Investigation On The Isothermal Evaporation Pathway At15℃for The Brines On The Laguocuo Salt Lake And About The Basic Dates Of Extracting Lithium

Salt lake resource is valuable mineral resources in our country, which contain extremely rich mineral resources. And the fully development and utilization of the salt lake resources, such as potassium resources, magnesium resources, lithium resources, boron resources and so on, are the key point of salt lake research, and phase chemical research is the foundation of this work.Firstly, as to the brines in Laguocuo Salt Lake, Tibet Plateau, the enrichment behavior and the crystallized pathway for the isothermal evaporation at15℃are investigated, which can provides basis data for the utilization of the brines.The experimental results show that: Na2SO4·10H2O begins to precipitate when the evaporation rate reaches52%, and it is largely precipitated in the whole evaporation process; potassium begins to precipitate when the evaporation rate reaches87%; the maximum mass concentration of Li+in the mother liquor is2.30g/L at evaporation rate of82%, and Li2CO3is precipitated when it has reached the dissolution equilibrium in brines; boron begins to precipitate when the evaporation rate reaches67%and the maximum mass concentration of B2O3in the mother liquor is15.92g/L.Secondly, this paper also studied salts crystallization law and lithium concentration variation during Laguocuo brine after add magnesium concentration process.Analyzed the constant chemical composition and determined the lithium concentration of the14brine-samples after experimental brine evaporation. The experimental results show that: Na2SO4·10H2O can be separation when the evaporation rate reaches69.88%, and it is largely precipitated after then; The concentration of K+gradually increasing in the evaporation process, potassium begins to precipitate when the evaporation rate reaches87%and K+has been precipitating until boil away. And the lithium, boron concentration increase as the evaporation rate improved-without absorbed by other salts, and at evaporation termination, the maximum mass concentration of B2O3in the mother liquor is21.56g/L, and the maximum mass concentration of Li+in the mother liquor is6.59g/L, all of those can be used to extract the lithium and boron products.In order to get the evaporating process of saturated solution of lithium in theory, lithium saturated salt water system, including a rich lithium saturated brine、 Li2SO4-Na2SO4-H2O and Li2SO4-LiOH-Na2SO4-NaOH-H2O, is studied in this paper.The lithium ion and the other ions concentration in saturated brine are fouded at different temperature.