Refractory castable is a kind of materials for unshaped refractory. It is made of refractory aggregate and powder, bonding agent and admixture. It has features of high temperature resistance, good thermal shock resistance, high mechanical strength and small bulk density. Refractory castable is mainly used for furnace linings, monolithic constructions, pre-cast shapes and other construction works of heating equipment.
Refractory castable structure defines the performance of the product. It must be designed and selected according to the working properties of materials and the temperature of the working environment, making sure that the finished refractory castability has the satisfactory performance. Refractory castable is a kind of self-formulation unshaped material that is easy to transport and to use. It not only can resist the high temperature erosion, but also can make into different shape components according to the design requirement.
Refractory castable requires good fluidity, permeability and consistency, easily to be formed and solidified. The particles need to be well distributed with no segregation. It is widely used for the transformation and maintenance of metallurgical equipment and for the construction of its protective parts like walls, linings, supports, etc. Heat retaining ducts, kiln liners, or high temperature furnaces with refractory castables are widely used in petrochemical, glass, ceramic and machinery manufacturing industries.
Refractory castable is usually a plastic material that has a short pot life, good mobility and strength. When heated to the use temperature, the castable will harden. The properties of the refractory castable can greatly influence the homogenization of heat distribution and strength of the castable parts. It is important for users to conduct a thorough technical evaluation and operational experience before making a final decision on the best product to be used.
Although refractory castables may offer different benefits, it is important to select the proper material for the particular application. The best way to do this is to do an analysis to evaluate the working environment, temperature, load and structural requirements before making a decision. There are many properties of the refractory castable that need to be considered. These include the bulk density, apparent porosity, mineral composition, refractoriness, thermal conductivity, thermal shock resistance and volume stability. All of these properties should be closely monitored as they can change over time with usage and conditions. The selection of the refractory castable should be made based on the specific requirements and conformance to the local and international standards.
The success of refractory castable lies in the correct selection of the right product and its correct utilization in the field. During installation and maintenance, the refractory castable must be firmly bonded and accurately pre-cast. The castable must be of the complete composition, free from voids and free from surface cracks. The whole operation of laying should be carried out in a systematic and orderly manner, according to the industrial standards or by using the specific operations manual of the manufacturer.
In order to guarantee the good performance of the castable, proper surface protection should be taken. When heat-treatment is necessary, proper pre-drying, pre-heating, slow heating and cooling cycles should be precisely followed. Moreover, adequate low temperature curing and finishing should be implemented. Performing routine inspections and establishing preventive maintenance procedures can help to ensure the highest quality of the refractory castable.
In sum, the refractory castable is an important material used in different applications to provide the necessary insulation and protection in various types of heating equipments, especially in the petrochemical, glass, ceramic and machinery manufacturing industries. The correct selection, installation, maintenance and heat-treatment of the castable should be highly considered to guarantee the best performance of the material and the whole system.
