Liquid–Vapor Equilibrium in the GaCl3–H2O and GaCl3–HCl–H2O Systems at the Boiling Point

Abstract

The liquid–vapor equilibrium in the GaCl₃–H₂O and GaCl₃–HCl–H₂O systems at the boiling point was studied. This study is relevant because of significant accumulation of gallium trichloride solutions as intermediates formed during the hydrochemical treatment of the metal with hydrochloric acid. The HCl concentration in both solution and vapor phases was measured using the standard techniques and instruments. The relative volatility and selectivity coefficients were calculated from the experimental data. Based on the data obtained, a region of concentrations (30.0–45.0 wt %) was identified in the gallium(III) chloride–water system where the effect of gallium chloride on the liquid–vapor phase equilibrium is abnormal; this is associated with the formation of structural complexes between gallium chloride and free water in solution. These tendencies in equilibria in the studied systems make it possible to determine the optimal parameters for hydrochloric acid regeneration in the required concentration and extraction of gallium with a lower consumption of alkaline reagents.