Cracking of high alumina bricks caused by mud and improvement measures

November 30, 2018

Cracking of high alumina bricks caused by mud and improvement measures

The critical particle size in the mud, the amount of fine powder added, and the mixing quality of the mud all will affect the cracking of the high-alumina bricks semi-finished products. For example, the matrix material is generally composed of fine powder, which shrinks during the firing process, and the particles generally expand, and a large difference in deformation between the two causes internal stress, thereby causing cracks in the products.

Improvement measures: When mixing high alumina bricks and mud, the feeding sequence must be strictly controlled. When mixing, add the pellets for 1 to 3 minutes, then add the pulp binder for 23 minutes, and finally add the fine powder for 6 to 8 minutes. The effective mixing time of pulp is not less than 10 minutes. Conventional control parameters for the particle size of aluminum brick: 32mm, 18% ± 5%; 0.5 ~ O.1mm, 15% ± 5%; <0.1mm, 40% ± 5%. The moisture content is <1.5%. In actual production, the critical particle size and the amount of fine powder can be adjusted. At the same time, an appropriate amount of expansion agent or pellets with a small thermal expansion rate can be introduced, and reasonable mud control parameters can be formulated to improve the mixing quality of the sludge.