With fotopomoschyu blogger victorprofessor we will visit the plant Silicium Kazakhstan, which produces silicon metal carbothermic process using a special ore-thermal furnaces. This is one of the largest factories in the country and the only silicon plant in Kazakhstan. The plant was launched in autumn 2010.
Prevalence in the crust silicon is second only to oxygen, occurs mainly in the form of oxygen compounds (quartz, silicates, etc.). High-purity silicon used in semiconductor technology, and technical grade (96-99% Si) - in ferrous and nonferrous metallurgy for non-ferrous alloys on the basis of (silumina et al.), Doping (silicon steels and alloys used in electrical equipment) and deoxidation Steel and Alloys (removal of oxygen), the production of silicides etc.
In the production process at the plant two kinds of products:
- Metal silicon (having a purity of not less than 98, 5% aluminum, and used in the chemical industry)
- Silicon dust (ultrafine material obtained in the process of gas purification furnaces, it is used in the production of extra strong dry construction mixtures)
In the industry of technical purity silicon is obtained by restoring melt SiO2 coke at a temperature of about 1800 degrees Celsius in the ore-smelting shaft furnaces. The purity of the thus obtained silicon can reach 99% 9 (major impurity - carbon and metals).
The basic unit of silicon smelting ore-thermal arc is one-three-phase electric power from 8 to 25 MVA. The oven is a round steel case with a bottom, lined with refractory brickwork. Hearth (bottom) and the height of the walls are lined with graphite blocks, the next layer of magnesite bricks and an outer layer - chamotte (porous brick made of special refractory clay).
Power supply to the working space of the furnace is carried out using an electrode made of graphite. Self-baking electrodes in silicon technology are not applicable due to possible contamination of the product components of the casing electrode and electrode mass (iron, calcium, aluminum). Electrical parameters of the recovery process mediated by the furnace transformer connected to the electrode short high current network, in which the current is 40-80 kA. As the consumption of the electrode socket are periodically lengthens via bypass mechanisms. Adjusting predetermined current in the electrode is accomplished by perescheniya electrode on the vertical axis.
Release of silicon is carried out almost continuously through Ledkov (hole in the lining) in a steel-lined mold.