Thermodynamic modeling and phase diagram prediction of salt lake brine systems Ⅱ. Aqueous Li+-Na+-K+-SO42- and its subsystems

作者：Huan Zhou^*; Peng Wu; Wenxuan Li; Xingfan Wang; Kuo Zhou; Qing Hao

来源：Chinese Journal of Chemical Engineering, 2021, 34(06): 134-149.

It is still a challenging task to accurately and temperature-continuously express the thermodynamic properties and phase equilibrium behaviors of the salt-lake brine with multi-component,multitemperature and high concentration.The essential subsystem of sulfate type brine,aqueous Li+-Na+-K’-SO42- and its subsystems across a temperature range from 250 K to 643 K are investigated with the improved comprehensive thermodynamic model.Liquid parameters(ΔgIJ,ΔhIJ,and ΔCp,IJ) associated with the contributions of Gibbs energy,enthalpy,and heat capacity to the binary interaction parameters,i.e.the temperature coefficients of eNRTL parameters formulated with a Gibbs Helmholtz expression,are determined via multi-objective optimization method.The solid constants ΔfGk°((298.15)) and ΔfHk°((298.15)) of11 solid species occurred in the quaternary system are rebuilt from multi-temperature solubilities.The modeling results show the accurate representation of(1) solution properties and binary phase diagram at temperature ranges from eutectic points to 643 K;(2) isothermal phase diagrams for Li2SO4-Na2SO4-H2O,Li2SO4-K2SO4-H2O and Na2SO4-K2SO4-H2O ternary systems.The predicted results of complete structure and polythermal phase diagram of ternary systems and the isothermal phase diagrams of quaternary system excellently match with the experimental data.