Fired magnesia calcium brick for AOD furnace

Magnesia-calcium brick is a composite refractory material with MgO and CaO as the main chemical components. Its main mineral composition is periclase and calcite, both of which are high melting point minerals and do not react at high temperatures to form new Complex minerals exist in independent forms and maintain their own inherent characteristics. Among them, calcite has good high-temperature plasticity, which can buffer the thermal stress generated inside the brick due to temperature changes; calcite reacts with SiO2 in the slag to form high-melting-point minerals C2S and C3S, which increases the viscosity of the slag and reduces the The penetration of molten slag into the brick improves the anti-stripping performance of the brick. Calcite can adsorb non-metallic inclusions such as S, P and AI2O3 in molten steel. Therefore, magnesia-calcium brick has good thermal shock stability, good resistance to structural spalling and slag penetration resistance, and also has the unique performance of purifying molten steel.

The fired magnesia-calcium brick is made of two-step waste sintering to synthesize magnesia-calcium sand and high-purity magnesia as the main raw materials, with industrial stone bees as the binding agent, and is fired at a temperature of 1550-1600 ° C by high pressure molding and then subjected to waterproofing treatment. and packaging. At present, the largest production and usage in my country is the fired magnesia-calcium brick with MgO>70% and CaO20%. 

Application

Fired magnesia-calcium bricks are mainly used in AOD furnaces for refining stainless steel. Most of the linings of AOD furnaces in Taigang, Baosteel, Jiugang and other stainless steel production enterprises in my country use fired magnesia-calcium bricks. With the continuous improvement of refining technology, the service life of furnace villages has been continuously improved. The service life of AOD furnaces in Taigang Stainless Steel Plant has reached 189 furnaces; the service life of 120t AOD furnaces in Baosteel Group Stainless Steel Branch has reached 181 furnaces.

Physical amd chemical analysis