GB2146316A - Precious metals recovery - Google Patents
Precious metals recovery Download PDFInfo
- Publication number
- GB2146316A GB2146316A GB08422593A GB8422593A GB2146316A GB 2146316 A GB2146316 A GB 2146316A GB 08422593 A GB08422593 A GB 08422593A GB 8422593 A GB8422593 A GB 8422593A GB 2146316 A GB2146316 A GB 2146316A
- Authority
- GB
- United Kingdom
- Prior art keywords
- base metal
- aqueous
- leach
- ion exchange
- carboxylic acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G55/00—Compounds of ruthenium, rhodium, palladium, osmium, iridium, or platinum
- C01G55/001—Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/42—Treatment or purification of solutions, e.g. obtained by leaching by ion-exchange extraction
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G5/00—Compounds of silver
- C01G5/003—Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G7/00—Compounds of gold
- C01G7/003—Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B11/00—Obtaining noble metals
- C22B11/04—Obtaining noble metals by wet processes
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/006—Wet processes
- C22B7/007—Wet processes by acid leaching
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Inorganic Chemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
Precious metals are recovered from bimetallic materials by treating a leach liquor filtrate with a carboxylic acid type ion exchange resin to form a waste liquor stream substantially free of base metal values. The ion exchange resin is regenerated by passing through it an aqueous leaching liquid comprising an ammonium salt in an ammoniacal solution. The resulting aqueous regenerating liquid then containing base metal values can be used in the process for recovering precious metals.
Description
SPECIFICATION
Precious metals recovery
The present invention relates to a method for improving the process of recovering precious metals from precious metal-bearing compositions. In particular, it relates to an improved method of treating the waste stream from a precious metal recovery process to enhance the isolation of base metal materials and to produce an environmentally advantageous, substantially metal-free waste stream.
In the fabrication of a variety of relatively high cost metallic items such as jewelry and the like precious metals, either as pure metals or as alloys, are mechanically bonded to one or more base metals or base metal alloys to form metal stock. Such metal stock, hereinafter termed bimetallic materials to distinguish them from alloys, have the precious metal adhered to one or more of their surfaces. In addition to jewelry, these bimetallic stocks are also useful in producing table flatware, electronic circuit components, machine parts and the like. The formation of such items gives rise to quantities of scrap that vary in shape, size and layered construction. It is economically advantageous to recover as much as possible of the precious metals from such scrap.
At present, the most widely used procedure for recovering precious metals from scrap comprises the electro-refining of base metal (usually copper) and the subsequent electrowinning of the precious metal from the insoluble slimes produced in the electrofining process. In such a process, the precious metal scrap is melted down to form an alloy, the principal constituent of which is (typically) copper. This alloy is then used as an anode in an electrolytic cell having a sulfuric acidcopper sulfate electrolyte. The initial cathode of the cell is high purity copper on which is plated additionally essentially pure copper electrochemically dissolved from the anode into the electrolyte. The precious metal, insoluble in the electrolyte, falls off at the anode as a fine mud or slime.After separation, the precious metals undergo a number of additional, purifying steps before they can be further commercially used.
In view of the complexity and expense associated with the prior art processes, other investigations of methods to recover precious metals from scrap have resulted in numerous related and non-related procedures. Recently, a simplified process for recovering precious metals from scrap has been disclosed in U.S.
Serial Number 6-081006, filed October 1, 1979, now U.S. Patent No. 4,261,738 issued April 4, 1981, which discloses a process for recovering a precious metal from bimetallic materials where these materials are subjected to a leaching process, the leaching fluid being formed from an aqueous solution of an ammonium salt in an ammoniacal solution containing reactive oxygen. A leachate fluid results that is rich in the base materials from which the scrap is composed. The precious metals are recovered essentially unchanged from the reaction vessel. The leachate fluid, termed the aqueous pregnant leach liquor, is subsequently thermally decomposed to precipitate the base metal as a recoverable solid and to form a condensable vapor, mostly water and ammonia, which is recovered.The precipitated base metals are separated from the precipitation liquor for recovery, and the remaining aqueous waste liquor stream is then disposed of. This aqueous waste stream may contain an undesirably high concentration of base metals that were not precipitated in the prior thermal decomposition process step. For example, the bimetallic materials where the base metal contains both copper and zinc, this aqueous waste stream may contain both soluble copper and soluble zinz, which in turn may render such waste streams unacceptable for disposal into the environment.
