Preparation of λ-MnO_2 by Column Method and Its Ion-Sieve Property

摘要

λ-MnO_2 was prepared by column method from normal spinel LiMn_2O_4 with purity of 99.38% . The influence of LiMn_2O_4 grain size and acidity of leaching solution on the lithium leaching process was studied. The results show that, the appropriate range of LiMn_2O_4 grain size was 60-160 meshes and the concentration of leaching solution HCl was 0.1 mol · L~(-1). The adsorption capacity Q of λ-MnO_2 for lithium increased with the increase of pH and changed markedly at pH 6.0-10.0. It was 3.80mmol/g at pH 12.0. The distribution coefficients K_d of Li~+ and Na~+ were 3.406 x 10~4 and 2.300 respectively, and the separation coefficient α_(Na)~(Li) was 1.481 x 10~4 at pH 6.5. As a result, λ-MnO_2 is a high performance ion-sieve material for lithium ion.