Silica fume is a collection of dust from exhaust gas generated during the production of metallic silicon, ferrosilicon, and electrofused zirconia in an arc electric furnace, and is used as an admixture, refractory material, fertilizer additive, etc. for concrete in many countries around the world. The particles of silica fume are spherical, much smaller than cement, and are composed mainly of amorphous silicon dioxide (SiO2).
