U.S. patent application number 11/047114 was filed with the patent office on 2005-08-11 for hydrogravity system and process for reclaiming and purifying a solid, multiple domain feedstock.
This patent application is currently assigned to Plastics Reclaiming Technologies, Inc.. Invention is credited to Bork, Joseph E., Engel, Ullrich, Paspek, Stephen C. JR., Schroeder, Alan.
Application Number | 20050173310 11/047114 |
Document ID | / |
Family ID | 34863850 |
Filed Date | 2005-08-11 |
United States Patent
Application |
20050173310 |
Kind Code |
A1 |
Bork, Joseph E. ; et
al. |
August 11, 2005 |
Hydrogravity system and process for reclaiming and purifying a
solid, multiple domain feedstock
Abstract
The hydrogravity separation of a multiple component solid
feedstock comprises granulating the feedstock to produce particles
substantially of individual components having different densities.
A dispersion mixer having a high shear and/or turbulent zone is
utilized to disperse agglomerated particles and a quiescent
hydrogravity tank is utilized to effect binary separation of one or
more of the heaviest or one or more of the lightest feedstock
components by utilizing an aqueous solution having a specific
gravity intermediate of the various components. A high degree of
purity is obtained by feeding particles of a selected component to
a plurality of sequential dispersion mixers and hydrogravity
separation tanks. In a similar manner, remaining thermoplastic
particle components can be selectively removed and purified.
Inventors: |
Bork, Joseph E.; (Westlake,
OH) ; Paspek, Stephen C. JR.; (Broadview Heights,
OH) ; Schroeder, Alan; (Cleveland, OH) ;
Engel, Ullrich; (Michigan City, IN) |
Correspondence
Address: |
HUDAK, SHUNK & FARINE, CO., L.P.A.
2020 FRONT STREET
SUITE 307
CUYAHOGA FALLS
OH
44221
US
|
Assignee: |
Plastics Reclaiming Technologies,
Inc.
|
Family ID: |
34863850 |
Appl. No.: |
11/047114 |
Filed: |
January 31, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11047114 |
Jan 31, 2005 |
|
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10774158 |
Feb 6, 2004 |
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Current U.S.
Class: |
209/172 |
Current CPC
Class: |
B29K 2077/00 20130101;
B29K 2075/00 20130101; B29K 2069/00 20130101; B29L 2031/302
20130101; Y02W 30/622 20150501; B29K 2023/12 20130101; B29B 17/02
20130101; B29B 17/0412 20130101; B29B 2017/0203 20130101; B29B
2017/0224 20130101; Y02W 30/523 20150501; B29L 2031/712 20130101;
B29L 2031/3462 20130101; B29K 2705/08 20130101; B03B 5/442
20130101; B29K 2705/10 20130101; B29B 2017/0015 20130101; B29K
2711/14 20130101; B29L 2031/3044 20130101; Y02W 30/52 20150501;
Y02W 30/524 20150501; Y02W 30/62 20150501; B29K 2023/06 20130101;
B29L 2031/3055 20130101; Y02W 30/625 20150501; B29B 17/04 20130101;
B29L 2031/10 20130101; B29K 2705/06 20130101; B29K 2705/12
20130101; B29K 2711/12 20130101; B29B 2017/0244 20130101; B29K
2027/06 20130101; B29L 2031/707 20130101; B29K 2705/02 20130101;
B29L 2031/7544 20130101; B29L 2031/7322 20130101; B29L 2009/00
20130101; B29K 2105/065 20130101; B29K 2705/00 20130101; B03B 5/28
20130101; B29L 2031/3005 20130101; B03B 9/061 20130101; B29L
2031/265 20130101 |
Class at
Publication: |
209/172 |
International
Class: |
B03B 005/28 |
Claims
What is claimed is:
1. A process for purifying a selected feedstock component,
comprising the steps of: a) mixing particles of a feedstock
comprising a plurality of components, each component having a
different specific gravity; b) feeding said mixed feedstock
component particles to a first hydrogravity tank containing a
solution having a specific gravity intermediate to one or more
heavier feedstock component particles and to one or more lighter
feedstock component particles and causing said particles of at
least one feedstock component to either sink or float; c) removing
selected specific gravity component particles from said
hydrogravity tank; d) mixing said removed selected component
particles; e) feeding said removed mixed selected component
particles to another hydrogravity separation tank containing a
solution having substantially the same specific gravity as said
first tank solution; and f) removing said selected component
particles from said second hydrogravity tank.
2. A process according to claim 1, wherein said feedstock comprises
at least three components, and wherein said selected specific
gravity component particles are substantially of a single feedstock
component.
3. A process according to claim 2, wherein each particle comprises
substantially a single component, and including mixing said
selected component particles from said second hydrogravity tank and
feeding to a third hydrogravity separation tank containing a
solution having substantially the same specific gravity as said
first tank solution.
4. A process according to claim 3, wherein a mixer for mixing said
feedstock component particles exists before each said hydrogravity
separation tank; wherein said feedstock component particles are fed
into the side of each said hydrogravity separation tank, wherein
the number of separation tanks is from about 2 to about 8, wherein
the specific gravity of said at least one different feedstock
component particles is at least 0.1 specific gravity units
different than the specific gravity solution in each said tank, and
wherein each said hydrogravity solution is substantially free of a
phosphorus containing compound.
5. A process according to claim 1, wherein said hydrogravity
solution is an aqueous solution.
6. A process according to claim 4, wherein said hydrogravity
solution is an aqueous solution.
7. A process according to claim 1, wherein each said mixer has at
least one substantially axial flow zone and at least one
substantially radial flow zone.
8. A process according to claim 6, wherein each said mixer has at
least one substantially axial flow zones and at least one
substantially radial flow zones.
9. A process according to claim 1, wherein said feedstock comprises
at least three different feedstock components including at least
one plastic component and at least one metal component, or at least
three different plastic components, or at least two different
plastic components and a wood component, or at least two different
plastic components and a cellulose component.
10. A process according to claim 6, wherein said feedstock
comprises at least three different feedstock components including
at least one plastic component and at least one metal component, or
at least three different plastic components, or at least two
different plastic components and a wood component, or at least two
different plastic components and a cellulose component.
11. A process according to claim 1, wherein said feedstock
components are derived from copper cables, aluminum cables, or
combinations thereof.
12. A process according to claim 6, wherein said feedstock
components are derived from copper cables, aluminum cables, or
combinations thereof.
13. A process according to claim 1, including purifying said
non-selected specific gravity feedstock component particles by
feeding said particles to at least one of a tandem comprising a
mixer and a subsequent hydrogravity tank having an aqueous solution
of a specific gravity such that one of said remaining non-selected
specific gravity feedstock component particles is separated.
14. A process according to claim 6, including purifying said
non-selected specific gravity feedstock component particles by
feeding said particles to at least one of a tandem comprising a
mixer and a subsequent hydrogravity tank having an aqueous solution
of a specific gravity such that one of said remaining non-selected
specific gravity feedstock component particles is separated.
15. A hydrogravity process for reclaiming particles of a ground
feedstock, comprising the steps of: feeding particles of a ground
feedstock containing a plurality of different components each
having a different specific gravity to a first hydrogravity
separation tank, said tank having substantially a phosphorus-free
aqueous solution of a specific gravity greater or less than the
specific gravity of at least one component of said feedstock
particles; removing particles of either at least one lighter
specific gravity component or at least one heavier specific gravity
component than the specific gravity of said aqueous solution;
subsequently feeding said selected removed lighter or heavier
component particles to a second hydrogravity separation tank having
substantially the same specific gravity of said substantially
phosphorus-free aqueous solution as said first tank; and purifying
said selected removed component particles by separating said
selected lighter or heavier component particles from any other
different specific gravity component particles of said
feedstock.
16. A hydrogravity process for reclaiming particles of a ground
feedstock according to claim 15, including a mixer before at least
one of said hydrogravity tanks for mixing said particles of said
selected removed lighter or heavier feedstock components, wherein
said selected removed lighter or heavier component are particles of
substantially a single feedstock component, and wherein the amount
of any phosphorus containing salt is less than about 3% by weight
of said aqueous solution.