Thus, it is apparent that it would be desirable to have an improved process for recovering precious metals from bimetallic materials which will produce an aqueous waste stream substantially free of soluble base metal values.
It is therefore an object of the present invention to provide an improved process for recovering precious metals from bimetallic materials which eliminates high soluble base metal values in the aqueous waste stream of the process.
It is an additional object of the present invention to increase the amounts of base metals recovered from the prior art process of recovering precious metals.
It is a further object of the present invention to provide a simple and efficient method of removing base metal values from an aqueous waste stream containing such base metal values and to recycle the base metal values within a closed loop system within the precious metal recovery process.
According to one aspect of the present invention, there is provided an improvement in a process for recovering a precious metal in pure or alloyed form from bimetallic materials comprising at least one base metal comprising the steps of
1. leaching the bimetallic material with an aqueous leaching liquid, comprising an ammonium salt in an ammonical solution containing reactive oxygen forming an aqueous pregnant leach liquor and the precious metal;
2. removing the precious metal from the pregnant leach liquor;
3. thermally decomposing with steam the pregnant leach liquor thereby precipitating the base metal; and
4. filtering the base metal thereby forming an aqueous waste liquor filtrate and the base
metal residue, the improvement comprising the steps of:
a. treating said aqueous waste liquor filtrate with a carboxylic acid type ion exchange resin forming a carboxylic type ion exchange resin having base metal values absorbed thereon and an aqueous waste liquor stream substantially free of base metal values;
b. contacting the carboxylic acid type ion exchange resin having base metal values absorbed thereon with at least a part of said aqueous leach liquid, thereby desorbing said base metal values from the ion exchange resin and adding said base metal values to said aquous leach liquid; and
c. using said aqueous leach liquid in said process for recovering precious metals.
According to another aspect of the present invention, there is provided an improvement in an apparatus for recovering precious metal in pure or alloyed form from bimetallic materials comprising at least one base metal comprising in combination leach reactor means; means to supply to said leach reactor means the bimetallic material, an aqueous leach liquid and reactive oxygen; means to form a pregnant leach liquor containing the base metal in solution; means to separate the precious metal from the pregnant leach liquor; means to convey the pregnant leach liquor from the leach reactor means to a steam treatment reactor means; means to steam treat the pregnant leach liquor to precipitate the base metal; and means to separate said base metal from said steam treated aqueous waste, the improvement comprising:
a. carboxylic acid type ion exchange means;
b. means to convey the steam treated pregnant leach liquor from the steam treatment reactor means to the carboxylic acid type ion exchange means to form a carboxylic acid type ion exchange means having base metal values adsorbed thereon and an aqueous waste liquor substantially free of base metal values;
c. means for contacting the carboxylic acid type ion exchange means having base metal values adsorbed thereon with said aqueous leach liquid to form an aqueous leach liquid solution containing base metal values; and
d. means to convey said aqueous leach liquid solution containing base metal values to the aqueous leach liquid means.
In the following detailed description of embodiments of this invention, it should be understood that the waste liquor filtrate steam treated in the method embodying the present invention comprises a mixture of metal values derived from the recovery of precious metals obtained from bimetallic materials (usually scrap). As such, these precious metals are those that do not dissolve in the ammoniacal leach solution of the prior art process, i.e.
gold, silver, palladium, rhodium, platinum, iridium, osmium and ruthenium along with their alloys. Conversely, the base metals going to form the bimetallic stock and appearing in the waste stream are those that are soluble in the ammonical leach liquid. Typically these
metals are copper and the various alloys of copper such as the brasses and the bronzes some of whose components form solutions in aqueous ammonia.
Referring to Fig. 1, a typical prior art pro
cess, such as disclosed in U.S. Serial No.
