Abstract:Chromium, nickel, copper and zinc were extracted from high chromium electroplating sludge with sulfuric acid as leaching reagent. Under room temperature conditions, the leaching ratios of chromium, nickel, copper and zinc in sludge reached 94.2%, 96.5%, 92.9% and 95.3%, respectively, when the sulfuric acid concentration was 4mol/L, the ratio of solid to liquid was 1:10 and the reaction time was 75min. The kinetic analysis showed that chromium, copper and zinc were controlled by interfacial mass transfer and solid film diffusion, while nickel was controlled by chemical reaction.