METHOD OF REMOVING PLATINUM METALS FROM MATERIAL CONTAINING THESE METALS Russian patent published in 1998 - IPC

FIELD: precious metal recovery. SUBSTANCE: method can be used to recover platinum and palladium from platinoid concentrate obtained in gold-containing crude processing after recovering major amounts of gold and silver. Method consists in melting initial material in presence of fluxes, precipitating platinoid concentrate by sodium thiosulfate, washing, drying, separating slags, granulation, and destroying excess of nitric acid by urea. Resultant slurry containing precious metals is filtered to separate insoluble precipitate mainly containing silver and lead chlorides. Filtrate is treated with ferrous sulfate to precipitate gold slime. Remaining platinum and palladium-containing solution is treated with ammonium chloride to give platinum and palladium in the form of choropalladate and chloroplatinate that are calcined at 750-900 C to form spongy platinum and palladium. EFFECT: increased degree of recovery and reduced operational expenses. 8 cl, 1 dwg