6-081,006 filed October 1, 1979 and incorporated herein by reference, an aqueous leaching liquid is employed to separate the
precious metal from the metal (or metals) of
base material without effecting any reaction with or changing the composition of the precious metal. The aqueous leaching liquid typically comprises an ammonium salt, formed of an acid essentially free from ions which complex with the precious metal, in an ammonical solution containing oxygen. Oxygen is eco
nomically supplied by sparging air or oxygen gas. The nature of the ammonium salt employed in the process is a function of the precious metal being recovered. Thus, in the case of gold or other platinum group metals, ammonium sulfate, ammonium nitrate or ammonium phosphate may be used whereas for recovering silver, ammonium carbonate is preferred.
As noted above, some components of the base metals may not dissolve in the aqueous leach liquid. As such, these insoluble components form a slime (a fine powder suspension) in the pregnant leach liquor. Exemplary of such metals forming a slime are tin in bronzes and babbitt metals, lead in bronzes, brasses and German silvers, and antimony in brasses.
Essentially two product streams result from the leach reactions, the solid unaffected precious metal and the liquid aqueous leaching liquid now containing soluble base metal values, termed the aqueous pregnant leach liquor. After filtration to remove any suspended fines, this latter solution is thermally treated with steam, which decomposes the soluble base metal ammonium complexes into the insoluble metal oxides or carbonates and free ammonia gas and water. The ammonia gas is collected and the solid oxides or carbonates are filtered from the steam-treated aqueous pregnant leach liquor. The wet filter cake is readily processed to recover the base materials in their elemental form. However, the liquid from the filtering operation (the aqueous waste liquor filtrate) is commonly discarded. Since the steam treatment of the pregnant leach liquor generally yields a steam treated aqueous waste liquor which is not completely free of ammonia, there remains in the aqueous waste liquor filtrate a certain amount of dissolved base metal, presumably present as ammine complexes. The actual concentration of these metal values is of course, a function of the efficiency of the steam treatment. With acceptable steam treatment, the concentration of metal values in the steam treated aqueous waste liquor is reduced to 110 mg liter or less.
The improved process embodying the present invention treats the aqueous waste liquor filtrate with a carboxylic acid type ion exchange resin, which as used herein are nonchelating, thereby removing by adsorption onto the ion exchange resin substantially all of the residual dissolved base metal values, and thereby producing an environmentally acceptable, treated waste liquor filtrate stream for disposal. Regeneration of the ion exchange resin, i.e., desorption of the base metal values, is advantageously accomplished by treating such with at least a part of the fresh aqueous leaching liquid which goes to the leaching process and used in the first step of leaching the precious metals containing bimetallic material. The loaded resins are stripped of metals using only ammoniacal solutions and are thus not subjected to acid/base cycling.The resulting leaching liquid is then combined with the aqueous leaching liquid stream and used in the leaching step or, if all of the aqueous leaching liquid is used for such desorption, the resulting leach liquid is used as is for the leaching step.
The carboxylic acid type ion exchange resin of use in this improved process is formed of synthetic polymeric hydrocarbon having appended to the polymer backbone a multiplicity of carboxylic acid groups. A further requirement of this resin is that it is not soluble in the waste liquor filtrate stream. The actual chemical identity of the polymer backbone is not an important consideration in selecting the carboxylic acid type ion exchange resin. Thus, polymers of methacrylic acid or acrylic acid are of use herein. The resins used in the practice of the invention disclosed herein are commercially available. The chemical composition is not available to the purchaser of the resins. However, an example of resin which has been successfully used in the process is;
AMBERLITE IRC-50. (registered trade mark).
Further, those carboxylic ion exchange resins described as macroreticular resins are preferably used in this process. These resins have large discrete pores which permits the ready removal of high molecular weight ions.
Similarly, these removed ions are easily removed from the resin on regeneration. It should be understood that the resin composition is not disclosed nor claimed to be part of the invention. It is the use of this type of resin in combination with the other phases of the process which is being disclosed as a part of the invention.
The above process is conveniently carried out at room temperature (around 25"C) although both higher and lower temperatures can be used in the absorption or desorption step.
