A novel precipitant for separating lithium from magnesium in high Mg/Li ratio brine

In the current study, a novel precipitant, sodium metasilicate nonahydrate, was investigated as a new magnesium precipitant for separating lithium from magnesium in brine with a high Mg/Li mass ratio. Various parameters and relative mechanisms of the precipitation process such as reaction time, agitation rate, sodium metasilicate nonahydrate dosage, and aging time were systematically studied. Sodium metasilicate nonahydrate exhibited superior performance in terms of precipitating magnesium and separating lithium from magnesium in brines with large ranges of initial Li+ and Mg2+ concentrations. It is demonstrated that appropriate agitation rate and aging time were beneficial for magnesium precipitation and enhancing the filtration capacity of the precipitates. The Li+ recovery in solution, Mg2+ precipitation rate, and mass ratio of Mg/Li reached approximately 86.73%, 99.94%, and 0.022, respectively, starting from an initial Mg/Li mass ratio of 30. The encouraging results suggest that Li can be recovered to a substantial degree from brines of different compositions via a precipitation method employing sodium metasilicate nonahydrate as the precipitant for Mg.