For ingot casting, common deoxidizing agents include aluminium, ferrosilicon and manganese. Bhutan Ferro Alloys Ltd. produced mainly ferrosilicon, which was exported to India and Japan. Silicon in the ferrosilicon reduces the vanadium in VO to vanadium metal. High purity quartzite is used to produce ferrosilicon, industrial silica sand, silicon and silicon carbide. Silica fume is obtained as byproduct from hot processes like ferrosilicon production. Elkem Bremanger has specialized in the manufacturing of silicon metal, ferrosilicon, and specialty inoculants. Local industries include production of cement, ferrosilicon, malt, livestock feed, gypsum powder and coal. Industrially, the most common dense media is a suspension of fine magnetite and/or ferrosilicon particles. Ferrosilicon is also used in the Pidgeon process to make magnesium from dolomite. The chemical reaction uses sodium hydroxide, ferrosilicon, and water. Ferrosilicon is an iron alloy that also contains some calcium and aluminium. The secondary and scavenger DMS correct mediums consist purely of atomised ferrosilicon. The most commonly used and cheapest form of silicon is as a ferrosilicon alloy. In 1958, Serov produced its first ferrosilicon. In arc welding, ferrosilicon can be found in some electrode coatings.