Magnesia-carbon bricks are made of high-melting alkaline oxide magnesium oxide (melting point 2800℃) high-melting carbon materials infiltrated by slag as raw materials, with various non-oxide additives added. A non-burning composite refractory material combined with a carbon binder. Magnesia carbon bricks are mainly used for lining of converters, AC electric arc furnaces, DC electric arc furnaces, slag lines of ladle. Magnesia calcium sand magnesia carbon brick as a composite refractory material, effectively utilizes the strong slag erosion resistance of magnesia the high thermal conductivity low expansion of carbon, which compensates for the disadvantages of poor spalling resistance of magnesia.
Its main features are: 1 good performance 2 strong slag resistance 3 good thermal shock resistance 4 low temperature creep low raw material influence on the performance of magnesia carbon bricks. The main raw material for the production of magnesia carbon bricks. The quality of magnesia The performance of carbon bricks has an important impact. How to choose magnesia reasonably is the key to producing magnesia carbon bricks. Magnesia has fused magnesia sintered magnesia, which have different characteristics. Fused magnesia: large grains, less impurities, less silicate phase, high degree of direct grain bonding, less grain boundaries. Sintered magnesia: small grains, relatively large amounts of impurities silicates, poor direct bonding. For magnesia raw materials, in addition to chemical composition, high density large crystallization are required in terms of organizational structure. Therefore, as the quality index of magnesia raw materials for the production of magnesia carbon bricks, the following content should be investigated 1. Magnesium oxide content (purity) 2 The types of impurities are C/S B2O3 content. 3 The density, pore diameter, pore morphology of magnesia (sinterability). The purity of magnesia has a great influence on the slag resistance of magnesia carbon bricks. The higher the magnesium oxide content, the lower the relative impurities, the lower the degree of silicate phase separation, the higher the degree of direct bonding of periclase, the higher resistance to slag penetration slag melting loss. The squeezed juice in magnesia mainly includes calcium oxide, silicon dioxide, iron oxide. If the content of impurities is high, it is a compound of boron oxide, which will adversely affect the refractoriness high temperature performance of magnesia. The impurities in magnesia mainly have the following inseparable influences: 1. Reduce the direct bonding degree of periclase 2. Form low-melting matter with magnesium oxide at high temperature 3. Iron oxide, silicon dioxide other impurities are first at 1500-1800℃ Because magnesium oxide reacts with carbon, pores are left the slag resistance of the product deteriorates. For magnesia raw materials, in addition to the total amount of impurities, the type relative content of impurities also have a significant impact on the performance of magnesia.