How to choose magnesia chrome bricks and their uses

Classification and application of magnesia chrome bricks 
 Magnesia-chrome brick is a kind of alkaline refractory heat-insulating material craftwork containing MgO55%-80%, Cr2O38%-20%, and is composed of periclase, composite spinel and a small amount of silicate phase. Composite spinel contains spinel solid solutions such as MgAl2O4, MgFe2O4, MgCr2O4 and FeAl2O4. Since the 1960s, it has been rapidly developed due to the improvement of raw material purity and firing temperature. At present, magnesia-chrome bricks can be divided into ordinary bricks, direct-bonded bricks, fused-bonded bricks and salt-impregnated magnesia-chrome bricks according to different production methods.
 Ordinary sintered magnesia-chrome brick: the raw material purity is not high, light-burned magnesia is used, and the sintering temperature is low; direct bonded magnesia-chrome brick: the raw material purity is high, heavy-burned magnesia is used, and the sintering temperature of the brick in the tunnel kiln is higher than that of ordinary sintered magnesia-chrome brick; fused semi-rebonded magnesia-chrome brick: the raw materials are heavy-burned magnesia and fused magnesia, and the sintering temperature is higher than that of ordinary sintered magnesia-chrome brick; fused rebonded magnesia-chrome brick: the raw material is made of fused magnesia, and the cost is high; salt-impregnated magnesia-chrome brick: in order to reduce the pores of magnesia-chrome bricks, it is difficult for the metal solution to enter the interior of the magnesia-chrome bricks, block the open pores, and extend the service life of the magnesia-chrome bricks. After vacuum salt impregnation, the magnesia-chrome bricks are immersed in molten industrial sodium chloride and potassium chloride salts.
 Magnesia-chrome bricks are mainly used in the metallurgical industry, such as flat furnace roofs, electric furnace roofs, external refining furnaces and various non-ferrous metal smelting furnaces. The high-temperature parts of the high-power electric furnace wall widely use fused-cast magnesia-chrome bricks, the high-erosion areas of the external refining furnace use magnesia-chrome bricks made of synthetic materials, and the high-erosion areas of the non-ferrous metal flash smelting furnace use fused-cast magnesia-chrome bricks and magnesia-chrome bricks made of synthetic materials. In addition, magnesia-chrome bricks are also widely used in the firing zone of cement rotary kilns and the regenerator of glass kilns.