Recovery of Lithium Carbonate from Dilute Li-Rich Brine via Homogenous and Heterogeneous Precipitation

An extensive experimental campaign on Li recovery<br> from relatively dilute LiCl solutions (i.e., Li+ ∼ 4000 ppm) is<br> presented to identify the best operating conditions for a Li2CO3<br> crystallization unit. Lithium is currently mainly produced via solar<br> evaporation, purification, and precipitation from highly concentrated<br> Li brines located in a few world areas. The process requires<br> large surfaces and long times (18−24 months) to concentrate Li+<br> up to 20,000 ppm. The present work investigates two separation<br> routes to extract Li+ from synthetic solutions, mimicking those<br> obtained from low-content Li+ sources through selective Li+<br> separation and further concentration steps: (i) addition of<br> Na2CO3 solution and (ii) addition of NaOH solution + CO2<br> insufflation. A Li recovery up to 80% and purities up to 99% at 80<br> °C and with high-ionic strength solutions was achieved employing NaOH solution + CO2 insufflation and an ethanol washing step.