U.S. patent application number 13/681553 was filed with the patent office on 2013-03-28 for method for recovering rhenium and other metals from rhenium-bearing materials.
This patent application is currently assigned to WRC WORLD RESOURCES COMPANY GMBH. The applicant listed for this patent is World Resources Company, WRC World Resources Company GmbH. Invention is credited to Peter T. HALPIN, Eberhard LUEDERITZ, Ulrich R. SCHLEGEL, Dale L. SCHNECK.
Application Number | 20130078166 13/681553 |
Document ID | / |
Family ID | 44647420 |
Filed Date | 2013-03-28 |
United States Patent
Application |
20130078166 |
Kind Code |
A1 |
LUEDERITZ; Eberhard ; et
al. |
March 28, 2013 |
METHOD FOR RECOVERING RHENIUM AND OTHER METALS FROM RHENIUM-BEARING
MATERIALS
Abstract
A method of recovering rhenium (Re) and other metals from
Re-bearing materials in the form of ammonium perrhenate having at
least the step of adding Re-bearing materials into a leaching
slurry. Additionally, the method has the step of adjusting the pH
of the slurry to obtain Re in soluble form in a metal salt solution
and insoluble residues; filtering the metal salt solution to remove
the insoluble residues; selectively precipitating Re from the metal
salt solution; and filtering the Re precipitate from the metal salt
solution to obtain a Re filtercake. The method further has the step
of drying and formulating Re to produce Re sulfide product.
Inventors: |
LUEDERITZ; Eberhard;
(Grimma, DE) ; SCHLEGEL; Ulrich R.; (Zurich,
CH) ; HALPIN; Peter T.; (Great Falls, VA) ;
SCHNECK; Dale L.; (Pottsville, PS) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
World Resources Company;
WRC World Resources Company GmbH; |
McLean
Wurzen |
VA |
US
DE |
|
|
Assignee: |
WRC WORLD RESOURCES COMPANY
GMBH
Wurzen
VA
WORLD RESOURCES COMPANY
McLean
|
Family ID: |
44647420 |
Appl. No.: |
13/681553 |
Filed: |
November 20, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13042520 |
Mar 8, 2011 |
|
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|
13681553 |
|
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|
|
61314493 |
Mar 16, 2010 |
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61374719 |
Aug 18, 2010 |
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Current U.S.
Class: |
423/22 ;
423/50 |
Current CPC
Class: |
C01G 47/00 20130101;
C22B 3/44 20130101; C22B 61/00 20130101; Y02P 10/234 20151101; C22B
7/007 20130101; C01G 39/02 20130101; Y02P 10/20 20151101 |
Class at
Publication: |
423/22 ;
423/50 |
International
Class: |
C22B 61/00 20060101
C22B061/00 |
Claims
1. A method of selectively recovering rhenium in the form of Re
sulfide from a Re-bearing material, comprising the steps of: (i)
adding Re-bearing materials into a leaching slurry; (ii) adjusting
the pH of the leaching slurry to obtain Re in soluble form in a
metal salt solution; (iii) filtering the metal salt solution to
remove insoluble fractions; (iv) selectively precipitating Re from
the metal salt solution; and (v) filtering the Re precipitate from
the metal salt solution to obtain a Re filtercake, and (vi) drying
and formulating Re to produce Re sulfide.
2. The method according to claim 1, wherein the Re-bearing material
is a super alloy waste, sludge, byproduct, or residue resulting
from the manufacturing and/or subsequent repair of high-temperature
industrial turbines, turbine components, superconductor components,
vacuum plasma metal deposition processes, and bimetallic reforming
catalyst materials.
3. The method according to claim 1, wherein the pH of the leaching
slurry in step (ii) is adjusted by adding an acid in an amount
sufficient to solubilize metals as metal salts.
4. The method according to claim 3, where the acid in step (ii) is
aqua regia.
5. The method according to claim 1, where an oxidant is added in
step (iv) in an amount sufficient to oxidize Re to the heptavalent
state.
