Thermodynamic calculation of activity interaction coefficients of Fe to P, Ti, Ni, Cu, Cr, and V in silicon-based solutions

Thermodynamic parameters of impurity components in silicon-based solution systems are of great significance to study the removal of impurities from silicon solutions. In this paper, the activity parameters of each component in Si-i (i: P, Ni, Cu, V, Ti, and Cr) binary solutions and Si-i-Fe (i: P, Ni, Cu, V, Ti, and Cr) ternary solutions, and the activity interaction coefficients of component Fe to component i (epsilon(Fe)(i)) in Si-i-Fe ternary solutions were calculated using the molecular interaction volume model (MIVM). The calculated results showed that the activity interaction coefficient of Fe to P was negative in the Si-i-Fe ternary solution, indicating that the presence of Fe was detrimental to the removal of P. Before refining to remove impurity P, reducing the content of Fe in the silicon solution can improve the removal rate of P. The activity interaction coefficients of Fe to Ti, Fe to Ni, Fe to Cu, Fe to Cr, and Fe to V were all positive, indicating that the former played a positive role in the removal of the latter. This paper provided a theoretical basis for the metallurgical removal of impurities from silicon while improving the database of thermodynamic parameters of silicon-based solutions.

Automated summary

This study calculated the activity parameters of each component and the activity interaction coefficients between Fe and other components in silicon-based solution systems using the MIVM model. The results showed that Fe had a negative interaction coefficient with P, indicating its detrimental effect on P removal. On the other hand, Fe had positive interaction coefficients with Ti, Ni, Cu, Cr, and V, indicating its positive role in their removal.