate recovery as the solubility is
significantly decreased in the increased pH environment.
[0128] In some embodiments, the multiple acid exposure via tanks
1410, 1412, 1414, and 1416 also simplifies the rinsing of the resin
after the acid treatment. In this way, less copper (or other
metals) may be left remaining on the resin. As a result, issues
regarding when to cut the recovery fraction and to switch to
rinsing may be eliminated. In traditional column reconditioning
approaches, the metal concentration in the effluent is slowly
increasing to a maximum (desired) concentration and then decreasing
during the ongoing. All this solution typically may be collected
into one tank. This introduces a dilatuion effect which is
counterproductive to the desire receiving highest metal recovery
concentrations (i.e. 100-150 g metal salt per liter). In the
described, repetitive exposure of the same saturated column to
pre-defined, pre-concentrated recovery solutions, these low
concentration fronts and tails of the column wash are avoided and
overcome. The last column exposure to fresh diluted acid provides a
perfect scenario to rinse the column acid free with fresh or
recycled rinse water before it switches back into the enrichment
train. This simplification makes the recovery process order more
efficient.
[0129] In some embodiments, while the columns in the core process
may be connected in series, the first column (e.g., purification
unit 1402) in line (or the primary columns) may be supersaturated
with copper ions. The copper ions, in this particular example, may
remove all lower affinity metal ions.
[0130] In operation, the primary column may then be taken out of
the system once all ion exchange sites have been occupied by the
target metal, for example, the copper ions discussed above. The
primary column may now move into the concentrate manager section of
system 1400, namely, acid tanks 1410, 1412, 1414, and 1416. Here,
acid solution which has already been exposed to two primary columns
may be pumped first over the column to receive a highly enriched,
low remaining free proton solution indicated by acid tank 1416,
i.e., strip D. The column may then be treated with further acid
rinses from acid tank 1412 (i.e., strip B) and acid tank 1414
(i.e., strip A) until fresh acid solution is pumped over the
column. All of the copper may now be removed and the primary column
may undergo a brief water rinse. The column may then ready to
return into the loading cycle.
[0131] In some embodiments, system 1400 may be configured to
utilize the protons delivered by the acid as effectively as
possible. System 1400 may also remove the necessity to manage the
eluting high concentration peak from the column in the metal
recovery process. The overall recovery process therefore provides a
more robust and simplified approach providing a much better, higher
concentrated and less acidic feed solution for the metal salt
crystallization.
[0132] Referring now to FIG. 15, a system 1500 configured to
process commercial metal salts is provided. At system 1500 the
metal salt concentrates from system 1400 may be processed into
commercial quality metal salts using processes, which may include,
but are not limited to, vacuum evaporation, crystallization, and
spray drying. The techniques employed may depend upon the desired
characteristics and specifications for the product. The high purity
and concentration of the concentrate may allow for very economical
production of a wide range of specifications depending on customer
demand. After undergoing quality checks, the end product may be
packaged and shipped to customers or other distribution
networks.
[0133] In some embodiments, system 1500 may include receiving
vessel 1502, which may be configured to receive and/or store the
output from system 1400. The metal solution may be transferred from
receiving vessel 1502 to evaporating chamber 1504. Water removed
from evaporating chamber 1504 may be redistributed to any of the
other systems of the present disclosure. The output from
evaporating chamber 1504 may be provided to crystallizer 1506,
which may be operatively connected to cooling machine 1508.
[0134] In some embodiments, the metal sulfates are recovered in the
central processing units as high concentration metal sulfate
solutions. Crystallizer 1506 may utilize various crystallization
techniques to recover the metal sulfates as solid products. This
may be achieved by cooling the highly concentrated metal sulfates,
which may reduce the solubility to a level where the solid metal
sulfates start to crystallize. The resulting crystallized metal
sulfates may be deposited in final crystallization tank 1510. The
crystallized metal sulfates may then be sent to electrowinning
chamber 1510. Electrowinning chamber 1510 may involve various
processes used to extract the target metals. It should be noted the
systems of the present disclosure may be used to produce metal
salts, which may be far more lucrative than producing metallic or
elemental products. For example, metal sulfates, like copper penta
hydro sulfate, may be fed directly back into printed circuit board
manufacturing, plating, chip manufacturing and many other
processes. For copper sulfate, the recovered mass as sulfate may be
approximately four times more than the pure metal. It should be
noted that although FIG. 15 primarily depicts copper as the metal,
the systems of the present disclosure may work with any number of
metals. Some other metals include, but are not limited to, nickel,
zinc, etc.
[0135] In some embodiments, the processes of the central processing
facility may be monitored by sensors and computers linked into a
central database software system, which may continually record all
of the operating parameters, criteria, performance, and results in
real time. Together with data from the front end column RFID tags,
this data may be evaluated by database mining software to identify
trends and optimum operating parameters for the various categories
of front end columns arriving at the central processing facility.
