Abstract:The equilibria of Al and Ca between silicon alloy and the SiO₂-Al₂O₃-CaO ternary slags were investigated using graphite crucible at 1 550 ℃. With increasing Al₂O₃ and CaO content in the slags, the Al and Ca content increase respectively. The variation of the impurities are also affected by the silica content in slag which provides the oxidant during the oxidation refining process. The distributions of the impurities Al and Ca in silicon were given in terms of isoconcentration curves for Al and Ca in the ternary slags of SiO₂-Al2O₃-CaO. The present experimental work provided available data to analyze the action of Al and Ca during oxidation refining process for silicon alloy.

Key words: silicon; oxidation refining; thermodynamic equilibrium