Research On Separation And Extraction Mg/Li From Mixed Ionic Solutions With Reaction-Separation Coupling Technique

China has abundant resources of salt lake brine, which have an important value for development.And their comprehensive development and utilization has been a hot research topic. But now, the separation of salt lake brine'resources only in the initial stage of the study. In the salt lake brine, Li and other elements, such as potassium, sodium, magnesium and calcium are in co-existence. Now, no one method can adapt to the demands of all, so the research on salt lake brine continues. Through years of research, China has formed several feasible technological route in lithium salt lake brine. But the low level of salt lake resources' comprehensive utilization and the high ratio of magnesium to lithium have seriously restricted the salt lake industry development.This study developed two methods of invention,which based on the reaction-separation coupling technology to extract magnesium and lithium resources in salit brine lake, meanwhile product magnesium based functional materials. The main research contents are as follows:1. The external aluminum source has been added to the solvent of salt lake brine,and then it would react with Mg2+ in the solvent by two ways,one is separate nucleation and aging steps,the other is single-drop method to synthesis MgAl-LDH.Then the the filtrate in the nucleation process is evaporated and concentrate the Li+ in it to a certain extent.Again plus aluminum source to synthesis LiAl2-LDH by co-precipitation method. In this process, I compared the nuclear crystallization separation method with the single drop method for MgAl-LDH and found, Mg2+ and Li+ in salt lake brine have been separated completely in this two ways,but taking into account the production of LDH morphology and other factors, nucleation crystallization separation rule is more suitable.2. The external aluminum source has been added to the solvent of salt lake brine,and then it would react with Mg2+ in the solvent by three ways, separate nucleation and aging steps, single-drop method and double-drop method to synthesis Mg(OH)2.Then the sythesised Mg(OH)2 in three methods have been compared on morphology, infrared factors, and other factorsto find the best method-- separate nucleation and aging steps.And in use of this method, changed the synthesis conditions: different precipitation agent proportion, crystallization temperature and crystallization time to come out the optimal conditions:precipitating agent ratio of 1:2.5, the crystallization temperature of 20?, crystallization time 2h.