Study On Extracting Lithium Ion From Saline Bittern Water

The lithium resource is rich in the saline bittern water in china,but the saline bittern water also contains abundant magnesium ion and kalium ion,which can influence the extraction of lithium ion.Spinel LiMn₂O₄ precursor and MnO₂ ion-sieve were synthesized via the Sol-Gel method.MnO₂ ion-sieve appears a high selectivity and exchange ability for lithium ion.The influences of Li/Mn ratio,the calcination temperature and acid leaching process on manganese dioxide precursor and the structure of ion-sieve were systematically studied.The surface composition,bulk phase and structure of the material were characterized by XRD,IR methods.The Li⁺ exchange ability and selectivity of ion-sieves were inverstigated via adsorption isotherm and kinetics.The relationship between ion-sieve structure,the adsorption properties and the effect of hydrochloric acid concentration on Li⁺ elution have also been discussed.The crystal structures of the four kinds of manganese dioxide have been discussed and used to adsorb the lithium ion.α-MnO₂ appears a good adsorption ability and selectivity.The influence on adsorption for lithium ion has been investigated at the different temperatures,α-MnO₂ shows a predominate adsorption for lithium ion in the simulant seawater or bittern water.m(SA-CS)bipolar membrane was prepared by sodium alginate(SA)and chitosan (CS),which were modified by Ca²⁺and glutaraldehyde(GA)as linking reagents, respectively.It was characterized by FTIR,SEM,TG,mechanism performance and swelling degree,m(SA-CS)bipolar membrane was used as septum in the separation of ions.The immigration rates of ions were obtained.The experimental results show that m(SA-CS)bipolar membrane can separate the different valence metal ion.Using this characterstic,it can remove divalent metal ions from bittern water,advoiding Mg ion's interference on lithium ion adsorption.