ABSTRACT
Silica fume is a by-product of the silicon metal and alloy industries. Silicon metal and alloys are produced in electric arc furnaces in which quartz is reduced at temperatures above 1,700°C. Among the many chemical reactions that occur in the furnace, one of them results in the formation of SiO vapour which, upon oxidation and condensation, turns into very small spheres of amorphous silica, as shown in Figure 5.1.
