Abstract:The effects of raw material granularity, grade, acidity, ratio of liquid to solid (L/S), leaching temperature, leaching time, oxidant dosage, potential of solution, and pretreatment on leaching rates of platinum group metals (PGMs) were investigated. The results show that the higher raw material grade is, the lower leaching residue rate and the higher leaching rate of PGMs will be under the conditions including granularity of -0.074 mm, L/S=5/1, leaching temperature of 90~100 ℃, leaching time of 8 h, and potential of solution of 1.0~1.2 V. Leaching rates of PGMs rise sharply with increase of concentration of mixing acid from hydrochloric acid and sulfuric acid, which are higher than those in single hydrochloric acid and sulfuric acid system. Leaching rates of platinum, palladium, especially rhodium are markedly improved after pretreated by adding sodium hydrogen sulfate roasting. The leaching rates of platinum and palladium are 99% above, and rhodium of 97% above.