Dynamic Wetting of Graphite and SiC by Ferrosilicon Alloys and Silicon at 1550°C

Abstract

Silicon-rich ferroalloys and coke are two of the most important raw materials used in the scrap-iron process, both reacting during melting. Fundamental study of high temperature interaction of ferrosilicon–graphite provides key knowledge for understanding the interfacial reaction and wettability at the solid/liquid interface. Although a large body of work has investigated the wettability for silicon and ferrosilicon on SiC, the dynamic wetting and the associated interfacial phenomena of the ferrosilicon alloys–graphite system has not been investigated in depth. Using the sessile droplet method, the dynamic wetting of synthetic graphite by liquid ferrosilicon alloys containing 24.7 and 74% Si and silicon (98.5% Si) at 1550°C is reported. A sharp decrease in contact angle was observed for high-silicon ferroalloys and silicon, until full wetting was reached within 90 s. However, the wettability changed slowly for FeSi 24.7% (FeSi 24.7) and the final contact angle remained constant at around 70°. X-ray diffraction (XRD) investigations were carried out on the graphite/metal droplet interface to study the interfacial products formed and its influence on the wetting phenomena. The dynamic wetting is seen to be strongly dependent on the time required for the formation of SiC in the interface of ferrosilicon–graphite.