U.S. patent application number 12/424863 was filed with the patent office on 2010-10-21 for methods and systems for recovering rhenium from a copper leach.
This patent application is currently assigned to FREEPORT-MCMORAN COPPER & GOLD INC.. Invention is credited to Steve Nels Dixon, Theresa Linne Morelli, Stefka Todorova Ormsby, George Owusu, Brett T. Waterman.
Application Number | 20100263490 12/424863 |
Document ID | / |
Family ID | 42045297 |
Filed Date | 2010-10-21 |
United States Patent
Application |
20100263490 |
Kind Code |
A1 |
Waterman; Brett T. ; et
al. |
October 21, 2010 |
METHODS AND SYSTEMS FOR RECOVERING RHENIUM FROM A COPPER LEACH
Abstract
Various embodiments provide new methods of rhenium recovery. The
methods can include subjecting a metal-bearing solution to an
activated carbon bed, and adsorbing rhenium onto the activated
carbon. The methods can also include heating a basic aqueous
elution solution and eluting the rhenium from the activated carbon
with the heated elution solution.
Inventors: |
Waterman; Brett T.; (Tucson,
AZ) ; Dixon; Steve Nels; (Safford, AZ) ;
Morelli; Theresa Linne; (Safford, AZ) ; Owusu;
George; (Thornton, CO) ; Ormsby; Stefka Todorova;
(Tucson, AZ) |
Correspondence
Address: |
SNELL & WILMER L.L.P. (Main)
400 EAST VAN BUREN, ONE ARIZONA CENTER
PHOENIX
AZ
85004-2202
US
|
Assignee: |
FREEPORT-MCMORAN COPPER & GOLD
INC.
Phoenix
AZ
|
Family ID: |
42045297 |
Appl. No.: |
12/424863 |
Filed: |
April 16, 2009 |
Current U.S.
Class: |
75/743 ; 204/242;
266/195; 75/711 |
Current CPC
Class: |
C22B 15/0086 20130101;
Y02P 10/236 20151101; C22B 15/0089 20130101; C01G 47/00 20130101;
C22B 3/24 20130101; Y02P 10/234 20151101; C25C 1/12 20130101; Y02P
10/20 20151101; C22B 61/00 20130101; C22B 5/00 20130101 |
Class at
Publication: |
75/743 ; 75/711;
266/195; 204/242 |
International
Class: |
C22B 61/00 20060101
C22B061/00; C25C 7/00 20060101 C25C007/00 |
Claims
1. A method for recovering rhenium, the method comprising: feeding
a metal-bearing leach solution comprising rhenium over activated
carbon; adsorbing said rhenium onto said activated carbon; heating
a basic aqueous solution to a temperature greater than 80.degree.
C.; and eluting said rhenium from said activated carbon with said
basic aqueous solution.
2. The method according to claim 1 further comprising removing a
rhenium lean metal-bearing leach solution from said activated
carbon.
3. The method according to claim 2 further comprising recovering at
least one metal value from said rhenium lean metal-bearing leach
solution.
4. The method according to claim 3, wherein said at least one metal
value is at least copper.
5. The method according to claim 1 further comprising recovering
rhenium metal.
6. The method according to claim 1 further comprising leaching a
metal-bearing material to yield said metal-bearing leach
solution.
7. The method according to claim 1, wherein said basic aqueous
solution comprises at least one of sodium hydroxide, ammonium
hydroxide, lithium hydroxide, and potassium hydroxide.
8. The method according to claim 1, wherein said basic aqueous
solution comprises sodium hydroxide in an amount from about 0.5% to
about 2.5%.
9. The method according to claim 1, wherein said basic aqueous
solution comprises ammonium hydroxide in an amount from about 0.5%
to about 3%.
10. The method according to claim 1, wherein heating a basic
aqueous solution to a temperature greater than 80.degree. C. is to
a temperature from about 100.degree. C. to about 115.degree. C.
11. The method according to claim 1, wherein heating a basic
aqueous solution to a temperature greater than 80.degree. C. is to
a temperature from about 108.degree. C. to about 110.degree. C.
12. A system for the recovery of rhenium from a metal-bearing leach
solution, the system comprising: a metal-bearing leach solution
feedstream; at least one bed of activated carbon in communication
with said metal-bearing leach solution feedstream; an elutate
feedstream in communication with said at least one bed of activated
carbon; a heater element coupled to said eluate feedstream; and at
least one exit port in communication with said at least one bed of
activated carbon, said at least one exit port distal to said
metal-bearing leach solution feedstream and said eluate
feedstream.
13. The system according to claim 12 wherein said at least one exit
port is at least one metal-bearing leach solution exit port and at
least one eluate exit port.
14. The system according to claim 13 further comprising a metal
recovery apparatus in communication with said at least one
metal-bearing leach solution exit port.
15. The system according to claim 14 wherein said metal-bearing
recovery apparatus is an electrowinning circuit.
16. The system according to claim 12 further comprising a rhenium
recovery apparatus in communication with said eluate exit port.
17. The system according to claim 16 wherein said rhenium recovery
apparatus is at least one of a solvent extraction apparatus, an ion
exchange apparatus, and a crystallization apparatus.
18. The system according to claim 12 further comprising a leaching
apparatus coupled to said metal-bearing leach solution feedstream
and operably producing a metal-bearing leach solution.
19. A method for recovering two metal values, the method
comprising: leaching a material comprising two metal values to
produce a leach solution comprising two metal values; subjecting
said leach solution to activated carbon; adsorbing a first metal
value on said activated carbon; removing a solution comprising a
second metal value from said activated carbon; heating an elutate
solution; eluting said first metal value with said elutate
solution; recovering said first metal value; and recovering said
second metal value.
