Ultra high purity halides and their preparation

This patent describes the process for purifying a chloro, bromo or iodo precursor salt of zirconium, hafnium or aluminum. It comprises: providing a molten thermal body of one or more alkali or alkaline earth metal halides and the precursor salt containing impurities, maintaining the body at a vaporizing temperature between bout 150 degrees C and about 460 degrees C to vaporize the precursor salt away from its impurities while effecting a reducing condition in the body with reducing agent which is fluid at the vaporizing temperature, mobile in the body, and non-reducing of the precursor salt, and isolating the purified volatilized precursor salt from the body