拡散透析法による亜鉛浸出残さ処理液の脱硫酸に関する基礎的研究

Abstract

The removal of sulfuric acid in the process solution of zinc leaching residue, which contains about 0.5 kmol/m3 sulfuric acid, 90kg/m3 Zn, 50kg/m3 Fe (II) and 50×10-3kg/m3 Ga, was investigated by diffusiondialysis using anion-exchange membrane.The following results were obtained.1. Sulfuric acid in the process solution of zinc leaching residue is effectively separated from the cations of metals such as Zn, Fe, Ga.2. The average overall dialysis coefficient for sulfuric acid was evaluated to be 4.5×10-3 mol/(h-m2-molm-3).3. At the flow rates of the process solution of 1.0×10-3m3 /h-m-2 and water of 5.0×10-3 m3 /hm-2, the concentration of sulfuric acid in the process solution can be reduced to 12.5 mol/m3. In this condition, the water phase after dialysis contains 97.5 mol/m3 sulfuric acid and less than 1.0kg/m3 of Zn and Fe, and less than 0.5×10-3kg/m3 of Ga.4. Consequently, when the concentration of sulfuric acid in the dialyzed solution is lowered down to 12.5 mol/m3, at the flow rate of process solution of 1.0 m3 /h, the required membrane area of a diffusiondialysis cell and volumetric flow rate of the generated water were evaluated to be 1, 000 m2 and 5.0 m3 /h, respectively.