20. The method according to claim 19 wherein said two metal values
are copper and rhenium.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the recovery of
rhenium and relates more specifically to the recovery of rhenium
from a copper leach.
BACKGROUND
[0002] Rhenium was the last naturally occurring element to be
discovered and the last element discovered having a stable isotope.
Rhenium is typically recovered as a byproduct of molybdenum
refinement. Since recovery of rhenium from molybdenite is difficult
and the concentrations of rhenium in molybdenite are very low,
typically from about 0.002% to about 0.02%, rhenium is one of the
most expensive metals available in commodity markets. Rhenium has
several characteristics that make it unique, such as, for example,
the second highest melting point amongst metals, amongst the
densest metals, a super conductor, and the greatest number of
oxidation states of any element. Industrial applications include
the use of rhenium in catalysts, electronics, thermocouples, high
temperature turbine blades, and photoflash devices.
[0003] Rhenium may be extracted from ores that contain copper and
molybdenum. Common practice for leaching copper from low-grade
copper ore is to place the ore in a heap leach pad and leach the
ore with dilute sulfuric acid solution. The resulting
copper-bearing solution is typically concentrated via solvent
extraction and/or electrowon to produce pure copper cathode.
Typically, the copper-bearing solution has less than one part per
million of dissolved rhenium and may contain significant amounts of
other metals in the copper-bearing solution. Recovery of rhenium
from the copper-bearing solution is not economically feasible and
hence rhenium is, along with other metal values, typically not
recovered from the copper-bearing solution before the
electrowinning stage.
[0004] Generally, rhenium is recovered as a result of the
molybdenite roasting to produce molybdenum. The acid blow-down from
the molybdenite roasting off-gas contains concentrations of rhenium
which are much higher than the concentrations of rhenium in the
copper-bearing solution. In addition, the acid blow-down stream
does not contain the metal values such as copper or molybdenum
since they have already been recovered upstream, and this allows
rhenium to be recovered from the acid blow-down stream by ion
exchange, solvent extraction and/or crystallization.
[0005] Since the demand for rhenium continues to increase on a
year-by-year basis, new methods for rhenium recovery from sources
other than molybdenum roasting processes are needed.
SUMMARY
[0006] In accordance with various embodiments, the present
invention provides new methods of rhenium recovery. The methods can
include subjecting a copper-bearing solution to an activated carbon
bed, and adsorbing rhenium onto the activated carbon. The methods
can also include heating a basic aqueous elution solution and
eluting the rhenium from the activated carbon with the heated
elution solution.
[0007] In addition, various embodiments of the present invention
provide systems for the recovery of rhenium from copper leach heap.
Systems can include an effluent entry in communication with at
least one activated carbon bed and an effluent exit in
communication with the activated carbon bed and distal to the
effluent entry. In such systems, effluent entry can feed a
copper-bearing solution comprising a rhenium metal value through
the activated carbon bed while the effluent exit allows the
remainder of the copper-bearing solution to exit the activated
carbon bed after allowing the rhenium to adsorb onto the activated
carbon. In an exemplary embodiment of the present invention, the at
least one activated carbon bed can be a plurality of activated
carbon beds connected to each other in series. Various embodiments
of the systems can include an elution stream controllably in
communication with the at least one bed of activated carbon. In an
exemplary embodiment, the systems can include an eluate port
controllably in communication with the bed of activated carbon and
the eluate exit can be operable to remove a rhenium stream.
[0008] Further areas of applicability will become apparent from the
description provided herein. It should be understood that the
description and the specific examples are intended for purposes of
illustration only, and are not intended to limit the scope of the
present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The drawings described herein are for illustration purposes
only and are not intended to limit the scope of the present
disclosure in any way. The present invention will become more fully
understood from the detailed description and the accompanying
drawings wherein:
[0010] FIG. 1 is a block diagram illustrating a rhenium recovery
process, according to various embodiments of the present
invention;
[0011] FIG. 2 is a block diagram illustrating a rhenium recovery
system, according to various embodiments of the present
invention;
[0012] FIG. 3 is a block diagram illustrating a first exemplary
process for recovering rhenium and a second metal value from a
metal-bearing material, according to various embodiments of the
present invention;
[0013] FIG. 4 is a block diagram illustrating a second exemplary
process for recovering rhenium and a second metal value from a
metal-bearing material, according to various embodiments of the
present invention;
[0014] FIG. 5 is a block diagram illustrating a third exemplary
process for recovering rhenium and a second metal value from a
metal-bearing material, according to various embodiments of the
present invention;
[0015] FIG. 6 is a block diagram illustrating a method for
recovering rhenium according to various embodiments of the present
invention; and
[0016] FIG. 7 is a flow diagram further illustrating a plant scale
process for recovering rhenium, according to various embodiments of
the present invention.
DETAILED DESCRIPTION
[0017] The following description is merely exemplary in nature, and
is not intended to limit the present invention, its applications,
or its uses. It should be understood that throughout the drawings,
corresponding reference numerals indicate like or corresponding
parts and/or features. The descriptions' specific examples
indicated in various embodiments of the present invention are
intended for purposes of illustration only and are not intended to
limit the scope of the invention disclosed herein. Moreover,
recitation of multiple embodiments having stated features is not
intended to exclude other embodiments having additional features or
other embodiments incorporating different combinations of the
stated features.
[0018] Various embodiments of the present invention are an
improvement to the recovery of rhenium from ore bodies comprising
copper and molybdenum. In various embodiments, rhenium can be
recovered from a copper-bearing stream produced from copper
leaching. Since the world demand for rhenium continues to increase,
improvements are needed to recover rhenium from new sources. Since
copper leach solutions can comprise dissolved rhenium, the present
invention provides methods and systems for the recovery of rhenium
from such solutions.
