Enriching lithium and separating lithium to magnesium from sulfate type salt lake brine

Abstract

Extraction of lithium from salt lake brine has become a research highlights due to the rapid development of lithium ion battery. There are abundant lithium resources in sulfate type salt lake in China. In this work, the process of enriching lithium and separating lithium to magnesium from simulated sulfate type brine was carried out based on the reaction of Al/Na2SO4 composite with brine. The results show that Al/Na2SO4 composite can be used to enrich lithium from Li2SO4 solution in the form of Li2Al4(OH)12SO4·xH2O and the lithium precipitation efficiency reaches 89.2% under the optimal conditions. The existence of magnesium in solution is adverse to the precipitation process of lithium. The coating of compact MgAl hydrotalcite on the surface of aluminum based material hinders the reaction of Al/Na2SO4 composite with brine and the lithium precipitation efficiency decreases to 54.7% when the Mg/Li mass ratio in solution is 20:1. However, the Mg/Li mass ratio in precipitate is less than 0.3 under the optimal conditions. The results are beneficial for the enriching lithium and separating lithium to magnesium from sulfate type brine.