The same or similar software may also analyze operating parameters
of the processes of the central processing facility. As the
database accumulates information over time, it may be able to
recommend optimized operating parameters for front end column
sorting and regeneration, target metal module loading and stripping
parameters, and overall process efficiency; further reducing costs
and chemical consumption.
[0136] As discussed above, embodiments of the present disclosure
may utilize an RFID tracking and management system. For example,
and referring again to FIG. 3, individual ion exchange tanks 302A-G
may be tracked and managed using a networked RFID (Radio Frequency
Identification) system. Each ion exchange tank may be fitted with a
unique RFID tag capable of recording and storing at least one
characteristic associated with the tank. For the purposes of this
disclosure the term "characteristic" may refer to the physical,
chemical and historical characteristics of a particular ion
exchange tank. A network of handheld, truck mounted, and factory
based RFID readers may connect wirelessly into an asset management
software system, which may be located at the central facility or
elsewhere, and mirrored at corporate headquarters. This system may
allow for the real time, simultaneous tracking of thousands of ion
exchange tanks through every stage of the service process. This may
result in maximized efficiencies for tasks such as ion exchange
transportation, exchange scheduling, management of resin
degradation, and categorization of like ion exchange tanks for
batch stripping and regeneration. Cost savings may also be realized
from the prevention of operational errors associated with incorrect
column/resin identification. This historical database may be
updated in real time and may operate in conjunction with a fuzzy
logic based process optimization software system to continuously
improve operational efficiencies.
[0137] In some embodiments, at the core process central facility
for example, operational parameters such as reagent selection and
dosing, resin batch composition, stripping efficiencies, and
product quality may be logged and managed by a fuzzy logic based
software system. This information, along with data collected from
the RFID Management System may be incorporated into a unified
database containing a detailed historical accounting of every
operational parameter of the service process. The fuzzy logic
system may continuously mine this database to identify optimally
efficient parameters and present suggested process parameters to
technicians. The system may "learn" from each ion exchange tank
processed such that as the database grows over time, it may
identify the most efficient set of parameters to process any given
ion exchange tank or set of tanks. Consequently, when a truck
carrying saturated ion exchange tanks enters the central facility,
and before the driver has even turned off the engine, the system
will know exactly what ion exchange tanks have arrived, which
client each ion exchange tank is from, how long the ion exchange
tank was in service operation, and how they should be sorted. From
the database, the system may review the historical data for each
ion exchange tank, including such variables as relative metal
concentrations and stripping reagents. Comparing the results from
each previous set of parameters, the software may then identify the
optimal set for the most efficient and cost effective processing of
the ion exchange tank. The system may also apply the same processes
to refining core process and product production operating
parameters. The data and optimized process parameters may minimize
the learning curve for new central facilities, as well as
international expansion.
[0138] In some embodiments, the teachings of the present disclosure
may be well suited to process the rinsewaters of the electroplating
and surface finishing industries. The principal objective of
electroplating may be to deposit a layer of a metal possessing a
desired property, such as aesthetic appearance, hardness,
electrical conductivity, or corrosion resistance, onto the surface
of a material which lacks such properties. Typically the material
being plated may be another metal, such as steel or zinc; though
other materials such as plastic may also be plated. Parts which are
plated may range from common items such as bolts, nails, buttons,
and zippers, and industrial items such as engine components,
turbine blades, hydraulic pistons, and aerospace components, to
high tech items such as integrated circuits, data discs, and copper
clad laminates used in printed circuit boards.
[0139] Electroplating, technically a process known as
electrodeposition, may be achieved by turning the part to be plated
into a cathode by running a negative charge through it, and then
immersing that part in an electrolyte (or plating bath) composed of
dissolved metal salts such as CuSO4; the metal to be plated
effectively becomes the anode. In solution, the dissolved metals
may exist in ionic form with a positive charge and are therefore
attracted to the negatively charged parts. When a direct current,
usually supplied by a rectifier, flows though the circuit, the
metallic ions are reduced at the cathode (part) and plate out. As
the process continues, the composition of the plating bath may
change as metals are removed from solution. Consequently, baths
must be maintained with the addition of supplemental ingredients.
While some baths may be maintained indefinitely, others (especially
where precision is required) must be periodically dumped and
replaced with a fresh bath; the discharge of spent plating baths is
a major source of wastewater. That is not accessible to this
process without extensive bath dilution prior to processing.
[0140] Once plating has reached the desired thickness, the parts
may be removed from the plating bath and may proceed through a
series of rinsing tanks in a counter-flow arrangement. Fresh water
may be supplied from the final tank, and fouled rinsewater from the
first tank may be continually discharged. Thorough rinsing may be
essential as any residual plating solutions may result in clouding,
blemishes or other surface irregularities; resulting often in the
use and discharge of large volumes of water. As the parts leave the
plating bath, they "drag out" the plating solution still adhered to
their surfaces. This dragout is one of the primary reasons why
rinsewaters are so heavily contaminated by heavy metals.