6. The method according to claim 1, where a precipitant is added in
step (iv) in an amount sufficient to precipitate the Re and obtain
Re.sub.2S.sub.7.
7. The method according to claim 6, where the precipitant is
NaHS.
8. The method according to claim 1, where a solution of metal salts
is separated from the Re filtercake in step (v) and the solution of
metal salts contain at least one metal selected from the group
consisting of Ni, Co, Cr, Hf, Ti, Ta, W, Mo and a platinum group
metal.
9. The method according to claim 8, where the pH of the solution of
metal salts is increased to precipitate metal hydroxides containing
at least one metal selected from the group consisting of Ni, Co,
Cr, Hf, Ti, Ta, W, Mo and a platinum group metal.
10. The method according to claim 9, further comprising filtering
the solution and precipitate to obtain a filtercake that contains
at least one metal selected from the group consisting of Ni, Co,
Cr, Hf, Ti, Ta, W, Mo and a platinum group metal.
11. The method according to claim 1, where the insoluble fractions
from step (iii) contain at least one metal selected from the group
consisting of Ni, Co, Cr, Hf, Ti, Ta, W, Mo and a platinum group
metal.
12. The method according to claim 11, where the insoluble fractions
are formulated or compounded to obtain a metal concentrate.
13. The method according to claim 1, where the Re-bearing material
is a super alloy waste, sludge, byproduct, or residue resulting
from the manufacturing and/or subsequent repair of high-temperature
industrial turbines, turbine components, superconductor components,
vacuum plasma metal deposition processes, and bimetallic reforming
catalyst materials.
14. The method according to claim 1 for producing ammonium
perrhenate, further comprising the steps of: roasting the Re
sulfide product to oxidize the rhenium sulfide to rhenium
heptoxide, wherein said rhenium heptoxide sublimes into flue gas
and a metal oxide; and treating the flue gas to obtain ammonium
perrhenate.
15. The method according to claim 1 for producing metal concentrate
further comprising the step of formulating or compounding the
insoluble fractions to obtain said metal concentrate.
16. The method according to claim 1 for producing molybdenum oxide
further comprising the step of combining the Re sulfide with
molybdenum concentrate containing Re to obtain a Mo/Re concentrate
and treating the Mo/Re concentrate to recover the molybdenum
oxide.
17. The method according to claim 1 for producing copper
concentrate further comprising the steps of combining the Re
sulfide with molybdenum concentrate containing Re to obtain a Mo/Re
concentrate, wherein the molybdenum concentrate containing Re is
obtained by treating copper ore containing Mo and Re with a
porphyry Cu ore flotation process to obtain Mo/Cu/Re/concentrate,
and treating the Mo/Cu/Re concentration with a flotation process to
obtain copper concentrate.
Description
RELATED APPLICATIONS
[0001] This application is a continuation application of Ser. No.
13/042,520, filed Mar. 8, 2011, which claims benefit under 35 USC
119(e) of U.S. Provisional Application Nos. 61/314,493, filed Mar.
16, 2010; and 61/374,719, filed Aug. 18, 2010, all of which are
herein incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a method of recovering
Rhenium (Re) from Re-bearing materials.
BACKGROUND
[0003] Rhenium (Re) is one of the rarest metals on earth and found
almost exclusively in copper sulfide ore deposits containing
extractable quantities of molybdenum (Mo). Re is found within the
molybdenite fraction of this specific type of copper (Cu) ore. As a
result, a number of processes have been developed to isolate Re
from this fraction.
[0004] U.S. Pat. No. 3,739,549 recovers Re from ore material by
using a roasting process. The Mo and Re is first separated from the
Cu by a froth floatation process. The Mo and Re containing fraction
is then subjected to a roasting process to separate the Mo and Re.
