Alumina magnesia carbon bricks are a non-burning product made of super high alumina bauxite clinker, fused magnesia or sintered magnesia and graphite, and liquid phenolic resin as a binder.
As a refractory material for lining of refining furnace, alumina magnesia carbon bricks give full play to the strong slag erosion resistance of magnesia and the low expansion and high thermal conductivity of carbon, making up for the defect of poor spalling resistance of magnesia. The excellent properties of aluminum magnesia carbon bricks are as follows:
(1) MgO and C have no eutectic relationship at high temperature. The melting point of carbon is above 3000 °C, and the melting point of MgO is 2800 °C. Both are refractory raw materials with excellent high temperature resistance.
(2) Excellent resistance to alkaline slag corrosion. MgO has strong resistance to alkaline slag and high iron slag. At the same time, the wetting angle of graphite to slag is large, the slag is not suitable for penetration, and the metamorphic layer is thin.
(3) Al2O3 reacts with MgO in the matrix to form aluminum-magnesium spinel at high temperature. The MA spinel has a small elastic modulus and a small thermal expansion coefficient, which can transfer the secondary MF spinel in the periclase, and is accompanied by The volume expansion can block the pores and inhibit the further penetration of the slag.
Due to the chemical reaction between Al2O3 and MgO in the matrix of aluminum-magnesium-carbon ladle brick, aluminum-magnesium spinel is formed, which causes the volume expansion of the product, which causes the ladle working lining to generate stress during use, causing the brick structure to peel off and affecting the safety of use.
In order to improve market competitiveness, some Steel Plant added a set of LF refining system to realize arc heating, gas stirring and out-of-furnace refining. By strengthening the kinetic and thermodynamic reaction conditions, the molten steel can be purified and uniform in a short time, and it has the effect of refining. Due to high temperature stirring and scouring during refining, strong alkaline slag erosion and long-term molten steel immersion, the working environment of the ladle lining becomes very harsh. In order to meet the normal use of the LF refining system in Steel Plant and the working conditions of the ladle, a long-life ladle aluminum-magnesium-carbon lining brick has been specially developed. Al2O3-MgO-C series ladle lining bricks have the characteristics of good high temperature performance, slag resistance and thermal shock stability.
Application of high-aluminum refractories in high-temperature industries
Classification of refractory properties and their application areas
High alumina bricks commonly used in industrial kilns
