Diffusion Coefficient of Calcium Ion in CaO-Al2O3-SiO2 Melts

The Nernst-Einstein equation is used to calculate the diffusion coefficient of calcium ion in the CaO-Al2O3-SiO2 system based on the data of the density and electrical conductivity. It is assumed that all the aluminium ions form tetrahedral structure and merge with chain or ring in the case of molar concentration of CaO higher than Al2O3. And in this case, calcium ion is assumed to be the conclusive charge carrier. A formula between the diffusion coefficient and concentration of calcium ion as well as temperature is deduced, which gives an increasing function relation between the diffusion coefficient and the concentration of calcium ions.