[0019] With reference to FIG. 1, rhenium recovery process 10 is
illustrated according to various embodiments of the present
invention. Rhenium recovery process 10 can comprise metal-bearing
stream 22, stationary phase 23, elution solution 25, and remainder
solution 24. Metal-bearing stream 22 can comprise one or more metal
values. In an exemplary embodiment, metal-bearing stream 22
comprises rhenium. In various embodiments, metal-bearing stream 22
can be a product resulting from a metal leaching process, such as,
for example, a pregnant leach solution. Generally, metal-bearing
stream 22 can be acidic, and may comprise sulfuric acid. In some
aspects of the present invention, metal-bearing stream 22 can be a
product of a solvent extraction process following a metal leaching
process, such as, for example, a raffinate solution. In other
aspect the metal-bearing stream 22 can be the product of leaching
prior to solvent extraction, such as, for example, a pregnant leach
solution. In other aspects of the present invention, metal-bearing
solution can be a solution exiting from an electrowinning
apparatus, such as, for example, lean electrolyte.
[0020] In various embodiments, stationary phase 23 can be any
material, which can operably adsorb rhenium. In general, any porous
material exhibiting adsorption properties due to high surface area
is suitable. In an exemplary embodiment, stationary phase 23 can
comprise carbon, such as, for example, activated carbon, activated
charcoal, and/or activated coal. Another example of carbon useful
for stationary phase 23 includes a coconut shell activated carbon
having a U.S. sieve mesh size of 6.times.12. Any type or size of
activated carbon, such as powder, particle, or granular sizes may
be used in the present invention. The size of the activated carbon,
typically measured in mesh size, can be determined by such factors
as metal-bearing stream flow rate, activated carbon bed volume,
adsorption capacity, and the like.
[0021] In various embodiments, stationary phase 23 can be static or
fluidized. In an aspect of the invention, stationary phase 23 can
be fluidized in the flow of metal-bearing stream 22. The fluidized
stationary phase 23 can be collected in a down stream process, such
as, for example, use of a screen or a sieve. The collected
stationary phase 23 can then be subjected to elution solution 25
for recovery of metal value 28. In another aspect of the invention,
stationary phase 23 can be static in a column with a mobile phase,
such as metal-bearing stream 22, passing over stationary phase 23
and adsorbing metal value 28 onto stationary phase 23. Stationary
phase 23 containing adsorbed metal value 28 can be subjected to
elution solution 25 for recovery of metal value 28.
[0022] In various embodiments, remainder solution 24 can comprise
metal-bearing stream 22 less material adsorbed on stationary phase
23. In an exemplary embodiment, remainder solution 24 comprises at
least 80% less rhenium than metal-bearing stream 22, and preferably
at least 90% less rhenium, and more preferably at least 95% less
rhenium. In an aspect of the present invention, remainder solution
24 can be further processed to recover at least one metal value. In
an exemplary embodiment, the at least one metal value is at least
one of copper and molybdenum. In another aspect of the present
invention, remainder solution 24 can be cycled for its acid content
to any other process in a metal recovery system, such as, for
example, a leaching process, a conditioning process, and/or a
solvent extraction process.
[0023] In various embodiments, elution solution 25 can comprise any
eluate, which can extract metal value 28 off of stationary phase
23. In general, elution solution 25 can be an aqueous solution
having a pH greater than about 7. In an exemplary embodiment,
elution solution 25 can comprise a hydroxide salt in an aqueous
solution. For example, a hydroxide salt can be at least one of
sodium hydroxide, ammonium hydroxide, lithium hydroxide, and
potassium hydroxide. In an exemplary embodiment, elution solution
25 can be an aqueous solution comprising sodium hydroxide in an
amount from about 0.1% to about 10% or preferably an amount from
about 0.2% to about 5%, or more preferably an amount from about
0.5% to about 2.5%. In another exemplary embodiment, elution
solution 25 can be an aqueous solution comprising ammonium
hydroxide in an amount from about 0.1% to about 10% or preferably
an amount from about 0.2% to about 5%, or more preferably an amount
from about 0.5% to about 2.5%.
[0024] With continued reference to FIG. 1, in various embodiments,
elution solution 25 can be heated to a temperature greater than or
equal to 80.degree. C. In an exemplary embodiment, elution solution
25 can be heated to a temperature from about 80.degree. C. to about
130.degree. C., and preferably to a temperature from about
90.degree. C. to about 120.degree. C., and more preferably to a
temperature from about 105.degree. C. to about 115.degree. C., and
even more preferably to a temperature from about 108.degree. C. to
about 110.degree. C. In an aspect of the invention, as the
temperature of elution solution 25 is increased, the amount of the
hydroxide salt in the aqueous solution can be decreased. As the
temperature of elution solution 25 is increased, the elution
efficiency increases. In addition, as the temperature of elution
solution 25 is increased, the costs of elution solution 25
decrease.
[0025] In various embodiments, a method for recovering rhenium can
comprise passing metal-bearing stream 22 through stationary phase
23 and adsorbing a metal value on stationary phase 23. The method
can comprise removing remainder solution 24 from stationary phase
23. The method can further comprise recovering a second metal value
from remainder solution 24. The method can comprise stopping the
metal-bearing stream 22 and eluting metal value 28 from stationary
phase 23. The method can further comprise heating elution solution
25 then eluting metal value 28 from stationary phase 23. In an
exemplary embodiment, metal value 28 is rhenium.
[0026] Now referring to FIG. 2, rhenium recovery system 20 is
illustrated according to various embodiments of the present
invention. Metal-bearing material 212 may be an ore, a concentrate,
or any other material from which metal values may be recovered.
