Ferro Alloys are usually produced by the reduction of a metallic ore (generally oxide)
by carbon with the addition of electric energy in a “Submerged Arc Furnace” (smelting process);
or by metals (metallo-thermic reduction), usually aluminium or silicon.
Silicon is commonly produced by a “Submerged Arc Furnace”. Polycrystalline silicon (PCS), a hyper form of Silicon (99.9999999), is produced for semi-conductors and solar cells by a chlorination process in a special reactor metallurgical-grade silicon followed by a reaction in the presence of hydrogen at high temperatures.
A very pure Silicon metal is also produced by a patented hydrometallurgical process. This process removes the impurities in high silicon by treatment in an iron chloride solution, followed by a further purification process.
Silica Fume is produced during the manufacture of silicon or ferrosilicon. This electro-metallurgical process involves the reduction of quartz. Silica fume is formed when SiO gas is oxidised to SiO2.
Depending on the alloying element, the grade and other economic/technological considerations, the details of the production processes can vary widely.
HCFeMn and SiMn
HCFeMn and SiMn involves a number of process steps as outlined in the adjoining diagram.