The Re is converted to a large extent to rhenium heptoxide
(Re.sub.2O.sub.7) which is volatile and passes off with the gaseous
effluents resulting from roasting. The flue gases are subjected to
a wet-scrubbing process, wherein the flue gas containing
Re.sub.2O.sub.7 is captured and condensed in a scrubbing solution.
The Re.sub.2O.sub.7 containing scrubber solution is then processed
by known techniques to produce ammonium perrhenate, i.e.,
NH.sub.4ReO.sub.4. Ammonium perrhenate is the primary source form
for the production of Re metal. A majority of the world's Re supply
is produced by extraction methods that isolate Re from Cu/Mo/Re
ores. However, the process is limited to recovering Re from these
types of ores and is not a practical for recovering Re from other
Re-bearing materials. A second but smaller source of Re is recycled
Re.
[0005] Re has a number of industrial uses. For example, U.S. Pat.
No. 5,562,817 discloses the use of a Re-platinum (Pt) alloy as a
catalyst for catalytic reforming. Catalytic reforming is a chemical
process that converts petroleum refinery napthas with low octane
ratings into high-octane liquid products. Re can also be added to
high-temperature super alloys that are used to make components,
such as jet engine parts (see U.S. Pat. No. 6,936,090). The
scarcity and cost of Re has brought about the development of a
number of methods that are used to recover Re, in particular from
Re-bearing product and materials.
[0006] For example, United States Patent Application Publication
No. 2003/0119658 relates to a process for the recovery of rhenium
from a spent Re-bearing catalyst by heating the catalyst in an
oxidizing atmosphere at a temperature effective to sublime a
portion of the rhenium as a volatized oxide. The Re and Pt in the
catalysts can be recovered. However, the process is limited to
recovering these metals from spent catalysts.
[0007] The recovery of Re from super alloy waste and residue
materials is also commercially interesting. Super alloys generally
contain 50 to 80% of nickel, 3 to 15% by weight of at least one or
more of the elements cobalt (Co), chromium (Cr), and aluminum (Al)
and 1 to 12% by weight of one or more of the elements Re, tantalum
(Ta), niobium (Nb), tungsten (W), Mo, hafnium (Hf) and Pt. United
States Patent Application Publication No. 2009/0255372 discloses a
process for recovering Re and other valuable metals from a super
alloy containing waste or residue material by digesting the super
alloy material in a salt melt. The salt melt contains 60-95% by
weight of NaOH and 5-40% by weight of Na.sub.2SO.sub.4. The Re and
other metals can then be recovered with the use of known techniques
such as selective precipitations and ion exchange techniques. For
example, Re is recovered by passing the digested material
containing Re over an ion exchange column (see also U.S. Pat. No.
6,936,090). However, the process does not describe being able to
recover Re from a variety of materials and suggests recovering Re
from ion exchange columns.
[0008] Thus, a need exists for a method that can recover Re from a
variety of Re-bearing materials at a low cost.
[0009] The present invention provides for an economical method of
extracting Re and other valuable metals from Re-bearing materials,
including nontraditional forms of industrial Re-bearing materials,
which were previously overlooked as a source from which to extract
Re because no economical extraction process existed. For example, a
number of Re-bearing materials have been disposed of in landfills
due to the lack of a process that could efficiently recover Re. In
some instances, this Re-bearing material was treated in
nickel/cobalt recycling processes but only for the recovery of
nickel and cobalt constituents and not for the Re content. Once
subjected to those nickel/cobalt recycling processes, the Re was
alloyed or otherwise diluted to the extent where the possibility of
efficiently recovering Re with previously known methods was remote
if not impossible.
SUMMARY
[0010] The present invention is based on the discovery of an
efficient and effective method for selectively recovering Re from
Re-bearing materials. The method is able to efficiently recover Re
and/or other metals such as Cu, Co, Cr, Mo, Ta, Ti, Hf, PGM and W
from a variety of Re-bearing materials containing such metals.
[0011] The term "leach" as used herein means to wash, extract, or
perform a chemical reaction to separate a soluble element or
compound from an insoluble material.
