Critical minerals: Challenges and opportunities in platinum group mineral flotation

Platinum group minerals (PGMs) are critical for the green energy transition, playing key roles as catalysts in fuel cells and catalytic converters. Their limited global supply as well as geopolitical challenges further elevate their strategic importance. Southern Africa continues to dominate the global supply of PGMs, but mining operations face increasing challenges as ore bodies become deeper and more mineralogically complex. These complexities include a higher prevalence of slower-floating PGM species, such as platinum arsenides, and problematic gangue minerals like talc and serpentine. This paper addresses these challenges by ranking the major PGM species in order of floatability and provides critical insights for optimizing flotation processes. Additionally, the importance of effective gangue management in mineralogically complex ores is illustrated through the decoupling of gangue recovered by entrainment or true flotation and, further, by mineral species. The findings offer broader implications for addressing mineralogical barriers to flotation, providing solutions applicable not only to PGM ores but also to other complex ore systems. These advancements aim to enhance the efficiency and sustainability of mineral processing in the face of evolving global resource challenges.