Selective Recovery of Cu(II) from Copper Smelting Dust Using Slow-Release Sulfide Precipitation Based on Activity-Controlled Pyrite

This chapter delves into the selective recovery of Cu(II) from copper smelting dust using a novel slow-release sulfide precipitation method based on activity-controlled pyrite. The study addresses the limitations of traditional sulfurizing agents, such as Na2S and NaHS, which include low purification efficiency, excessive H2S gas production, and difficulties in filtration. The research introduces a method that involves the multi-scale reconstruction of crystal structure and FeS bonds, combined with iron powder doping, to enhance the preparation of high-activity slow-release sulfide agents. The chapter explores the thermodynamic analysis of pyrite decomposition and co-pyrolysis with reducing iron powder, highlighting the phase transitions and the formation of monoclinic and hexagonal pyrrhotite. It also examines the screening of high-activity crystalline slow-release agents and their effectiveness in copper and arsenic separation. The study compares the H2S release rates and escape behaviors of the prepared slow-release agents with traditional Na2S, demonstrating significant reductions in H2S escape. The chapter concludes with the application of these agents in actual systems, showcasing their efficiency in copper recovery and deep arsenic removal. This innovative approach offers a promising solution for the selective recovery of valuable metals from copper smelting dust, addressing both environmental and economic concerns.