[0141] In some embodiments, to process these electroplating
rinsewaters and spent plating baths, a front end system may be
installed on site containing a suitable volume of ion exchange
resin (housed in columns or tanks) relative to the daily volume of
rinsewaters and concentration of metals. Each process step may
treat or remove contaminants within the wastewater, with the metals
being captured in the columns.
[0142] In some embodiments, upon exiting the front end system, the
treated water could then be directly recycled into the rinsing
process. If the water quality requirement of the electroplating
process so requires, the treated water could be further processed
with a reverse osmosis or traditional demineralization system prior
to reintroduction into the rinsing process. The saturated front end
columns may be replaced with freshly reconditioned columns, and
then sent to a central processing facility for stripping and
reconditioning. The extracted metals may then undergo the
separation and purification process (as described above), and then
be processed into commercially salable end products. Embodiments of
the present disclosure may confer the benefits of onsite wastewater
recycling, as well as reclamation of metals, at a cost lower than
currently available alternatives.
[0143] Embodiments of the present disclosure may utilize a
multi-stage process to collect, transport, and treat wastewater
having various metals. More specifically, this disclosure refers to
an ion exchange based wastewater treatment and recycling system for
the treatment of metal bearing wastewater, comprised of an
independent front end unit located at the site of the wastewater
generation, and a central processing facility where components of
the front end module are collected and processed. After treatment,
wastewater exiting the invention may be suitable for recycling or
legal discharge, while metals are collected, separated, purified
and processed into end products. As economic, regulatory, or other
considerations so require, the central processing facility may also
be located on the same site as the front end system.
[0144] In stage one, metals may be stripped from the resins and the
resins regenerated to their original proton form by an innovative
conveyer belt vacuum filter band unit (as shown in FIG. 10); which
may utilize a cascading setup to minimize rinsewater consumption
and enhance control over operational parameters. After extraction
from their individual columns or ion exchange tanks, resin may be
spread onto a filter band which travels through a number of zones,
each with a discrete process step (e.g., rinsing, stripping, and
reconditioning). After undergoing stage one processing, resins may
be reconditioned to their original proton form and ready for reuse
in front end units, while the metals may be stripped into a
solution for further processing in stage two.
[0145] In stage two, the mixed metal strip solution, or regenerant,
from stage one may be pumped into a series of chelating ion
exchange resin purification units; each consisting of a number of
columns or tanks, arranged in a merry go round configuration, and
loaded with selective ion exchange resins. Each purification unit
may selectively target and capture an individual metal by using
supersaturation to leverage the inherent relative affinity of the
resin to different metals. By arranging a number of purification
units in series, individual metal fractions may be extracted from
the mixed metal regenerant.
[0146] Once a column in a particular purification unit reaches
supersaturation, it may then be taken offline, stripped of the
metal, and regenerated using an innovative repetitive stripping
process controlled by an automated concentrate manager as shown in
FIGS. 12-14. In this process, each batch of acid may be used to
strip several different columns and each column may be stripped by
a series of acid batches of decreasing metal and increasing free
proton concentration. This may result in markedly decreased
chemical consumption and a strip solution of high concentration and
purity. The high purity and concentration of the metal may allow
for the regenerant from stage two to be directly and economically
processed into a metal salt chemical end product. In stage three,
the stage two single metal regenerant may be processed directly
into commercially salable end products using processes such as
vacuum evaporation, crystallization, and spray drying as shown in
FIG. 15.
[0147] Some of the embodiments (e.g., those associated with the
RFID tracking and management system) described above may be
implemented in a computer program product that may be stored on a
storage medium having instructions that when executed by a
processor perform the messaging process described herein. The
storage medium may include, but is not limited to, any type of disk
including floppy disks, optical disks, compact disk read-only
memories (CD-ROMs), compact disk rewritables (CD-RWs), and
magneto-optical disks, semiconductor devices such as read-only
memories (ROMs), random access memories (RAMs) such as dynamic and
static RAMs, erasable programmable read-only memories (EPROMs),
electrically erasable programmable read-only memories (EEPROMs),
flash memories, magnetic or optical cards, or any type of media
suitable for storing electronic instructions. Other embodiments may
be implemented as software modules executed by a programmable
control device.
[0148] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0149] It should be noted that any dimensions, sizes, lengths,
dosing amounts, densities, flow rates, dosing agents, etc, are
merely provided for exemplary purposes and are not intended to
limit the scope of the present disclosure. For example, any
dimensions or sizes listed on any of the Figures are merely
provided as an example, as these sizes may be varied by persons of
ordinary skill in the art.
[0150] A number of implementations have been described.
Nevertheless, it will be understood that various modifications may
be made. Accordingly, other implementations are within the scope of
the following claims.
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