サブハライド反応によるAlの精製について

抄録

Although several reports have been published in regard to an Al extracting method called the “gross process” utilizing the subhalide reaction between Al and AlCl₃, very little has been known about the purity of Al produced by this reaction. On selecting the composition of the raw material, quality of the reaction vessel and purpose of the produced Al, it is very important to make clear the contamination route and contents of impurities.
In the present work, in order to clarify the contamination route and degree, Fe, Cu and Si in Al produced from Al-Fe, Al-Cu and Al-Si binary alloys have been determined by spectroscopic analysis.
As a result, the purification factors for Fe and Cu are about 2×10⁴ and 1×10⁴ respectively, but concentration of Si in the obtained Al is 0.25% constantly regardless of the presence of Si in the raw material.
The contamination route of the impurities is discussed from the experimental results and thermodynamic calculations. It has been made clear that the contamination by Fe, Cu and Si arises from the reaction between the oxides of the impurities and AlCl and AlCl₃.