Introduction Of Refractory Castable

Refractory castable is a mixture of refractory aggregate, powder, and binder. After adding water, it is suitable for construction using pouring and vibration methods. It can also be pre made into prefabricated components with specified shape and size, used to construct industrial furnace lining. In order to improve the physical and chemical properties and construction performance of refractory castables, an appropriate amount of additives are often added, such as plasticizers, dispersants, accelerators, retarders, expansion agents, etc. Refractory aggregate is the main body of refractory casting materials, and various refractory clinker or waste bricks that have been calcined can be used as refractory aggregates to a certain extent. The particle size of aggregates has a significant impact on the quality of products, so in addition to certain limitations on the size of aggregate particles, there are also certain proportion requirements in terms of quantity. Refractory aggregates are equivalent to crushed stones and sand of ordinary building concrete. In the ingredient of refractory casting materials, aggregates generally account for 70% to 80%. Among them, coarse aggregate (5-20mm) accounts for 35-45% of the ingredients; Fine aggregate (0.15-5mm) accounts for 30-35%. The binder plays a role in bonding and hardening, giving the product a certain strength. Common Portland cement, Aluminate cement, magnesia cement, water glass, phosphoric acid, etc. can be used as binders. To ensure sufficient fire resistance of refractory castables (the binder is a flux at high temperatures, and the more it is used, the lower the fire resistance of refractory castables), and to reduce volume shrinkage during use, the amount of binder should be kept as low as possible, usually 10% to 25%. Some refractory castables (such as phosphate refractory castables) must also add a small amount of accelerator in the ingredient to accelerate hardening and consolidation. In addition, for the refractory castables used in the parts with large mechanical force or strong Thermal shock, if appropriate amount of stainless steel fiber is added, the toughness of the materials will be significantly increased. If inorganic fibers are added to lightweight insulation refractory castables, it can not only enhance toughness but also help improve their insulation performance.
Refractory castables are usually classified based on porosity and whether they contain cement components: according to porosity, they can be classified into dense refractory castables and lightweight insulation refractory castables; According to whether the refractory castables contain cement or CaO content, they can be divided into ordinary refractory castables, low cement refractory castables, ultra-low cement refractory castables, and cementless refractory castables.
Due to the basic material composition, setting and hardening process, and construction methods of refractory castables, which are similar to concrete in civil engineering, refractory castables are also known as refractory concrete. The production process of refractory casting materials is simple, labor-saving and energy-saving, with high construction efficiency and good quality. Materials with excellent performance can be prepared or selected on site according to needs. Therefore, refractory castable is a kind of unshaped refractory material with a large amount and a wide range of applications in furnace construction engineering.