How can we improve the production quality of high alumina brick

 

Production of high alumina refractory bricks generally use soft clay, this material has good plasticity, so the production of high alumina refractory bricks generally use soft clay as a separation agent. However, the free SiO2 in the clay and the free Al2O3 in the bauxite were slightly reduced at 1200 ℃, the porosity of the silicon increased and the strength decreased. Therefore, with the guess in the amount of clay powder to participate in the amount of not more than 5% is appropriate. The following is a detailed material ratio.

In addition, the use of high bauxite powder as a separation agent; or high bauxite powder and clay powder in accordance with the necessary share preparation, the composition of mullite as a separation agent. With these separators can be made without secondary shortening of the high alumina brick.

High alumina brick mud commonly used coarse, medium and fine three ingredients. Coarse particles upper limit is generally 2 ~ 3mm, the participation of 40% ~ 50% (for shaped products, coarse particles can be reduced to 2 ~ 1mm) 1 ~ 0.1mm of the central particles to participate in the amount of 10% to 20% <0.1mm fine powder participation should be controlled at 40% to 50%.

The cost theory indicates that the coarse particles are appropriately increased in size and the bulk density of the advanceable mud can be easily formed. When firing, the secondary mullite reaction near the material is weak and easy to sinter. However, the expansion of particle size also has a certain limit. Assuming the expansion to 4 ~ 5mm, prone to missing edge angle phenomenon, and arrange the average level of the arrangements have been affected. Therefore, the maximum particle size to 3mm is appropriate.

With the guess in the fine powder is conducive to the green body sintering, add the density of finished products. It is necessary to participate in the fine powder because the shortening of the firing during the sintering can weaken or counteract the volume reduction of the secondary mullite reaction. However, the amount of fine powder involved too much, not only difficult to form, but also prone to cracks, firing shortened, the rejection rate to add. Therefore, the fine powder to participate in the amount of 40 to 50% is appropriate.

The central particles do not play the role of particles of the skeleton, nor is the fine powder sintering effect. Thus, the participation of the central particles is generally limited at the minimum number. However, the central particles can not be revoked in full. Assuming the revocation, the finished product is prone to cracking, the appearance of poor quality, but also to the material handling must be difficult. In general, the central particles involved in the amount of 10% is appropriate.