The difference between 1680 and 1650 silica bricks

Application of GUIMO abrasion resistant bricks in cement rotary kiln

GUIMO abrasion resistant bricks have been widely used in 2000-10 000 t/d large-scale CRK-cement rotary kiln designed in China. It is understood that some kiln shells use GUIMO abrasion resistant bricks, except for the direct-bonded magnesia bricks used in the firing zone with a length of about 20 m, and the castables used for the front and rear kiln openings of about 0.8 m each. The rear part of the firing zone is generally the same as the firing zone, using directly bonded magnesia refractory bricks, but the kiln skin is difficult to stabilize. Due to the poor thermal shock stability and low abrasion resistance of magnesia bricks, the joint part between the brick and the kiln skin is easy to peel off with the kiln skin, which affects the service life of this section. GUIMO abrasion resistant bricks have good thermal shock stability and do not break during use. No peeling, corrosion resistance, significantly extended service life.

GUIMO abrasion resistant bricks are characterized by good high temperature resistance and wear resistance, corrosion resistance, low thermal conductivity, low energy consumption, etc. At present, they cover most of the cooling belt and transition belt of CRK-cement rotary kiln. GUIMO abrasion resistant bricks not only have very good thermal shock resistance, but also fully meet the thermal conductivity of CRK-cement rotary kiln. According to the proof of use, the temperature on the outside of CRK-cement rotary kiln should not exceed 320 degrees. When using GUIMO abrasion resistant bricks The temperature detected after the test is basically only 250-280 degrees, which greatly reduces the surface temperature of the kiln shell and reduces the energy consumption. GUIMO abrasion resistant bricks also have very good heat resistance, their softening temperature under load can reach 1600 degrees, while the carrier in CRK-cement rotary kiln is generally about 1400 degrees, and there is no problem in repeated use for one year.

Technical properties of GUIMO abrasion resistant bricks

(1) The product has a compact structure and good wear resistance.

The main crystal phase of GUIMO abrasion resistant bricks is composed of mineral corundum (Mohs hardness 9.0-9.2), silicon carbide (Mohs hardness 9.0-9.5) and mullite (Mohs hardness 7.0-7.5) with high hardness. The structure of the product is high in density, and the bulk density is generally 2.7 to 3.0 g/cm3. According to the literature [8], the normal temperature wear resistance of refractory materials depends on its strength and the compactness of the structure. Materials with high strength and compactness have better wear resistance. CRK-cement rotary kiln lining is subject to rolling friction of materials for a long time, and wear is one of the main reasons for the damage of refractory lining. The density, strength and abrasion resistance of GUIMO abrasion resistant bricks are significantly better than those of spalling resistant high alumina bricks and magnesia-alumina spinel bricks. GUIMO abrasion resistant bricks are used in CRK-cement rotary kiln firing belts, filter belts and other parts. The use effect is good, it can be said that the good wear resistance plays a very important role.

(2) High softening temperature under load and good high temperature performance.

The load softening temperature of GUIMO abrasion resistant bricks is above 1450℃, and the high temperature is above 1650℃. Different brands of products have different softening temperatures under load. The temperature of the brick surface in different parts of the CRK-cement rotary kiln lining is different. The temperature of the secondary firing zone and the front transition zone is about 1400°C, which is higher than the brick surface temperature of the firing zone (because the firing is protected by kiln skin, the temperature of the brick surface is higher than that of the fired zone). 900～1000℃). Therefore, ZJAS-1680 can be selected for the secondary firing zone and the front transition zone, and ZJAS-1650, ZJAS-1550 and other grades can be selected for the lower temperature parts such as the rear transition zone and the cooling zone. The load softening temperature index of these refractory bricks also exceeds the commonly used anti-stripping high-alumina bricks and phosphate high-alumina bricks (the load softening temperature is 1300-1520 ° C).

Compared with the firing zone, the transition zone is easily affected by reducing atmosphere and heat load due to the lack of kiln skin protection. Its service life has always been the bottleneck of CRK-cement rotary kiln. Therefore, some cement plants use magnesia— Alumina spinel bricks products. According to the research of magnesia-alumina spinel bricks used in the transition zone of a 5000 t/d large-scale cement rotary kiln in a factory, it is concluded that the magnesia-alumina spinel bricks used in the front transition zone are basically free of erosion, but the structure is dense due to the deposition of alkali in the open pores. , resulting in the formation of different sections of the same brick, and the hot surface of the brick peels off and produces cracks, resulting in damage to the lining. However, GUIMO abrasion resistant bricks have a dense structure and form a continuous dense layer on the brick surface, which prevents the penetration of molten substances. In addition, the chemical properties are stable, and they do not react violently with the gas generated in the kiln or chemically react with the cement material, so they are resistant to erosion. Strong ability. Secondly, GUIMO abrasion resistant bricks have good thermal shock stability. Since GUIMO abrasion resistant bricks contain a certain amount of silicon carbide, it is well known that silicon carbide has high thermal conductivity and relatively small thermal expansion coefficient, which significantly improves the thermal shock stability of the product. The 1100 ℃ water cooling test is more than 10 times, up to 46 times , so GUIMO abrasion resistant bricks for CRK-cement rotary kiln do not peel or break, and can significantly improve the service life.