Extraction of precious metals from ores and other precious metal containing materials using halogen salts
AssigneeSouth Dakota School of Mines and Technology
InventorsKenneth N. Han, Xinghui Meng
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Abstract
Platinum group metals, gold and silver are extracted from complex ores, automobile scrap, refractory ores and as naturally occurring by leaching the precious metal containing materials with a solution containing halogen salts such as potassium or sodium iodide and bromide in the presence of ammonium ions and oxygen. The precious metal containing materials and reactants are charged into a reaction zone held at high temperatures and pressures to form a slurry containing a precious metal ion solution. The precious metal ion solution is separated from the slurry and subjected to recovering techniques to recover the precious metals.
Claims22
A method for the extraction of precious metals by a leaching process comprising the steps of:
- I. charging to a reaction zone:
- A. precious-metal bearing materials;
- and
- B. water, either a halide, an elemental halogen or a mixture thereof, and ammonium ions as a leaching solution to form a charged reaction zone;
- II. heating the charged reaction zone to a temperature of about 50.degree. C. to about 300.degree. C. under oxidizing conditions at a pressure of from about 30 psig to about 1300 psig for a time sufficient to leach the precious metals from the precious-metal ore thereby producing a slurry containing a precious-metal-ion-solution;
- III. separating the precious-metal-ion-solution from the slurry;
- and
- IV. recovering the precious metals from the precious-metal-ion-solution.
A method for the extraction of precious metals from carbonaceous refractory ores, by a leaching process comprising the steps of:
- I. charging to a reaction zone:
- A. precious-metal bearing refractory materials;
- B. water;
- C. either a halide, an elemental halogen or a mixture thereof;
- and
- D. ammonium ions;
- to form a charged reaction zone;
- II. heating the charged reaction zone to a temperature of about 50.degree. C. to about 300.degree. C. under oxidizing conditions at a pressure of from about 30 psig to about 1300 psig for a time sufficient to leach the precious metals from the precious-metal material thereby producing a slurry containing a precious-metal-ion-solution;
- III. separating the precious-metal-ion-solution from the slurry;
- and
- IV. recovering the precious metals from the precious-metals-ion-solution.
Dependencies are inferred from the claim text.