RECOVERY OF SPENT ACID BY ELECTRODIALYSIS IN THE ZINC HYDROMETALLURGYINDUSTRY - PERFORMANCE STUDY OF DIFFERENT CATION-EXCHANGE MEMBRANES

A performance study of four different cation-exchange membranes was co nducted on laboratory and pilot scale (172 cm(2)/membrane, model CS-0 from Asahi Glass Co.) electrodialysis cells, using Neosepta CMS from T okuyama Soda Co.; Morgane CRA from Solvay; Selemion CHV from Asahi Gla ss Co, and Nafion 117 from DuPont coupled with a Morgane ARA 17-10 ani on-exchange membrane. Comparisons were made of the sulphuric acid reco very rate, water transport, metal leakage and energy intake for these membranes. Proton permselectivity and metal leakage, co- and counter-i on transport numbers of the CMS membrane were investigated using Hitto rf's method and radiotracer methods. This study shows that electrodial ysis is suitable for the treatment of zinc hydrometallurgy effluents, However, R&D work must still be done in order to improve and optimize the technology for its use in future industrial applications, In parti cular, research efforts must concentrate on the synthesis of affordabl e and stable cation-exchange membranes showing high selectivity toward s protons.