Review on Pyrometallurgical Smelting Options for Recycling Precious and Platinum Group Metals from Secondary Resources

Over the past few decades, there has been a growing global focus on the recovery of Platinum Group Metals (PGMs) and Precious Metals (PMs), which are classified as critical raw materials. However, diminishing ore resources have underscored the importance of selecting effective recovery methods. The low concentration of PGMs and PMs in primary ores, combined with the complexity of extraction processes, can make their extraction from by-products of nickel and copper smelting operations costly. Conversely secondary resources such as spent automotive catalysts (SACs) and waste electrical and electronic equipment (WEEE) have emerged as both technologically feasible and economically viable alternatives. From an industrial standpoint, pyrometallurgy remains the predominant recovery technology due to its high recovery efficiencies, and as needed, scalability for smaller or larger-scale operations. This review examines the recovery processes and the corresponding distribution coefficients of valuable metals such as gold, silver, and PGMs in different smelting systems under various conditions, offering insights into the behavior of these metals during recovery. It also explores the primary pyrometallurgical smelting technologies employed for PGMs and PMs extraction. Additionally, this review highlights the “waste-to-waste” recycling approach, where two waste streams are co-smelted to improve resource recovery efficiency. These advanced recovery methods contribute significantly to fostering a circular economy and achieving carbon neutrality.