[0012] The phrase "insoluble residue" means an element in free form
or compound incapable of or that resists dissolving in a particular
solvent.
[0013] A "rhenium-bearing material" is any material that contains
Rhenium (Re). This includes waste, residue, ore, ore concentrate,
byproduct, processed, and/or unprocessed material. Re-bearing
materials include nickel, cobalt, and/or molybdenum-bearing
manufacturing sludge residues, wastes, and byproducts. These
materials have a physical consistency of a powder, sand or sludge
and are typically comprised of metal compounds, metal alloys, metal
grinding polishing fines, etchant compounds, and mixtures thereof.
Re-bearing materials also include granular filter media, fibrous
filter media, abrasive grinding material and plasma deposition
overspray particles. In one aspect of this invention, the
Re-bearing material is a super alloy waste, sludge, byproduct, or
residue resulting from the manufacturing and/or subsequent repair
of high-temperature industrial turbines, turbine components,
superconductor components, vacuum plasma metal deposition
processes, and bimetallic reforming catalyst materials.
[0014] The phrase "substantially pure" means that a given compound
has a purity of about 90-99% be weight of the collected
material.
[0015] A "platinum group metals" (PGM) includes metals such as
platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), Osmium
(Os), and palladium (Pd).
[0016] A "scrubber" is a device that can be used to remove
particulates and/or gases from industrial exhaust streams. For
example, the term "scrubber" includes devices that use liquid to
wash metal-bearing materials from a gas stream.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a flowchart exemplifying a method for separating
and recovering Re and other metal from a raw material containing
Ni, Co, Cr, PGM and Re.
DETAILED DESCRIPTION
[0018] A variety of Re-bearing materials can be processed in
accordance with the present invention. For example, FIG. 1 shows
that these materials may include super alloy residues and wastes
that contain Re 20, Re-bearing plasma spray deposition overspray
residues 40, other source materials such as Re-bearing ore
materials 50, and/or Re-bearing waste materials and cermet
catalysts 60.
[0019] When the Re-bearing material is from a super alloy waste or
residue material 20 such as a machining fluid or filter media, the
super alloy waste or residue material 20 is first mixed with a
slurry liquid 10 such as an aqueous solution. The aqueous solution
and super alloy waste or residue material 20 is vigorously stirred
or subjected to a media emulsification process 30 to form a
Re-bearing mixture. The Re-bearing mixture is then combined with
other Re-bearing materials such as the super alloy residues and
wastes that contain Re 20, Re-bearing plasma spray deposition
overspray residues 40, other source materials such as Re-bearing
ore materials 50, and/or Re-bearing waste materials and cermet
catalysts 60 to form a leaching slurry 70.
[0020] The super alloy residues and wastes that contain Re 20,
Re-bearing plasma spray deposition overspray residues 40, other
source materials such as Re-bearing ore materials 50, and/or
Re-bearing waste materials and cermet catalysts 60 are optionally
subjected to a comminution process 80 prior to being added to the
leaching slurry 70. A variety of comminution processes 80 can be
used to crush the materials into a powder in preparation for
subsequent processing methods that generally require a fine
particle size.
[0021] All metals are solubilized in the leaching slurry 70, where
acids are added to the slurry in an amount sufficient to solubilize
the metals in the form of their corresponding metal salts. The
leaching slurry 70 is preferably kept at a pH below 2, and
preferably below 1. A variety of acids can be used to obtain this
pH but typically a mixture of hydrochloric acid and nitric acid is
used. For example, the slurried materials are acidified, preferably
with hydrochloric acid (HCl) or a mixture of HCl and nitric acid
(HNO.sub.3) commonly referred to as aqua regia (AR). The acidified
solution is agitated for up to 24 hours, and preferentially 4 to 6
hours to allow sufficient reaction time to convert contained metals
in their alloyed metallic state to their corresponding metal
salts.
