The production process of magnesia zirconium brick

There are basically three process routes for the production of magnesia zirconium bricks.

1) Using magnesia-zirconium sand as raw material to produce materials with uniform distribution of MgO and ZrO2. This type of material consists in first synthesizing magnesia-zirconium sand. It is obtained by mixing MgO and ZrO2 raw materials according to requirements - fine grinding - forming into balls (blank) - sintering/electric melting to obtain sintered/fused magnesia-zirconium sand. Then the magnesia-zirconium sand is crushed—classified—batched—mixed—formed—sintered to obtain ZrO2 composite magnesia refractory with uniform MgO/ZrO2 distribution. It can be seen that their production process is the same as that of magnesia refractories.

2) ZrO2 is combined with magnesia to produce magnesia-zirconium bricks. The production method of this type of material is to mix ZrO2 into magnesia to produce ZrO2 composite magnesia refractories with different MgO/ZrO2 ratios.

Their production process is basically the same as the production of magnesia-chromium refractories.

3) Special magnesia zirconium bricks. The difference between the production process of this type of material and the ordinary magnesia refractory is that the surface of the magnesia refractory aggregate particles is coated with a refractory material with ZrO2 as the main component, and the surface of each particle is uniformly formed into a thin film. The ZrO2 coating is dried and fired to form a solid ZrO2 sintered layer between the periclase particles. This product has very good performance. The material does not produce cracks, cracks, and peels during use, and has good thermal stability.

The magnesia-zirconium brick with the addition of 20% of ZrO2·SiO2 actually belongs to the MgO-2MgO·SiO2-ZrO2 series refractory material. The high corrosion resistance of the bonded matrix layer in the material, the corrosion resistance of this brick has been proven in the use of regenerators and melting chambers. Since its first use, this material has shown good performance in the condensation zone for 10 years, making it possible to use it in the upper part of the regenerator and even in the vault.

A manufacturing method of continuous casting upper nozzle brick is to mix and knead a mixture of non-spherical sintered or fused magnesia (70% to 99%) and zirconia powder (30% to 1%) with a particle size of less than 1 mm, and shape After being fired, zirconia powder can be replaced by chrome stone powder. When 100% of the mixture is added with 20% or less of silicon oxide raw material fine powder (calculated as SiO2), the peeling resistance can be improved. In addition, the continuous casting nozzle brick produced by the above method also has good corrosion resistance and high temperature strength.

The use of magnesia zirconium brick

Used in glass kiln regenerators and in the steel industry.

Physical and chemical analysis