Production of semiconductor grade high-purity iron

Semiconductor grade high-purity Fe will be required in practical use of β-FeSi₂. However, high-purity Fe with more than 99.9999% in purity has not been produced commercially. Then, a process consisting of anion exchange in a HCl solution, hydrogen reduction and plasma arc melting has been developed for the production of high-purity Fe. All metallic impurities can be virtually removed from Fe by the two anion-exchange steps, in which some elements such as Cu and Mo are separated efficiently under reducing conditions by the addition of Fe powder at the 1st step, and the rest of impurities are surely separated under oxidizing conditions at the 2nd step. Non-metallic impurities such as oxygen, carbon and nitrogen also can be eliminated to very low levels by the hydrogen reduction and the hydrogen plasma arc melting steps.