EP0057684A1 - Recuperation de metaux precieux - Google Patents

Recuperation de metaux precieux

Info

Publication number
EP0057684A1
EP0057684A1 EP81902033A EP81902033A EP0057684A1 EP 0057684 A1 EP0057684 A1 EP 0057684A1 EP 81902033 A EP81902033 A EP 81902033A EP 81902033 A EP81902033 A EP 81902033A EP 0057684 A1 EP0057684 A1 EP 0057684A1
Authority
EP
European Patent Office
Prior art keywords
gold
silver
solvent
salts
solution
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Withdrawn
Application number
EP81902033A
Other languages
German (de)
English (en)
Inventor
Alan James Parker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anumin Pty Ltd
Original Assignee
Anumin Pty Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Anumin Pty Ltd filed Critical Anumin Pty Ltd
Publication of EP0057684A1 publication Critical patent/EP0057684A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G7/00—Compounds of gold
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G5/00—Compounds of silver
    • C01G5/02—Halides
    • 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
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
    • C22B3/16—Extraction of metal compounds from ores or concentrates by wet processes by leaching in organic solutions
    • 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

Definitions

  • THIS INVENTION relates to the reccvery of metal values and particularly gold and silver.
  • Australian Patent Application No. 39230/78 is directed to a process for the recovery or refining of silver comprising the steps of, if required, converting the silver to silver chloride, dissolving the silver chloride in dipolar aprotic solvent such as dimethylsulfoxide in the presence of additional chloride salts such that the silver chloride dissolves as the dichloroargenate salt, separat ing any insoluble solids, precipitating purified silver chloride from solution by the addition of water or methanol and separating the silver chloride precipitate.
  • dipolar aprotic solvent such as dimethylsulfoxide
  • additional chloride salts such that the silver chloride dissolves as the dichloroargenate salt
  • halide refers only to chloride or bromide. It has now been established that copper (II) halides, or ferric halides dissolved in dimethylsulfoxide, dimethylformamide or acetonitrile or other water miscible dipolar aprotic solvents or mixtures of such dipolar aprotic solvents containing halide salts of cations such as sodium, copper, potassium, lithium, tetraalkylammonium, calcium and magnesium are very good oxidising agents for oxidising metals which form halo-complexes, such as copper, silver and gold, and that such an oxidising agent is very useful in the recovery of metal values from materials which can be oxidised to form halo-complexes. Other oxidants, such as chlorene or bromine in acetonitrile containing halide ions, can oxidise gold or silver.
  • the invention resides in an oxidising agent comprising a water miscible dipolar aprotic solvent or mixtures of such solvents containing halide ions, copper (II) and/or ferric ions and cations (including cupric and ferric) which forms soluble salts with the halo complex anions in the appropriate solvent.
  • the invention resides in a method of oxidising gold, silver and their sulfides selenides or tellurides and dissolving them as their gold or silver halo-complex salts leaving insoluble elemental sulfur, selenium or tellurium as appropriate, comprising leaching the material containing gold and/or silver with a water miscible dipolar aprotic solvent containing halide salts and an oxidant which does not react extensively with the solvent but does oxidise gold, silver and their sulfides selenides and tellurides in solution in the solvent.
  • DMSO dimethylsulfoxide
  • cupric chloride is the oxidant.
  • Dimethylformamide and acetonitrile are also preferred water miscible dipolar aprotic solvents, and cupric bromide or ferric halides are other preferred oxidants.
  • the invention may be applied to a method of dissolving copper, silver, and gold such as are found in anode slimes and of recovering silver halide and gold from the resulting solutions. It also may be applied to a method of refining silver and gold from oxidisable materials such as bullion or dental alloys containing those elements.
  • Refining is achieved by leaching said materials with copper (II) halide in a dipolar aprotic such as dimethylsulfoxide (DMSO) containing halide salts of inert cations such as sodium, potassium, lithium, calcium, tetraalkyl ammonium, magnesium, copper and iron, separating the resulting solution, containing halo-complexes of silver, gold and copper, from insoluble material then adding a hydroxylic solvent, such as water or methanol. On addition of the hydroxylic solvent, silver halide precipitates and is separated. If copper (I) halide and gold halo-complex are present, gold is reduced and precipitated and is separated also. Any remaining copper (I) halide may be oxidised to copper (II) halide for recycling, using for example oxygen and HCl or chlorine or bromine as oxidants.
