The converter magnesia carbon brick has high fire resistance, good thermal shock resistance, peeling resistance and slag resistance. As a furnace lining material, it is popularized and used on converters. Compared with other lining materials, the life of the converter is greatly improved. This article describes the production process, technological process and application of magnesia carbon bricks in various parts of the converter. Magnesium oxide powder manufacturers
Preface The steel-making converter is a vertical cylindrical furnace that does not require an external heating source and mainly uses liquid pig iron as raw material for steelmaking. Its main feature is: relying on the physical heat of the liquid pig iron in the converter and the heat generated by the chemical reaction of the various components in the pig iron (such as carbon, manganese, silicon, phosphorus, etc.) with the oxygen sent into the furnace, the metal can reach the steel. The required composition and temperature. According to the nature of the refractory material of the furnace lining, it can be divided into two types: acid converter and alkaline converter; according to the position where the gas is blown into the furnace, the converter is divided into bottom blowing, top blowing, side blowing and top-bottom combined blowing converter. Magnesia carbon bricks have high refractoriness, good slag resistance, excellent stability under heat shock and high temperature, good thermal conductivity, good damage and peel resistance. It is widely used in electric furnaces, converters and refining furnaces, and its service life is greatly improved. At the same time, magnesia carbon bricks do not need to be fired at high temperatures, save energy, and have simple manufacturing processes, so they are quickly promoted and applied in many countries around the world. my country started to develop magnesia-carbon bricks in the early 1980s. After small batches of electric furnaces and refining furnaces, they have received better results. Subsequently, steel plants such as Anshan Iron and Steel, Wuhan Iron and Steel, Baosteel and other iron and steel plants successively tested magnesia-carbon bricks on large and medium-sized converters, and the age of the converters was greatly improved. Now my country has become a producer of special-shaped magnesia carbon bricks in the world. With the continuous improvement of the grade of magnesia-carbon bricks, the life of converters has also been greatly improved, laying a foundation for reducing steelmaking costs.
Research and practice show that the quality of raw materials has a greater impact on the use of magnesia-carbon bricks for converters. Therefore, various raw materials are strictly selected. 1.1.1 The choice of magnesia, the corrosion process of magnesia particles during the use of magnesia carbon bricks is roughly as follows: ①The solid phase reaction between periclase particles and graphite under high temperature vacuum is as follows: MgO+C→Mg↑+CO ↑The generated steam and CO volatilize; ②The periclase particles are chemically lost by the slag, including the melting loss of various oxides in the foreign slag and magnesia impurities; ③After the oxidative decarburization of the magnesia carbon brick working layer matrix, its The bonding strength is reduced. Under the infiltration and erosion of the slag, the periclase particles are separated from the brick body and washed into the slag. Japanese scholars have conducted in-depth studies on the relationship between the MgO content in fused magnesia and the depth of erosion and the relationship between the slag resistance of magnesia carbon bricks and the periclase grain size in magnesia. The results can be clearly seen, Do not pay attention to the purity of magnesia in the production of magnesia carbon bricks, but also pay attention to the selection of large crystal fused magnesia, and hope that /SiO2≥2. After fully considering the above factors, the magnesia-carbon bricks used choose magnesia with high magnesia content with large periclase crystal grains, strong binding force and few impurities as the main raw material. This magnesia cannot reduce the periclase crystals. The degree of separation by the silicate phase reduces the erosion rate of the slag on the grain boundary, and can also improve the stability of the coexistence of magnesia and graphite at high temperatures.
Yingkou Dingfeng Metallurgical Technology Co., Ltd.
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