DISSOLUTION OF WATER-VAPOR IN LIQUID ALUMINATES

The solubilities of water vapor and the rates of water vapor dissolution in liquid CaO-Al2O3, CaO-MgO-Al2O3, CaO-SrO-Al2O3 and CaO-BaO-Al2O3 slags have been measured by using a thermo-balance at the temperature ranging from 1 773 K to 1 973 K. The solubilities of water vapor in liquid aluminate slags were shown with water vapor capacities, defined by K′=(%H2O)s/PH(2)O 1/2 . The rate controlling step of the water vapor dissolution into aluminate slags are considered to be diffusion of water in bulk slag. The apparent diffusion coefficients of water vapor, DH(2)O, were evaluated, and the effects of slag composition and temperature on DH(2)O were discussed. Water vapor capacity increases and the apparent diffusion coefficient of water vapor decreases with increasing alkaline earth oxide content in the aluminates. The effect of alkaline earth oxide on increase in water vapor capacity follows the order of cation radius (Ba2+>Sr2+>Ca2+>Mg2+), and that on decrease in the diffusion coefficient follows the same order.