17. A hydrogravity process for reclaiming particles of a ground
feedstock according to claim 16, including a mixer before each
hydrogravity tank, mixing said particles of said selected component
and feeding said particles into the side of each hydrogravity
tank.
18. A hydrogravity process for reclaiming particles of a ground
feedstock according to claim 17, wherein said feedstock comprises a
total of at least three different feedstock components comprising
at least one plastic component and at least one metal component, or
at least three different plastic components, or at least two
different plastic components and a wood component, or at least two
different plastic components. and a cellulose component.
19. A hydrogravity process for reclaiming particles of a ground
feedstock according to claim 18, including purifying said
non-selected specific gravity component particles by feeding said
particles to at least one of a tandem comprising a mixer and a
subsequent hydrogravity tank having an aqueous solution of a
specific gravity such that one of said remaining non-selected
specific gravity feedstock component particles is separated.
20. A hydrogravity process for reclaiming particles of a ground
feedstock according to claim 19, wherein said aqueous solution
comprises a salt of an alkali metal, an alkaline earth metal, a
transition metal from groups 3 through 15 of the Periodic Table
other than phosphorus, and an anion comprising a halogen, oxygen or
an oxygen-containing compound, hydroxide, carbonate, a
nitrogen-containing compound, or a sulfur-containing compound; or
wherein said aqueous solution is a drilling fluid, or a completion
fluid, or an aqueous suspension.
21. A hydrogravity process for reclaiming particles of a ground
feedstock according to claim 17, wherein said aqueous solution
comprises potassium carbonate, zinc chloride, ferric chloride,
ferrous chloride, calcium chloride, calcium bromide, calcium
sulfate, zinc chloride, zinc bromide, zinc sulfate, zinc oxide,
sodium hydroxide, sodium zincate, magnesium chloride, or a
polytungstate complex, or mixtures thereof.
22. A hydrogravity process for reclaiming particles of a ground
feedstock according to claim 20, wherein said aqueous solution
comprises potassium carbonate, zinc chloride, ferric chloride,
ferrous chloride, calcium chloride, calcium bromide, calcium
sulfate, zinc chloride, zinc bromide, zinc sulfate, zinc oxide,
sodium hydroxide, sodium zincate, magnesium chloride, or a
polytungstate complex, or mixtures thereof.
23. A hydrogravity process for reclaiming particles of a ground
feedstock according to claim 19, wherein each said mixer has at
least two substantially axial flow zones and at least two
substantially radial flow zones.
24. A hydrogravity process for reclaiming particles of a ground
feedstock according to claim 15, wherein said feedstock components
are derived from copper cables, aluminum cables, or combinations
thereof.
25. A system for reclaiming particles of a ground feedstock
comprising: a) a first set of at least one mixer and a plurality of
hydrogravity separation tanks each containing a substantially
phosphorus-free aqueous solution having substantially the same
specific gravity for separating particles of one component of said
ground feedstock containing at least three different components,
each aqueous solution having a specific gravity which is either.
greater or less than the particles of a single selected component
of said feedstock components, each said feedstock component having
a different specific gravity; said mixer located at least before
one of said hydrogravity separation tanks for mixing said particles
of said feedstock components before said components are fed to said
at least one hydrogravity separation tank, b) a second set of at
least one mixer and a plurality of hydrogravity separation tanks
for further separating a single selected remaining component of
said feedstock components, said at least one mixer of said second
set located before a hydrogravity separation tank for mixing said
particles of said feedstock components before they are fed to at
least one said second set hydrogravity separation tank, each said
second set tank having a substantially phosphorus-free aqueous
solution of substantially the same specific gravity but which is
different than the specific gravity of said first aqueous solution,
and is greater or less than only said single selected remaining
component of said feedstock so that said second set aqueous
solution is capable of separating said second selected component
from the remaining feedstock components.
26. A system according to claim 25, wherein in each said set of
said mixers and said tanks, independently, the number of mixers and
mixing tanks is each from about 3 to about 10.
27. A system according to claim 26, wherein said solution,
independently, in each said set of hydrogravity separation tanks is
a phosphorus free compound comprising a salt of an alkali metal, an
alkaline earth metal, a transition metal from groups 3 through 15
other than phosphorus of the Periodic Table, and an anion
comprising a halogen, oxygen or an oxygen-containing compound,
hydroxide, carbonate, a nitrogen-containing compound, or a
sulfur-containing compound; or wherein said aqueous solution is a
drilling fluid, or a completion fluid, or a suspension.
28. A system according to claim 27, including in each set a mixer
before each said hydrogravity separation tank, and wherein,
independently, the number of mixers and tanks in each said set is
at least two, and wherein the amount of any phosphorus containing
compound is less than about 3% by weight of said aqueous solution
of said first set and said second set.
29. A system according to claim 28, wherein said hydrogravity
aqueous solution comprises potassium carbonate, zinc chloride,
ferric chloride, ferrous chloride, calcium chloride, calcium
bromide, calcium sulfate, zinc chloride, zinc bromide, zinc
sulfate, zinc oxide, sodium hydroxide, sodium zincate, magnesium
chloride, or a polytungstate complex, or mixtures thereof.
30. A system according to claim 29, wherein said feedstock
comprises a total of at least three different feedstock components
comprising at least one plastic component and at least one metal
component, or at least three different plastic components, or at
least two different plastic components and a wood component, or at
least two different plastic components and a cellulose
component.
31. A system according to claim 25, wherein said feedstock is
derived from copper wire cable, aluminum wire cable, or
combinations thereof.
32. A system according to claim 30, wherein said feedstock is
derived from copper wire cable, aluminum wire cable, or
combinations thereof.
Description
CROSS REFERENCE
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 10/774,158 filed Feb. 6, 2004 for A
HYDROGRAVITY SYSTEM AND PROCESS FOR RECLAIMING AND PURIFYING A
SOLID, MULTIPLE DOMAIN FEEDSTOCK.
FIELD OF THE INVENTION
[0002] The present invention relates to reclaiming one or more
selective, different density solid components, such as plastic
(e.g. polyvinyl chloride, polyethylene), metal (e.g. copper, iron),
etc., which initially can be physically bonded to each other, from
a multiple domain solid feedstock. More specifically, the present
invention relates to using binary hydrogravity separation of small
sized particles of the solid multiple domain feedstock to
selectively separate the particles into at least two different
density components in a quiescent settling tank containing an
aqueous solution having a specific gravity intermediate to one or
more of the heaviest feedstock components or intermediate to one or
more of the lightest thermoplastic feedstock components.
BACKGROUND OF THE INVENTION
[0003] Heretofore, plastics have been selectively dissolved by
certain solvents and separated from other plastics or non-plastic
materials as by filtration. This format requires high temperatures,
and potential problems with solvent vapors, and the like.
[0004] U.S. Pat. No. 5,616,641 relates to a floatation separation
process wherein in a floatation bath sufficient alkali metal salt
or alkaline earth metal salt of a phosphate, a pyrophosphate, a
metaphosphate or a polyphosphate is dissolved to provide a
concentration greater than 1.0 grams per cubic centimeter and
generally about 1.05 to about 1.6. g/cc. A particular salt is
sodium dihydrogen phosphate. Preferably, the floatation process is
employed to separate physical mixtures of plastic parts.
SUMMARY OF THE INVENTION
[0005] Articles and products which serve as feedstock and contain
multiple domains such as layers or regions of two or more different
solid components are reclaimed by a binary hydrogravity separation.
