Recovery Of Lithium From Salt Lake Brine By Composite Adsorbent

China has rich lithium rescources in salt lakes. Lithium and lithium containing compounds play an important role in modern industries. In this thesis, synthesis of composite adsorbent based on surface modification, and the performance of recovering lithium ion from salt lake were intensively investigated.The experimental results confirmed that the optimal conditions for adsorbent synthesis were pretreatment of diatomite by using4mol.l-1sodium hydroxide, using10%hydrogen peroxide as oxidant and1mol.l-1lithium chloride as the template molecule. In the static adsorption experiment, effects of several parameters were investigated. The results indicate that the adsorption equilibrium was reached within2hours; higher temperature, rotating speed and pH value were beneficial to the adsorption; the Li+adsorption capacity increased with increased initial concentration, and tended to equilibrate at last. The adsorption isotherm had Langmuir monolayer adsorption characteristics, the adsorption rate could be well described by second-order kinetic equation, and the rate-determining step was film diffusion and chemical reaction. The elution process takes30minutes under certain conditions.When other metal ions exist in the solution, Li+adsorption capacity was reduced, and the distribution coefficient of Li+was much higher suggesting that composite adsorbent could adsorb Li+selectively. The influence on the selectivity of Mg2+and Ca2+is higher than that of Na+and K+.