Kinetic of carbothermal reduction of zinc, tin and lead from electroplating sludge

Copper-containing sludge, the industrial waste after treatment of industrial waste water from metallurgical and chemical industries, has been added to the list of the national hazardous wastes. It includes such valuable metals as copper, zinc, nickel, tin, lead. In order to recover these metals, this paper studies the volatilization law and kinetics of carbothermal reduction of zinc, tin and lead by electroplating sludge. According to the experiment, when the carbothermal reduction temperature was raised to 1 523 K, the volatilization rate of Zn, Sn and Pb could reach 96.98%, 96.24% and 95.37% respectively under the condition of carbothermal reduction for 60 mins, and high temperature was favorable for volatilizing Zn, Sn and Pb. The results showed that the reaction system of carbothermal reduction of electroplating sludge could be described by Mckwan reaction equation effectively. The activation energies of Zn, Sn and Pb reduction volatilization were 149.50, 138.01 and 132.26 kJ/mol, respectively. The carbothermal reduction process of electroplating sludge was controlled by interface chemical reaction.