Metal values such as, for example, copper, gold, silver, zinc,
platinum group metals, nickel, cobalt, molybdenum, rhenium,
uranium, rare earth metals, and the like may be recovered from
metal-bearing material 212 in accordance with various embodiments
of the present invention. Various aspects and embodiments of the
present invention, however, prove especially advantageous in
connection with the recovery of copper from copper sulfide
concentrates and/or ores, such as, for example, chalcopyrite
(CuFeS.sub.2), chalcocite (Cu.sub.2S), bornite (Cu.sub.5FeS.sub.4),
covellite (CuS), enargite (Cu.sub.3AsS.sub.4), digenite
(Cu.sub.9S.sub.5), and/or mixtures thereof. Thus, in various
embodiments, metal-bearing material 212 is a copper ore or
concentrate, and in an exemplary embodiment, metal-bearing material
212 is a copper sulfide ore or concentrate.
[0027] In various embodiments, processed metal-bearing material 213
may comprise metal-bearing material 212 prepared for metal recovery
process 20 in any manner that enables the conditions of processed
metal-bearing material 213 to be suitable for a chosen processing
method, as such conditions may affect the overall effectiveness and
efficiency of processing operations. Desired composition and
component concentration parameters may be achieved through a
variety of chemical and/or physical processing stages, the choice
of which will depend upon the operating parameters of the chosen
processing scheme, equipment cost and material specifications. For
example, metal-bearing material 212 may undergo comminution,
flotation, blending, and/or slurry formation, as well as chemical
and/or physical conditioning to produce processed metal-bearing
material 213. In an exemplary embodiment, processed metal-bearing
material 213 is a concentrate.
[0028] With continued reference to FIG. 2, after metal-bearing
material 212 has been suitably prepared, processed metal-bearing
material 213 is subjected to reactive processing 214 to put a metal
value or metal values in processed metal-bearing material 213 in a
condition for later metal recovery steps, namely metal recovery
218. For example, exemplary suitable processes include reactive
processes that tend to liberate the desired metal value or metal
values from the metal-bearing material 212. In accordance with an
exemplary embodiment of the present invention, reactive processing
214 may comprise leaching. Leaching can be any method, process, or
system that enables a metal value to be leached from processed
metal-bearing material 213. Typically, leaching utilizes acid to
leach a metal value from processed metal-bearing material 213. For
example, leaching can employ a leaching apparatus, such as, for
example, a heap leach, a vat leach, a tank leach, a pad leach, a
leach vessel or any other leaching technology useful for leaching a
metal value from processed metal-bearing material 213.
[0029] In accordance with various embodiments, leaching may be
conducted at any suitable pressure, temperature, and/or oxygen
content. Leaching can employ one of a high temperature, a medium
temperature, or a low temperature, combined with one of high
pressure, or atmospheric pressure. Leaching may utilize
conventional atmospheric or pressure leaching, for example, but not
limited to, low, medium or high temperature pressure leaching. As
used herein, the term "pressure leaching" refers to a metal
recovery process in which material is contacted with an acidic
solution and oxygen under conditions of elevated temperature and
pressure. Medium or high temperature pressure leaching processes
for chalcopyrite are generally thought of as those processes
operating at temperatures from about 120.degree. C. to about
190.degree. C. or up to about 250.degree. C. In accordance with
various embodiments of the present invention, reactive processing
214 may comprise any type of reactive process to put a metal value
or values in processed metal-bearing material 213 in a condition to
be subjected to later metal recovery steps.
[0030] In various embodiments, reactive processing 214 provides a
metal-bearing slurry 215 for conditioning 216. In various
embodiments, conditioning 216 can be, for example, but is not
limited to, a solid liquid phase separation step, an additional
leach step, a pH adjustment step, a dilution step, a concentration
step, a metal precipitation step, a filtering step, a settling
step, and the like, as well as combinations thereof. In an
exemplary embodiment, conditioning 216 can be a solid liquid phase
separation step configured to yield a metal-bearing solution 217
and a metal-bearing solid.
[0031] In other various embodiments, conditioning 216 may be one or
more leaching steps. For example, conditioning 216 may be any
method, process, or system that further prepares metal-bearing
material 212 for recovery. In various embodiments, conditioning 216
utilizes acid to leach a metal value from a metal-bearing material.
For example, conditioning 216 may employ a leaching apparatus such
as, for example, a heap leach, a vat leach, a tank leach, a pad
leach, a leach vessel or any other leaching technology useful for
leaching a metal value from a metal-bearing material.
[0032] In accordance with various embodiments, conditioning 216 may
be a leach process conducted at any suitable pressure, temperature,
and/or oxygen content. In such embodiments, conditioning 216 may
employ one of a high temperature, a medium temperature, or a low
temperature, combined with one of high pressure, or atmospheric
pressure. Conditioning 216 may utilize conventional atmospheric or
pressure leaching, for example, but not limited to, low, medium or
high temperature pressure leaching. Medium or high temperature
pressure leaching processes for chalcopyrite are generally thought
of as those processes operating at temperatures from about
120.degree. to about 190.degree. C. or up to about 250.degree.
C.
[0033] In various embodiments, conditioning 216 may comprise
dilution, settling, filtration, solution/solvent extraction, ion
exchange, pH adjustment, chemical adjustment, purification,
concentration, screening, and size separation. In various
embodiments, conditioning 216 is a high temperature, high pressure
leach. In other embodiments, conditioning 216 is an atmospheric
leach. In further embodiments, conditioning 216 is a solid liquid
phase separation. In still further embodiments, conditioning 216 is
a settling/filtration step. In various embodiments, conditioning
216 produces metal-bearing solution 217.
[0034] With further reference to FIG. 2, in various embodiments,
metal-bearing solution 217 may be passed through stationary phase
23. As described above, metal value 28 can be adsorbed onto
stationary phase 23. A remainder solution 24 can be removed from
stationary phase 23. Metal value 28 can be eluted off stationary
phase 23 with elution solution 25. Elution solution 25 can be
heated as described herein. In a preferable embodiment, metal value
28 is rhenium.