  • DMSO dimethylsulfoxide
  • halide salts of inert cations such as sodium, potassium, lithium, calcium
  • the invention is also applicable as a method of recovering gold from solutions containing halo-complexes of gold in dipolar aprotic solvents, whereby water or methanol are added to such solutions to destabilize the gold halo complex. In the presence of copper (I) halide or other reductant, gold is reduced and precipitates.
  • the gold is believed to be in solution as Au(Eal 2 )-.
  • Other reductants besides Cu(I) salts include ferrous salts, oxalic acid, SO 2 , hydrazine as are familiar to those skil led in the art of reducing gold (I) and gold (III).
  • the invention is also applicable as a method of leaching copper, silver or gold from suitably masked materials to produce circuit boards for electronic devices.
  • the reactions in dipolar aprotic solvents containing chloride ions are believed to be as follows:-
  • the method of leaching halo-complexes of precious metals from materials containing the metals, their sulfides, their selenides their tellurides and their halides is especially well suited to processing anode slimes from copper refineries.
  • the precious metals are recovered as metal, or halide by adding hydroxylic solvents, such as water or methanol, to the dipolar aprotic leach solution containing the metal halo-ccmplexes and ferrous or cuprous halides and collecting the precipitated solids.
  • the halo-complexes are destabilized by adding hydroxylic solvents to the dipolar aprotic. Impurities such as silicates and sulfur selenium and tellurium remain in the leach residue.
  • the methods are based en the following chemistry.
  • dry dipolar aprotics such as DMSO
  • a source of halide ions either as a suspension or in solution
  • iron (III) or copper (II) halides are powerful oxidising agents of E° greater than 0.6V nhe.
  • dry acetonitrile cupric halides are even more powerful , even in the absence of other sources of halide ions, because of strong solvation of copper (I) by acetonitrile.
  • halo-complexes e.g. AgCl 2 3 - than we have written may be present.
  • the gold may be oxidised to the +3 oxidation state.
  • DMSO dry dipolar aprotic solvents
  • the halide salt be chosen so that its cations form soluble salts with halo-complexes of the metals being treated, even if the halide salt ⁇ eg. NaCl) itself is not appreciably soluble in the dipolar aprotic solvent (eg.
  • Oxygen was bubbled through the filtrate for 5 hours and the PH was maintained below 2 by the addition of HCl.
  • the resulting CuCl 2 , CaCl 2 , DMSO, H 2 O solution was distilled under reduced pressure to remove the water and the dry oxidant in DMSO dissolved a further 5g of particulate silver.
  • 150ml of methanol silver chloride precipitated.
  • Example VII In another experiment with the material of Example VII, the mild steel face was masked as were portions of the silver face. After submersion in the DMSO oxidising solution for one hour, the unmasked silver faces were etched. Thus composition has application for etching copper and silver.
  • the invention resides in a method of recovering gold and silver from materials containing same which comprises leaching the material containing the gold and silver with a water miscible dipolar aprotic solvent containing halide salts and an oxidant which does not react extensively with the solvent but does oxidise gold and silver and their sulfides and selenides in the solvent, separating the leach solution from the material, adding water to the leach solution to precipitate silver halide and, in the presence of a reducing agent such as CuCl- 2 or FeCl 2 or SO 2 to precipitate gold, said reducing agent being sufficiently reactive to reduce chlorine, bromine and gold salts in aqueous dipolar aprotic solvents but insufficiently reactive to reduce copper halides to copper metal .
  • a reducing agent such as CuCl- 2 or FeCl 2 or SO 2
  • the source of chloride and bromide ions may be excess Cu Cl 2 or Cu Br 2 when using dipolar aprotic solvents other than acetonitrile.
  • Cu 2+ in the presence of bromide ions in DMF and DMSO is a more powerful oxidant for gold and silver than Cu 2+ in the presence of chloride ions. Materials containing silver are oxidised faster and at lower potentials than are materials containing gold.
