The Role of Oxidizing Agents in the Recovery of Precious Metals and PGMs During the Alkaline Leaching of Selenium-Rich Metallurgical Wastes - SME Annual Meeting 2025

Selenium-rich metallurgical waste, also known commercially as “crude selenium,” is a byproduct of the copper (Cu) refining process. This by-product, contains ~ 90% selenium (Se), precious metals, platinum group metals (PGMs), and other critical elements. This study investigated the leaching efficiency of Se from the sludge under alkaline conditions using different oxidizing agents to enrich PGMs and precious metals in the leach solid residue. The effectiveness of each oxidizing agent during leaching was assessed and compared. Additionally, Eh-pH diagram for Se was established under specific experimental conditions and utilized to inform process optimization. Key variables, including leaching time, temperature, and oxidant concentration, were evaluated for their impact on the efficiency and the selectivity of the oxidative alkaline leaching process.