Introduction to magnesia bricks

Magnesia bricks are made from high melting point Basic oxide magnesium oxide (melting point 2800 ℃) and high melting point carbon materials that are difficult to be wetted by slag, and various non oxide additives are added. A unburned carbon composite refractory material formed by combining carbon based binders. Magnesia carbon bricks are mainly used for the lining of converters, AC arc furnaces, DC arc furnaces, and slag lines of steel ladles. Magnesium brick supplier

As a composite refractory material, magnesia brick effectively utilizes the strong slag erosion resistance of magnesia and the high thermal conductivity and low expansion of carbon, compensating for the major disadvantage of poor peeling resistance of magnesia.

Its main characteristics are: 1. It has good high-temperature resistance, 2. It has strong slag resistance, 3. It has good thermal shock resistance, 4. The influence of low temperature creep of raw materials on the performance of magnesia carbon bricks. The main raw materials for producing magnesia carbon bricks are the quality of magnesia sand, which has an extremely important impact on the performance of magnesia carbon bricks. How to reasonably select magnesia sand is the key to producing magnesia carbon bricks. Magnesia includes fused magnesia and sintered magnesia, which have different characteristics. Electric fused magnesia: with large grain size, less impurities, less silicate phase, high degree of direct grain bonding, and few grain boundaries.

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

For magnesia raw materials, in addition to chemical composition, high density and large crystallization 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 contents should be investigated: 1. Magnesium oxide content (purity) 2. Types of impurities, especially. C/S and B2O3 content 3. Density, pore size, pore morphology, etc. (sintering properties) of magnesia.

The purity of magnesia has a significant impact on the slag resistance of magnesia carbon bricks. The higher the content of magnesium oxide, the less impurities, the lower the degree of silicate phase division, the higher the direct binding degree of periclase, and the improved resistance to slag penetration and melting loss of slag. The juice extracted from magnesia mainly includes Calcium oxide, silicon dioxide and iron oxide. If the impurity content is high, especially the compound of boron oxide, it will have adverse effects on the refractoriness and high-temperature performance of magnesia.

The impurities in magnesia mainly have the following effects: 1. reducing the direct binding degree of periclase; 2. forming low melting substances 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.