  • the invention resides in a method of recovering gold and silver separately from materials containing same which comprises leaching the material containing the gold and silver with a water miscible dipolar aprotic solvent containing halide salts and an oxidant which does not react extensively with the solvent but does oxidise gold and silver in solution in the solvent, separating the leach solution from the material, if necessary oxidising the leach solution to remove any reducing agents present in the leach solution, adding water to the leach solution to precipitate silver halide, separating the precipitated silver halide, and adding a reducing agent to the separated solution to precipitate the gold, said reducing agent being sufficiently reactive to reduce chlorine, bromine and gold salts in aqueous dipolar aprotic solvents but insufficiently reactive to reduce copper halides to copper metal .
  • a 0.69g lump of a dental allow containing 90% gold was leached with 15ml 1M CuCl 2 , 1M CaCl 2 in DMF at room temperature for 7 days. 35% of the alloy dissolved and 0.23g of gold entered the solution. After 1 further day, only 2% more gold dissolved. On addition of water, 95% of the leached gold precipitated. The remaining lump (0.442g) was leached with 0.2M CuCl 2 , 0.5M LiBr in 15ml of DMSO. After 6 hours the weight had reduced to 0.420g.
  • 0.2475g of -200 mesh chalcopyrite was oxidised with 5ml of 0.7M CuCl 2 , 0.7M CaCl 2 in DMSO at 80° for 1 hour.
  • the residue weighed 0.115g and contained 0.08g sulfur.
  • CuFeS 2 is oxidised by this oxidant.
  • AuCl 3 in dipolar aprotics containing chloride ions is also an oxidant for gold and a reducing agent like CuCl is needed if gold is to be precipitated from solutions of AuCl- 2 in such solvents by adding water.
  • gold metal precipitates from solutions of gold (I) or gold (III) salts include powders, flakes, colloidal suspensions and mirrors.
  • Gold flakes, powders and colloids have many practical applications which are described in the literature.
  • Gold mirrors are especially desirable and so called electroless or chemical deposition of gold onto surfaces relies on in-situ reduction of a soluble gold compound with chemical reductants, such as hydrazine, and borohydrides or else via replacement or a less noble metallic surface (e.g. copper or nickel).
  • chemical reductants such as hydrazine, and borohydrides or else via replacement or a less noble metallic surface (e.g. copper or nickel).
  • Such methods have the disadvantage that the reaction products of the reductant build up in the solution in a continuous process.
  • the soluble gold compounds are often cyano comp lexes which are undesirable for environmental reasons.
  • Halo complexes of gold (I) are preferable as sources of soluble gold, for mirrors, colloids, flakes and powders
  • solutions of gold halo-complexes containing cuprous or ferrous halides and other halide salts in dimethylformamide, acetonitrile or dimethylsulfoxide give flakes, powders, colloidal suspensions and mirrors on surfaces such as glass, when water is added to the solutions, suggests a new method of making gold films, gold flakes, colloidal gold and gold powders.
  • solutions of a variety of concentrations up to 0.5M gold can be prepared by dissolving gold with cupric halide in dimethylformamide acetonitrile or dimethylsulfoxide containing salts of halide ions.
  • the copper (I) halide acts as a reductant and a gold mirror forms on surfaces, such as glass, which are clean.
  • the solution is colloidal but in time, gold powders and flakes form in addition to the gold mirror.
  • the method involves a reversible redox couple CuCl 2 /CuCl 2 - or CuBr 2 /CuBr- 2 or FeCl 3 /FeCl 2 or FeBr 3 /FeBr 2 so that the solutions can be recycled, after removing water, to dissolve more gold and precipitate new films without further addition of oxidant or reductant. Thus impurities do not build up in the solutions on cycling.
  • the method involves dissolving gold as the AuCl- 2 or AuBr- 2 complex as described herein, then reducing it with cuprous or ferrous halide as a film onto surfaces prepared by methods familiar to those skilled in the art, by adding water to the dry DMF acetonitrile or DMSO solution.
  • the invention resides in a method o producing gold mirrors which comprises applying a solution of gold as the AuCl- 2 or AuBr- 2 complex in a water miscible dipolar aprotic solvent as described herein as a film to a suitably prepared glass surface, reducing it by the addition of water in the presence of cuprous or ferrous halides to deposit a film of gold on the surface.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Inorganic Chemistry (AREA)
  • Geology (AREA)
  • Geochemistry & Mineralogy (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

