Model for diffusion coefficient estimation of calcium ions in CaO–Al₂O₃–SiO₂ slags

Abstract

As a common component in metallurgical slag, CaO plays an important role in desulphurisation, dephosphorisation and absorption of non-metallic inclusions. In order to better understand the mechanism of the slag/metal reactions, the diffusion dynamics of calcium ions in CaO–Al₂O₃–SiO₂ slags were studied. It was found that there was almost a linear relation between the logarithms of pre-exponential factor and diffusion activation energy. By combining the relation between the diffusion activation energy and the optical basicity corrected in the CaO–Al₂O₃–SiO₂ slags, a simple model used to estimate the diffusion coefficient of calcium ion is proposed. The estimated values of the CaO–SiO₂ and CaO–Al₂O₃–SiO₂ systems agree well with the experiment data, with a mean deviation of 35·3 and 22·5% respectively.

Keywords:

• Slag
• Dynamics
• Diffusion coefficient
• Optical basicity

The financial support from the National Science Foundation of China (grant no. 51090384) is gratefully acknowledged.