Initially, the feedstock is granulated to reduce the size of the
multiple components into small particles of substantially a single
component, optionally screened to remove oversize particles and
fibers, and washed to remove dirt. Optionally, but desirably, fines
are removed. The particles are then slurried in a liquid and fed
through a dispersion mixer to a hydrogravity separation tank
containing desirably a non-phosphorous aqueous solution, having a
specific gravity which is intermediate to the specific gravity of
one or more of the feedstock components whereby they are separated
into feedstock components of a higher specific gravity or a lower
specific gravity than the aqueous solution. A plurality of
processing units each preferably containing a hydrogravity
separation tank and a dispersion mixer to disperse agglomerated
particles enable recycling, and subsequent reclaiming of selected
component(s) in a substantially pure form. In a similar manner, the
various remaining components can be separated, recycled, and
purified using different specific gravity solutions. Such a system
is suitable for the separation of particles having different
specific gravities.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a schematic flow diagram of one embodiment of a
hydrogravity reclaiming system of the present invention containing
different operation stages for removal and purification of solid
components having different specific gravities;
[0007] FIG. 2 is a side elevation of a hydrogravity separation
tank;
[0008] FIG. 3 is an end side elevation of the hydrogravity
separation tank;
[0009] FIG. 4 is a cross-sectional view of a dispersion mixer which
disperses agglomerated particles; and
[0010] FIG. 5 is a block diagram of an alternative embodiment for
removing oversized and fine particles.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The system and process of the present invention for
reclaiming individual thermoplastic components relate to a
feedstock comprising solid, multiple domain or region components
having different densities or specific gravities. One large class
of components are various individual particles of plastics such as
thermoplastic or thermoset polymers. The polymers can either be a
homopolymer or a copolymer. While not desired, included within the
plastic class are various melt blends of two or more compounds
which contain multiple components on a molecular scale. Generally,
feedstocks of the present invention contain less than about 10%,
desirably less than about 5%, and preferably less than about 1% by
weight of a melt blended material based upon the total weight of
the feedstock. Non-plastic components include metals, inorganic
fillers, various woods, paper, and the like. The multiple domain
components are often in the form of layers, regions, areas, and the
like.
[0012] Numerous feedstocks can be utilized provided that the
components thereof when reduced in size to particles as by
granulation, chopping, etc., have different specific gravities or
densities. Desirably feedstocks contain at least two or three
different plastics; at least one plastic and at least one metal; at
least one plastic and at least one type of wood; or at least one
plastic and at least one type of paper, and the like. Plastics
generally encompass thermoplastic polymers and less desirably
thermoset polymers as set forth hereinbelow.
[0013] Examples of specific thermoplastic polymers which can be
separated include, but is not limited to, polyolefins such as
polyethylene and polypropylene; styrenic polymers; acrylic
polymers; polyvinyl esters such as polyvinyl acetate; polyvinyl
alcohol; chlorine-containing polymers such as polyvinyl chloride
and polyvinylidene chloride; various fluorocarbon polymers such as
polytetrafluoroethylene, polyvinyl fluoride, and the like; nylons
and other polyamides; polyesters; polyurethanes; polycarbonates;
copolymers of the above, and the like.
[0014] Examples of specific thermoset polymers include various
phenolic resins, various amino resins, various polyester resins,
epoxy resins, various urethanes including urethane foams, various
silicone resins, and the like including copolymers of various
thermoset resins.
[0015] Other solid items which can be reclaimed by hydrogravity
separation include metals such as iron, nickel, platium, platinum,
silver, copper, gold, zinc, aluminum, tin, antimony, titanium,
chrome, metal oxides, metal sulfides and other metallic compounds,
and the like. Still other solid items include various types of wood
including plywood, particle board, etc., various types of paper
including cardboard, corrugated paper, and the like. Inorganic
materials include silica oxides, metal carbonates, clay, limestone,
alumina silicates, glass, and the like.
[0016] Examples of articles or products utilized as feedstocks in
various embodiments of the invention include polymer insulated wire
or cable including thermoplastics such as PVC, nylon, polyolefin,
etc.; metal articles such as aluminum, copper, or steel and/or
paper; sharps which include medical devices such as syringes, etc.
which contain both plastic and metal components; plastic laminates
or layered items; plastics items containing inorganic or other
non-plastics; carpeting which has a foam backing of one polymer and
fibers of another polymer; extrusion "bleeders"; recycled materials
containing thermoplastics; vinyl-clad materials such as various
window frames, door frames, and the like; automotive components
including laminated or layered thermoplastic and/or thermoset parts
such as trim, bumpers, paneling, multi-layer gaskets; automotive
recycle shredded floss, i.e. components obtained after shredding an
entire automobile; and the like. Other articles include various
hoses which contain one or more layers, in any order, of a plastic
such as PVC, nylon, polytetrafluoroethylene, polyolefin, and the
like wherein the fibers can be made from polyester, nylon, and the
like. Other items include plastic sprues from different molding
operations; change over waste from conversion of one plastic to
another plastic as in an extruder; molded items, cast plastics;
etc., and various buckets or containers containing a combination of
metal reinforcing parts or handles and paper, thermoplastic, and
the like. Still other sources include windshield gaskets, molded
parts, cast plastics, laminated rigid piping, and the like. Various
laminates, or layered plastic including rigid plastics are also
suitable as a feedstock.
[0017] In summary, generally any type of article can be utilized
having more than one component which can be reduced to particles
wherein the various components such as plastic, metal, paper, etc.
can be readily separated as by grinding or granulation.
[0018] Overall Operation
[0019] The overall reclaiming system and process include, but is
not limited to, the following operation stages.
[0020] Granulation involves sizing the feed stock by cutting the
same into suitable lengths and then breaking the same into sized
particles of substantially separated domains, desirably screening,
washing and/or air separating the particles to remove dirt, dust,
grime and the like, and optionally screening the particles to
remove fines which may hinder or inhibit subsequent operations.
[0021] A binary hydrogravity separation occurs in a quiescent tank
preferably having steep angled walls generally greater than the
angle of repose to prevent particle buildup thereon. The specific
gravity of the aqueous solution, which is achieved by adding one or
more salts, which include metal hydroxides, metal oxides, metal
halides, metal sulfates, metal nitrates, metal nitrites, metal
carbonates, and metal complexes, to water is selected to achieve
the separation of one or more of the lightest feedstock components,
or one or more of the heaviest feedstock components. Thus, an
intermediate specific gravity can be selected so that granulated
particles added to hydrogravity separation tank will be separated
into one or more lighter components as well as one or more heavier
components. Alternatively and often preferred, the specific gravity
of the aqueous solution is slightly greater than the specific
gravity of only the lightest solid component, or is slightly less
than the specific gravity of the heaviest solid component which
allows recovery of particles of substantially a single feedstock
component. The component(s) selected to be reclaimed is desirably
added to at least one additional gravity separation tank and then
to preferably to a plurality of additional separation tanks
(recycled) to further increase the yield and purify the selected,
reclaimed component. Desirably both the top and bottom streams of
at least an initial separation tank are recycled.
[0022] While the preferred embodiment of the present invention
relates to an aqueous solution, it is never the less within the
scope of the present invention to utilize non-aqueous solutions
such as silicone solutions, oils including hydrocarbon and halo
hydrocarbon oils, dry cleaning fluids, and even liquid solutions
comprising ammonia or carbon dioxide. The solutions can be used
"neat", in blends, or admixed with other chemicals for the purpose
of altering their specific gravity. For example, the specific
gravity of an aqueous solution of a specific hydrogravity tank can
be changed or "dialed in" by adding thereto a second specific
gravity solution having either a higher or lower specific gravity
to achieve a different specific gravity in the tank or to fine tune
an existing specific gravity.
[0023] Dispersion mixers are preferably utilized before each
hydrogravity separation tank to sever, divide, and especially to
break up agglomerated particles of the feedstock before they are
added to a hydrogravity separation tank.
[0024] The selected separated particles from the last hydrogravity
tank of a purification operation are collected, optionally washed,
dried, and utilized for any desirable purpose such as reuse or
resale. Optionally, additional purification processes such as melt
filtration can be utilized to remove the last traces of contaminate
from the particles.
[0025] In a similar manner, each remaining domain(s) or
component(s) is selectively removed and purified.
[0026] System and Processing Components
[0027] The present invention will now be described with respect to
reclaiming one or more solid components from an article such as an
insulated copper cable, it being understood that, as noted above,
generally any article or product having multiple domains of
different plastics or other components such as metal, wood, paper,
etc., can serve as feedstock which is reclaimed with a high degree
of purity.
[0028] Referring to FIG. 1, a hydrogravity system and process for
reclaiming and purifying a solid feedstock is generally indicated
by reference number 10. In one embodiment, the reclaimed article is
a wire cable which contains a plurality of separated copper wires
each surrounded with a thermoplastic such as polyethylene or other
thermoplastic with the same being contained or encapsulated within
an insulating thermoplastic such as polyvinyl chloride or other
thermoplastic. The insulated cable has an outer jacket which is
generally a thermoplastic nylon or other thermoplastic. In other
embodiments, any number of components can be present.
