Solubility of Zirconium(IV) Hydrous Oxides

Abstract

The solubility of zirconium(IV) hydroxide and oxide was measured in the acidic, neutral and alkaline pH at 25°C by an undersaturation method. No influence of the formation of polynuclear and colloidal species on the apparent solubility was observed in the case of the ZrO2. By using the solubility data of the ZrO2 and by considering the contributions of the mononuclear species, Zr4+, ZrOH3+ and Zr(OH)4(aq), to the solubility curve in the lower pH region, the solubility product was obtained to be log K°sp = --62.46 ± 0.10. In the case of the Zr(OH)4, no equilibrium was observed during the experimental period up to four months.