L'or et l'argent, ainsi que leurs sulfures, seleniures et tellurures sont oxydes avec des solvants aprotiques dipolaires melangeables a l'eau contenant des bromures et/ou des chlorures et des ions cuivriques et/ou ferriques en tant qu'oxydants. La reaction d'oxydation est utilisee pour recuperer l'or et l'argent; pour produire des miroirs dores et pour graver le cuivre et l'or.
EP81902033A 1980-08-06 1981-07-24 Recuperation de metaux precieux Withdrawn EP0057684A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AU4901/80 1980-08-06
AUPE490180 1980-08-06
AU7554/81 1981-02-11
AUPE755481 1981-02-11

Publications (1)

Publication Number Publication Date
EP0057684A1 true EP0057684A1 (fr) 1982-08-18

Family

ID=25642401

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81902033A Withdrawn EP0057684A1 (fr) 1980-08-06 1981-07-24 Recuperation de metaux precieux

Country Status (2)

Country Link
EP (1) EP0057684A1 (fr)
WO (1) WO1982000478A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5401296A (en) * 1994-06-28 1995-03-28 Martenson; Irvin Precious metal extraction process
AUPP265398A0 (en) * 1998-03-27 1998-04-23 Elutech Pty Ltd Recovery of precious metals and copper from copper/gold ores using resin technology
US11427886B2 (en) 2015-04-21 2022-08-30 Excir Works Corp. Methods for simultaneous leaching and extraction of precious metals
CN112280990A (zh) * 2020-10-19 2021-01-29 廖殷 提炼黄金白银的方法
CN114807613A (zh) * 2022-04-18 2022-07-29 上海第二工业大学 一种极性非质子溶剂反应体系选择性回收固体废物中贵金属金的方法
CN114807610A (zh) * 2022-04-18 2022-07-29 上海第二工业大学 一种极性非质子溶剂体系选择性分步提取废弃电路板中贵金属的方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3826750A (en) * 1970-01-08 1974-07-30 Golden Cycle Corp Noble metals solvation agents-hydroxyketones and iodine and iodide
US3963841A (en) * 1975-01-06 1976-06-15 International Business Machines Corporation Catalytic surface preparation for electroless plating
AU507314B2 (en) * 1976-05-12 1980-02-14 Emperor Mines Ltd Extraction of au, ag and te
BE847441A (fr) * 1976-10-19 1977-02-14 Procede pour recuperer des metaux precieux de matieres en contenant.
ZA775210B (en) * 1977-08-29 1979-04-25 Nat Inst Metallurg Silver recovery of refining

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8200478A1 *

Also Published As

Publication number Publication date
WO1982000478A1 (fr) 1982-02-18

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Inventor name: PARKER, ALAN JAMES