[0029] The solid article, such as a copper cable is generally
precut at an angle into lengths generally greater than 4
millimeters (mm) and fed from feedstock container 110 to granulator
120. Generally any type of cutting device or machine can be
utilized with a reel type high shear cutting blade being
desired.
[0030] The purpose of the granulator is to size, that is to break,
chop, shred, etc. the precut lengths into particles of 4 mm or less
and desirably from about 0.5 mm or about 1 mm to about 2 mm or
about 3 mm or about 4 mm. The exact size desired is a function of
the domain size in the feedstock materials and can be readily
determined by one skilled in the art. The granulator reduces the
feedstock containing layers of different domains, regions, etc.,
into small particles containing substantially only one domain or
component, e.g. a specific thermoplastic or metal. That is, since
the various layers, regions, etc., of the feedstock are only
physically bonded, granulation of the same readily separates the
various components to produce particles of substantially only a
single component. Thus, the amount of any particles having two or
more thermoplastic components therein is very small, generally less
than about 5% by weight, desirably less than about 3% by weight,
and preferably less than about 1% by weight, or no percent by
weight based upon the total weight of the feedstock. Granulators
for producing metal and/or thermoplastic particles are well known
to the art and to the literature and generally any suitable
granulator 120 can be utilized such as a CMG, made in Italy. For
reasons set forth below, fines are desirably removed and filtered
or screened in unit 130 and collected in unit 140. Fine sized
particles can vary but often are from about 0.1 to about 1.0 mm in
size.
[0031] The dry granulated particles often contain dirt, grime, and
fines and are thus fed to wash unit 150 wherein they are mixed
under high agitation to create a suspension of the particles in
water. Any type of high agitation mixing tank can be utilized with
high shear agitation and/or turbulent flow being preferred. The
washing step may be continuous or batch. The amount of the
granulated article, such as thermoplastic and copper feedstock is
desirably such that the solids loading of the slurry in the wash
unit is desirably from about 10% to about 40% by weight. Generally
any soap such as laundry soap or any conventional surfactant,
detergent, or wetting agent, known to the art and to the literature
which is non-foaming or low foaming can be utilized and aids in
wetting the granulated thermoplastic and copper particles.
[0032] The removal of fines from the particular article feedstock,
while optionally, is often an important aspect of the present
invention since otherwise, they generally clog the reclaiming
system because they generally do not settle or float in the
hydrogravity tanks but remain in suspension. Generally any
conventional compounds or methods of removing the fines from the
slurry can be utilized such as flocculating agents, coagulation
agents, and the like which alter the zeta potential of the fines,
centrifuging, air separation, sifting, or desirably screening. For
example, a screen containing openings of generally less than about
1.0 mm and desirably less than about 0.5 mm can be utilized to
permit the fines to fall there through. A vibrating screen or a
centrifuging screen is preferred. In addition to the fines, dirt,
and grime, the surfactant or soap solution also falls through the
screen. A series of one or more spray bars can be utilized to spray
a solution or water onto the retained material to aid in removing
fines, dirt, grime, soap or detergent solution therefrom. The fines
can be collected in container 160.
[0033] The washed thermoplastic and copper particles are
substantially dewatered so when they are fed to a hydrogravity
separator tank, dilution of the aqueous salt solution is prevented.
Generally any type of drying process or apparatus 170 can be
utilized with a mechanical or vibratory screen, basket centrifuge
or a conventional spin dryer being preferred to remove the excess
solution leaving a product having about 0% or about 0.1% to about
15% and desirably from about 3% to about 7% by weight of
solution.
[0034] Another embodiment of the present invention with respect to
granulating feedstock particles and removing fines therefrom is set
forth in FIG. 5. Precut feedstock 710 is fed to scalper 720 which
removes and feeds to container 724 oversized particles such as
those generally larger than 4 mm, fibers, as well as angel hair
which is generally strips or strings of fibers derived from paper,
polymer, and the like. Fines fall through a fine size screen and
are collected in container 722. The remaining precut feedstock is
fed to granulator 730, which can be similar to that described
above, wherein the feedstock is broken, chopped, shredded, etc.
into small particles of from about 0.5 mm or about 1 mm to about 2
mm or about 3 mm or about 4 mm. The granulator separates the dry
feedstock containing different components into particles
substantially containing only one component such as a specific type
of thermoplastic or metal. Since fines are undesired because they
can become suspended or entrained in the aqueous hydrogravity
solution, they are removed by fine separator 740 which utilizes one
or more fine screens to selectively remove fines and dirt and
deliver the same to container 742.
[0035] The dry substantially single component particles are then
subjected to a wet system which further removes fines and dirt. The
water removal system comprise the various feedstock component
particles which. are fed to wash tank 750 generally having
agitation therein, and contain soap, surfactants, wetting agents,
etc., from tank 742. After the washing operation which may be batch
or continuous, the wet feedstock particles are fed to wet screen
operation 760 wherein water from tank 762 washes the particles to
remove the soap or surfactant therefrom and is subsequently
collected in container 766. The removed fines and dirt are fed to
container 764. The various washed feedstock component particles
which are semi-wet are fed to any conventional dryer 770 such as a
Gala dryer wherein water is removed to container 772. The dried
multiple feedstock component particles can then be fed to any
series of hydrogravity separation tanks to remove at least two
components, for example at least two different thermoplastics,
through a plurality of mixing and hydrogravity separation
steps.
[0036] While specific embodiments have been described with regard
to the removal of undesired components from the feedstock such as
dirt, angel hair, oversized particles, and fines, it is to be
understood that numerous different types of operations and other
embodiments can be utilized and that the same are within the
concepts of the present invention.
[0037] With respect to the embodiment of copper cable particles,
although generally any type of feedstock can be utilized, in the
various reclaiming stages a selected component is separated out
such as a metal or copper in a first stage. The washed and
granulated dewatered feedstock comprising different domain
thermoplastic particles as well as copper particles is continuously
fed preferably to a plurality of sequential hydrogravity separator
tanks wherein the copper, or other non-thermoplastic materials is
separated from the thermoplastic components. Desirably before each
tank they are fed to a dispersion mixer for de-agglomeration and
subsequently fed to the mid portion of a sequential hydrogravity
tank. By mid portion it is meant from about 10% to about 90%,
desirably from about 20% to about 80%, and preferably from about
30% to about 70% of the total aqueous solution height in the
tank.
[0038] Another important aspect of the present invention in one
embodiment is the utilization of an aqueous solution having a
selected specific gravity which permits binary separation of one or
more of the heaviest components to be separated out from the bottom
of the hydrogravity tank. Alternatively, a specific gravity can be
selected which permits one or more of the lightest components to
float to the top of the tank and to be removed therefrom. As
previously noted, the one or more selected solid component
particles to be reclaimed are sequentially subjected to a plurality
of hydrogravity tanks (recycled) having essentially the same
specific gravity to obtain a high yield and purity of the selected
components. Yet another important aspect is that the aqueous
solution has a relatively low viscosity to allow ready separation
of the desired component. The viscosity of the aqueous solution
will vary depending upon the types of the particles, the size and
shape thereof, and type of the one or more salts. A rule of thumb
is that the viscosity is generally about 50 centiposes or less and
desirably about 25 or less or about 10 centiposes or less.
[0039] Various specific gravity aqueous solutions are utilized
which are known to the art and to the literature generally
comprising salts that are highly soluble in water and thus create
desired, predetermined specific gravities as low as about 1.001 or
about 1.1 to as high as about 2.0 or about 3.0.
