Recovery of scattered and precious metals from copper anode slime by hydrometallurgy: A review

Scattered and precious metals (SPMs: Se, Te, Au, Ag, Pt, and Pd) play an irreplaceable role in advanced methods and materials, and their global consumption has been growing in recent decades. However, SPM consumption and recycling are very unbalanced, resulting in a shortage of supply and some uncertain risk regarding their sustainability. Copper anode slime (CAS) is an important component of secondary resources, and it contains a large amount of SPMs. Because of the complicated occurrence state of SPMs, the technique of extracting and separating them from CAS is quite different from that of raw ore. This paper focuses on the distribution of minerals and current non-cyanide hydrometallurgical methods for extracting Se, Te, Au, Ag, Pt, and Pd from CAS. In particular, in terms of recovery technology, some representative methods, including selective separation, extraction, precipitation, and reduction of hydrometallurgical method, as well as the recovery process, chemical reaction formulas, and the optimization and recycling situations of SPMs are reviewed, and the recycling potential, value, and supply risks of CAS are elaborated. Although these methods have achieved quite satisfactory results in recovering certain SPMs from CAS, it is undeniable that these still face challenges for further promotion. In addition, from the perspective of economic assessment of recovery potential, supply sustainability, and technical improvement, future strategies for recovering SPMs from CAS are proposed. This paper is intended to serve as a guide for the future development research on CAS, and provides detailed information on the promotion of SPMs recycling.