Selection of Refractory Materials for Burning Belt of Cement Rotary Kiln

      The firing zone of cement rotary kiln is the key area for cement to complete the transformation of silicate crystal phase.

      The sintering temperature of the clinker in the firing zone is 1300°C~1450°C, and the flame temperature is as high as 1800°C~2000°C, which emits a large amount of radiation energy to the surroundings. The long-term licking effect of the flame will quickly decompose and damage the refractory bricks. In order to resist the high temperature, a layer of kiln skin needs to be glued to protect the lining bricks.

      In addition to high temperature, the infiltration of cement clinker melt and low-melt silicate in coal ash, overheating, thermal shock, thermal fatigue and mechanical stress of firing belt refractory materials also cause cement rotary kiln to burn lining bricks. The main factor of damage is that the silicate low-melt in clinker and fuel intensifies the speed of chemical erosion; the kiln skin is unstable or not operating normally, and the frequent opening and closing of the kiln causes frequent thermal stress in the lining brick.

      When the comprehensive mechanical stress of pressure, tension, twisting force, shearing force and other alternating changes on the refractory brick exceeds the structural strength of the brick, the brick will crack and be damaged. Therefore, the selection of high-quality refractory materials, the hanging and protection of the kiln skin, the pre-homogenization of raw materials, and the use of qualified fuels to slow down chemical erosion are the key factors to prolong the service life of the rotary kiln firing zone.

      At present, the chromium-free products suitable for the firing zone of cement rotary kiln in the market include: dolomite bricks, magnesium-zirconium bricks, and magnesium-iron-spinel bricks. Among them, magnesia-iron spinel brick is the most widely used chromium-free alkaline product in the firing zone of cement kiln.

      ZHENJIN REFRACTORIES is the first company in China to develop perclase-hercynite refractory bricks adapted to China's national conditions and obtain an invention patent, which meets the market demand for environmentally friendly chromium-free alkaline refractory materials in the cement industry under the new situation.

      The perclase-hercynite refractory bricks developed by ZHENJIN REFRACTORIES not only have the characteristics of high compressive strength, good thermal shock stability, good flexibility, and high softening temperature under load, but also have the characteristics of being directly combined with magnesia-chrome bricks to easily stick to the kiln skin , effectively solved the pollution problem of magnesia-chrome bricks used in cement kilns, met the market demand for chrome-free basic refractory materials in the cement industry under the new situation, changed the demand elasticity of imported basic refractory materials, and realized the The localization of chrome-free bricks has been widely recognized in the cement industry.

      "ZHENJIN" perclase-hercynite refractory bricks have an operating cycle of more than 12 months, and have achieved excellent results in domestic large-scale cement companies such as Huaxin Cement, Starship Cement, Zoomlion Cement, Tianye Group, and Mengdian Cement. And exported to South Korea.

      In 2020, the 10,000t/d cement production line of Huaxin Cement Huangshi Company will use real gold brand magnesia-iron spinel bricks. The first cycle will run safely for 410 days, the second cycle will run for 414 days, and the third cycle will be ignited on January 28, 2023. is running safely.

      In practice, ZHENJIN REFRACTORIES uses perclase-hercynite refractory bricks and silica molybdenum bricks in the connection area between the firing zone and the transition zone. Due to the frequent changes in the temperature field, it is very easy to peel off and damage the industry status quo. For magnesia-iron spinel The brick technology has been optimized and improved. According to the characteristics of various raw materials, a special process of compounding synthetic magnesia-iron spinel and magnesia-aluminum spinel is used to develop and produce magnesia-iron-aluminum composite spinel bricks, which make iron-aluminum spinel and magnesia-aluminum spinel The excellent characteristics of magnesium aluminum spinel complement each other. The product has good alkali erosion resistance and wear resistance. When the temperature is high, a layer of kiln skin can be quickly attached to protect the lining brick from high temperature flame erosion. It has good wear resistance and is not worn at low temperature. Applicable to the entire rotary kiln.