On the Silicon Transfer from Molten Slag to Molten Iron

Abstract

Some experiments on the rate of silica reduction by carbon saturated iron have been carried out in the range of 1550-1620°C and kinetics of silica reduction has been considered combining the present results with already published data by many investigators.
The results obtained are as follows:
1. The reduction of silica in a graphite crucible is promoted by the increase of slag-graphite interface area, Al addition to metal and application of external electric potential.
2. Present result and the results already published by many investigators on the silica reduction have been put in order by considering the ratio γ=S_s-G/S_s-M-. In small value of γ, the rate of reaction is pro-portional to activity of silica in CaO-SiO₂binary slag and apparent activation energy of silica reduction is about 90-100 kcal/mol. In this condition, silica reduction is controlled by chemical reaction in general but diffusion sometimes affect the rate according to the composition and transport properties such as viscosity of slag. On the contrary, in the range of γ>30 up to the present experiment diffusion step of silicate ion in slag is considered to be the limiting step.