Recovery of rhenium from dust and waste acid generated from copper-molybdenum smelting: A critical review

Rhenium (Re), as a scarce metal, is primarily essential for producing high-temperature superalloys and platinum–rhenium catalysts, which together consume over 90 % of global Re production. As a significant aerospace power, China relies on Re imports for more than 50 % of its demand. This paper comprehensively reviews the Re separation and extraction from secondary resources, focusing on copper-molybdenum smelting dust and waste acid, which account for over 80 % of Re occurrence. Recovery process needs to consider variations in raw materials and develop tailored technologies. The main industrial route for dust pretreatment involves pyrometallurgical processing followed by solution leaching. However, it faces issues such as high energy consumption and low leaching selectivity. Achieving deep recovery from leaching solution lies in the high-precision separation of Re from impurities. Both chemical and non-chemical precipitation methods are widely used. Non-chemical precipitation typically achieves recovery rates above 95 % but requires weakly acidic or neutral conditions, necessitating prior wastewater treatment. Chemical precipitation is simple, efficient, and rapid for strongly acid wastewater, but the traditional precipitation process often leads to co-precipitation of impurity ions, which reduces product purity. Effective control of sulfur ion concentration during sulfide precipitation is crucial for improving separation precision. The selective precipitation can be optimized by finely adjusting the properties and addition methods of the sulfurizing agent. This paper proposes a new approach to Re recovery through three key dimensions: source control-process enhancement-precise separation. It also addresses the current challenges and outlines future directions for improving Re recovery from smelting dust and waste acid, guiding its deep, efficient separation and high-value utilization in metallurgical by-products.