Efficient Step-by-Step Desorption to Reduce Boron in Brine Lithium Extraction

Boron, as an associated impurity ion, has a negative impact on brine lithium extraction for lithium products. In this study, based on the interlayer ion transformability and adjustability of the plate composition, an effective boron reduction strategy was investigated in the Li+ extraction process by layered double hydroxides (Li/Al-LDHs), substituting the traditional washing stage with step-by-step desorption. It was observed that boron intercalation was unavoidable during the adsorption in brines, while the layer structure of Li/Al-LDHs would not be damaged. A higher NaCl concentration, lower pH, and lower temperature were favorable in the boron reduction stage. Besides, the boron concentration in lithium-extracting solutions decreased significantly with the strategy, which was reduced by nearly 75% during the lithium extraction from the Yiliping Salt Lake brine. The practical boron reduction approach would provide clear guidance for further resolving the issue of boron impurities in lithium resource recovery processes.