Recently, I learned about laterite nickel smelting process, in its smelting process of blast furnace, electric furnace and so on are mentioned in the process of development, so here I also found some knowledge about electric furnace, here to learn together with you!
Classification of electric arc furnaces
Electric furnace for melting metals and other materials using the thermal effect of electric arc. It can be divided into three types according to the heating method:
(1) Indirect heating electric arc furnace. The arc is generated between the two electrodes, does not contact the material, heating the material by thermal radiation. Such stoves are noisy and inefficient, and they are becoming obsolete.
(2) Direct heating electric arc furnace. The arc is generated between the electrode and the material, which directly heats the material. The three-phase arc furnace for steelmaking is the most commonly used direct heating arc furnace (see arc furnace steelmaking).
(3) submerged arc furnace, also known as reduction furnace or mineral heat furnace. One end of the electrode is embedded in the material layer, forming an arc in the material layer and heating the material using the resistance of the material layer itself; Often used for smelting ferroalloy (see ferroalloy furnace), melting ice nickel, matte (see nickel, copper), and the production of calcium carbide (calcium carbide), etc.
Vacuum electric arc furnace is an electric furnace in which metal is directly heated by arc in a vacuum furnace. The gas in the furnace is thin, mainly by melting metal vapor arc, in order to make the arc stable, generally for direct current. According to the characteristics of melting, it is divided into metal remelting furnace and casting furnace. According to whether the electrode is consumed in the melting process (melting), it is divided into consumptive furnace and non-consumptive furnace. Most industrial applications are consumptive furnace. Vacuum arc furnace is used to melt special steel, active and refractory metals such as titanium, molybdenum, niobium.
Arc heating can be considered as arc resistance heating. Arc stability is a necessary condition for normal furnace production. Ac arc furnace usually uses power frequency electricity, in order to make the arc stable, the furnace power supply circuit should have appropriate inductive reactance, but the existence of inductive reactance will reduce the power factor and electrical efficiency. Reducing current frequency is the way to develop AC arc furnace. The arc resistance value is quite small, in order to obtain the necessary heat, the furnace needs a considerable working current, so the resistance of the furnace short net should be as small as possible, so as to avoid excessive circuit loss. For three-phase arc furnace, the impedance of the three phases should be close to the same, so as to avoid the unbalanced load of the three phases.