Modeling and application of continuous ion exchanges process for lithium recovery from salt lake brine

A composite model has been developed to simulate and optimize the continuous multi-column lithium adsorption based on the continuous adsorption of lithium from high Mg/Li ratio brines. The model not only simulates all the adsorption columns of the adsorption process, but also the auxiliary equipment connected to the adsorption columns such as pumps and valves, to describe the multi-column continuous lithium extraction process in detail. To improve the efficiency of lithium extraction, a 4-zone, 20-column carousel-type continuous lithium extraction process was proposed and optimized using the composite model. When the feed flow rate was set to 25 mL/min in the adsorption zone, 8 mL/min in the washing zone and 15 mL/min in the product zone, the Li+ extraction rate in the adsorption zone was 98.26%, the lithium loss in the washing zone was 16.12%, the magnesium removal rate in the washing process was 98.77%, the concentration of lithium solution obtained in the product zone was 488.55 mg/L, and the magnesium-lithium ratio was 6.45, with a lithium recovery of 79.68% for the whole continuous lithium extraction process. Overall, the continuous carousel lithium extraction process achieved the expected magnesium separation and continuous lithium extraction from the brine of the Qarhan Salt Lake.