Abstract:Old brine with Li+ 0.15 g/L and Mg2+ 119.5 g/L after potassium extraction from a salt lake was researched. Saturated adsorption capacity of magnetic aluminum-based adsorbent is 4.3 mg/g. Separation of adsorbent from brine was carried out by superconducting magnetic separator to realize synchronization salt leaching and desorption. Final product is lithium-bearing stripping solution. The results show that retention rate of adsorbent is 99% above under the conditions including superconducting magnetic separator adopting steel mesh medium, background magnetic field strength of 2 400 kA/m, adsorbent concentration of 10%, and feeding speed of 10 cm/s. Recovery rate of lithium from brine in whole process is 80% above under the conditions including salt leaching with 500 mL fresh water, desorption with 1.5 L fresh water, and concentration of Li+ and Mg2+ in desorption solution of 0.28 g/L and 0.57 g/L respectively. Lost of adsorbent is 8.9% after 100 adsorption desorption cycles in magnetic separation system. This process has certain industrial value in practice.