[0035] In an exemplary embodiment, stationary phase 23 can be
combined with metal-bearing solution 217 to create a slurry. In
this exemplary embodiment, stationary phase 23 is fluidized in the
slurry. A course carbon powder can be advantageous for use as
stationary phase 23. Metal value 28 can be adsorbed on to
stationary phase 23. Fluidized stationary phase 23 can be collected
by use of a screen or a sieve. Metal value 28 can be eluted off
stationary phase 23 with elution solution 25 as described
herein.
[0036] In various embodiments, remainder solution 24 may be
subjected to metal recovery 218 to yield metal value 220. In
exemplary embodiments, metal recovery 218 can comprise
electrowinning remainder solution 24 to yield recovered metal value
220 as a cathode. In one exemplary embodiment, metal recovery 218
may be configured to employ conventional electrowinning processes
and include a solvent extraction step, an ion exchange step, an ion
selective membrane, a solution recirculation step, and/or a
concentration step. In one preferred embodiment, metal recovery 218
may be configured to subject remainder solution 24 to a solvent
extraction step to yield a rich electrolyte solution, which may be
subject to an electrowinning circuit to recover a desired metal
value 220. In another exemplary embodiment, metal recovery 218 may
be configured to employ direct electrowinning processes without the
use of a solvent extraction step, an ion exchange step, an ion
selective membrane, a solution recirculation step, and/or a
concentration step. In another preferred embodiment, metal recovery
218 may be configured to feed remainder solution 24 directly into
an electrowinning circuit to recover a desired metal value 220. In
an especially preferred embodiment, metal value 220 is copper.
[0037] Turning to FIG. 3, a first exemplary process 30 for
recovering rhenium and a second metal value from a metal-bearing
material 212 is illustrated according to various embodiments of the
present invention. After metal-bearing material 212 has been
suitably prepared, processed metal-bearing material 213 is
subjected to reactive processing 214 to put a metal value or metal
values in processed metal-bearing material 213 in a condition for
later metal recovery steps, namely first metal recovery 225 and
second metal recovery 218. In accordance with an exemplary
embodiment of the present invention, reactive processing 214
comprises a leaching process.
[0038] In various embodiments, reactive processing 214 provides
metal-bearing slurry 215 for conditioning 216. In an exemplary
embodiment, conditioning 216 can be a solid liquid phase separation
step configured to yield metal-bearing solution 217 and a
metal-bearing solid. In various embodiments, metal-bearing solution
217 is subjected to first metal recovery 225 to recover first metal
value 28. First metal recovery 225 comprises valve 222 in
communication with conditioning 216, and first stationary phase 23A
and second stationary phase 23B connected in parallel with valve
222. Valve 222 can control flow of metal-bearing solution 217 to
either first stationary phase 23A or second stationary phase 23B.
In various embodiments, metal-bearing solution 217 passes through a
first stationary phase 23A until first stationary phase 23A is
loaded with metal value 28 to near capacity. Then valve 222
switches the flow of metal-bearing solution 217 to pass through
second stationary phase 23B. After valve 222 switches, elution
solution 25A can be passed through stationary phase 23A to elute
metal value 28. When second stationary phase 23B is loaded with
metal value 28 to near capacity, valve 222 switches flow of
metal-bearing solution 217 back to stationary phase 23A. After
valve 222 switches the second time, elution solution 25B can be
passed through stationary phase 23B to elute metal value 28.
[0039] In various embodiments, remainder solution 24 may be
subjected to metal recovery 218 to yield metal value 220. In
exemplary embodiments, metal recovery 218 can comprise
electrowinning remainder solution 24 to yield recovered metal value
220 as a cathode. In a preferred embodiment, metal recovery 218 may
be configured to feed remainder solution 24 directly into an
electrowinning circuit to recover a desired metal value 220. In an
especially preferred embodiment, metal value 220 is copper.
[0040] Moving to FIG. 4, a second exemplary process 40 for
recovering rhenium and a second metal value from a metal-bearing
material 212 is illustrated according to various embodiments of the
present invention. After metal-bearing material 212 has been
suitably prepared, processed metal-bearing material 213 is
subjected to reactive processing 214 to put a metal value or metal
values in processed metal-bearing material 213 in a condition for
later metal recovery steps, namely first metal recovery 225 and
second metal recovery 218. In accordance with an exemplary
embodiment of the present invention, reactive processing 214
comprises a leaching process.
[0041] In various embodiments, reactive processing 214 provides
metal-bearing slurry 215 for conditioning 216. In an exemplary
embodiment, conditioning 216 can be a solid liquid phase separation
step configured to yield metal-bearing solution 217 and a
metal-bearing solid. In various embodiments, metal-bearing solution
217 is subjected to first metal recovery 225 to recover first metal
value 28. First metal recovery 225 comprises valve 222 in
communication with conditioning 216, and first stationary phase 23A
and second stationary phase 23B connected in parallel with valve
222. Valve 222 can control flow of metal-bearing solution 217 to
either first stationary phase 23A or second stationary phase 23B.
In various embodiments, metal-bearing solution 217 passes through a
first stationary phase 23A until first stationary phase 23A is
loaded with metal value 28 to near capacity. Then valve 222
switches the flow of metal-bearing solution 217 to pass through
second stationary phase 23B. After valve 222 switches, elution
solution 25A can be passed through stationary phase 23A to elute
metal value 28. When second stationary phase 23B is loaded with
metal value 28 to near capacity, valve 222 switches flow of
metal-bearing solution 217 back to stationary phase 23A. After the
valve 222 switches the second time, elution solution 25B can be
passed through stationary phase 23B to elute metal value 28.
