PURPOSE: To efficiently recover tin from a soln. contg. recovered tin at a high rate and to regenerate and use the remaining soln. without draining by recovering tin from Cu (alloy) coated with tin by dissolution in a specified removing soln., regulating the concn. of Cu ions in the soln. contg. the recovered tin and carrying out electrolytic recovery.
CONSTITUTION: Cu (alloy) coated with a tin layer is immersed in an aqueous sulfuric acid soln. contg. Cu ions to dissolve and remove the tin layer. The concn. of Cu ions in the soln. is regulated to ≤4g/l, that of Sn2+ ions to 5W30g/l and tin is electrolytically recovered. The concn. of Cu ions in the remaining soln. is regulated to 5W25g/l by adding copper sulfate. When tin is electrolytically recovered with the anode isolated by an anion exchange membrane, the rate of recovery is considerably increased.
INOUE SUMIO
SUMI KUSUO
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