Solubility and Dissolution Rate of Water Vapor in Liquid CaO-SiO₂-Al₂O₃ Slags

Abstract

The solubility of water vapor and the rate of water vapor dissolution in liquid CaO-SiO₂-Al₂O₃ slags have been measured at 1 400°C by a sampling method.
From the results obtained, solubilities of water in slags were shown with water-vapor capacity, defined by K' =(%H₂O)_s/√P_H2O.
The apparent rate of water vapor dissolution was independent of the flow rate of Ar-H₂O gas mixture over the range of 200910 ml/min. The dissolved water content was a linear function of the square root of time during the initial period of dissolution with a slope proportional to the square root of P_H2O in the gas.
Consequently, the reaction would be controlled by the non-steady-state diffusion of H₂O in the bulk slag. The obtained apparent diffusion coefficient of water vapor, D_H2O, in 44 mol% CaO-44 mol%SiO₂-12 mol%Al₂O₃ slag at 1 400°C was 1.9×10^-5 cm²/s. The effects of slag composition, such as alumina content or basicity and temperature on D_H2O were discussed.