[0042] In various embodiments, remainder solution 24 can be
subjected to solvent extraction 230. In accordance with various
aspects of this embodiment of the present invention, solvent
extraction 230 can be configured to selectively extract a metal
value, such as, for example copper. During solvent extraction 230,
a metal value, such as, for example copper, from metal-bearing
solution may be loaded selectively onto an organic chelating agent,
for example, an aldoxime/ketoxime blend, resulting in a metal value
containing organic stream and a raffinate solution. In various
embodiments, the metal value containing organic stream may comprise
a copper compound. Solvent extraction 230 can be configured to
select for a metal value, such as copper by the selection of an
appropriate mixture of ketoximes and/or aldoximes. Solvent
extraction 230 can produce a raffinate solution and a rich
electrolyte 32. In various embodiments, solvent extraction 230 can
yield a rich electrolyte 32 comprising a metal value.
[0043] Raffinate from solvent extraction 230 advantageously may be
used in a number of ways. For example, all or a portion of
raffinate may be recycled to reactive processing 214, such as, for
example to aid with temperature control or solution balancing, or
it may be used in other leaching operations, or it may be used for
any combination thereof. The use of raffinate in reactive
processing 214 may be beneficial because the acid values contained
in raffinate may act to optimize the potential for leaching oxide
and/or sulfide ores that commonly dominate heap leaching
operations. It should be appreciated that the properties of
raffinate, such as component concentrations, may be adjusted in
accordance with the desired use of raffinate.
[0044] In various embodiments, rich electrolyte 32 may be subjected
to metal recovery 218 to yield metal value 220. In exemplary
embodiments, metal recovery 218 can comprise electrowinning rich
electrolyte 32 to yield recovered metal value 220 as a cathode. In
a preferred embodiment, metal recovery 218 may be configured to
feed rich electrolyte 32 directly into an electrowinning circuit to
recover a desired metal value 220. In an especially preferred
embodiment, metal value 220 is copper.
[0045] With reference to FIG. 5, a third exemplary process 50 for
recovering rhenium and a second metal value from a metal-bearing
material 212 is illustrated according to various embodiments of the
present invention. After metal-bearing material 212 has been
suitably prepared, processed metal-bearing material 213 is
subjected to reactive processing 214 to put a metal value or metal
values in processed metal-bearing material 213 in a condition for
later metal recovery 218. In accordance with an exemplary
embodiment of the present invention, reactive processing 214
comprises a leaching process. In various embodiments, reactive
processing 214 provides metal-bearing slurry 215 for conditioning
216.
[0046] With further reference to FIG. 5, in various embodiments,
metal-raffinate 36 may be passed through stationary phase 23. As
described above, metal value 28 can be adsorbed onto stationary
phase 23. A remainder solution 24 can be removed from stationary
phase 23. Metal value 28 can be eluted off stationary phase 23 with
elution solution 25. Elution solution 25 can be heated as described
above. In a preferable embodiment, metal value 28 is rhenium.
[0047] With reference to FIG. 6, an exemplary method 60 for
recovery of rhenium is illustrated according to various embodiments
of the present invention. A column comprising a stationary phase,
such as activated carbon 302, can be placed in communication with a
rhenium-rich pregnant leach solution 304 ("Re-rich PLS 304"). In an
exemplary embodiment, Re-rich PLS 304 can comprise rhenium and
copper. Re-rich PLS 304 can originate from an active copper leach
or a stockpile copper leach, for example, residing in a pond or a
pit. In an exemplary embodiment, Re-rich PLS 304 can be an acid
blow-down stream or leach of molybdenite roaster flue fumes and
dusts. In another exemplary embodiment, Re-rich PLS 304 can be a
raffinate stream. One skilled in the art will appreciate that any
solution comprising rhenium, in any concentration, is suitable for
use herewith, For example, solutions containing more or less than 1
mg/L rhenium, even in the presence of iron, copper, molybdenum,
vanadium and other metals, are suitable for use herewith. One
skilled in the art will further appreciate that flow through a
plurality of columns, in series, in parallel, or in any other
arrangement, is within the scope of this disclosure.
[0048] Rhenium can be adsorbed 306 onto activated carbon 302 of the
column and a rhenium-lean pregnant leach solution 308 can exit from
the column. The rhenium-loaded column 310 can be placed in
communication with elution solution 312. Elution solution 312 can
be heated 314 to a temperature. In various embodiments, elution
solution 312 can comprise any eluate, which can extract rhenium off
of the loaded column 310. In general, elution solution 312 can be
an aqueous solution having a pH greater than about 7.
[0049] In an exemplary embodiment, elution solution 312 can
comprise a hydroxide salt in an aqueous solution. For example, a
hydroxide salt can be at least one of sodium hydroxide, ammonium
hydroxide, lithium hydroxide, and potassium hydroxide. In an
exemplary embodiment, elution solution 312 can be an aqueous
solution comprising sodium hydroxide in an amount from about 0.1%
to about 10% or preferably an amount from about 0.2% to about 5%,
or more preferably an amount from about 0.5% to about 2.5%. In
another exemplary embodiment, elution solution 312 can be an
aqueous solution comprising ammonium hydroxide in an amount from
about 0.1% to about 10% or preferably an amount from about 0.2% to
about 5%, or more preferably an amount from about 0.5% to about
2.5%.
[0050] In various embodiments, elution solution 312 can be heated
314 to a temperature greater than or equal to 80.degree. C. In an
exemplary embodiment, elution solution 312 can be heated 314 to a
temperature from about 80.degree. C. to about 130.degree. C., and
preferably to a temperature from about 90.degree. C. to about
120.degree. C., and more preferably to a temperature from about
105.degree. C. to about 115.degree. C., and even more preferably to
a temperature from about 108.degree. C. to about 110.degree. C. In
an aspect of the invention, as the temperature of elution solution
312 is increased 314, the amount of the hydroxide salt in the
aqueous solution can be decreased. As the temperature of elution
solution 312 is increased 314, the elution efficiency increases. In
addition, as the temperature of elution solution 312 is increased
314, the costs of the elution solution 312 decrease.
