Ferroalloy electric furnaces are divided into reduction electric furnaces and refining electric furnaces.
Reduction electric furnace, also known as submerged arc electric furnace or submerged arc electric furnace, adopts submerged arc* in which electrodes are inserted into the charge. The reduction electric furnace is open, closed (or semi-closed), and the furnace body has various forms such as fixed and rotating. Before the 1950s, open-ended fixed electric furnaces were generally used. With the improvement of environmental protection requirements and the progress of waste heat utilization technology, closed electric furnaces or low hoods and semi-closed electric furnaces were used for different products.
The rotation of the furnace body can eliminate the suspended material, reduce the “thorn fire” of crusts, make the cloth uniform, and expand the reaction zone to facilitate the smooth flow of the furnace. Electric furnace capacity (referring to the capacity of electric furnace transformers in ferroalloy production, measured in kilovolt amperes, used to mark the capacity of electric furnaces) generally ranged from a few hundred to ten thousand kVA before the 1950s, and then gradually developed to large-scale development. In the 1970s, the newly-built electric furnaces were generally 20,000 to 40,000 kVA, the largest enclosed furnace reached 75,000 kVA, and the largest semi-closed furnace reached 96,000 kVA.
Refining electric furnace is used for refining medium-carbon, low-carbon and micro-carbon ferroalloys. The capacity of the electric furnace is generally 1500～6000 kVA, and it adopts open fixed or tilting mode with cover. The former is similar to a reduction electric furnace and can be equipped with continuous self-baking electrodes; the latter is similar to an electric arc steelmaking furnace and uses graphite or carbon electrodes.