A Novel Method to Remove Iron Impurity from Aluminum

Abstract

A novel method for iron removal from aluminum by electroslag refining using KCl-NaCl-Na₃AlF₆ flux containing P was studied. After electroslag refining, the Fe content in commercial purity aluminum decreased from 0.48% to 0.30 mass%, and the mechanical properties of commercial purity aluminum were improved, especially in tensile elongation increased by 33%. XRD and TEM analysis of the sludge indicated that the reaction between the melt and the molten slag to form Fe₂P in the electroslag refining process was the main reason for iron reduction. The thermodynamic phase diagram calculation for Al-Fe-P system accounts for the formation of Fe₂P theoretically in the electroslag refining process.