Advancements in hydrometallurgical processes for rare earth elements recovery from coal ash

Abstract

Recent advancements in the hydrometallurgical extraction of rare earth elements (REEs) from coal ash have transformed the landscape of REEs recovery. This review critically synthesizes the latest developments and emphasizes key innovations. Coal ash, often overlooked, has emerged as a promising REEs reservoir due to its remarkable ability to retain these valuable elements during coal burning. Researchers have shifted their focus from feasibility studies to pilot-scale production, recognizing the potential of this unconventional source. Various hydrometallurgical techniques, including acid leaching, ion exchange, and solvent extraction, are explored as efficient methods for REEs recovery. Notably, acid leaching, when combined with additives, alkaline pretreatment, or thermal pretreatment, yields promising results. REEs find applications in renewable energy, security technologies, consumer goods, and national defense. Understanding the chemistry in coal is crucial for efficient extraction. Evaluating the global distribution of REEs informs strategic decisions. Hydrometallurgical procedures emerge as effective, affordable, and environmentally friendly technologies for REEs extraction from coal ash. This study bridges the gap between scientific advancements and practical implementation, positioning REEs as critical resources for a sustainable future.