[0040] Suitable salts are capable of achieving a desired specific
gravity for the particular operation stage, and produce a desired
low viscosity. The salts or mixtures thereof are generally defined
as ionic compounds containing an electropositive component and an
electronegative component. Examples of positive components such as
ions include alkali metals such as sodium and potassium, alkaline
earth metal such as magnesium and calcium, and various transition
metals (groups 3-15 of the periodic table) such as aluminum, tin,
iron, zinc, and the like. The negative components such as ions
include halogens such as chloride, bromide, oxygen or
oxygen-containing compounds such as oxide, or hydroxide, or
carbonate, nitrogen-containing compounds such as nitrate, sulfur
containing compounds such as a sulfate, or the non-metal portion of
a metal complex, and the like. Examples of specific suitable salts
include potassium carbonate, zinc chloride, ferric chloride,
ferrous chloride, calcium chloride, calcium bromide, calcium
sulfate, zinc chloride, zinc bromide, zinc sulfate, zinc oxide,
sodium chloride, sodium hydroxide, sodium zincate, magnesium
chloride, various polytungstate complexes such as hydrated sodium
heteropolytungstates, and mixtures thereof, with calcium chloride
being preferred.
[0041] Another class of suitable aqueous specific gravity solutions
are various drilling or completion fluids such as those generally
utilized in well drilling. Such fluids are known the art and to the
literature. An example of such drilling or completion fluids
generally comprise water, a density increasing agent, and various
stabilizers such as a clay stabilizing agent. Examples of such
fluids are set forth in U.S. Pat. No. 4,536,297 which is hereby
fully incorporated by reference. Another class of suitable aqueous
solutions are suspensions of various particles in water. Suspension
can be a colloidal dispersion of particles, or obtained through the
use of a dispersing aid, and the like. Suspended particles include
magnetite such as Fe.sub.3O.sub.4, barite, shale, galena, clay,
limestone, and the like. Such solutions are known to the literature
and to the art such as set forth in U.S. Pat. No. 5,240,626, which
is fully incorporated by reference.
[0042] Saline solutions are desired but aqueous solutions
containing a phosphorus atom such as various phosphates,
pyrophosphates, metaphosphates, polyphosphates, or hydrides thereof
are not desired and are avoided since they are not environmentally
friendly and can lead to build up of algae and the like. In other
words, the aqueous solutions of the present invention are generally
phosphorus free meaning that the amount of any phosphorus
containing salt is generally less than about 5% by weight,
desirably less than about 3% by weight, and preferably less than 2%
by weight or nil, that is no amount whatsoever, based upon the
total weight of all salts in the aqueous specific gravity solution.
It is noted that treated water such as that delivered by various
municipalities, cities, and other water purification and treatment
plants generally inherently contain small amounts of phosphorus
salts which are generally less than 5% by weight.
[0043] A small amount of a soap, surfactant, detergent, wetting
agent, or defoamer is desirably utilized to reduce surface tension,
to hinder crystallization of the salt, to promote the release of
air bubbles and to reduce the attraction between particles.
Generally any conventional soap, surfactant, etc., can be utilized
such as household soaps, laundry detergents, industrial detergents,
and the like.
[0044] It has been unexpectedly found that the addition of
surfactants, detergents and wetting agents to the aqueous solutions
control surface tension and lower the freezing point thereof so
that higher density or specific gravity solutions can be formed
than otherwise possible. Depending upon the amount and type of
surfactant, etc., the freezing point of a solution having a
particular specific gravity can be depressed or reduced anywhere
from about 0.1.degree. F. to about 30.degree. F.; desirably from
about 1.0.degree. F. to about 25.degree. F.; and preferably from
about 2.0.degree. F. or about 3.0.degree. F. or about 5.0.degree.
F. to about 10.degree. F. or about 15.degree. F., or about
20.degree. F.
[0045] Surfactants can generally be anionic, cationic, nonionic,
amphoteric, and the like and the same are known to the art and to
the literature. Examples of suitable cationic surfactants include
the various quaternary amines such as a quaternary ammonium salt
having four alkyl and/or aryl bonds connected to the nitrogen atom
wherein, independently, each hydrocarbon or functional containing
hydrocarbon group has from 1 to 100 carbon atoms. Examples of
suitable quaternary ammonium salts are known to the art and to the
literature. Examples of other surfactants are set forth in 2003
McCutheon's Volume 1: Emulsifiers & Detergents (The
Manufacturing Confectioner Publishing Company; Glen Rock, N.J.)
which is hereby fully incorporated by reference. Whether a
surfactant is suitable or not can be readily determined by adding
various amounts to the aqueous solution containing particles of the
various components and determining whether the particles are wetted
out. Anionic surfactants ordinarily comprise alkyl hydrophobic
hydrocarbon chains having terminal anionic hydrophilic polar groups
such as carboxylate, sulfonate, sulfate, phosphonate and phosphate
polar groups. The alkyl can contain from about 2 to about 24 carbon
atoms and desirably from about 8 to about 20 carbon atoms. Suitable
surfactants comprise fatty acid chains containing about 10 to about
20 carbon atoms and may contain one or more double bonds, if
desired, as in naturally occurring fatty acid vegetable oils.
Carboxylate surfactants ordinarily comprise alkyl hydrocarbon
hydrophobic chains whereas sulfonate surfactants comprise alkyl,
aryl, or alkyl-aryl hydrophobic chains which may contain double
bonds, ester or amide groups.
[0046] Desired surfactants include the following: Sodium
Caprylamphopropionate (Miranol JEM), Sodium 2-ethylhexyl sulfate
(Rhodapon BOS, Sulfotex OA), sodium octyl sulfate (Standapol LF),
Sultech 2113, Disodium Cocoamphodiacetate (Mackam 75/2C), Disodium
Capryloamphodipropionate (Mackam 2CYSF), Cocamidopropyl
Hydroxysultaine (Mackam CBS 50), Sodium
Capryloamphohydroxypropylsufonate (Mackam JS), Caprylamidopropyl
Betaine (Mackam OAB, DV 6836), methyl ester soybean oil (Septosol
SB-D), Diphenylene Oxide Disulfonate (Rhodacal DSB),
Lauraminopropionic Acid (Deriphat 151C), alkylpolyglucosides
(Glucopon 425), Sodium laurylether sulfate (SLES), Octylamine Oxide
(Mackamine C-8), octyl betaine (Mackam BW 139), Sodium Alkyl
Naphthalene Sulfonate (Petro ULF), linear alkylbenzene sulfonates
(Biosoft S-101), Lauramine Oxide, alkylamine oxides (AO 728),
alkylether sulfonates (Avanel S-74), anionic and nonionic
fluorosurfactants such as the various Zonyl surfactants made by
DuPont, (e.g. Zonyl FS-62, FSA, FSP, FSE, FS-62, 9361, FSH, FSO,
FSN, etc.), cationic/nonionic surfactant blends (Burcoterge CSB),
alkylpolyglucosides (AG 6202), tall oil based amides
(Burcoimidozoline), propoxylated and ethoxylated fatty acids
(Burcoterge LFE 1000), modified ethoxylated carboxylates (Deterge
LF 7315), phosphated amphoterics (Deteric CSP), ethoxylated complex
amines (Deterge AT 100), diphenyl sulfonate derivatives (Dowfax
8390), phosphate esters (Colatrope 555, Colafax 3373 PE, Colafax
3371 PE), alkylether hydroxysultaines (Mirataine ASC), anionic
proprietary blends (Colonial ZF 20), diphenyl sulfonate derivatives
(Surfedon LP 300), organic phosphated amphoteric (Deteric CSP),
salts of N-lauryl beta iminodiproprianate (Deriphat 160C),
iminodipropionate amphoteric (Amphoteric 400), proprietary
hydrotropes (Monatrope 1250), Cocamide DEA (Ninol 40-CO) and
dodecylbenzene sulfonic acid (Biosoft S 101), wherein the number of
carbon atoms in any alkyl group is as noted above.
[0047] Another compound which has been found to promote particle
dispersion in an aqueous system is various defoamers which are
known to the art and to the literature. Examples of suitable
defoamers include compounds containing amorphous silica, various
siloxanes such as polydimethyl siloxane, and the like such as Dow
Corning 200, 1430, 1520, etc.
[0048] The amount of such surfactants, detergents, wetting agents,
defoamers, etc., generally varies with the strength of the
surfactant, etc., and/or the chemical nature of the aqueous
solution, and/or according to specific gravity desired and/or the
amount of freezing point depression desired with generally greater
proportional amounts yielding a higher specific gravity and/or a
larger freezing point depression.
