Patent ID: 7291202

Claim:
A process for mutual separation of platinum group metals (PGM) from a raw material which also contains impurity elements, comprising the following steps: (1) first step, wherein the raw material containing PGM is leached in the presence of an oxidant while being suspended in a hydrochloric acid solution to prepare a leach liquor containing the PGM, (2) second step, wherein the leach liquor prepared in the first step is separated by solvent extraction with diethylene glycol dibutyl ether into the organic phase containing impurity elements and a raffinate, (3) third step, wherein the raffinate prepared in the second step is treated by solvent extraction with an alkyl sulfide to extract palladium and the resulting loaded solvent is then treated by stripping, to prepare a stripping liquor containing palladium and raffinate, (4) fourth step, wherein the raffinate prepared in the third step is separated by solvent extraction with bis(2-ethylhexyl)phosphoric acid into the organic phase containing cationic impurity elements and raffinate, (5) fifth step, wherein the raffinate prepared in the fourth step is hydrolyzed in the presence of an oxidant, after being adjusted at a pH of 5 to 12, to prepare a precipitate containing iridium, ruthenium and rhodium, and aqueous solution containing platinum, (6) sixth step, wherein the precipitate prepared in the fifth step is leached in the presence of an oxidant in a strongly alkaline aqueous solution kept at a pH of 12 or more, to prepare a residue containing iridium and rhodium, and leach liquor containing ruthenium, and (7) seventh step, wherein the residue prepared in the sixth step is dissolved in a hydrochloric acid solution to prepare an aqueous solution containing iridium and rhodium, the aqueous solution is treated by solvent extraction with tributyl phosphate to extract iridium, and the resulting loaded solvent is then treated by stripping, to prepare a stripping liquor containing iridium and raffinate containing rhodium.