Brief introduction of temperature control and precautions for producing clay bricks

 
Clay bricks generally contain more than 40% Al2O3, and Fe2O3 content is less than 2.0 ~ 2.5%. The clinker in the ingredients is 65-85%, and the combined clay is 35-15%. The pulverized combined clay and the fine clinker are mixed and ground, and then mixed with the granulated clinker to form a semi-dry mud, which is formed under high pressure and fired at about 1400 ° C, which has better performance. Clay bricks are weakly acidic at high temperatures, and their resistance to alkaline slag erosion is slightly worse, but they increase with increasing Al2O3 content. Thermal stability is better than silicon brick, magnesium brick (see magnesia brick) and so on. Qualified blast furnace clay bricks are dried and treated with vacuum phosphoric acid impregnation and phosphoric acid impregnation products fired at low temperature for the second time.
 
When firing first- and second-grade clay refractory bricks, the firing temperature is generally 1430 to 1450 ° C, and the temperature is maintained for 40 hours. When firing the third-grade refractory bricks, the firing temperature is 1390-1400 ° C, and the heat preservation is 24h to 32h. If one or two kinds of clay refractory bricks are fired in a tunnel kiln, the firing temperature is usually 1500 to 1560 ° C.
 
The heating rate varies with different raw materials and products. In the low temperature stage before 600 ℃, the temperature should be slowly increased from 600 to 1200 ℃. The heating rate can be slightly faster: 1200 ℃ to the firing temperature should be controlled. The cooling rate should also be controlled during the cooling phase.