Study on the Conditions and Kinetics on Sulfuric Acid Leaching Zinc and Chromium from Electroplating Sludge

This article,using sulphuric acid as acid leaching agent,investigates the effects of leaching time,acid concentration and leaching temperature on the leaching effect of zinc and chromium which are heavymetals from electroplating sludge,and uses Avrami equation to fit the leaching kinetics of zinc and chromi-um. The results showed that:both the optimum leaching time,acid concentration and temperature of sulph-uric acid leaching zinc and chromium are 4h,3mol/L and 20°C. Avrami equation could be used to fit boththe leaching process of zinc and chromium very well,and the apparent activation energy of the leaching re-action are 3.58 and 3.06 k J/mol respectively,that is,both the leaching process are controlled by diffusion,which provides the theory reference for the sulfuric acid leaching zinc and chromium from electroplatingsludge on an industrial scale.