Lithium enrichment and migration mechanism in the evaporation process of sodium aulphate subtype salt lake brine

Abstract

Based on the natural evaporation experiment conducted on approximately 460 tons of sodium sulfate subtype salt lake brine over a period of more than three years, and utilizing the unique natural energy of Tibet, a new lithium enrichment salt field process called “ three times salt water-twice winter brine “ has been proposed for the Laguocuo brine. On-site natural evaporation achieved high yield of lithium and a “ultra high multiple enrichment” of 134 times. Using first-principles calculations, the adsorption behavior and mechanism of Li+ on the surfaces of Na2SO4·10H2O, NaCl, and KCl crystals were investigated. It was found that the migration of lithium during mineral precipitation in brine evaporation was restricted by the adsorption capacity of Li+ on the surface of minerals (Na2SO4·10H2O > NaCl > KCl). The specific surface area, adsorption concentration of Li+, and surface roughness of the three crystals were tested. The results indicated that the specific surface area and roughness of the three crystals were in the following order: Na2SO4·10H2O > NaCl > KCl, which is consistent with the simulation results. These research findings provide a reference basis for the efficient lithium extraction from Tibetan sodium sulfate subtype salt lakes.