[0022] The reactions are exemplified as follows:
Me.sup.0+HCl=MeCl+H.sup.+
Me.sup.0+HNO.sup.3=Me NO.sub.3+H.sup.+ Scheme 1
where Me=any metal.
[0023] Any remaining insoluble residues from the filtered leaching
slurry 90 can be further processed to recover valuable metals that
may be present in the residues 300. For example, insoluble residues
from 90 can contain compounds and metals such as Ni, Co, Cr,
platinum group metals, and other metals. The insoluble residues are
then reformulated/compounded 310 into other metal bearing materials
to produce a metal concentrate. The reformulated/compounded
material 310 is optionally mixed with other metal concentrates that
occur naturally or are in secondary form 305. For example, the
reformulated/compounded material 310 can be processed with a Ni
concentrate 305 to obtain a metal concentrate that contains Ni, Co,
and other platinum group metals 315.
[0024] The resulting filtrate from the filtered leaching slurry 90
is subjected to a selective Re precipitation process 100, creating
an insoluble Re compound, while other metals remain as their
soluble salts. In one embodiment of this invention, the Re
precipitation process 100 comprises first oxidizing contained Re to
the heptavalent state (ReVII) by the addition of an oxidizing
agent, preferentially permanganate or peroxide, then adding
sulfide, preferentially sodium hydrosulfide (NaHS), to the filtrate
from 90 while maintaining an acidic pH and preferably ranging from
a pH of less than 1 to 5. Rhenium sulfide (Re.sub.2S.sub.7), as
well as platinum group metal sulfides, precipitate under these
conditions preferentially over other contained metals.
[0025] The reaction is exemplified as follows:
2ReCl.sub.7+7NaHS=Re.sub.2S.sub.7+7NaCl+7HCl Scheme 2
[0026] The sulfide can be added as any compound capable of
providing the required H.sub.2S, but it is preferentially sodium
hydrosulfide (NaHS) or hydrogen sulfide (H.sub.2S) gas. The
addition of sulfide at this low pH will cause for the evolution of
H.sub.2S gas, requiring that the reaction vessel be either vented
through a gas scrubbing device, or be a closed vessel so as to
prevent the escape of H.sub.2S fumes. The release of H.sub.2S fumes
can be minimized by the slow addition of the sulfide compound,
allowing reaction to the desired Re.sub.2S.sub.7 without
significant release of H.sub.2S.
[0027] The precipitate is then filtered 110 to create a Re sulfide
filtercake 120. For example, the precipitate from 100 is typically
filtered 110 to separate a Re sulfide filtercake 120 from the
solution resulting from filtration step 110. Filtration can be
achieved by methods and devices known to those skilled in the
art.
[0028] However, in most instances, the Re sulfide filtercake 120 is
formulated and dried 130 to yield a Re sulfide product 150. The Re
sulfide filtercake 120 is dried 130 as necessary using devices and
methods known to those skilled in the art to produce a Re sulfide
concentrate product 150. The Re sulfide concentrate product 155
contains up to about 100,000 parts per million Re, or up to about
10% by weight of Re. The Re sulfide concentrate product can be
optionally isolated and sold as a finished commercial product
itself 155. For example, the Re sulfide concentrate product 155 has
a variety of industrial applications. For example, the Re sulfide
concentrate product 155 can be used in petrochemical cracking
catalysts, automotive catalysts, textiles and water treatment
methods.
[0029] When the Re sulfide produced 150 is found to also contain
significant concentrations of platinum group metals (PGM's) the
rhenium sulfide product is processed by methods normally used for
recycling of spent Re/PGM catalysts. The rhenium sulfide with PGM's
900 is subjected to a roasting process 910 in a roaster at
temperatures greater than 700.degree. C., and preferably greater
than 750.degree. C., sufficient to oxidize the rhenium sulfide to
rhenium heptoxide via the following reaction:
2Re.sub.2S.sub.7+21O.sub.2+heat=2Re.sub.2O.sub.7
(sublimes)+14SO.sub.2
[0030] In the reaction, the rhenium heptoxide is then immediately
sublimed to flue gas 180 discharged from the roaster, and captured
in scrubbing solution 190. The Re containing scrubber solution is
then treated with ammonium chloride 700 to produce ammonium
perrhenate.
