In order to improve the thermal shock resistance of magnesia alumina bricks, more and more enterprises introduce alumina or bauxite clinker into the ingredients to form magnesia alumina spinel matrix, thus making magnesia alumina bricks. Magnesia alumina brick is an alkaline refractory with periclase as main crystal phase and magnesia alumina spinel as matrix, also known as periclase spinel brick.

In the production of magnesia alumina brick, in order to make the magnesia alumina spinel evenly distributed in the matrix of the brick, magnesia and bauxite are usually finely ground in the barrel mill. The addition amount of bauxite is generally calculated according to the content of 7% ~ 8% Al2O3 in the products. The principle of "big at both ends and small in the middle" should be strictly adopted for the particle composition of magnesia alumina brick material to ensure the quantity of large particles and fine powder and reduce the intermediate particles. The addition amount of common fine grinding powder in the ingredients must adapt to the content of Al2O3 and the content of fine powder in the particle composition. When producing magnesia alumina brick, CaO content in raw magnesia should be strictly limited, because Cao forms calcium forsterite (CMS) in magnesia alumina brick, and 1% Cao forms 2.8% CMS. The more CMS, the more liquid phase volume appears at high temperature. For example, in the mgo-ms-ma system, the initial temperature for the formation of liquid phase is 1700 ℃. In the presence of CMS, the liquid phase appears at 1500 ℃. The temperature of liquid phase in ma-cms binary system is only 1410 ℃. At the same time, the solution formed due to high CaO content has low viscosity and good fluidity, which will significantly reduce 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 properties of the products. The firing temperature of magnesia alumina brick is about 30 ~ 50 ℃ higher than that of ordinary magnesia brick, and the other firing systems are the same as ordinary magnesia brick.

The magnesia alumina brick has good thermal shock resistance, high mechanical strength at high temperature and high softening temperature under load. The main fiber structure of magnesia alumina brick is that the matrix is evenly dispersed with in-situ reaction spinel, and the crystal size is generally less than 20 mm. The magnesia alumina brick has good slag resistance, high temperature performance and thermal stability, and its price is cheaper than that of magnesia spinel brick. The laminated tube rice is used in the top of open hearth furnace, and is still used in ladle and steelmaking furnace Long lining, regenerator of glass kiln, mixer, top of steel-making reverberatory kiln and high-temperature furnace of refractory industry.