The refractory needles steel fiber has a great influence on the refractory castable, especially in the new dry process cement firing system, the kiln mouth is a very critical and special part. The use conditions of this part are harsh and complex, and the lining material is damaged quickly, so the use of refractory castables is more suitable than the use of shaped bricks. However, adding refractory needles steel fibers will further increase the stress and strength of the castable.
The quality of the kiln lining material directly restricts the operation rate of the clinker firing system and the output of cement clinker. More than 80% of kiln shutdowns are caused by local corrosion of refractory materials. Therefore, the cement kiln kiln mouth castable is very important.
The service life of ordinary refractory castables used in the kiln mouth of the cement kiln is 4 to 6 months. The use of corundum castables can play an anti-cracking effect. If refractory needles steel fibers are added to the low cement-bonded corundum castable, the internal stress distribution of the refractory castable during drying and heating can be better changed, the crack propagation is prevented, and the brittle fracture mechanism of the refractory can be changed into toughness and fracture resistance. strength is at its highest.
The amount of refractory needles steel fiber added has different effects on the flexural strength of the refractory castable. The addition of refractory needles steel fiber to the refractory castable can improve the mechanical properties of the refractory castable, but the more the better, the dosage should be 1% ~ 1. 5% is ideal. The melting temperature and critical oxidation temperature of heat-resistant refractory needles steel fibers are around 1350 °C. If the temperature exceeds 1400 °C, refractory needles steel fibers cannot be added. Otherwise, due to the melting and oxidation of refractory needles steel fibers, the structure of the refractory castable will be damaged.
When the addition of refractory needles steel fiber is 1%, the compressive strength after burning is the largest, mainly because the refractory needles steel fiber has high thermal conductivity and reinforcing and toughening effect, so that the thermal stress caused by the rapid temperature change is reduced, which not only can It can better improve the performance of refractory castables for cement kiln kiln mouth, and at the same time, it is also beneficial for enterprises to reduce production costs, and it is also a reasonable and effective use of resources.
The physical and mechanical properties of refractory castables are also closely related to the types of cement and aggregates used. Active a-A12O3 micropowder, uf-SiO2 micropowder, pure CA cement, SiC fine powder and corundum powder also play a key role in the sintering reaction in the refractory castable matrix and the amount and particle size of SiC fine powder added to the castable properties. So a reasonable ratio is very important.
In a word, a reasonable proportion of refractory needles steel fibers is the key to refractory castables. Adding a reasonable proportion to the refractory castable can reasonably distribute the internal stress and prevent the crack propagation, and also have a great influence on increasing the strength of the refractory castable.