Since certain changes may be made in carrying out the above methods and apparatus set forth without departing from the scope of the invention, it is intended that all matter in the above description shall be interpreted as illustrative and not in a limiting sense.
Claims (6)
1. In a process for recovering a precious metal in pure or alloyed form from bimetallic materials, the base material of which is comprised of at least one base metal, comprising the steps of:
(a). leaching said bimetallic material with an aqeuous leaching liquid comprising an ammonium salt in an ammoniacal solution containing reactive oxygen forming an aqueous pregnant leach liquor and the precious metal;
(b). removing said precious metal from said pregnant leach liquor;
(c). thermally decomposing with steam said pregnant leach liquor thereby precipitating the base metal as a recoverable base metal compound; and
(d). filtering said base metal compound, thereby forming a waste liquor filtrate and the base metal residue;
the improvement comprising the steps of:
a. treating said waste liquor filtrate with a carboxylic acid type ion exchange resin thereby forming a treated waste liquor stream substantially free of dissolved base metal values;
b. contacting the carboxylic acid type ion exchange resin from step a. with at least a part of said aqueous leach liquid which goes to the leaching process of (a)., thereby removing said base metal values from said carboxylic acid type ion exchange resin and adding said base metal values to said aqueous leach liquid; and
c. using said aqeuous leach liquid containing said base metal values in said process for recovering precious metals.
2. The process in accordance with claim 1, wherein said carboxylic acid type exchange resin is a polymer of methaclic or acrylic acid.
3. The process in accordance with claim 1, wherein said carboxylic acid type ion exchange resin of step a. is selected from the group described as macroreticular resins.
4. In apparatus for recovering precious metal in pure or alloyed form from bimetallic materials comprising at least one base metal comprising in combination leach reactor means; means to supply to said leach reactor means the bimetallic material. an aqueous leach liquid and reactive oxygen; means to form a pregnant leach liquor containing the base metal in solution; means to separate the precious metal from the pregnant leach liquor; means to convey the pregnant leach liquor from the leach reactor means to a steam treatment reactor means; means to steam treat the pregnant leach liquor to precipitate the base metal; and means to separate said base metal from said steam treated aqueous waste,
the improvement comprising:
a. carboxylic acid type ion exchange means;
b. means to convey the steam treated pregnant leach liquor from the steam treatment reactor means to the carboxylic acid type ion exchange means to form a carboxylic acid type ion exchange means having base metal values adsorbed thereon and an aqueous waste liquor substantially free of base metal values;
c. means for contacting the carboxylic acid type ion exchange means having base metal values adsorbed thereon with said aqueous leach liquid to form an aqueous leach liquid solution containing base metal values; and
d. means to convey said aqueous leach liquid solution containing base metal values to the aqueous leach liquid means.
5. The processes for recovering precious metals substantially as hereinbefore described.
6. Apparatus for recovering precious metals substantially as hereinbefore described.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US53044583A | 1983-09-08 | 1983-09-08 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8422593D0 GB8422593D0 (en) | 1984-10-10 |
| GB2146316A true GB2146316A (en) | 1985-04-17 |
Family
ID=24113661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08422593A Withdrawn GB2146316A (en) | 1983-09-08 | 1984-09-07 | Precious metals recovery |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS6070132A (en) |
| DE (1) | DE3433022A1 (en) |
| FR (1) | FR2551768A1 (en) |
