Smelting process of silicon for chemical industry
The process of chemical silicon includes charge preparation, electric furnace melting, silicon refining and casting, and crushing by removing slag inclusion. All raw materials are treated as necessary before the charge is prepared. The silica is broken in the jaw crusher to a lumpiness of no more than 100mm, and the fragments less than 5mm are screened out and washed with water. Because the fragments in the furnace melt in the upper part of the furnace, the permeability of the charge is reduced, making the production process difficult to carry out. Petroleum coke has a high conductivity, to be broken to a lumpiness of no more than 10mm, but also to control the amount of petroleum coke powder. Because of its direct combustion at the mouth of the furnace, it will cause insufficient reducing agent.
In the production of chemical silicon, bituminous coal can completely replace charcoal, such as Hunan Zhuzhou fine washed bituminous coal, fixed carbon reached 77.19%, volatile fraction 19.4%, ash content 3.41%, Fe2O3 content 0.22%, Al2O3 content 0.99%, CaO content 0.17%. Through production practice, it is feasible to use this kind of bituminous coal to smelt chemical silicon.
Wood blocks and chips for the production of chemical silicon are processed by wood cutters and chip chippers. The carbon reducing agent in the charge is mainly petroleum coke and bituminous coal, and the amount of wood block and wood chip depends on the furnace condition. Production does not use wood, but the product quality is more stable. The ratio of the charge is determined according to the product grade required to be produced. The ratio of petroleum coke to bituminous coal is determined according to the amount of carbon required for each batch of ore silicon. The ratio of petroleum coke to bituminous coal has a great influence on the working resistance of the charge.
After weighing each component of the charge, the charge is mixed evenly, and after ramming the furnace, the uniformly mixed charge is concentrated into the furnace. Maintain a certain level of material, adding evenly.
Chemical silicon production is continuous. Conditions inside the furnace are not permanent.
Chemical silicon production is the process of converting electrical energy into heat energy in an electric furnace, and then directly heating the material with heat energy to produce a chemical reaction. Therefore, the electrical characteristics in the furnace are very important, the smelting implementation of closed arc operation, maintain a high temperature furnace, improve thermal efficiency, improve the utilization rate of the electric furnace, in the study the capacity of 3200KVA and 6300KVA metal silicon furnace each. The smelting is carried out by the operation method of braising for a certain period of time and regular concentrated feeding. Under normal circumstances, it is difficult to automatically sink the charge, and it is generally necessary to force sedimentation. The furnace condition fluctuates easily and is difficult to control. Therefore, in the production must be correct judgment, timely treatment. Every 4 hours out of the furnace, for precision casting, crushing and slag sorting into storage.
