Aqueous speciation of zinc to 2N chloride solution was determined experimentally at 500 to 700°C and 0.5 to 1.0 kb by monitoring the effect of NaCl on ion exchange equilibria in the system CaTiO3-ZnTiO3-CaCl2-ZnCl2-H 2O. The Ca/(Ca + Zn) value of the 2N aqueous chloride solution in equilibrium with both CaTiO3 and ZnTiO3 decreased with the increase of NaCl under all experimental conditions. This is due to the formation of tri-chloro zinc complex. The formation constant of tri-chloro zinc complex was estimated to be 1.1, 2.1 and 2.7 at 500, 600 and 700°C, 1 kb, respectively, and 2.6 at 600°C, 0.5 kb in logarithm. The formation constant of tri-chloro zinc complex increases with increasing temperature and decreasing pressure. This suggests that zinc can be effectively leached from rocks and magmas under higher temperature and lower pressure conditions.
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