Oxygen Permeation of Partly Molten Slags

The conductivities, oxygen ion transference numbers, and oxygen permeation fluxes of NiO-30, 36, 42, and 48 wt pct Bi2O3, In2O3-30, 36, 42, and 48 wt pct Bi2O3, ZnO-15, 20, 25, and 30 wt pct Bi2O3, ZrV2O7-16, 20, 24, and 28 wt pct V2O5, and BiVO4-5, 7, 10, and 12 wt pct V2O5 partly molten slags have been measured by using the four-probe DC, volumetric measurements of the faradaic efficiency, and gas flow techniques, respectively, under various temperatures and oxygen partial pressure gradients. Results indicate that in the ranges of slag layer thicknesses 1 to 5 mm and temperatures 923 K to 1173 K (650 A degrees C to 900 A degrees C), used in the present study, the overall oxygen permeation kinetics is controlled by both chemical diffusion and surface exchange reactions. The oxygen permeation fluxes (3 x 10(-9) to 9 x 10(-8) mol/cm(2) s) were found to increase with volume fraction of liquid. The oxygen ion transference number was found to be in the range 0.2 to 0.8. The ambipolar conductivity, characteristic thickness, and surface exchange coefficient were estimated to be in the ranges 1.1 x 10(-3) to 2.3 x 10(-1) S/cm, 2 x 10(-2) to 7 x 10(-2) cm, and 1.3 x 10(-6) to 2.1 x 10(-6) cm/s, respectively.