Selective Fractionation and Valorization of Lithium Refinery Residues: A Critical Review

The rapid expansion of the lithium industry has generated large quantities of lithium refinery residue (LRR), whose stockpiling and landfilling cause environmental risks and the loss of potentially recoverable resources. This review critically examines LRR generated from the processing of spodumene and lepidolite, with particular emphasis on how differences in their mineralogical and chemical characteristics affect subsequent utilization and resource-recovery strategies. Current utilization pathways are classified into bulk utilization and selective fractionation followed by product-oriented valorization. Bulk utilization mainly includes direct incorporation into construction materials, activated cementitious materials, and sintered products, offering high residue-consumption capacity but generally limited added value. Selective fractionation employs leaching, flotation, magnetic separation, and gravity separation to separate Si-Al, Ca-S, and Fe-bearing fractions and to recover residual valuable elements, including Li, Ta, Nb, Rb, and Cs. The removal or stabilization of hazardous constituents, particularly F, Be, and Tl, is also evaluated as a prerequisite for safe valorization. The recovered fractions can subsequently be converted into products such as aluminosilicate powders, porous ceramics, zeolites, glass-fiber feedstocks, high-strength α-hemihydrate gypsum, and anhydrite II. Finally, the reviewed pathways are critically compared in terms of technical feasibility, resource efficiency, environmental risks, economic potential, technological maturity, and scale-up constraints. Priority is given to integrated processing strategies that combine hazardous-element control, selective recovery of valuable components, and large-volume utilization of bulk fractions to improve the overall sustainability and industrial viability of LRR valorization.