[0051] In various embodiments, rhenium can be eluted 316 from
rhenium-loaded column 310 to produce Re-rich aqueous eluate 318.
Optionally, the stationary phase of the column can be regenerated
320 and recycled as activated carbon 302. Optionally, Re-rich
eluate 318 can be subjected to a rhenium recovery 322 to produce
pure rhenium 326 and Re-lean aqueous eluate 324. Optionally Re-lean
eluate 324 can be recycled 328 to elution solution 312.
[0052] Finally turning to FIG. 7, plant scale process 70 for
recovering rhenium is illustrated according to various embodiments
of the present invention. According to plant scale process 70,
rhenium rich PLS 704 flows into a first adsorption column 728
containing first partially loaded carbon 730 from second adsorption
column 732. Any suitable adsorption column may be used with the
present invention, for example, a twelve-foot diameter by
twelve-foot high adsorption column.
[0053] First partially adsorbed rhenium PLS 734 flows from first
adsorption column 728 into second adsorption column 732 containing
second partially loaded carbon 736 from third adsorption column
738. The amount of rhenium adsorbed onto second partially loaded
carbon 736 can be less than that adsorbed onto first partially
loaded carbon 730.
[0054] Second partially adsorbed rhenium PLS 740 flows from second
adsorption column 732 into third adsorption column 738 containing a
third partially loaded carbon 742 from a fourth adsorption column
744. The amount of rhenium adsorbed onto third partially loaded
carbon 742 is less than that adsorbed onto second partially loaded
carbon 736.
[0055] Third partially adsorbed rhenium PLS 746 flows from third
adsorption column 738 into fourth adsorption column 744 containing
fourth partially loaded carbon 748 from fifth adsorption column
750. The amount of rhenium adsorbed onto fourth partially loaded
carbon 748 is less than that adsorbed onto third partially loaded
carbon 742.
[0056] Fourth partially adsorbed rhenium PLS 752 flows from fourth
adsorption column 744 into fifth adsorption column 750 containing
stripped activated carbon 702. Rhenium lean PLS 708 flows away, for
example, for other metal recovery. Loaded activated carbon 710 from
first adsorption column 728 flows to an elution vessel 754. Any
suitable elution vessel may be used with the present invention, for
example, one or a plurality of 2600 gallon elution vessels. One
skilled in the art will appreciate that flow through any number of
columns, in series, in parallel, or in any other arrangement, is
within the scope of this disclosure.
[0057] Water 756 and eluate 758 are mixed in mix tank 760 to yield
an elution solution 712. In an exemplary embodiment, elution
solution 712 comprises one or more of sodium hydroxide, ammonium
hydroxide, lithium hydroxide, and potassium hydroxide. Boiler 762
heats water 764 recycled through a plate heat exchanger 766. One or
a plurality of heat exchanges can be used. Plate heat exchanger 766
in turn heats elution solution 712 to yield heated elution solution
768, which flows to elution vessel 754. In an exemplary embodiment,
the temperature of elution solution 712 is increased, for example,
to about 100.degree. C. to about 140.degree. C., or to about
100.degree. C. to about 120.degree. C., or to about 100.degree.
C.-110.degree. C.
[0058] Spent carbon 770 flows from elution vessel 754 to carbon
pre-treatment tank 772. New carbon 774 is washed with water 776 in
wash tank 778 to yield washed carbon 780, which also flows to
carbon pre-treatment tank 772. Wash 782 with reject fine carbon
flows to a carbon super sack 784. Carbon super sack 784 can be
drained of excess water 786. Carbon in carbon pre-treatment tank
772 flows through carbon rotary kiln 773 for re-activation of
carbon via pumps 775 and 777. In an exemplary embodiment, carbon
rotary kiln 773 is rated at 200 lb/hour. Stripped activated carbon
702 then flows into fifth adsorption column 750 via pump 779.
[0059] A rhenium eluate 781 flows from elution vessel 754, via pump
783, to eluate tank 785, where it is mixed with aqueous solution
788. Any suitable eluate tank may be used with the present
invention, for example, one or a plurality of 15000 gallon eluate
tanks. In an exemplary embodiment, aqueous solution 788 is sulfuric
acid. A resulting rhenium rich aqueous eluate 718 flows to a
solvent extraction (SX) process tank 790. Any suitable SX process
tank 790 may be used with the present invention, for example, one
or a plurality of 1000 gallon SX process tanks.
[0060] Rich organic 792 flows to a solvent extraction stripper 794,
where it is stripped with a striping solution 796. In an exemplary
embodiment, solvent extraction stripper 794 is rated at 20
gal/minute. In an exemplary embodiment, stripping solution 796 is
sodium hydroxide. Lean organic 798 returns to SX process tank 790.
A resulting rhenium lean aqueous eluate 724 flows to a raffinate
pond or is recycled and reused. Concentrated rhenium 726 is
available for storage and use.
EXAMPLE 1
[0061] A stationary phase comprising activated carbon was loaded
with rhenium. Three aqueous elution solutions comprised ammonium
hydroxide in varying concentrations can be prepared (see Table 1).
Ammonium hydroxide was formed by adding ammonia to water. Each
elution solution was heated to a temperature of about 108.degree.
C. to about 110.degree. C. and passed through the stationary phase
at a rate of about 1.5 bed volumes per hour to about 2.0 bed
volumes per hour. The complete elution cycle was about 4 bed
volumes to about 6 bed volumes. Rhenium can be recovered through
the elution and results are shown in Table 1.
