Characteristics of magnesia carbon brick making bricks

There are two methods for producing magnesia carbon bricks: fired oil immersed magnesia carbon bricks and unburned magnesia carbon bricks. The former brick making process is relatively complex and rarely used. Here, we will only briefly describe the characteristics of the brick making process without firing magnesia carbon bricks. Magnesia carbon bricks for converter use

Preparation of mud. The selection of critical particle size during breeding is important. The refinement of aggregate particles can reduce the porosity of openings and enhance antioxidant capacity. However, small aggregate particles can increase closed pores and reduce bulk density. In addition, fine-grained MgO aggregates are prone to react with graphite, and it is generally considered appropriate to have a particle size of 1mm. Under the condition of high-pressure molding equipment, the particles of magnesia tend to be slightly refined. The pressure of forming equipment in our country is relatively low. In order to improve the density of refractory bricks, many manufacturers use particle diameters greater than 5mm. Magnesium brick manufacturer

The quality and quantity of graphite added to the ingredients are crucial. Generally speaking, increasing the graphite content in Fire brick will improve the slag resistance and thermal shock stability of Fire brick, but both the strength and oxidation resistance will be reduced. If the carbon content in magnesia carbon bricks is too small (<10%), and the network skeleton cannot be formed in Fire brick, the advantages of carbon cannot be effectively used. Therefore, a carbon content range of 10-20% is more suitable.

Magnesia carbon bricks for converter use

During the mixing process, in order to evenly surround the graphite around the magnesia particles, the feeding sequence should be: magnesia particles → binder → graphite → magnesia fine powder and additive powder. Due to the high graphite content, low density, and very low dosage, it takes a long time to mix evenly. However, if the mixing time is too long, it can easily cause the graphite and fine powder around the magnesium sand particles to fall off, so the mixing time should be appropriate.

The forming of magnesia carbon brick is an important factor to densify the organizational structure of Fire brick: since the amount of graphite in the mud is large and the critical particle of aggregate is small, it is advisable to adopt high-pressure forming and press strictly in accordance with the operating procedures of light first, heavy second and repeated pressurization to avoid forming cracks. Z adopts the operating procedures of vacuum pumping and exhaust pressurization. In addition, the surface of high-pressure formed bricks is very smooth and easy to slide during transportation and construction. Therefore, the formed bricks should be impregnated or coated with 0.1-12mm thick thermosetting resin to form a resin film to prevent sliding. This treatment is generally referred to as anti slip treatment.

Formed magnesia carbon brick blank can only be used after hardening treatment, and the temperature of hardening treatment has a great impact on the performance of Fire brick. After research, it has been proven that hardening treatment at 200-250 ℃ is more suitable for ensuring the bulk density of bricks and reducing porosity. When the temperature is above 250 ℃ and below 200 ℃, hardening treatment will bring adverse effects. We must strictly elevate and control the sky. Usually at 50-60 ℃, due to resin softening, appropriate insulation should be applied; At 100-110 ℃, due to a large amount of solvent being discharged, insulation should be maintained; Living at 200-250 ℃, in order to achieve complete reaction, appropriate insulation should also be maintained.