Mg solute effects on the dissolution kinetics of silicate glass

The dissolution of soda lime silicate glass was studied in sodium borate buffer solutions (pH 8-1) containing varying concentrations of Mg. The experimental data were expressed in terms of the equation Q=kt α . In the absence of Mg, at pH 8-1, α was found to be 1 and changing the concentration of Na in the solution did not influence α. However, Na concentration did after the rate constant (k). The higher the Na concentration in the buffer the faster the dissolution. Under conditions of constant concentration of sodium in the buffer, increasing Mg concentrations in the leachant reduced the glass leach rate and changed the kinetics of glass leaching. At the lower Mg concentration range, α≃1, the leach rates are high; at the higher Mg concentration range, α≃0.5, the leach rates are low