At present, there are generally four types of refractory products made of andalusite: ① fired bricks; ② unfired bricks: ③ refractory fibers: ④ amorphous refractory materials, and amorphous refractory materials of andalusite include castables, ramming materials and casting sand.
Andalusite
Among the Al2O3-SiO2 series refractory materials currently used in my country’s metallurgical industry, most of them shrink in volume under high-temperature conditions. In this way, the use and life of the materials are limited under the effects of high-temperature load, heat shock resistance and slag erosion. The micro-expansion of andalusite changes the weakness of this product and increases its service life. At the same time, my country’s high-alumina bauxite resources are rich, but the impurity content is generally high and it is easy to melt at high temperatures. However, after adding andalusite to bauxite, the mullite phase can be increased, the matrix mineral composition and microstructure of the material can be changed, and the load softening temperature of the material can be increased. Therefore, the refractory materials made of andalusite are mainly used in the metallurgical industry. In the steel and metallurgical industries, it is generally used in the following aspects: Blast furnace: used for the top of the furnace roof to ensure resistance to CO.
Andalusite bricks for hot blast furnace:
Hot blast furnace: used for furnace walls, checker bricks, furnace roofs, and combustion chambers.
For the taphole: taphole mud is used to block the taphole, and coatings and ramming materials are used for iron ditches.
Mobile iron mixing furnace: fired products and unfired products used for lining the permanent layer and working layer, which can ensure that the working layer of the andalusite SiO2-C composite masonry obtains good results.
Andalusite bricks
Hot metal tank car: used for lining permanent lining and working lining.
Tundish: used for permanent lining and replaceable lining, as well as for the preparation of low-cement and ultra-low-cement refractory castables containing finely crushed andalusite.
Heating furnace: plastic and ramming materials for furnace walls and roofs.
Auxiliary equipment: steel pouring nozzle base bricks, blowing plug bricks, stirring tuyere bricks, anchoring bricks and heating furnace burner bricks: protective refractory coatings and low-cement refractory castables for burners. General-purpose amorphous refractory materials (including materials requiring high stability, cement with andalusite as the basic component), mullite formed at a lower temperature (1350℃) can make the surface of the product bonded to have a “strong weldability” effect.
Secondly, andalusite-based high-temperature materials have also been widely used in pre-baked anode tanks in the aluminum industry, heating furnaces in the glass industry, caskets in the ceramic industry, and rotary kilns in the cement industry.
In addition, andalusite is also used in the production of multiphase composite materials (such as andalusite-silicon carbide series composite materials) and insulating ceramics.