What kind of coke is suitable for smelting ferrosilicon?
2017-02-13
Coke is the main raw material to melt ferrosilicon. It is smelting ferrosilicon reductant, so the coke within the fixed carbon content of the higher the better, to more than 84%, while requiring low coke ash. Because of the high ash content of coke, the amount of slag increases, due to ash containing about 60% of aluminum oxide (AI2O3), resulting in slag sticky is not easy to rule out. In addition, the high ash coke into the furnace easy to make the material sintering, affecting the permeability. Therefore, the requirement for coke ash content should be less than 13%.
Most of the carbon in the coke is in the form of fixed carbon, but a small portion of the carbon is present as a hydrocarbon (usually called volatiles). This part of the hydrocarbons in the high temperature that is destined to run away, so the coke volatile content of not more than 2%.
Apart from the coke has a chemical composition requirements, the physical properties are also required. The higher the resistance of the coke at high temperatures, the deeper the electrode is inserted into the charge, helping to increase the furnace temperature, thereby expanding the crucible. Coke porosity is large, not only resistance, surface area is also large, increasing the chemical reaction area, speed up the chemical reaction speed.
The size of the coke has a great impact on smelting. When the particle size is too large, the charge resistance decreases, the electrode is not easy to insert into the charge, resulting in low furnace temperature and crucible small, smelting is not normal. Particle size is too small or more powder, the burning is greater, easy to make the furnace condition becomes sticky, affecting the material surface permeability. Therefore, the coke to have a certain use of particle size. The size of the coke used in the ferrosilicon furnace is less than 8 mm. Small silicon ferroelectric furnace furnace temperature is low, in order to improve the temperature in the operation to take "smoldering" process, add some coke can help the surface of the sintering, so that the electrode deeper into the charge. Therefore, small-capacity ferrosilicon furnace smelting, the use of a small amount of coke.
The physical properties of coke do not require specific provisions, according to production practice, to select the more appropriate coke. At present, China's smelting
ferrosilicon with coke, mostly blast furnace smelting coke under the use of small particles under the coke.
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