The Application of Nanofiltration for Separating Aluminium and Lithium from Lepidolite Leaching Solution

Abstract This paper concerns the feasibility of separating Al 3+ and Li + by nanofiltration, and a new method for separating and recovering lithium from lepidolite leaching solution was proposed. Factors like salinity, mass ratio of Al 3+ /Li + , operating pressure, temperature and proportion of SO 4 2− were investigated under single‐stage cycle mode. Multiple linear regression was used to further study the mixed effect of pressure and temperature on separation efficiency and membrane flux. The results suggest that the combination of charge effect and steric hindrance effect plays a decisive role in the separation of lithium and aluminum. When the salinity of the feed solution is 45 g/L and the mass ratio of Al/Li is 6, a combination of higher temperature and pressure within the range that the membrane can withstand is beneficial to improve separation efficiency. And a proper amount of SO 4 2− is beneficial for the separation of aluminum and lithium. Overall, it is found that nanofiltration has a relatively good separation efficiency of lithium and aluminum and provided a novel vision for future separation from lepidolite leaching solution.