The magnesia carbon brick of electric furnace is made of high melting point basic oxide magnesium oxide (melting point 2800 ℃) high melting point carbon material which is difficult to be infiltrated by slag as raw materials. It is a kind of unburned composite refractory made of magnesia carbon brick carbon binder. The magnesia carbon brick of electric furnace is mainly used for lining of converter, alternating current arc furnace direct current electric arc furnace, slag line of ladle, etc.

As a kind of composite refractory material, magnesia carbon brick can effectively make use of magnesia's strong slag resistance carbon's high thermal conductivity low expansion, compensate for the poor spalling resistance of magnesia.

Its main characteristics are: 1. Good high temperature resistance; 2. Strong slag resistance; 3. Good thermal shock resistance; 4. Low high temperature creep

Magnesia carbon brick for electric furnace

Effect of raw materials on properties of magnesia carbon brick for electric furnace

The quality of magnesia has a very important influence on the performance of magnesia carbon brick. How to choose magnesia reasonably is the key to produce magnesia carbon brick. Magnesia includes fused magnesia sintered magnesia, which have different characteristics. Fused magnesia: large grains, less impurities, less silicate phase, high degree of direct combination of grains, less grain boundaries.

Sintered magnesia: the grain size is fine, the impurity silicate phase are relatively more, the direct bonding degree is poor.

For magnesia raw materials, in addition to chemical composition, high density large crystallization are also required in terms of structure. Therefore, as the quality index of magnesia raw materials for producing magnesia carbon bricks for electric furnace, the following contents should be investigated: 1. Magnesium oxide content (purity). 2. Types of impurities, especially C / s B2O3 contents. 3. Density, pore size pore morphology of magnesia (sinterability).

The purity of magnesia has great influence on slag resistance of magnesia carbon brick. The higher the MgO content is, the less impurities are, the lower the degree of silicate phase separation is, the higher the direct binding degree of periclase is, the slag penetration resistance slag melting loss ability are improved. The impurities in magnesia mainly include calcium oxide, silicon dioxide iron oxide. [1] if the content of impurities is high, especially boron oxide compounds, it will have adverse effects on the fire resistance high temperature performance of magnesia.

The impurities in magnesia mainly have the following adverse effects: 1. Reduce the direct binding degree of periclase; 2. Form low melting substance with magnesium oxide at high temperature; 3. Impurities such as iron oxide silicon dioxide react with carbon prior to magnesium oxide at 1500-1800 ℃, leaving pores, which makes the slag resistance of products worse.

For magnesia raw materials, in addition to the total amount of impurities, the type relative content of impurities also have a significant impact on the properties of magnesia. Cao / SiO2 ratio B2O3 content have the most obvious influence. CaO / SiO2 ≥ 2 is usually required to improve the high temperature stability of magnesia carbon brick for electric furnace

Flake graphite is the main carbon material for the preparation of magnesium carbon brick for electric furnace