Basic knowledge of magnesia brick

Magnesia brick is an alkaline refractory with magnesia content of more than 90% and periclase as the main crystalline phase. Generally, it can be divided into sintered magnesia brick (also known as fired magnesia brick) and chemically bonded magnesia brick (also known as unburned magnesia brick). Magnesia alumina brick manufacturers, magnesia bricks with high purity and firing temperature are called directly bonded magnesia bricks due to the direct contact of periclase grains; The bricks made from fused magnesia are called fused and bonded magnesia bricks, which are suitable for various large and medium-sized lime kilns such as rotary kilns, sleeve kilns, shaft kilns, etc. Magnesia brick has the advantages of strong alkaline corrosion resistance, strong erosion resistance, good thermal stability, high pressure strength, high load softening temperature and so on. The fired magnesia brick uses high-quality sintered magnesia as the main raw material and pulp as the binder. After mixing and high-pressure molding, it is fired in a high-temperature tunnel kiln above 1550 ℃. It has good thermal stability, corrosion resistance and spalling resistance. It is widely used as lining refractory for industrial furnaces such as converter and electric arc furnace.

Fused magnesia brick has the advantages of compact brick structure, high mechanical strength, low impurity content and so on. It is mainly used in large-scale glass kilns. The compact refractory brick with certain shape and size has high density and weight per unit volume, which indicates that the compactness is good, and the strength may be high. It is also called the deformation temperature of high-temperature load, called the reheating line change or the residual line change, which refers to the change of volume expansion and contraction in the same temperature change each time, High temperature resistance, about 1800 ℃, load softening temperature at 1620 ℃ -1640 ℃, and small thermal expansion coefficient.

Dense refractory brick is a kind of siliceous clay rich in hydrated aluminum silicate, which has the ability of no deformation, no fragmentation, no softening and no paste formation at high temperature. In the amorphous material sector, refractory brick has a variety of products. Its basic quality requirements are that alumina is higher than 38% and low iron and low alkali metal content. These products can be calcined or not calcined, such as refractory clay, plastic material for overload, high alumina plastic Refractory clay and high alumina castables, etc.

Unburned alumina Ma gnesia brick for ladle refers to unburned refractory products made from bauxite clinker and magnesia used for lining bricks of ladle. With the development of new steelmaking technologies such as converter oxygen blowing, continuous casting and refining outside the furnace, the increase of molten steel temperature and the extension of residence time in the ladle make the service conditions of the ladle lining harsh, resulting in serious erosion of clay lining bricks, Unburned alumina Ma gnesia brick for ladle refers to unburned refractory products made from bauxite clinker and magnesia for steel ladle lining bricks. With the development of new steel-making technologies such as converter oxygen blowing, continuous casting and refining outside the furnace, the increase of molten steel temperature and the extension of residence time in the ladle make the service conditions of ladle lining harsh, resulting in serious erosion of clay lining brick, and the use of this kind of lining brick has better application effect.