The Production of Silicon Carbide and Achievements in the Field of Furnace Gases Collection and Purification

Abstract

Silicon carbide is obtained in ore-thermal furnaces by reduction of silica (quartzite) with carbon. The use of silicon carbide in the production of technical silicon as a carrier of the target element and as a reducing agent can significantly improve the technical and economic performance (TEP) melting. The process of reducing silicon melting in electric furnaces takes place in two stages. First, silicon carbide is formed as a pseudomorphosis over the carbon of the reducing agent, then silicon carbide interacts with silicon oxide to form elementary silicon. Physical and chemical properties of silicon carbides obtained with the use of various reducing agents were studied. The reducing potential and reaction ability of carbides depends on how their surface is developed. Carbide volume and density characteristics are obtained on the matrices of charcoal and petroleum coke. For comparison, data for carbide obtained in the Acheson furnace are presented. Measurements of relative electrical resistivity of the reducing agent were performed and obtained on the carbides basis with temperature in the range of 700–1700∘C. For comparison, the RER values of silicon carbide obtained in the Acheson furnace are given, the resistance of carbides is several times higher than the RER of the corresponding reducing agents, which favorably affects the furnaces smelting silicon electric mode. As a result of the silicon carbide addition to the charge, the power of the arc discharge increases and the intensity of the reduction process increases.