Recovery of zinc and nickel from electrogalvanisation sludges using glycine solutions

The paper deals with a novel technique for metal recovery from electrogalva nisation sludges using glycine. Zinc and nickel contained in these sludges can be recovered by leaching with glycine and upon addition of sodium hydro xide: high efficiency and selectitivity were obtained from other metal spec ies e.g. iron or calcium. Zn-Ni alloy deposition was investigated with both synthetic media and solutions prepared by leaching samples of industrial s ludges at pH 8. The electrolytic treatment of the solutions prepared was ca rried out in a batch reactor operated in recycle mode. Zinc was found to de posit with current efficiencies of approx. 50%, hydrogen evolution competin g with the deposition. More than 90%, of the zinc contained was recovered a t the cathode. Besides, nickel deposition appeared to be inhibited by glyci ne and the efficiency of the overall technique was quite poorer for nickel than for zinc. (C) 2000 Elsevier Science Ltd. All rights reserved.