Antimony Hydrometallurgy from Primary and Secondary Sources (2020–2025): Critical Review of Leaching Systems and Downstream Separation

Antimony (Sb) is a critical element with growing strategic importance, yet its hydrometallurgical processing remains challenged by complex mineralogy, impurity-rich feeds, and limited industrial validation. This review critically examines recent advances in pretreatment, leaching, purification, and final recovery strategies for Sb-bearing materials, with emphasis on their integration at the flowsheet level. Pretreatment approaches primarily condition mineralogical accessibility rather than directly enhance Sb recovery, while diverse leaching systems consistently achieve high extraction efficiencies but generate chemically complex pregnant leach solutions. Across the literature, downstream purification is identified as the principal bottleneck, driven by impurity co-dissolution, selectivity limitations, and solution stability. Despite extensive laboratory-scale investigations, many separation strategies remain weakly validated with respect to reagent regeneration, long-term operability, and compatibility with final recovery routes. This review highlights that technical success at the unit-operation level does not necessarily translate into industrial feasibility, underscoring the need for integrated flowsheet validation, impurity-aware design, and technology readiness assessment. Future research should prioritize holistic process integration and scale-relevant evaluation to bridge the gap between academic development and sustainable antimony production.