Study On The Salt Precipitation Law Of La Guocuo Salt Lake Brine With Pretreatment At5℃

China’s Tibet salt lake brine is rich in potassium, magnesium, lithium, boron, rubidium, cesium and other resources. At present the development and utilization of salt lake resources is mainly based on studying on the salt precipitation law, so as to determine the technological process and technological parameters. The paper mainly studied on the salt precipitation law of the La Guocuo brine, and determined the technological process of salt lake resource utilization.Considering the concentration of carbonate ions in the brine, it can cause untimely precipitation of lithium carbonate in the process of evaporation, the brine from La Guocuo was pretreated with adding magnesium chloride hexahydrate (by MMg/MC=1,1.5,2.0), and it evaporated. So it make the lithium salt precipitation significantly delayed, obtain the brine of higher lithium concentration.The paper study the brine from La Guocuo was pretreated with adding magnesium chloride hexahydrate, and it evaporated at5℃. Solution composed of different evaporation rates are obtained by evaporation experiments, and the different phase precipitation species are determined through the phase diagram analysis and XRD analysis, then the salt precipitation law of this pretreated brine is obtained.The brine from La Guocuo was pretreated with adding magnesium chloride hexahydrate (by MMg/MC=1), and it evaporated at5℃. In the evaporation concentration process, the salts precipitate phases are successively:magnesium carbonate salt, Glauber’s salt, borate salts, sodium chloride and glaserite. The quality percentage of Li+in the mother liquor is0.377%(4.76g/L).The brine from La Guocuo was pretreated with adding magnesium chloride hexahydrate (by MMg/MC=1.5), and it evaporated at5℃. In the evaporation concentration process, the salts precipitate phases are successively:magnesium carbonate salt, boron oxygen acid salt, Glauber’s salt, sodium chloride and glaserite. The quality percentage of B2O3in the mother liquor is3.760%(49.71g/L). and the quality percentage of Li+in the mother liquor is0.408%(5.39g/L).The brine from La Guocuo was pretreated with adding magnesium chloride hexahydrate (by MMg/MC=2.0), and it evaporated at5℃. In the evaporation concentration process, the salts precipitate phases are successively:magnesium carbonate salt, boron oxygen acid salt, Glauber’s salt, sodium chloride and glaserite. The quality percentage of B2O3in the mother liquor is4.941%(67.31g/L), and the quality percentage of Li+in the mother liquor is0.333%(4.53g/L).By the salt precipitation law obtained of the brine magnesia carbon ratio (1:1), brine magnesia carbon ratio (1.5:1) and magnesia carbon ratio (2.0:1) in the evaporation concentration process, it is concluded that MMg/MC in this experiment ranges inside, the influence it had on the degree of concentration of lithium ions is not obvious, and it has no influence on the degree of concentration of potassium ions, and has a significant effect on the types of boric acid salt.These studies provide basic data for the comprehensive utilization of La Guocuo salt lake resources, and have certain guiding role on the exploitation and utilization. At the same time the utilization of the relevant type of salt lake resources has a certain reference.