METHOD FOR SELECTIVE EXTRACTION OF RHODIUM RH, RUTHENIUM RU AND IRIDIUM IR FROM HYDROCHLORIC ACID SOLUTIONS OF CHLORINE COMPLEXES OF PLATINUM PT (IV), PALLADIUM PD (II), GOLD AU (III), SILVER AG (I), RHODIUM RH (III), RUTHENIUM RU (IV) AND IRIDIUM IR (IV) Russian patent published in 2021 - IPC C22B11/00 C22B3/44 C01G55/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to hydrometallurgy of platinum metals. Selective release of rhodium, ruthenium and iridium is carried out from a hydrochloric acid solution containing chlorine complexes of platinum Pt (IV), palladium Pd (II), gold Au (III), silver Ag (I), rhodium Rh (III), ruthenium Ru (IV), iridium Ir (IV). Solution is treated with carbon monoxide CO at atmospheric pressure, intensive stirring and heating with subsequent filtration. Hydrochloric acid solution is used at HCl content of 1.5–3 mol/l. After filtration there is obtained a precipitate containing Pt, Pd, Au, Ag, and a filtrate containing Rh, Ru, Ir in form of carbonyl chloride complexes Rh(I)-Rh(CO)₂Cl₂^-, Ru(II)-Ru(CO)₂Cl₄^-2 and Ir(I)-Ir(CO)₂Cl₂^-. Obtained filtrate is neutralized to HCl = 2 mol/l. Then Rh, Ru and Ir are sequentially separated from the filtrate by varying acidity of the solution. Rhodium is separated from solution at temperature 95 °C and pH 2 for 6 hours to obtain a filtrate containing ruthenium and iridium, and ruthenium is separated at temperature 95 °C and pH 5 for 6 hours. Filtrate residue containing Ir is treated with chlorine to an oxidative potential of 850 mV to form a solution of the chloro-complex Ir (IV) - [IrCl₆]^-2, into which NH₄Cl is added and precipitated (NH₄)₂[IrCl₆]. Obtained residue is calcined to obtain Ir.

EFFECT: method increases degree of selectivity of extraction of rhodium, ruthenium and iridium from solution of noble metals with high degree of purity.

1 cl, 4 tbl, 10 ex