モータ屑からの銅・鉄の分離回収に関する研究 （第１報） Ｃｕ（ＩＩ）アンミン水溶液による銅の溶解

Abstract

A hydrometallurgical process, in which aqueous Cu (II) ammine solution is used as leachant, is proposed for the selective recovery of copper and iron from motor scrap. In this paper, the chemistry of the selective dissolution of copper with aqueous Cu (II) ammine solution is described, and some fundamental experiments have been carried out. Copper is dissolved easily with aqueous Cu (II) ammine solution, leaving iron as unattacked. Copper can be dissolved from the enamel coated copper wire which is treated by heating or shot blasting. These findings suggest that copper can be dissolved selectively from motor scrap with aqueous Cu (II) ammine solution after the removal of the enamel coat. The dissolution rate of copper increases with the increase in NH3 concentration up to 7 kmol m-3. The concentration of (NH4)2SO4 affects the dissolution rate. The optimum (NH4)2SO4 concentration exists corresponding to NH3 concentration. The dissolution rate of copper is negligibly small in the Cu (II) ammine solution without (NH4)2SO4. The dissolution of copper can be accelerated by the exposure of the leachant to the air, by which the Cu (I) produced by the dissolution reaction is oxidized to Cu (II).