Selective Recovery of Copper from Acid Leaching Solution through Slow Release Sulfide Precipitant

A new kind of sulfide precipitant, namely, slow release sulfide precipitant (SRSP), was developed and prepared first to realize the selective recovery of copper from an acid leaching solution. The experimental results indicated that SRSP as a precipitant could selectively and efficiently recover copper and the high purity of copper sulfide slag with a Cu grade of 48.16%, and a Cu recovery rate of 97.84% could be obtained. Moreover, copper in leaching solution could be recovered more efficiently and selectively by SRSP compared with Na2S. The results of H2S gas release, chemical reaction energy calculation, and SEM image analyses illustrated that realizing the selective recovery of copper mainly depended on the ions of S2− and HS− produced by the dissolution of SRSP. Moreover, the concentrations of S2− and HS− should always be kept at a low level in the process of selective recovery of copper; this is the biggest difference from the traditional precipitant and the key to preventing the escape of H2S gas in the copper recovery process. More pivotally, SRSP provides an alternative sulfide precipitant for the selective recovery of copper from the acid leaching solution of copper smelting dust.