The kiln mouth is an important part of the rotary kiln, which has long-term contact with the friction of materials and mechanical thermal stress. Due to the limitation of the kiln mouth, the lining of the kiln mouth is generally cast with unshaped refractory castables. The quality of the castable used in the rotary kiln mouth can directly affect the normal operation of the rotary kiln.
Most refractory castables used in rotary kilns have excellent wear resistance and corrosion resistance. Unshaped refractory castables account for 70% of the application of rotary kilns, and the remaining 30% are lined with refractory bricks, regardless of the new type of rotary kiln It is still a traditional rotary kiln, and the selection of lining materials is based on this standard requirement.
In the lining of the rotary kiln, the unshaped refractory castables are mainly used for the front and rear kiln mouths and the chain belt parts of the rotary kiln. The new type of rotary kiln is used in decomposition furnace, preheater, tertiary air duct, cooler and other parts. These parts in the rotary kiln are the parts with harsh environment and inconvenient construction. The refractory castables are required to have good high-temperature sintering properties, volume stability, wear resistance, and corrosion resistance.
Common castables for rotary kilns include corundum castables, high-strength low-cement castables, high-strength anti-skinning castables, anti-stripping castables, steel fiber reinforced castables, self-flowing castables, high-aluminum wear-resistant castables, etc. The materials are basically made of aluminum-silicon refractory castables, which are made of wear-resistant and corrosion-resistant refractory materials through scientific formulas.
The castable for the kiln mouth is generally made of aluminum silicon carbide anti-stripping castable. Silicon carbide (SiC) is an excellent wear-resistant refractory material. In order to improve the wear resistance of refractory castables, in addition to adding corundum, an appropriate amount of silicon carbide can be added to improve its wear resistance. Silicon carbide uses natural silica with a SiO? content of more than 97% and coke with a slightly equal amount of ash as the basic synthetic raw materials. It has the advantages of low thermal expansion coefficient, Mohs hardness of 9.0 to 9.5, and strong chemical stability.
Aluminum silicon carbide castable is made of high bauxite with aluminum content above 75%, plastic and silicon carbide as main materials, using pure aluminate cement and silica micropowder composite binder, adding explosion-proof fiber, kyanite, and shrinkage inhibitor It is a kind of castable made of materials such as additives.
There are many types of kiln mouth castables, and high-aluminum silicon carbide castables are commonly used. Because of their good wear resistance and peeling resistance, they are also called anti-stripping castables.