Low-cement and ultra-low-cement castables are an important type in the field of refractory materials. They are characterized by a significant reduction in cement content, thereby improving the overall performance of the material. The following is detailed knowledge about it:
1.Definition and characteristics:
Low cement castables, as the name suggests, refer to refractory castables with lower cement content. Specifically, when the addition amount of calcium aluminate cement is lower than a certain standard (for example, the CaO content is generally considered to be less than 2.5%, sometimes more strictly defined as between 1.0% and 2.5%), it can be called low cement castable. When the CaO content is further reduced to less than 1%, it is called ultra-low cement castable. This type of material reduces the amount of cement and introduces additives such as ultra-fine powder to achieve the purpose of improving refractoriness, high-temperature strength, slag resistance, and reducing porosity.
2. Ingredients and preparation:
Low-cement and ultra-low-cement castables are mainly composed of refractory aggregates, refractory powders, appropriate amounts of ultrafine powder, a small amount of calcium aluminate cement (as a delayed-acting accelerator) and trace dispersants. During the preparation process, the proportion of each ingredient needs to be strictly controlled and fully mixed to ensure the uniformity and stability of the material. In addition, in order to further improve the performance of the material, an appropriate amount of water reducing agent and delayed-acting coagulant are sometimes added.
3.Applications and advantages:
Low cement and ultra-low cement castables are widely used as lining materials in industrial kilns in metallurgy, petrochemical, machinery manufacturing, electric power and building materials industries. Its advantages include higher refractoriness, high temperature strength and slag resistance, as well as low porosity and high bulk density, which can significantly improve the service life and operating efficiency of the kiln. In addition, this type of material also has good construction performance and can be made into self-flowing or vibrating castables as needed to adapt to the construction needs of different structures.
In summary, low-cement and ultra-low-cement castables occupy an important position in the field of refractory materials due to their excellent performance and wide application prospects.
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