What is magnesia carbon brick

Magnesium carbon brick is made from high melting point alkaline oxide magnesium oxide (melting point 2800 ℃) and high melting point carbon material that is difficult to be infiltrated by slag, with various non oxide additives added. A non burning carbon composite refractory material made by combining carbonaceous binders. Magnesia carbon bricks are mainly used for lining converters, AC arc furnaces, DC arc furnaces, slag lines in steel ladles, and other parts.

Magnesia carbon brick, as a composite refractory material, effectively utilizes the strong slag erosion resistance of magnesia sand and the high thermal conductivity and low expansion of carbon, compensating for the biggest disadvantage of poor spalling resistance of magnesia sand.

Its main characteristics are: 1. It has good high temperature resistance, 2. It has strong slag resistance, 3. It has good thermal shock resistance, and 4. It has low high-temperature creep

The influence of raw materials on the properties of magnesia carbon bricks

The quality of magnesia sand, which is the main raw material for producing magnesia carbon bricks, has a significant impact on the performance of magnesia carbon bricks. How to choose magnesia sand reasonably is the key to producing magnesia carbon bricks. Magnesia sand includes fused magnesia sand and sintered magnesia sand, which have different characteristics. Electric fused magnesia: large grain size, few impurities, few silicate phases, high degree of direct bonding between grains, and few grain boundaries.

Sintered magnesia: The grain size is small, with relatively more impurities and silicate phases, and the degree of direct bonding is poor.

For magnesia raw materials, in addition to chemical composition, high density and large crystallinity are also required in terms of organizational structure. Therefore, as a quality indicator for magnesia raw materials used in the production of magnesia carbon bricks, the following should be examined: 1. Magnesium oxide content (purity) 2. Types of impurities, especially Density, pore size, pore morphology, etc. (sintering properties) of magnesia sand with C/S and B2O3 content of 3.

The purity of magnesia has a significant impact on the slag resistance of magnesia carbon bricks. The higher the magnesium oxide content, the less impurities there are, the lower the degree of silicate phase segmentation, the higher the degree of direct binding of magnesia, and the improved resistance to slag penetration and slag melting. The juice extracted from magnesia mainly contains calcium oxide, silicon dioxide, and iron oxide. If the impurity content is high, especially boron oxide compounds, it will have an adverse effect on the refractoriness and high-temperature performance of magnesia.

The impurities in magnesia mainly have the following effects: 1. Reducing the direct bonding degree of periclase; 2. Forming low melting point with magnesium oxide at high temperatures; 3. Impurities such as iron oxide and silicon dioxide react with carbon before magnesium oxide at 1500-1800 ℃, leaving pores that deteriorate the slag resistance of the product.

For magnesia raw materials, in addition to the total amount of impurities, the type and relative content of impurities also have a significant impact on the performance of magnesia. The influence of CaO/SiO2 ratio and B2O3 content is most significant among them. Generally, magnesia refractory materials require CaO/SiO2 ≥ 2 to improve the high-temperature stability of magnesia carbon bricks

The carbon material for preparing magnesia carbon bricks is mainly flake graphite