TABLE-US-00001 TABLE 1 Rhenium Yields at varying Concentrations of
Ammonia Eluate Conc. % Re Yield, % NH.sub.3 0.5 95.2 NH.sub.3 1.0
95.9 NH.sub.3 2.5 96.1
EXAMPLE 2
[0062] A stationary phase comprising activated carbon was loaded
with rhenium. Eight aqueous elution solutions comprised ammonium
hydroxide in varying concentrations can be prepared (see Table 2).
Ammonium hydroxide was formed by adding ammonia to water. Each
elution solution was heated to a temperature (see Table 2) and
passed through the stationary phase at a rate of about 1.5 bed
volumes per hour to about 2.0 bed volumes per hour. The complete
elution cycle was an average of about 16 bed volumes. Rhenium was
recovered through the elution and results are shown in Table 2.
TABLE-US-00002 TABLE 2 Rhenium Yields at varying Concentrations of
Ammonia Eluate Conc. % Temp, .degree. C. Re Yield, % NH.sub.3 15 22
80.8 NH.sub.3 15 50 92.0 NH.sub.3 15 80 91.4 NH.sub.3 29 22 88.1
NH.sub.3 5 50 88.0 NH.sub.3 5 75 93.3 NH.sub.3 5 50 87.2 NH.sub.3 5
50 89.4
EXAMPLE 3
[0063] A stationary phase comprising activated carbon was loaded
with rhenium. Three aqueous elution solutions comprised sodium
hydroxide in varying concentrations can be prepared (see Table 3).
Each elution solution was heated to a temperature of about
108.degree. C. to about 110.degree. C. and passed through the
stationary phase at a rate of about 1.5 bed volumes per hour to
about 2.0 bed volumes per hour. The complete elution cycle was
about 6 bed volumes to about 8 bed volumes. Rhenium was recovered
through the elution and results are shown in Table 3.
TABLE-US-00003 TABLE 3 Rhenium Yields at varying Concentrations of
Sodium Hydroxide Eluate Conc. % Re Yield, % NaOH 1.0 98.6 NaOH 2.0
97.1 NaOH 5.0 96.9
EXAMPLE 4
[0064] A stationary phase comprising activated carbon was loaded
with rhenium. Eight aqueous elution solutions comprised sodium
hydroxide in varying concentrations can be prepared (see Table 4).
Each elution solution was heated to a temperature (see Table 4) and
passed through the stationary phase at a rate of about 1.5 bed
volumes per hour to about 2.0 bed volumes per hour. The complete
elution cycle was an average of 16 bed volumes. Rhenium was
recovered through the elution and results are shown in Table 4
TABLE-US-00004 TABLE 4 Rhenium Yields at varying Concentrations of
Sodium Hydroxide Eluate Conc. % Temp, .degree. C. Re Yield, % NaOH
15 22 59.0 NaOH 15 50 88.3 NaOH 15 80 93.6 NaOH 40 23 69.9 NaOH 40
50 85.3 NaOH 40 50 79.6 NaOH 40 50 84.7 NaOH 40 80 89.0
EXAMPLE 5
[0065] A copper heap leach solution was contacted with four columns
in series containing a stationary phase comprising activated
carbon. The copper leach solution contains 0.65 mg/L of dissolved
rhenium. Other metals, such as aluminum, cadmium, calcium, cobalt,
copper, iron, magnesium, manganese, sodium, nickel, silicon,
vanadium, yttrium and zinc, were present in the copper leach
solution at concentrations greater than the concentration of
dissolved rhenium. The copper leach solution was contacted with the
stationary phase at a rate of 0.125 bed volume per minute for a
period of 3 to 4 days. Rhenium was measured in the recovered
elution solution exiting each column and results are shown as in
Table 5. The average rhenium recovery from the copper leach
solution was 96%. The average rhenium loading onto the stationary
phase in column 1 was greater than 2000 mg Re per kg carbon.
TABLE-US-00005 TABLE 5 Average Rhenium Concentration of Copper
Leach Solution exiting a Series of Four Activated Carbon Columns
Column Rhenium Concentration, mg/L 1 0.314 2 0.155 3 0.072 4
0.025
[0066] Finally, as used herein, the terms "comprise", "comprises",
"comprising", "having", "including", "includes", or any variation
thereof, are intended to reference a non-exclusive inclusion, such
that a process, method, article, composition or apparatus that
comprises a list of elements does not include only those elements
recited, but can also include other elements not expressly listed
and equivalents inherently known or obvious to those of reasonable
skill in the art. Other combinations and/or modifications of
structures, arrangements, applications, proportions, elements,
materials, or components used in the practice of the instant
invention, in addition to those not specifically recited, can be
varied or otherwise particularly adapted to specific environments,
manufacturing specifications, design parameters or other operating
requirements without departing from the scope of the instant
invention and are intended to be included in this disclosure.
[0067] Moreover, unless specifically noted, it is the Applicants'
intent that the words and phrases in the specification and the
claims be given the commonly accepted generic meaning or an
ordinary and accustomed meaning used by those of reasonable skill
in the applicable arts. In the instance where these meanings
differ, the words and phrases in the specification and the claims
should be given the broadest possible, generic meaning. If it is
intended to limit or narrow these meanings, specific, descriptive
adjectives will be used. Absent the use of these specific
adjectives, the words and phrases in the specification and the
claims should be given the broadest possible meaning. If any other
special meaning is intended for any word or phrase, the
specification will clearly state and define the special
meaning.
[0068] Various embodiments and the examples described herein are
exemplary and not intended to be limiting in describing the full
scope of compositions and methods of this invention. Equivalent
changes, modifications and variations of various embodiments,
materials, compositions and methods may be made within the scope of
the present invention, with substantially similar results.
* * * * *