[0049] The hydrogravity separation tank is designed to promote good
separation of the multiple domain thermoplastic feedstocks after it
is granulated. As a general concept of the present invention, one
or more of the heaviest components are removed from the bottom of
the hydrogravity separation tank as a slurry, and one or more of
the lightest particles float to the top of the tank and are removed
or skimmed off, desirably with both the top and bottom each being
separately recycled to produce purified components. The specific
gravity of the solution in the tank is thus generally intermediate
of the one or more heaviest and the one or more lightest density
particles. Accordingly, the specific gravity of the solution is at
least about 0.02 or at least about 0.05 lighter or heavier and
preferably at least about 0.10 or at least about 0.15 lighter or
heavier specific gravity units than the specific gravity of any
selected component particles. Preferably, in any given stage of the
reclaiming operation, only a single heaviest particle component is
substantially removed from the bottom or only a single lightest
particle component is removed from the top of the separation tank
with the remaining particles being removed from the opposite end of
the tank.
[0050] An essential aspect of the hydrogravity tanks is that they
have a non turbulent or slow flow rate such that the tank
effectively separates particles of the heaviest component(s) or
separates particles of the lightest component(s) from the remainder
of the solution. Accordingly, the separation tanks are not
agitated, stirred, mixed, or the like. Such a quiescent tank has
sides and bottom surfaces which are greater than the angle of
repose of the particles thus eliminating and preventing build up
thereof. The angle of repose of the various sides will vary with
the physical and chemical properties of the solution, the types of
components such as plastic or metal, the shape of the particles,
and the like. However, such angles of repose can be readily
determined by one skilled in the art. Generally, any side surface
or wall of the tank has an angle A or B of at least 45 degrees from
the horizon. The angle of the various sides is generally at least 1
degree greater, desirably at least 5 degrees greater, and
preferably at least about 10 degrees greater than the angle of
repose.
[0051] As long as the above requirements are met, numerous tank
designs and configurations exist. One such configuration of a
generalized tank of the present invention is set forth in FIG. 2
wherein tank 200 has a top 205, a vertical upper first end wall
210, an inclined upper second end wall 215, and as shown in FIG. 3,
generally vertical upper first and second side walls 220 and 225
respectively. The upper first end wall 210 of the upper portion of
the tank extends into inclined lower first end wall 230. As shown
in FIG. 3, the upper first side wall 220 also merges into an
inclined lower first side wall 235 and the same is true of upper
second side wall 225 which merges into inclined lower second side
wall 240, all of which are greater than the angle of repose.
[0052] Utilization of the above described hydrogravity separation
tank of FIG. 2 thus permits the washed and dewatered particles from
dryer 170 to be fed through tank inlet 245 to tank 200 and
subsequently separated into components, such as at least one
component which is discharged as a slurry from the tank bottom
egress 250. The aperature size of egress 250 is sufficient to
maintain a fairly constant and continuous removal and can be
readily controlled by any conventional valve, with a pitch valve
being preferred. The aperature size is also such that a sufficient
particle residence time exists in the hydrogravity tank to permit
efficient separation of the one or more heavier components and to
achieve an aqueous slurry velocity flow which avoids back mixing,
entrainment, and the like.
[0053] As shown in FIG. 2, hydrogravity separation tank 200 in one
embodiment optionally can contain skimmer 260 which comprises a
conveyor type belt 265 having paddles 270 dependent therefrom.
Rotation of conveyor 265 will cause the paddle to be immersed into
the top of the aqueous slurry and skim the floating particles to
one edge of the tank where they are collected and transferred to
mixing apparatus 300. Otherwise, the floating particles can simply
flow through an outlet opening, weir or other types of removal
devices known to the art and to the literature to the next stage of
the system or process.
[0054] According to the concepts of the present invention,
separation and purification of granulated solids of different
components, e.g. plastic, metal, is conducted as opposed to
purification of a solution. In order to obtain a high yield and
purity of any specific particles of one or more components, such
selected particles are feed to a plurality or multiple of
subsequent hydrogravity separation tanks wherein the removal
operation is repeated with the selective component particles being
reclaimed being transferred to all the tanks in one operation
stage. The number of such sequential hydrogravity tanks in any
operation stage can vary from at least 2 to about 10, desirably
from about 3 to about 8, and preferably from about 3 to about 5
until the selected component(s) are highly purified. Naturally, the
specific gravity of the aqueous solutions in any plurality of
hydrogravity separation tanks of any single operation stage is
substantially the same.
[0055] Inasmuch as the various granulated particles upon immersion
into an aqueous solution may or will tend to agglomerate due to
surface tension or electrostatic attraction, it is preferred to
utilize a dispersion mixer before each separation tank to disperse,
sever, etc., such agglomerated particles. Alternatively, in a
series of purification or recycling steps as shown in FIG. 1 with
regard to separation and purification of the polyolefin, the nylon,
the PVC, and the copper, at least one dispersion mixer is utilized
per about 2 to about 10 total hydrogravity tanks or, some
dispersion mixers can be utilized, that is from about 15% to about
30%, per total number of separation tanks. Desirably a majority,
that is greater than 50%, of mixers are utilized and more
desirably, a substantial number, that is from about 70% to about
95%, of dispersion mixers per total number of hydrogravity
separation tanks in any recycling purification stream.
[0056] A dispersion mixer 300 shown in FIG. 4 is preferably located
before the first hydrogravity tank of the first removal stage and
desirably also before every hydrogravity tank therein. The same
principle is true with respect to the other removal stages of other
component particles. Although dispersion mixer 300 can be a batch
mixer, it is highly preferred that a continuous flow mixer be
utilized. The dispersion mixer can be of any shape but desirably is
elongated and can have one or more mixing zones, with a plurality
of zones, such as from about 2 to about 10, and from about 3 to
about 5 zones being preferred. Desirably dispersion mixer 300 is in
the shape of an elongated tube or cylinder 310 and has a zone
separation element such as an annulus 315 located between and
defining each zone. Annulus apertures 316A, 316B and 316C can vary
from zone to zone so long as it is less than the tube diameter with
a desired aperature area of from about 10% to about 50% and
preferably from about 15% to about 30% or about 35% of the total
tube diameter area. The linear location of each zone separation
annulus 315 can vary so that each zone can be of any desirable
length and each zone length need not be the same. The zone length
to diameter ratio can be of from about 0.5 or about 0.8 to about 5
or about 10.
[0057] One or more shafts can be utilized to rotate a mixing
impeller, with one axial shaft 320 being preferred, which extends
through mixer 300 and can be rotated by any conventional apparatus
such as motor 325. Generally two types of mixing impellers are
utilized. The first is an axial mixing impeller 330, located in
axial flow zone 335, which sucks in and propels the granulated
component particles into the mixer. One or more mixing impellers
can be contained in any zone. Any conventional impeller can be
utilized in the first or ingress zone such as a marine propeller
having two or more blades, or any other substantially axial flow
generating impeller.
[0058] The aqueous solution containing the granulated particles
therein is then forced through first annulus 315A, and into first
radial flow zone 345 which contains a second type of mixing
impeller, one or more radial flow dispersion impellers 340 designed
to break up substantially any particles which have agglomerated. It
is essential that the radial flow dispersion impeller create high
shear and/or high turbulence to separate the agglomerated
particles. Such impeller dispersion blades are more functional than
a simple impeller inasmuch as the dispersion blades create a
hydraulic action which tears agglomerated particles apart and
disperses them uniformly throughout the solution. This is believed
to be achieved by two different mechanisms. In the first,
agglomerated particles hitting the blade are broken apart (sheared)
and then in the intense turbulence surrounding the blade, particles
hit one another at high speeds and are further broken up. This
intense turbulence around the blade generally occurs at a zone
extending a couple of inches outward therefrom and is called the
zone of attrition. Beyond the turbulent zone the various particles
are thoroughly mixed and dispersed. The diameter of the high sheer
and/or turbulent impeller 340 can vary in length but is generally
from about 20% to about 50% and desirably from about 25% or about
30% to about 35% or about 40% of the dispersion mixer diameter.
