# US 4,397,690 A · Process for recovering gold

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- Number: US 4,397,690 A
- Document ID: US4397690A
- Status: Granted
- Kind: A
- Application number: 06/420,458
- Filed: 1982-09-20
- Granted: 1983-08-09
- Earliest claimed: 1982-09-20
- Assignees: GTE Products Corporation
- Inventors: Clarence D. Vanderpool; Brice E. Martin; Richard G. W. Gingerich
- Web page: https://patentgrep.com/patent/US4397690A

## CPC

- C22B 7/006: {Wet processes}
- C01G 7/00: Compounds of gold
- C22B 11/04: {by wet processes (extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26)}
- Y02P 10/20: Recycling
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Gold is recovered from a material including gold and molybdenum or tungsten by contacting the material with an aqueous solution of hydrogen iodide and iodine to solubilize the gold without solubilizing the molybdenum or tungsten and recovering the gold from the solution.

## Claims

### Claim 1

A process for recovery of gold from material including gold and molybdenum or tungsten comprising contacting said material with an aqueous solution consisting essentially of hydrogen iodide and iodine and water, said iodine being present at a desired concentration and an amount sufficient to solubilize a major portion of said gold and leaving molybdenum or tungsten said hydrogen iodide being present in an amount sufficient to provide for increased solubility of said iodine at said desired concentration.

### Claim 2 (depends on 1)

A process according to claim 1 wherein said aqueous solution of hydrogen iodide and iodine comprises from about 1 to about 10 parts of hydrogen iodide per 100 parts of water and from about 1 to about 10 parts of iodine per 100 parts of water.

### Claim 3 (depends on 1)

A process according to claim 1 wherein said material comprised gold bonded to tungsten or molybdenum.

### Claim 4 (depends on 1)

A process according to claim 1 wherein about 200 to about 400 grams of iodine is used per troy ounce of gold.

### Claim 5 (depends on 1)

A process according to claim 1 wherein said aqueous solution is heated to a temperature of about 40 to about 70 degrees centigrade during contacting.

### Claim 6 (depends on 1)

A process according to claim 1 werein successive additions of water, hydrogen iodide and iodine are made during said contacting.

### Claim 7 (depends on 1)

A process according to claim 1 wherein after sulubilizing said gold, said aqueous solution contining solubilized gold is heated to a sufficient temperature to vaporize said iodine and precipitate gold.

### Claim 8 (depends on 7)

A process according to claim 7 wherein said vaporized iodine is condensed for reuse as iodine.