A Study on Lithium Recovery from Seawater: Separation of Lithium from Hydrochloric Acid Solutions Containing CaCl2, MgCl2, MnCl2, NaCl, KCl, and LiCl

摘要

The adsorption method using manganese oxide is used for lithium recovery from seawater and the product solutions (acidic condition) after adsorption contains other elements such as Ca, Mg, Mn, Na, and K as well as lithium. Thus, Li recovery from hydrochloric acid solutions containing CaCl2, MgCl2, MnCl2, NaCl, KCl, and LiCl by hydrometallurgical process was investigated. A two-stage precipitation was adopted in this process using NaOH to remove Ca, Mg, and Mn and using Na2CO3 to separate Li. In the result, Ca, Mg, and Mn could be mostly removed from target solutions by precipitation as Ca(OH)2, Mg(OH)2, and Mn(OH)2 at a range of pH from 11.5 to 12.5 in the first stage. The residual Li that was precipitated as Li2CO3 by Na2CO3 in the second stage could be concentrated by evaporation at 100°C to make high lithium recovery. The final precipitation of lithium after evaporation produced crystalline lithium carbonates with high purity (99.4%).