Abstract

BALDERRAMA FLORES, Fausto Alfredo. Predicting the solubility of the Li2SO4.H20 using the Pitzer model. Rev. Met. UTO [online]. 2016, n.39, pp. 3-8. ISSN 2078-5593.

Abstract During one of the stages of evaporation-crystallization of the Uyuni salt lake brines, a mix of salt rich in Li2SO4.H20 crystallizes, from which it is possible to obtain Li₂CO₃. In this paper it has been used the thermodynamic model of ion interaction of Pitzer for predicting the Li2SO4.H2O solubility in aqueous solution at 25 °C. Initially a program in Excel for estimating the Pitzer model parameters for electrolytic salt solutions from experimental data of activity coefficients has been developed. For aqueous solutions of lithium sulphate the estimated values are: 0.14344, 1.12698 and -0.00544 respectively. Subsequently, for the prediction of the solubility, another program has been developed in which the input data is the constant of salt solubility product constant and the Pitzer parameters. For a KPS value of 2.62 at 25 °C and the parameters estimated above, the calculated value for the solubility of is 3.130 molal. The experimental value is 3.131 molal. Finally, using Pitzer model parameters and solubility product constants reported in the literature, the solubility for different salts, which are part of the Uyuni salt lake brines, have been calculated.

Keywords : Pitzer model; solubility of salts; Li₂SO₄.H₂O; modelling; Uyuni salt lake.