calcium silicon factory

Calcium silicon alloy is a binary alloy of silicon and calcium containing very little iron. It is mainly used for deoxidation of high-temperature alloys such as steel. With the development of continuous casting and ladle refining, the consumption of calcium silicon alloys has increased rapidly. Accordingly, the requirement are getting more strict to those calcium silicon factories. There are two methods of calcium silicon factory to choose: The one-step method and the two-step method. The one-step method uses calcium to reduce silica and lime in an electric furnace to produce calcium silicon alloy. The two-step method first produces calcium carbide (or high-carbon ferrosilicon) in an electric furnace, and then uses calcium carbide to add silica and coke Carbon (or high-carbon ferrosilicon plus lime) produces calcium silicon alloy in another electric furnace.
 
The one-step method is further divided into a mixed feeding method and a layered feeding method. The mixed feed method is to add silica, lime and coke into the reduction electric furnace together. The simultaneous reduction of CaO and SiO2 with carbon to calcium silicon alloy, the reaction equation is: CaO + 3SiO + 7c = CaSi2 + Si + 7CO. The disadvantage of this method is that after contacting calcium oxide and silicon dioxide, a low melting point silicate is formed, and it is difficult to reduce silicon and calcium from the silicate. Based on this situation, a layered feed method has been produced. The purpose is to reduce the contact between calcium oxide and silica to reduce the Cao-SiO2 formation reaction.The layered feeding method is to first add lime and coke (calculated based on the reaction of calcium carbide) near the electrode, melt the CaO to generate CaC2 as much as possible, then mix the silica and the remaining carbon into the furnace to produce calcium silicon alloy.There are two types of two-step method. One is to first produce lime and calcium carbide in an electric furnace and then crush the calcium carbide together with coke and silica to produce calcium silicon alloy in another electric furnace. The first is to produce high-silicon ferrosilicon in an electric furnace, and then use high-silicon ferrosilicon as a reducing agent to reduce calcium oxide in the electric furnace to obtain a calcium silicon alloy. The calcium content of alloys produced by this method is generally less than 20%, but calcium silicon alloys containing 30-32% calcium can also be produced.
 
China calcium silicon factory mainly adopts the one-step method to produce calcium silicon alloy, and Germany and France calcium silicon manufacturers use two-step method.