Dissolution Behavior of Sn in CaO–CaF2 Molten Flux and Its Distribution Ratio Between CaO–CaF2 Molten Flux and Liquid Iron

The dissolution behavior of Sn in CaO– $$\hbox {CaF}_2$$ flux was investigated. A chemical equilibration technique was employed which allows pure liquid Sn dissolves into the molten flux under various oxygen partial pressure and the flux composition. At an equilibrium, (% Sn) in the flux increased by increasing (% CaO) and $$p_{\text{O}_2}$$ . It was found that Sn dissolves into the molten flux as ( $$\hbox {SnO}_3$$ ) $$^{4-}$$ in the condition of the present study. Distribution of Sn between CaO saturated flux and C saturated liquid Fe was measured under a pure CO atmosphere. Sn distribution ratio ( $$L_{\text{Sn}} = (\%\,\text{Sn})_{\text{flux}}/[\%\,\text{Sn}]_{\text{iron}}$$ ) was as low as $$\sim 10^{-4}$$ , which was consistent with a thermodynamic prediction. Sn distribution was favored at a lower temperature. Thermodynamic modeling was carried out for the Sn dissolution in the flux. A noticeable negative deviation between CaO and SnO was identified.