METHOD OF RECOVERING OSMIUM FROM PLACER PLATINUM Russian patent published in 1998 - IPC

FIELD: precious metal recovery. SUBSTANCE: placer platinum is heated under inert atmosphere to be molten at 2023-2123 K and is held at that temperature for 0.25 to 0.33 h in presence of slag resulting in formation of solid residue. The latter is melted, overheated to 2173-2373 K and isothermally held for 0.83 to 1 h to release gaseous osmium oxides in the both heating steps. All oxides are trapped in absorption solutions and then converted into metal osmium, while intermediate recovery products are isolated and recycled. Increased degree of osmium recovery is due to more completely opening placer platinum and completely transferring osmium into gas phase at high temperatures. EFFECT: increased osmium recovery. 2 cl, 1 dwg , 3 tbl