1, Normal temperature to 200 degree : At this time, the temperature should not be raised too quickly to prevent cracking of the refractory brick body. When firing in the tunnel kiln, the temperature of the first 4 parking spaces should not exceed 200 degree .

2, 200~900 degree : In this stage, the heating rate should be accelerated to facilitate the chemical reaction of organic matter and impurities in refractory bricks. During the temperature range of 600-900 degree , a strong oxidizing atmosphere should be maintained in the kiln to avoid the occurrence of black core refractory brick waste.

3, 900 degree to maximum firing temperature: During the high temperature stage, the thermometer should remain stable and continue to maintain an oxidizing atmosphere to evenly heat the refractory brick body, while also preventing cracking of the refractory brick body. Due to the strong sintering shrinkage at temperatures above 1100 degree , with a shrinkage rate of 2-5%, it is crucial to maintain a smooth temperature gradient and eliminate internal stresses.

The stopping temperature of refractory bricks is generally 100-150 degree higher than the sintering temperature. If the sintering temperature range of the used sintered clay is narrow, the stopping temperature should be appropriately lower, around 50-150 degree is more suitable. The firing temperature of refractory bricks should be kept at the right temperature to fully soften the bonding clay, allowing it to react fully with the surface layer of fine powder and coarse particles of the clinker. Achieve bonded clinker. The purpose is to obtain appropriate strength and volume stability for refractory brick products. The firing temperature is generally between 1350-1470 degree . If the Al2O3 content is high, the firing temperature of the product should be appropriately increased, approximately between 1350 degree and 1490 degree . The insulation time for firing is generally 2-10 hours to ensure sufficient reaction in the product and to ensure consistent surface and internal quality of refractory brick products.

4, Cooling stage: According to the character changes of refractory brick products in the cooling stage, rapid cooling should be carried out in the high temperature stage above 800~1000 degree , and the cooling rate should be slowed down below 800 degree . In fact, in production practice, the actual cooling rate used will not cause cold cracking danger to refractory brick products.