[0031] The remainder after roasting 920 is then processed for PGM
recovery by established methods.
[0032] Alternately, the rhenium sulfide produced 150 may sometimes
contain insignificant PGM concentrations, and then the Re sulfide
concentrate product is preferentially formulated with molybdenum
Re-bearing concentrates 160, which have been derived from porphyry
copper molybdenum floatation 820, an established mining industry
process for the recovery of Mo/Re contained in select copper ores.
For example, a porphyry copper ore flotation process 800 is used to
obtain a Mo, Cu, Re containing concentrate. A Mo/Re flotation 820
is used to produce a Mo/Re concentrate 160 and a Cu containing
fraction. The Mo/Re concentrate is mixed with the Rhenium sulfide
concentrate product 150. The Cu containing fraction is separately
recovered as a Cu concentrate 825.
[0033] The material from Re sulfide concentrate product 150 and
Mo/Re flotation product 820 is then subjected to a roasting process
170 (see e.g., U.S. Pat. No. 3,739,549). The Re is sublimed during
the roasting process 170.
[0034] The combination of Re sulfide and the Mo/Re product provides
an enriched Re-containing flue gas 180. The Mo concentrates
obtained from the roasting process 170 are recovered as MoO.sub.2
175.
[0035] The enriched Re-containing flue gas 180 is forwarded to a
scrubber 190 where the sublimed Re is condensed and solubilized in
a scrubber solution. The scrubber 190 treats the Re-containing flue
gas 180 so that a solution containing Re is obtained 400. The
solution containing Re 400 is treated with an ammonia salt and
subjected a solid/liquid separation filterpress 410 to obtain an
ammonium perrhenate product 420. Spent liquid 195 from the scrubber
190 can be disposed of or reused in the process. Spent liquid from
filtration step 410 can also be disposed of, or reused in the
process.
[0036] For example, Re sublimed from the Mo concentrates is
condensed and captured in flue gas scrubbing liquors as perrhenate
(ReO.sub.4) 400. The scrubbing liquors containing ReO.sub.4 are
then treated by the addition of ammonium chloride 700 to produce a
substantially pure ammonium perrhenate 420, which is crystallized
as a white crystalline material, and is used as the primary supply
to most of the world for further refining and consumption of Re.
The liquid from the solid/liquid separation 410 can be disposed of
or even reused in the process 215.
[0037] The liquid from the solid-liquid separation of 110 is also
further processed. For example, the pH of the filtrate from the
solid-liquid separation of 110 is precipitated by raising the pH of
the solution to 8.5 to 10, preferably 9.0 to 9.5 to produce a
solution containing insoluble metal compounds 200. Hydroxides such
as NaOH (caustic soda) or KOH can be added to raise the pH.
[0038] The reaction is exemplified as follows:
MeCl.sub.2+2NaOH=Me(OH).sub.2+2NaCl Scheme 3
where Me=any metal.
[0039] This resulting precipitate is then filtered 220 to produce a
metal containing filtercake 230. For example, the filtercake 230
can contain Ni, Co, and platinum group metals. Spent water from
filtration step 220 can then be disposed of or reused 225. The
filtercake 230 is further formulated/compounded 310 to produce a
metal containing concentrate 315, such as Ni, Co, platinum group
concentrate. The formulated/compounded material 310 is optionally
combined with other feedstocks 305 and/or insoluble residues 300 to
produce the metal containing concentrate 315. Filtration methods
and devices known to those skilled in the art can be used for this
filtration step.
[0040] The foregoing description of the invention has been
presented describing certain operable and preferred embodiments. It
is not intended that the invention should be so limited since
variations and modifications thereof will be obvious to those
skilled in the art, all of which are within the spirit and scope of
the invention.
* * * * *