Refractory castables refer to the mixture composed of refractory aggregates, binders and admixtures, which are mixed with water (or liquid binders) to form mud that can be constructed by pouring. Refractory aggregate and refractory powder in refractory castables are collectively referred to as main raw materials, and the rest are called auxiliary raw materials.
1. Main raw material
The refractory aggregate is the part of +0.088mm or +0.1mm in the refractory castable, which is the main material in the structure of the refractory castable and acts as a skeleton. Therefore, the refractory aggregate is a part of the decisive factor of the physical and mechanical properties and high temperature performance of the cast body. Generally, the raw materials required for the preparation of refractory aggregates should be high-quality raw materials with dense structure, low water absorption (generally less than 5%), high strength and low impurity content.
Refractory powder is the matrix component in refractory castables. After being subjected to high temperature, it can link or cement refractory aggregates, fill pores, achieve close packing, ensure the fluidity and volume stability of the mixture, and can promote sintering, improving the material ( Casting body) density, strength, high temperature performance and performance.
2. Raw material selection
By selecting raw materials of different qualities as the main raw materials for manufacturing refractory castables, refractory castables with different properties, different service temperatures and different use ranges can be made. Composite raw materials are generally used as the main raw material of refractory castables, which can obtain refractory castables with good comprehensive performance and long service life.
The main raw materials in modern high-efficiency refractory castables have used a large number of high-purity raw materials, homogeneous raw materials, fused raw materials, synthetic raw materials, transformed raw materials and ultra-fine powders, as well as carbon and synthetic non-oxide raw materials, so that the performance of refractory castables has been greatly improved. Improvement, even surpassed fired refractory products.
The performance of refractory castables mainly depends on the raw materials used in the formulation, so the raw materials in refractory castables, especially the main raw materials, play an important role in the final product and receive special attention.
3. 24 raw materials
In addition to the main raw materials, refractory castables also contain 24 other raw materials, and the main characteristics are also different in different proportions. Sintered corundum; fused corundum; fused white corundum; fused brown corundum; sub-white corundum; mullite; zirconium corundum mullite; magnesium aluminum spinel; sillimanite, andalusite, kyanite; high alumina Bauxite; soft clay; clay clinker; magnesite; sintered magnesia; fused magnesite; silicon carbide; silica fume; graphite; pitch; calcium aluminate cement; silica sol; sodium silicate; phosphoric acid and phosphate ; ρ-Al2O3