| GB (1) | GB2146316A (en) |
| IT (1) | IT1180222B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000040512A1 (en) * | 1999-01-04 | 2000-07-13 | Advanced Micro Devices, Inc. | Sludge-free treatment of copper cmp wastes |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05195103A (en) * | 1991-11-13 | 1993-08-03 | Sumitomo Metal Ind Ltd | Method for separating and recovering copper in ferroscrap |
| JPH0625764A (en) * | 1992-07-08 | 1994-02-01 | Sumitomo Metal Ind Ltd | Method for removing and recovering copper in ferroscrap |
| CN116462221A (en) * | 2023-03-24 | 2023-07-21 | 达高工业技术研究院(广州)有限公司 | Production process of high-purity silver nitrate, high-purity silver nitrate and application thereof |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB492344A (en) * | 1936-04-04 | 1938-09-19 | Ig Farbenindustrie Ag | Improved treatment of ammoniacal solutions of metal salts |
| GB517933A (en) * | 1937-09-14 | 1940-02-13 | Ig Farbenindustrie Ag | Process of working up ammoniacal solutions of heavy metals |
| GB894392A (en) * | 1957-04-20 | 1962-04-18 | Bayer Ag | Recovery of heavy metals from solutions |
| GB1309964A (en) * | 1970-05-02 | 1973-03-14 | Heraeus Gmbh W C | Method for purifying aqueous solutions of rhenium |
| GB1423897A (en) * | 1972-07-13 | 1976-02-04 | Inst Textile De France | Cellulose cation exchanger and treatment of industrial effluents therewith |
| GB1482930A (en) * | 1974-05-21 | 1977-08-17 | Laporte Industries Ltd | Removing metal ions from solution |
| GB1503571A (en) * | 1974-02-08 | 1978-03-15 | Yeda Res & Dev | Organic reagents |
| GB2017109A (en) * | 1978-03-24 | 1979-10-03 | Sumitomo Chemical Co | Chelate resin |
| EP0011484A1 (en) * | 1978-11-15 | 1980-05-28 | The British Petroleum Company p.l.c. | Removal of metals from solution |
| US4261738A (en) * | 1979-10-01 | 1981-04-14 | Arthur D. Little, Inc. | Process for recovering precious metals from bimetallic material |
-
1984
- 1984-09-07 DE DE19843433022 patent/DE3433022A1/en not_active Withdrawn
- 1984-09-07 GB GB08422593A patent/GB2146316A/en not_active Withdrawn
- 1984-09-07 IT IT2256484A patent/IT1180222B/en active
- 1984-09-07 FR FR8413773A patent/FR2551768A1/en not_active Withdrawn
- 1984-09-08 JP JP59187296A patent/JPS6070132A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB492344A (en) * | 1936-04-04 | 1938-09-19 | Ig Farbenindustrie Ag | Improved treatment of ammoniacal solutions of metal salts |
| GB517933A (en) * | 1937-09-14 | 1940-02-13 | Ig Farbenindustrie Ag | Process of working up ammoniacal solutions of heavy metals |
| GB894392A (en) * | 1957-04-20 | 1962-04-18 | Bayer Ag | Recovery of heavy metals from solutions |
| GB1309964A (en) * | 1970-05-02 | 1973-03-14 | Heraeus Gmbh W C | Method for purifying aqueous solutions of rhenium |
| GB1423897A (en) * | 1972-07-13 | 1976-02-04 | Inst Textile De France | Cellulose cation exchanger and treatment of industrial effluents therewith |
| GB1503571A (en) * | 1974-02-08 | 1978-03-15 | Yeda Res & Dev | Organic reagents |
| GB1482930A (en) * | 1974-05-21 | 1977-08-17 | Laporte Industries Ltd | Removing metal ions from solution |
| GB2017109A (en) * | 1978-03-24 | 1979-10-03 | Sumitomo Chemical Co | Chelate resin |
| EP0011484A1 (en) * | 1978-11-15 | 1980-05-28 | The British Petroleum Company p.l.c. | Removal of metals from solution |
| US4261738A (en) * | 1979-10-01 | 1981-04-14 | Arthur D. Little, Inc. | Process for recovering precious metals from bimetallic material |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000040512A1 (en) * | 1999-01-04 | 2000-07-13 | Advanced Micro Devices, Inc. | Sludge-free treatment of copper cmp wastes |
| US6306282B1 (en) | 1999-01-04 | 2001-10-23 | Advanced Micro Devices, Inc. | Sludge-free treatment of copper CMP wastes |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2551768A1 (en) | 1985-03-15 |
| IT8422564A0 (en) | 1984-09-07 |
| JPS6070132A (en) | 1985-04-20 |
| DE3433022A1 (en) | 1985-03-28 |
| GB8422593D0 (en) | 1984-10-10 |
| IT1180222B (en) | 1987-09-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |