Ferroalloy furnace

A typical large three-phase ferroalloy furnace using prebaked carbon electrodes is shown in Eigure 4. The hearth and lower walls where molten materials come in contact with refractories are usually composed of carbon blocks backed by safety courses of brick. In the upper section, where the refractories are not exposed to the higher temperatures, superduty or regular firebrick may be used. The walls of the shell also may be water-cooled for extended life. Usually, the furnace shell is elevated and supported on beams or on concrete piers to allow ventilation of the bottom. When normal ventilation is insufficient, blowers are added to remove the heat more rapidly. The shell also may rest on a turntable so that it can be oscillated slightly more than 120° at a speed equivalent to 0.25—1 revolution per day in order to equalize refractory erosion or bottom buildup. 

Ferritic stainless steels, 23 305 Ferritic steel, tellurium in, 24 422-424 Ferroalloy furnace, 12 306 Ferroalloys, 22 515 23 262... 

Let us consider the system of wet clearing of the gases departing from the closed ferroalloy furnace 1. On this furnace, comparative researches of the described system of wet dust separation (see Figure 14.2) have been conducted. 

Submerged-Arc Furnace. Furnaces used for smelting and for certain electrochemical operations are similar in general design to the open-arc furnace in that they are usually three-phase, have three vertical electrode columns and a shell to contain the charge, but dkect current may also be utilised They are used in the production of phosphoms, calcium carbide, ferroalloys, siUcon, other metals and compounds (17), and numerous types of high temperature refractories. 

During the years 1981 to 1986, the average consumption of manganese units (as ferroalloys) for the EEC, the United States, and Japan combined, decreased from 6.5 to 5.5 kg/t of steel. Eor the same period in the United States, the consumption of manganese decreased from 6.2 to 4.7 kg/t of steel (33), and apparendy decreased further in the years of 1990, 1991, and 1992 to 4.15, 4.11, 3.85 kg/t of steef respectively (9). In contrast, in 1984, the steel industry of the former USSR, where 50% of steel production was stiU made in open-hearth furnaces, had an average consumption of manganese units of 13 kg/t steel (35). 

Plant Safety. Of the many ferroalloy products produced in electric furnaces, ferromanganese has the greatest potential for furnace emptions or the more serious furnace explosions. The severity of the explosions increases with the size of the furnace. Such incidents are infrequent, but can occur, and when they do are often disastrous. Explosions usually result in extensive damage to the furnace and surrounding area, and often severe injuries or death to personnel in the immediate area. An emption is the sudden ejection of soHds, Hquids, or gases from the furnace interior. A more violent and instantaneous ejection of material, accompanied by rapid expansion of burning gas, is considered an explosion (38). 

The only new sihcon capacity since the early 1990s is by the Gulf Ferroalloys Company in Saudi Arabia. This plant is expected to have four furnaces and produce silicon metal, ferrosihcon, sihcomanganese, and manganese alloys by late 1996. 

With the exception of carbon use in the manufacture of aluminum, the largest use of carbon and graphite is as electrodes in electric-arc furnaces. In general, the use of graphite electrodes is restricted to open-arc furnaces of the type used in steel production whereas, carbon electrodes are employed in submerged-arc furnaces used in phosphoms, ferroalloy, and calcium carbide. 

H. J. Kammeyer, K. U. Maske, and G. Pugh, Open-Bath Production ofFerrochromium in a DC Plasma Furnace, Paper in Proceedings of the 5th International Ferroalloys Congress, New Orleans, La., Apr. 23—26, 1989, Ferroalloys Association, 1989, pp. 95—102. 

Phosphate Fertilizer Industry Granular Triple Superphosphate Storage Facilities Goal Preparation Plants Ferroalloy Production Facilities Steel Plants Electric Arc Furnaces Constructed after October 21, 1974, and on or before August 17,1983... 

Plant Safety. Of the many ferroalloy products produced in electric furnaces, ferromanganese has the greatest x>teniial for fiimace eruptions or the more serious furnace explosions. 

Until the 50 s, companies showed little interest in recovering the cadmium, which was not considered hazardous and the negative electrodes available weighed very little. Moreover, putting complete nickel-cadmium batteries in the furnace to produce nickel-based ferroalloys posed absolutely no problem. The cadmium was vaporised on the surface, where it burned to produce cadmium oxide, which was usually released into the environment. At best, some of the dust was picked up by relatively efficient filters, in the case of zinc, lead and other forms of dust. 

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