Various types of radial dispersion impeller blades are known to the
art and to the literature and can be utilized such as a Cowles.RTM.
impeller, a Hockmeyer impeller, a so-called "high vane blade", and
also a combination of a blade imparting both radial and axial
flow.
[0059] In a preferred embodiment of the present invention, the
slurry solution is fed from first radial flow zone 345 through
second zone separation annulus 315B to a second radial flow zone
355 having a dispersion impeller 350 which further breaks up the
agglomerated particles, etc., and further disperses the same into
individual particles. The mechanisms are the same as with regard to
first radial flow zone 345 and hence will not be repeated.
[0060] In a preferred embodiment, the aqueous slurry flows through
third zone separation annulus 315C into a fourth zone, which is a
second axial flow zone 365 containing one or two axial flow
impeller 360. The axial flow impeller is desirably the same as
axial flow impeller 330 and the same, along with the various other
aspects of axial flow zone 365, will not be repeated but rather
incorporated by reference with respect to the first axial flow zone
335. Of course, axial flow zone 365 serves to suck the aqueous
slurry from radial zone 355 into axial zone 365 and then expel it
as through an egress in the mixer to a pipe or conduit leading to a
subsequent hydrogravity separation tank and preferably to a
mid-portion side inlet thereof.
[0061] The rpm of rotating shaft 320 can vary considerably
depending upon desired throughput or flow rate but generally is
from about 500 to about 5,000 and preferably from about 1,700 or
about 2,500 to about 3,500 rpm. The flow rate through mixer 300
will generally vary with the tube diameter as well as the diameter
of apertures 316A, 316B, and 316C and can be from about 1 to about
50, desirably from about 10 to about 45, and preferably from about
20 to about 40 gallons per minute with respect to a dispersion
mixer having a 10 inch diameter.
[0062] While a specific dispersion mixer has been described in
detail, it is to be understood that many variations thereof as well
as other mixers can be utilized so long as they generally contain
at least one and preferably a plurality of dispersion zones which
serve to further break up the particles as through high shear and
turbulence. For example, a dispersion mixer can contain an inlet
pump and/or an outlet pump in lieu of an impeller. Moreover, in the
radial flow zones, high turbulence pumps can be utilized or a pump
can be run backwards to produce high turbulence and/or shear..
[0063] Hydrogravity Separation
[0064] The hydrogravity separation of a specific wire cable feed
stock will now be discussed in view of the above principles,
concepts, structures, and descriptions. As noted above, the wire
cable comprises a plurality of copper wires each surrounded with a
polyethylene thermoplastic with the same being encapsulated in
polyvinyl chloride thermoplastic insulation. The outer jacket of
the insulated cable is a nylon thermoplastic. In the preferred
separation embodiment, only one component is separated (recycled)
in each stage or operation with the remaining components to be
purified transferred to the next stage.
[0065] The granulated, washed, and dewatered feedstock is fed to
first dispersion mixer 415 which, is described herein above, the
description, concepts, principles, etc. which are hereby
incorporated by reference, contains a plurality of zones having a
first axial flow zone, a first radial dispersion zone wherein a
dispersion impeller breaks up agglomerated particles as by high
shear and/or turbulence, a second radial dispersion zone followed
by an axial output zone. The dispersed particles are then fed to a
mid or lower portion of a first hydrogravity separation tank 410,
the description, concepts, principles, etc., of which as set forth
herein above such as with regard to tank 200 are hereby fully
incorporated by reference. The specific gravity of the calcium
chloride aqueous solution in tank 410, and all subsequent
sequential tanks 420, 430 and 440, is about 1.40 to about 1.50
which is greater than all of the thermoplastic components but less
than that of the copper component. The viscosity of the calcium
chloride aqueous solution is low, for example less than about 10
centipose. The sides of tank 410 have an angle sufficient to
prevent buildup of any copper solids and the flow rate throughout
the tank is slow and generally free of any turbulence so that
quiescent separation is achieved. That is, generally there is a
small velocity component in the horizontal direction with a greater
velocity flow component in either vertical direction. After a
desired residence time to permit good specific gravity separation,
the copper-rich particles or stream are emitted from the bottom of
tank 410 in the form of a slurry which is transferred to
conventional purification unit 470. Any conventional purification
unit can be utilized such as a concentrating table, e.g. a Deister
or a Wilfley table, generally of a rectangular shape and tilted
towards one corner so the copper particles are directed thereto and
collected. The remaining thermoplastic domain particles of nylon,
PVC and polyethylene either flow out of the top of the tank as
through a weir or are skimmed off and fed to second dispersion
mixer 425. The second dispersion mixer is desirably the same as the
first mixer and thus has two radial flow zones for breaking up and
separating various agglomerated particles which are primarily a
thermoplastic. The various thermoplastic component particles are
then fed to a second hydrogravity separation tank 420, and
desirably to a middle or lower portion side inlet thereof.
[0066] Tank 420 preferably contains the same specific gravity
aqueous solution as first separation tank 410 and in all aspects is
desirably the same as first tank 410. In other words, the
structure, flow, etc., can be a duplicate of the first hydrogravity
separation tank. Thus, additional settled copper particles from the
bottom of tank 420 are fed to purification unit 470 and the
remaining floating particles are either skimmed or flow to third
dispersion mixer 435 which is desirably the same as first
dispersion mixer 415 and has multiple axial mixing zones, and
multiple dispersion zones which further break up agglomerates.
[0067] In a similar manner, the system and process can be repeated
any number of desirable times until essentially all of the copper
component has been removed from the hydrogravity separation tanks
which all contain essentially the same structure and conditions as
well as the same specific gravity aqueous solution as first tank
410, with the remaining thermoplastic particles being removed from
the top of the tank and passed through a mixer having the same
structure and conditions as first dispersion mixer 415 and then
transferred to a succeeding tank. In the embodiment shown in FIG.
1, a total of four tanks are utilized including third hydrogravity
separation tank 430, fourth dispersion mixer 445, and fourth
hydrogravity separation tank 440.
[0068] The specific gravity solutions in any unit operation or
stage purification of particles of a selective feedstock component
are stored so that they can be subsequently reused or recycled.
Thus, after use of a long period of time such as a week, a few
weeks, a month, or several months, any specific gravity solution
utilize in any purification stage of purification of various
feedstock components can be cleansed as by filtration or
clarification, and subsequently stored in the tank until needed and
then reused.
[0069] In accordance with the concepts of the present invention,
inasmuch as only copper was removed from the first operation stage,
the remaining thermoplastic components are purified in that they
are subjected to a plurality of dispersion mixers and hydrogravity
separation tanks and contain very little, if any, remaining copper
particles therein.
[0070] After the last tank or mixer of the copper separation stage,
the aqueous slurry is fed to dewaterer 460 to remove the high
specific gravity aqueous solution from the plastic particles and
the solution returned to tank 410 (not shown) so that no
significant amount thereof is sent to the second purification or
operation stage which would alter the specific gravity of the
subsequent stage and potentially have a detrimental effect thereon.
Generally any conventional dryer or dewaterer 460 can be utilized
such as a vibration screen, or a centrifuge dryer, with a spin
dryer such as a Gala 3016 dryer manufactured by Gala Corporation
being suitable.
[0071] The utilization of the above system and process with regard
to a copper cable can result in a yield of generally at least 90%,
desirably at least about 95% and preferably at least about 98% or
about 99% percent by weight from copper purification unit 470 based
upon the total weight of copper added to first separation tank 410.
The purity of copper from purification unit 470, which separates
thermoplastic particles from the copper, is generally at least
about 80%, desirably at least about 90%, and preferably at least
about 95% or at least about 98% by weight based upon the total
weight of material collected.
[0072] Considering the second operation stage of the system and
process of the present invention, the purified thermoplastic
particles obtained from the first stage or operation are fed to a
plurality of a dispersion mixer and subsequent hydrogravity
separation tank units desirably in accordance with the concepts,
principles, structure and the description set forth hereinabove and
for the sake of brevity will not be repeated. However, the same is
hereby fully incorporated by reference with regard to all aspects
thereon such as to the structure, shape, flow conditions of the
various hydrogravity tanks, the type of dispersion mixers which
utilize a plurality of zones having at least one axial flow zone
and at least radial dispersion zone.
