Low-creep mullite brick is a high-alumina refractory material with mullite (3Al2O3 · 2SiO2) as the main crystalline phase. Generally, the alumina content is between 65% and 75%. In addition to mullite, the composition of the mineral deposit also contains a small amount of glass phase and cristobalite with lower alumina content; Those with higher alumina content also contain a few corundum.
High fire resistance, up to 1790 ℃. The starting temperature of softening under load is 1600~1700 ℃. Normal temperature compressive strength 70~260MPa. Excellent thermal shock resistance. There are two kinds of mullite insulation bricks—sintered mullite bricks and fused mullite bricks. Sintered mullite brick is made of high-alumina bauxite clinker as the main material, a few clay or raw bauxite as the binder, and then formed and fired. The fused mullite brick is made of high alumina, industrial alumina and refractory clay, and is added with charcoal or fine coke particles as the restoring agent. After forming, it is manufactured by the restoring electric melting method. The crystallization of fused mullite is higher than that of sintered mullite, and its thermal shock resistance is better than that of sintered products. Their high-temperature property mainly depends on the content of alumina and the uniformity of mullite phase and glass phase dispersion.
Next issue we will continue to introduce creep rate of low creep mullite brick. Please stay tuned.