Application field

Magnesium chrome bricks are mainly used in the metallurgical industry, such as building open hearth furnace tops, electric furnace tops, refining furnaces outside the furnace, and various non-ferrous metal smelting furnaces. The high-temperature part of the wall of the ultra-high power electric furnace is made of fused-cast magnesia-chrome bricks, the high-erosion area of the refining furnace outside the furnace is made of synthetic materials, and the high-erosion area of the non-ferrous metal flash smelting furnace is made of fused-cast magnesia-chrome bricks and synthetic materials Made of magnesia chrome bricks. In addition, magnesia-chrome bricks are also used in the burning zone of cement rotary kilns and regenerators of glass kilns.

Production Process

The production process of fired magnesia chrome bricks is roughly similar to that of magnesia bricks. In order to eliminate the loosening effect caused by the expansion of MgO and Cr2O3, Al2O3 or iron oxides during the firing process to generate spinel, synthetic co-sintered materials can also be used to make magnesia-chrome bricks. In addition, there are unburned magnesia chrome bricks, for example, unburned magnesia chrome bricks combined with inorganic magnesium salt solutions. The production process of unfired magnesia chrome brick is simple, low cost, and good thermal stability, but the high temperature strength is far less than that of fired bricks. At the end of the 1950s, a so-called "direct bonding" magnesia-chrome brick was developed. The characteristics of this kind of brick are that the raw materials are pure, the firing temperature is high, the high-temperature phases such as periclase and spinel are directly combined, and the low-melting phases such as silicate are distributed in islands. Therefore, the high temperature of the brick is significantly increased. Strength and slag resistance.

The method of using chromite-magnesia co-grinding compacts and calcining compacts to make bricks with coarse particles of magnesia is an effective measure to eliminate the loosening effect. Compared with ordinary magnesia-chrome bricks, the magnesia-chrome bricks made by this method have lower porosity, higher compressive strength, load softening temperature and flexural strength. The magnesia-chrome bricks made of chrome ore-magnesite powder compacts and high-temperature-calcined synthetic magnesia-chrome sand have better slag resistance and high-temperature strength than other magnesia-chrome bricks.

In addition, there are fused-cast magnesia-chrome bricks directly cast by melting magnesia-chromium materials in an electric arc furnace (see the microstructure diagram, see color picture), and the molten particles produced by the fused magnesium-chromium materials according to the brick making process are combined with magnesium Chrome bricks, etc.