There are many uses for ferroalloys, especially in some steel plants and casting foundries, and various ferroalloy processing products are used in daily production. There are many methods of processing ferroalloys, most of which are pyrometallurgy. The smelting equipment, operation method and heat source used, it is mainly divided into the following types:
1. Classification by Production Equipment:
Ferroalloy processing can be divided into blast furnace method, electric furnace method, out-of-furnace method, converter method and vacuum resistance furnace method according to production equipment.
(1) Electric furnace method. The electric furnace method is the main method of ferroalloy processing, and its output accounts for about 80% of the total output of ferroalloys. Moreover, the products produced by this processing method are also widely used in the market.
(2) Blast furnace method. The main equipment used in the blast furnace method is the blast furnace. The blast furnace method is a relatively early ferroalloy production method. The production of ferroalloy by blast furnace method has the advantages of high labor productivity and low cost. However, due to the limitation of blast furnace hearth temperature and the complete saturation of metal with carbon under blast furnace smelting conditions, the blast furnace process is generally only used to produce easily reducible element ferroalloys and low-grade ferroalloys.
(3) Out-of-furnace method (metal heating method). The out-of-furnace method uses silicon, aluminum or aluminum-magnesium alloy as a reducing agent, and relies on the chemical heat generated by the reduction reaction to process ferrous alloys. The main equipment used is a cylindrical furnace. There are raw materials such as molten ore, concentrate, reducing agent and iron ore.
(4) Oxygen converter method. The main equipment used in the oxygen converter method is the converter. According to its oxygen supply method, there are top blowing, bottom blowing, side blowing and top-bottom blowing. The raw materials used are liquid high carbon iron alloy, pure oxygen, coolant and slag-forming materials. The liquid high-carbon iron alloy is mixed into the converter, and high-pressure oxygen is blown into the furnace through an oxygen lance. Production is carried out batch-wise by decarburization using the heat released by the oxidation reaction.
(5) Vacuum resistance furnace method. The vacuum resistance furnace method is used in the processing of iron alloys with extremely low carbon content such as micro-carbon ferrochromium, ferrochromium nitride, and ferromanganese nitride. The main equipment is a vacuum resistance furnace.
2. Classification by heat source:
According to different heat sources, ferroalloy processing methods can be divided into carbon heating method, electric heating method, silicon electric heating method and metal heating method.
(1) Carbothermal method. The heat source of the carbothermal smelting process is mainly the combustion heat of coke. Coke is used as a reducing agent to reduce oxides in the ore. The production of this method takes place continuously in a blast furnace.
(2) Electrothermal method. The heat source of the electrothermal smelting process is mainly electric energy. The carbonaceous reducing agent is used to reduce the oxides in the ore, and the continuous operation process is adopted in the reduction electric furnace.
(3) Electro-silicon thermal method. The heat source in the electro-silicon thermal smelting process is mainly electric energy, and the rest is the heat released during the silicon oxidation process. Silicon (ferrosilicon, intermediate manganese-silicon alloys and silicon-chromium alloys) is used as a reducing agent to reduce oxides in ores. Production is a batch operation in an electric refining furnace.