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. © 2011 The Japan Institute of Metals.