REGENERATION TREATMENT OF WASTE TIN PEELING LIQUID

摘要

PURPOSE:To efficiently recover tin from a waste tin peeling liquid and to execute the economical regeneration treatment thereof by adding H2O2 to the waste liquid of the tin peeling liquid of an aq. sulfuric acid soln. contg. Cu ions used for treating the tin coating layer for copper and separating and removing the formed precipitate. CONSTITUTION:The copper or copper alloy coated with the tin layer is im mersed in the tin peeling liquid consisting of the aq. sulfuric acid contg. the Cu ions. The reaction of Cu2+Sn Sn2+Cu is effected in this way, by which the copper layer is preferentially dissolved and peeled into the peeling liquid and the copper powder is reduced and deposited. The H2O3 is sufficiently added to the waste tin peeling liquid obtd. in such a manner. The above-mentioned copper powder is oxidized and ionized in this way and is dissolved; in addition, Sn ions are oxidized to form H2SnO3. The precipitate of this H2SnO3 is separat ed and recovered by a centrifugal sepn. method or filtration preferably under addition of a high-polymer flocculating agent thereto. The resultant recovering liquid is replenished with the Cu ions until the initial concn. is attained and thereafter, said liquid is reutilized repeatedly for peeling of the tin layer.