Extraction of lithium from coal gangue by manganese ion sieve adsorption

Due to the high content of lithium in the Pingshuo coal gangue, it is of great research value to find a suitable lithium extraction method. In this paper, the method of acid leaching with hydrochloric acid is used to dissolve the lithium of coal gangue into the solution, and then the lithium in the solution is adsorbed by a self-made manganese ion sieve to realize the recovery of lithium. The effects of activation ratio, activation temperature, acid leaching temperature, acid leaching volume and acid leaching concentration on lithium leaching rate in coal gangue were investigated. The optimum calcination and leaching conditions were determined by a single controlled variable method to achieve a dissolution rate of lithium of over 79%. Moreover, the effects of temperature and time on the formation of ion sieves were studied. The crystal form and adsorption properties of the ion sieve were characterized by XRD, SEM and ICP-OES. The results showed that the crystalline LiMn2O4 spinel was synthesized by calcination at 800℃ for 15h. The adsorption capacity of the H-type ion sieve reached 24mg/g under the condition of a solution pH of 14 and a solid-liquid ratio of 1:500. The results of ICP showed that the adsorption rate of lithium in the activated coal gangue acid leaching solution by H-type ion sieve was over 99%. © 2019, Chemical Industry Press. All right reserved.