[0073] In the second operation stage of the reclaiming system and
process, PVC is purified by collecting it from the bottom of each
tank and feeding it to a sequence of dispersion mixers and
hydrogravity separation tanks (i.e. recycled). Any remaining domain
thermoplastics such as polyethylene and nylon float to the top and
are removed from each tank.
[0074] With respect to the three thermoplastic components derived
from a copper cable, the PVC component has the highest specific
gravity with nylon having a lower specific gravity and polyethylene
the lowest. Accordingly, the specific gravity of each tank within
the second operation stage is approximately the same and is about
1.15 to about 1.2 which is slightly lighter than the PVC but
heavier than the polyethylene and the nylon. The thermoplastic
particles from the dewaterer 460 are thus fed to dispersion mixer
515 where they pass through different mixing zones separated by an
annulus and are subjected to a dispersion impeller whereby an
agglomerates of any of the three thermoplastic components are
substantially broken into separate and individual thermoplastic
particles. The thermoplastic particles are then fed to quiescent
hydrogravity tank 510 which have walls of non-repose and
non-turbulent flow conditions with adequate residence times such
that the various particles can separate from one another and
subsequently the lighter polyethylene and nylon are collected from
the top of tank 510 and directly fed to the third operation stage.
The polyvinyl chloride particles are collected from the bottom of
first tank 510, fed to second dispersion mixer 525 where they pass
through different mixing zones and are subjected to a dispersion
impeller whereby any agglomerates are substantially broken into
individual thermoplastic particles. The particles are then fed
generally to the middle portion of second hydrogravity tank 520
wherein the separation (recycling) process is repeated. Thus, the
lighter polyethylene and nylon particles float to the top and flow
out of or are skimmed off the top of second tank 520 are then
directly fed to the third operation stage. Any remaining PVC
particles settle out of the bottom of second tank 520 and are fed
to third dispersion mixer 535, and then to third hydrogravity tank
530 for further separation. Once again, in a manner as described
hereinabove, the polyethylene and nylon particles are separated and
collected from the top of tank 530 and fed directly to the third
operation stage. The PVC particles are collected from bottom of
tank 530 and fed to fourth dispersion mixer 545 wherein
agglomerates are severed and broken apart and fed to generally the
middle of fourth hydrogravity separation tank 540. The fourth and
last tank once again permits any remaining polyethylene and nylon
particles to be directly fed to the third operation stage. The PVC
thermoplastic polymers which are collected from the bottom of
fourth separation tank 540 are washed and dried in any conventional
manner as a fluid bed, a screen, or a centrifuge 550, with the
above noted Gala spin dryer being preferred. The PVC component
particles are then bagged, etc. and placed in storage unit 560 for
subsequent reuse and/or sale. The aqueous solution from dryer 550
is then recycled desirably to first hydrogravity tank 510.
[0075] In the third unit operation or stage, the thermoplastic
components of nylon and polyethylene particles from the second unit
operation are fed to first dispersion mixer 615 and then to
hydrogravity separation tank 610. As with the prior two
purification operations, the component which is desired to be
cleaned or purified is recycled to a second dispersion mixer and
tank, then to a third dispersion mixer and tank, and then to a
fourth dispersion mixer and hydrogravity separation tank. Multiple
stages of hydrogravity separation improve product purity. The
remaining thermoplastic polyethylene component can be directly
collected and dried as for reuse and/or resale. Alternatively, the
polyethylene can be subjected to a plurality of a combination of a
mixer and hydrogravity tank (i.e. a fourth stage) to improve the
purity thereof. Once again, with respect to the overall system and
process of the third and/or optional fourth units of operation, the
concepts, principles, structures, and description as set forth
hereinabove with regard to the mixers, the hydrogravity tanks, and
the like are hereby fully incorporated by reference and hence will
not be repeated.
[0076] Thus, by way of quick summary, the feed stream from the end
of the second operation stage is fed to first dispersion mixer 615
wherein any agglomerated particles are substantially broken apart
with the slurry then being fed to first hydrogravity separation
tank 610 wherein the heavier nylon particles settle to the bottom
of the tank and are collected, washed, and directly fed to nylon
dryer 650. The specific gravity of the aqueous solution of all of
the tanks of the third stage operation are all essentially the same
and are all slightly less than the specific gravity of nylon and
hence is approximately 1.0. Thus, as with the first and second
operation stages, if any or a small amount of a thermoplastic
component is contained with the heaviest component or an
agglomerated particle containing more than one domain, it will
float to the top whereupon it is de-agglomerated and fed to a
subsequent tank, and so forth until all of the heaviest component
has been removed therefrom. Accordingly, the particles which float
to the top of first tank 610 are fed to second mixer 625 where
agglomerated particles are broken apart, added to second
hydrogravity separation tank 620 with the nylon collected from the
bottom thereof and fed directly to nylon dryer 650 and the
remaining floating polyethylene particles fed to third mixer 635.
The process is once again repeated purifying the polyethylene
particles by collecting the heavy nylon particles from the bottom
of tank 630 and further breaking any agglomerated floating
particles by feeding them to mixer 645. Finally, any remaining
nylon particles are collected from the bottom of tank 640, washed,
and dried in nylon dryer 650 with the remaining particles which
float being purified polyethylene particles which are washed, and
fed to polyethylene dryer 660. Both nylon dryer 650 and
polyethylene dryer 660, as before, can be any conventional dryer
such as a centrifuge dryer, vibrating screen with a spin dryer such
as a Gala dryer being preferred. The separate dried nylon particles
can be collected in storage unit 670 for subsequent use and/or
sale. The polyethylene particles can also be dried and placed in
storage unit 680 for subsequent use and/or sale. As before, the
collected aqueous solution from dryers 650 and 660 are recycled to
hydrogravity 610 to replenish the aqueous solution thereof.
[0077] With regard to any unit operation concerning separation of
particles and preferably only particles of one feed stock
component, the particles can be collected and stored as shown in
FIG. 1. Alternatively, either before or after storage they can be
fed to a suitable melt mixing device such as an extruder, and
subsequently pelletized for use as such. Melt mixing devices and
various extruders, melt filters, and pelletizers are well known to
the art and to the literature.
[0078] The above described system and process will be better
understood by reference to the following example which serves to
illustrate but not to limit the present invention.
[0079] With respect to reclamation of a copper cable containing
1,000 lbs. by weight of feedstock, and according to the format
generally described hereinabove and shown in FIG. 1, 995 lbs. of
feed stock was obtained from granulator 120 with the remaining 5
lbs. being recovered as fines. Depending upon the amount of wire in
the cable feedstock, the amount of copper recovered from first
operation stage 400 can range from about 10 lbs. to about 150 lbs.
with the purity of the copper being generally at least about 80%,
at least about 90%, or at least about 95% by weight, and preferably
at least about 98% or at least about 99% by weight. The recovery of
the PVC from the second operation stage 500 can range from about
750 to about 975 lbs. with the purity of the PVC being at least
about 85% to at least about 90% or, desirably at least 95% by
weight, and preferably at least about 98% or at least about 99% by
weight of the total weight of the collected PVC stream.
[0080] The amount of the nylon and polyethylene being recovered
from the third operation stage 600 each can independently vary from
about 5 lbs. to about 100 lbs. based upon the total weight of both
components with the purity of each component being at least 85% or
at least about 90% by weight, desirably at least about 95% by
weight, and preferably at least about 98% or at least about 99% by
weight.
[0081] Generally, the system and process of the present invention
readily recovers at least about 95%, desirably at least about 98%,
and preferably at least about 99% by weight of the initial
feedstock.
[0082] If desired, each of the above reclaimed component particles
of copper, PVC, polyethylene, and nylon can be further purified by
other methods known to the art and to the literature if so
desired.
[0083] While the above invention has been described with regard to
a copper cable feed stock, it is understood that generally any type
of solid feed stocks containing separate domains which are not melt
blended, can be utilized including feedstock containing various
metals such as aluminum cable, etc.
[0084] While in accordance with the Patent Statutes, the best mode
and preferred embodiments have been set forth, the scope of the
invention is not limited thereto, but rather by the scope of the
attached claims.
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