METHOD OF SELECTIVE EXTRACTION OF METALS OF PLATINUM GROUP FROM ANODE SLUDGE Russian patent published in 2003 - IPC

FIELD: hydrometallurgy; extraction of metals of platinum group by electrolysis from anode sludge formed during electric refining of copper and nickel. SUBSTANCE: proposed method ensures purity of extracted metals to 99.95-99.98% . Process is fully automated and pyrometallurgical stages are excluded, thus excluding use of gas cleaning, dust collecting and solution draining systems. Proposed method includes dissolving of anode sludge and electrolytic extraction of metals. Dissolving of anode sludge is performed by treatment of it with nitric acid and electrolytic separation of metals is performed by potentiostatic electrolysis in line of potentiostatic cells; each cell includes three-dimensional porous electrode made from carbon material. Working potential of each cathode corresponds to definite metal of platinum group. At residual concentration of metals in waste electrolyte of 1-5 mg/l, metals are concentrated by passing waste electrolyte through at least one column with solid extractant and are re-extracted at return to beginning of cycle of electrolytic separation of metals. EFFECT: facilitated procedure; enhanced efficiency. 7 cl