Solubilities, Densities and Refractive Indices in the Aqueous Quaternary System of Lithium Sulfate, Lithium Metaborate, and Lithium Carbonate at 288.15, 298.15, 308.15 K and 0.1 MPa

Abstract

Solubilities, densities and refractive indices of the aqueous quaternary system of lithium sulfate, lithium metaborate, and lithium carbonate at 288.15, 298.15, 308.15 K and 0.1 MPa were determined with isothermal dissolution method. According to the experimental results, the dry-salt phase diagrams, water-phase diagrams, and the diagrams of physicochemical properties including density, pH, and refractive index versus composition of lithium sulfate at three temperatures were plotted. In the dry-salt phase diagrams at three temperatures, there are four crystallization regions corresponding to lithium metaborate octahydrate (LiBO2·8H2O, LB), lithium carbonate (Li2CO3, LC), and lithium sulfate monohydrate (Li2SO4·H2O, LS), and three univariant-solubility curves corresponding to minerals of LS, LB, and LC, and one invariant point of three coexisted minerals (LS + LB + LC). A comparison of the phase diagrams at 288.15, 298.15, and 308.15 K shows that the areas of lithium sulfate monohydrate and lithium metabor...