Desorption enhancement of aluminum-based adsorbent in lithium extraction from sulfate-type salt lakes

Abstract

Aluminum-based lithium adsorbent has the unique advantage of neutral desorption, while the adsorption performance declines sharply in sulfate-type brines due to the deficient de-intercalation. In this study, the desorption process was systematically investigated and the pivotal influencing mechanism was perceived to enhance the cyclic lithium extraction from sulfate-type systems. It was found that increasing temperature and desorption solution consumption could availably improve the desorption of intercalated ions, while pH has little effect in the range of 4.0–10.0. Besides, the crystal structure of aluminum-based lithium adsorbent would transform from lithium aluminum layered hydroxide to gibbsite under excessive desorption, resulting in the gradual decrease of adsorption capacity. A low concentration of Li+ ions in the desorption solution could reinforce structure stability and maintain the adsorption capacity of the adsorbent under excessive desorption conditions. The optimized desorption condition enhanced the cyclic lithium adsorption capacity in the adsorption-desorption column experiment, reflecting the promising potential application of the aluminum-salt lithium adsorbent in lithium extraction from the sulfate-type salt lakes.