Chrome Magnesite Bricks

Magnesia-chrome brick is a kind of refractory product with magnesium oxide (MgO) and chromium trioxide (Cr2O3) as the main components,  periclase and spinel as the main mineral components. This type of brick has high refractoriness, high temperature strength, strong corrosion resistance to alkaline slag, excellent thermal stability, and certain adaptability to acidic slag. The main raw materials for the manufacture of magnesia-chrome bricks are sintered magnesia and chromite. The purity of magnesia raw materials should be as high as possible, and the chemical composition requirements of chromite are: Cr2O3: 30~45%, CaO: ≤1.0~1.5%.

Production process：

The production process of fired magnesia-chrome bricks is generally similar to that of magnesia bricks. In order to eliminate the loosening effect caused by the expansion of spinel due to the reaction of MgO and Cr2O3, Al2O3 or iron oxide during the firing process of the brick, the synthetic co-sintering material 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 sulfate solutions. The production process of unburned magnesia-chrome bricks is simple, the cost is low, and the thermal stability is good, but the high temperature strength is far less than that of fired bricks. In the late 1950s, a so-called "direct-bonded" magnesia-chrome brick was developed. The characteristics of this kind of brick are pure raw materials, high firing temperature, direct bonding between high temperature phases such as periclase and spinel, and low melting phases such as silicate are distributed in islands. Therefore, the high temperature of the brick is significantly improved. Strength and Slag Resistance

The method of making bricks by co-grinding and calcining the fine powder with chrome ore-magnesia and the 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 and higher compressive strength, softening temperature under load and flexural strength. The magnesia-chrome brick made of chrome ore-magnesite powder compacted and synthetic magnesia-chrome sand calcined at high temperature has better slag resistance and high-temperature strength than other magnesia-chrome bricks.

In addition, there are also fused-cast magnesia-chrome bricks obtained by directly casting magnesia-chromium materials in an electric furnace, and fused magnesia-chromium bricks produced by fused magnesia-chromium materials according to the brick-making process combined with magnesia-chrome bricks.

Application areas:

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