Shock Heating Test of Quartz for Si and FeSi Production

Abstract

Six different quartz types used as raw material for Si and FeSi production, were shock heated to 1500 °C in an induction furnace. The amounts of fines produced were measured and compared. The method has been used before on other quartz types. Several parallels were done for each type. The differences between the various quartz types were larger than the differences between the parallels for each type. The standard sample deviation was calculated for each quartz type. It varied from 1.3 wt% to 30.5 wt%. Quartz type D produced the lowest amount of fines, with 3.9-6.6 wt% below 10 mm. Sample F showed the largest disintegration. The amount of fines below 10 mm was around 70 wt%. For silicon and ferrosilicon production the amount of fines produced during shock heating is important for the furnace operation. Together with other high temperature properties of the quartz, the amount of fines will affect the process and hence the product yield and quality. The work presented here is part of a larger project, where the aim is to investigate and identify how and in what way different properties of quartz are affecting the furnace. This knowledge can be used to make decisions when choosing new quartz sources and when operating the furnace, so that the quartz properties are utilized.