2025 Deng Lithium Salt Percrystallization

Membrane percrystallization is an emerging and productive crystallization technology. This research explores the production of lithium hydroxide, carbonate, chloride, sulfate, and acetate using sugar-derived carbon membranes from feed solutions with concentrations of 1 to 20 wt.%. The membranes, coated on a porous alumina substrate, achieved high chemical robustness and tailorable porosity. Notably, the highest flux was observed with a 20 wt.% lithium chloride solution, resulting in an impressive annual salt production rate of 70 tons per square meter of membrane. In comparisons, the productivity of the percrystallizer was 54 times greater than that of traditional evaporative crystallization, which was evaluated at equivalent initial solution conditions, temperature, and vacuum. The crystallized solids were examined through scanning electron microscopy, x-ray diffraction, and thermogravimetric analysis, marking the first comprehensive characterizations of lithium salts and basic compounds produced via this innovative technology. This study highlights the potential of membrane percrystallization for enhancing lithium recovery and production in the hydrometallurgical sector.