Mass Production of High-Purity Iron Using Anion-Exchange Separation and Plasma Arc Melting
- PDF / 808,844 Bytes
- 4 Pages / 593.972 x 792 pts Page_size
- 22 Downloads / 201 Views
metals have been investigated since the 1970s.[1] In the early days, the study on refining was carried out with academic interest, because the purity is a significant factor for investigating the intrinsic properties of the material. During the past decades, the demands for highly purified materials have grown in proportion to the growth of the electronic device industry. High-purity Fe has been required as a source material of b-FeSi2, which is expected as photovoltaic and optoelectronic materials.[2,3] Behr et al.[4] revealed that the purity is a significant factor that decides the characteristics of b-FeSi2. For this reason, high-purity Fe is required in industrial scale. Kraus and Nelson[5] pointed out that anion-exchange separation (AES) is effective for separating metallic ions from each other. There have been reports applying AES to the purification of transition metals. Igaki and Isshiki[6] have successfully produced high-purity Fe using AES employed to both Fe(II) and Fe(III). However, the elimination of Cu is less complete than that of the other elements (Mn, Ni, Cr, and Co). Ke´kesi et al.[7] subsequently developed valence-controlled anion-exchange separation (VC-AES) and improved the removal of Cu. Using this novel method, we have successfully produced 99.998 mass pct of high-purity Fe M. UCHIKOSHI, Assistant Professor, K. MIMURA, Associate Professor, and M. ISSHIKI, Professor, are with the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan. Contact e-mail: [email protected] H. SHIBUYA, Researcher, is with Tanaka Chemical Corporation, Fukui, Japan. T. KE´KESI, Professor, is with the Faculty of Materials Science and Engineering, University of Miskolc, Miskolc, Hungary. Manuscript submitted January 11, 2009. Article published online August 6, 2009. METALLURGICAL AND MATERIALS TRANSACTIONS B
in pilot scale.[8] However, this high-purity Fe still contains 12 mass ppm Si. Furthermore, W often contaminates from W-ThO2 cathode during plasma arc melting. Recently, it has been reported that the oxidation refining with plasma arc melting (O-PAM) is useful to remove impurities having a higher affinity for oxygen than Fe.[9] Because Si has a high affinity for oxygen, the combination of VC-AES and O-PAM is expected to improve the purity of Fe. The objective of this research is manufacturing highpurity Fe using VC-AES and O-PAM in industrial scale. The process was scaled up from pilot to industrial scale so as to meet the demands of high-purity Fe. Technical issues on scaling up are also discussed. Figure 1 shows the manufacturing processes of highpurity iron. Three kinds of mass production processes, noted as C, D, and E in Figure 1, were tested in order to confirm the refining efficiency of each process. Specimen A is the raw material. Specimen B is refined by the pilot scale experiment reported previously.[8] Specimen C is purified by the manufacturing process, which was basically the same process applied to specimen B. The difference was only the size of the apparatuses. The fundame
Data Loading...
