Nowadays, more and more companies producing magnesia alumina bricks are introducing alumina or bauxite clinker into their ingredients to improve the thermal shock resistance of magnesia alumina bricks, forming magnesia alumina spinel matrix and thus producing magnesia alumina bricks. Magnesia alumina brick is an alkaline refractory product with periclase as the main crystal phase and magnesia alumina spinel as the matrix, also known as periclase spinel brick. Ramming material

In the production of magnesia alumina bricks, in order to evenly distribute magnesia alumina spinel in the matrix of the bricks, magnesia alumina is generally finely ground together in a cylindrical mill. The amount of high alumina bauxite added is generally calculated based on the content of 7% to 8% Al2O3 in the product. The particle composition of magnesium aluminum bricks should strictly follow the principle of "large at both ends and small in the middle" to ensure the quantity of large particles and fine powder, and reduce the number of intermediate particles. The amount of common fine powder added to the ingredients must be adapted to the Al2O3 content and the fine powder content in the particle composition. When producing magnesia alumina bricks, the CaO content in the raw material magnesia should be strictly limited, as CaO forms calcium magnesium olivine (CMS) in magnesia alumina bricks, and 1% CaO forms 2.8% CMS. The more CMS there is, the more liquid phase appears at high temperatures. For example, in the MgO-MS-MA system, the starting temperature for the formation of the liquid phase is 1700 ℃ When CMS is present, a liquid phase appears at 1500 ℃. The temperature at which the liquid phase appears in the MA-CMS binary system is only 1410 ℃. At the same time, due to the high CaO content, the viscosity of the solution formed is low and the flowability is good, which significantly reduces the load softening temperature. Therefore, the C/S ratio and CaO content of magnesia should be strictly controlled in order to improve the high-temperature performance of the product. The firing temperature of magnesia alumina brick is about 30-50 ℃ higher than that of ordinary magnesia brick, and the rest of the firing process is the same as that of ordinary magnesia brick.

Magnesium aluminum bricks have good thermal shock stability, high mechanical strength at high temperatures, and high softening temperature under load. The main fiber structure feature of magnesia alumina bricks is the uniform dispersion of in-situ reactive spinel in the matrix, with a general crystal size of less than 20mm. Magnesia alumina bricks have good slag resistance, high temperature performance, and thermal stability, and are cheaper than magnesia spinel bricks. Layered tube rice is used on the top of steelmaking open hearth furnaces, and is still used in steel ladles, permanent lining of steelmaking furnaces, glass kiln heat storage chambers, mixed iron furnaces, steelmaking reflection kiln roofs, and industrial high-temperature kilns for refractory materials.