Method for hydrometallurgical processing of a noble metal-tin alloy

Patent metadata

Field	Value
Publication number	US-2021071284-A1
Application number	US-201816963661-A
Country	US
Kind code	A1
Filing date	Jul 30, 2018
Priority date	Feb 9, 2018
Publication date	Mar 11, 2021
Grant date	—

Abstract

A method for the hydrometallurgical processing of a noble metal-tin alloy consisting of (i) 0.45 to 25% by weight of at least one metal A selected from the group consisting of gold and platinum, (ii), 35 to 99.2% by weight of at least one metal B selected from the group consisting of palladium, silver, and copper, (iii) 0.3 to 30% by weight tin, and (iv) 0 to 50% by weight of at least one element other than gold, platinum, palladium, silver, copper, and tin, and has a weight ratio of metal A:tin of ≥0.7:1, comprising the steps of:
(a1) specifically selecting a noble metal-tin alloy

or

(a2) specifically producing a noble metal-tin alloy;

(b) dissolving nitric acid-soluble components of the noble metal-tin alloy with nitric acid while forming a nitric acid-containing solution comprising the at least one metal B in the form of the dissolved nitrate, and an undissolved residue;

(c) separating the undissolved residue from the nitric acid-containing solution; and

(d) dissolving the separated residue in a medium that comprises hydrochloric acid and at least one oxidation agent.

First claim

1 . A process for hydrometallurgical processing of a precious metal-tin alloy consisting of (i) 0.45 to 25% by weight of at least one metal A selected from the group consisting of gold and platinum, (ii), 35 to 99.2% by weight of at least one metal B selected from the group consisting of palladium, silver, and copper, (iii) 0.3 to 30% by weight of tin, and (iv) 0 to 50% by weight of at least one element other than gold, platinum, palladium, silver, copper, and tin, and has a weight ratio of metal A:tin of greater than 0.7:1, comprising the steps of:
(a1) specifically selecting a precious metal-tin alloy or (a2) specifically producing a precious metal-tin alloy; (b) dissolving nitric acid-soluble components of the precious metal-tin alloy with nitric acid while forming a nitric acid-containing solution comprising the at least one metal B in the form of a dissolved nitrate, and an undissolved residue; (c) separating the undissolved residue from the nitric acid-containing solution; and (d) dissolving the separated undissolved residue in a medium that comprises hydrochloric acid and at least one oxidation agent.

2 . The process of claim 1 , wherein the precious metal-tin alloy consists of (i) 3 to 20% by weight of the at least one metal A, (ii), 40 to 95% by weight of the at least one metal B, (iii) 2 to 17.5% by weight of tin, and (iv) 0 to 50% by weight of the at least one element other than gold, platinum, palladium, silver, copper, and tin, and the weight ratio of metal A:tin is in the range of 1:1 to 10:1.

3 . The process of claim 1 , wherein step (a2) is selected from one of procedures (a2-1)-(a2-5), wherein
procedure (a2-1) comprises melting at least one recyclable material to be recycled while forming a multi-phase system comprising a lower phase made of the molten precious metal-tin alloy of the type, and an upper phase made of molten slag having a lower density, if applicable while adding collecting metal and/or slag forming agent and/or reducing agent, and separating the upper phase from the lower phase making use of the difference in density, followed by cooling the separated molten materials and allowing them to solidify, and obtaining the solidified precious metal-tin alloy; procedure (a2-2) comprises treating a molten alloy that is different from the precious metal-tin alloy with an oxidation agent while forming a multi-phase system comprising a lower phase made of the molten precious metal-tin alloy and an upper phase made of molten slag having a lower density, in which the oxidation products produced are present, if applicable while adding collecting metal and/or slag forming agent, and separating the upper phase from the lower phase making use of the difference in density, followed by cooling the separated molten materials and allowing them to solidify, and obtaining the solidified precious metal-tin alloy; procedure (a2-3) comprises alloying at least two alloys that are different from each other, possibly while adding into the alloy at least one element while forming the precious metal-tin alloy; procedure (a2-4) comprises alloying at least one element into an alloy while forming the precious metal-tin alloy; and procedure (a2-5) comprises removing tin by distillation from an alloy while forming the precious metal-tin alloy.

4 . The process of claim 3 , whereby the at least one recyclable material to be recycled contains, aside from precious metal and base metal, at least one substance that is not a precious metal and not a base metal.

5 . The process of claim 4 , whereby the at least one substance that is not a precious metal and not a base metal is selected from the group of inorganic refractory materials.

6 . The process of claim 5 , whereby the group of inorganic refractory materials consists of silicon dioxide, aluminium oxide, calcium oxide, iron oxide, calcium sulfate, calcium phosphate, and tin dioxide.

7 . The process of claim 4 , whereby the at least one substance that is not a precious metal and not a base metal is a component of ceramic filter materials, abrasives, polishing agents and/or inorganic carrier materials.

8 . The process of claim 3 , whereby the at least one recyclable material to be recycled is selected from the group consisting of mining concentrates, waste and mixed waste, whereby the waste is selected from the group consisting of waste from jewellery production, waste from dentistry, electronics scrap, precious metal scrap, precious metal-containing scrap from precious metal-processing operations, precious metal sweepings, spent precious metal catalysts, precious metal catalyst dusts, precious metal-containing slag, precious metal dross, precious metal-containing and possibly dried sludge, and overburden from precious metal mines.

9 . The process of claim 1 , whereby the concentration of the nitric acid used in step (b) is in the range of 10 wt % to 67 wt. %.

10 . The process of claim 1 , whereby the concentration of the hydrochloric acid used in step (d) is in the range of 3 mol/L to 12 mol/L.

11 . The process of claim 1 , whereby the at least one oxidation agent used in step (d) is selected from the group consisting of nitric acid, chlorates, nitrates, bromates, iodates, chlorites, bromites, iodites, hypochlorites, hypobromites, hypoiodites, perchlorates, ozone, ozonides, superoxides, oxygen, chlorine, bromine, iodine, peroxo compounds, permanganates, and chromates.

Assignees

• Heraeus Deutschland Gmbh & Co Kg

Inventors

• Röhlich Christoph

Classifications

• C22B23/0438

  Nitric acids or salts thereof · CPC title

• C22B23/0407

  Leaching processes · CPC title

• C22B11/042

  Recovery of noble metals from waste materials · CPC title

• C22C5/04

  Alloys based on a platinum group metal · CPC title

• C22C5/08 Primary

  with copper as the next major constituent · CPC title