Magnesium iron spinel bricks are made of bivalent iron aluminum spinel (FeO Al2O3) and high-purity magnesia as the main raw materials. During the firing process, the firing temperature and firing atmosphere are strictly controlled to ensure that the iron in the brick is oxidized. The substance exists in the form of FeO.
During the use of mafic-iron spinel bricks, a layer of highly viscous calcium-iron and calcium-iron-aluminum compounds is formed on the hot surface of the brick, which is easy to hang on the kiln. In addition to the excellent kiln-hanging properties of magnesia-chrome bricks, Magnesium iron spinel bricks also have higher thermomechanical and thermo chemical properties.
In the process of using magnesium iron spinel brick, a layer of highly viscous calcium-iron and calcium-iron-aluminum compound is formed on the hot surface of the brick, which is easy to hang the kiln skin. Magnesia-iron spinel bricks have high thermomechanical properties and thermochemical properties in addition to the excellent kiln skin properties of magnesia-chrome bricks. In some countries in Europe, it has been widely used in cement rotary kiln firing belts and transition belts, becoming a new type of chromium-free refractory material that is likely to completely replace magnesia chrome bricks.
The physical and chemical indicators of the magnesia spinel brick produced by a refractory manufacturer are: MgO86%, Al2O33%, Fe2O38%, CaO1.7%, SiO20.8%, apparent porosity of 15%, bulk density of 3.06g/cm3, The normal temperature compressive strength is 66 MPa, and the high temperature flexural strength (1400 ° C) is 2.5 MPa.
