Refractory castable cement is a kind of refractory cement used in making refractory castable. It can be used as binder, additive and other ingredients. Castable cement is an indispensable refractory raw material because of its stable performance and good use effect.
Castable refractory cement is a kind of cement with a fire resistance of no less than 1580 ℃. It takes high-quality bauxite and lime as raw materials and mixes them into raw materials with appropriate components in a certain proportion. After sintering, the clinker with aluminate as the main component is ground into fine powder to make hydraulic cementitious material with fire resistance. It is a kind of refractory clinker, which can be directly added and used when making castable. According to different raw materials and components, it can be divided into aluminate refractory cement, low calcium aluminate refractory cement, calcium magnesium aluminate cement and dolomite refractory cement.
Application of refractory castable cement: 1. Refractory cement can be used to cement various refractory aggregates (such as corundum, calcined high alumina bauxite, etc.) to make refractory mortar or concrete, and can be used as lining of cement rotary kiln and other industrial kilns. 2. It can be prepared with lightweight aggregate into thermal insulation concrete and heat-resistant concrete. 3. Asbestos cement products with insulation and heat resistance are prepared with asbestos.
Technical requirements for refractory cement: 1. Fineness of refractory cement: the finer the cement particles, the larger the specific surface area, the faster and more sufficient hydration reaction, and the higher the early and late strength. National regulations: the specific surface area shall be greater than 300 square meters per kilogram, otherwise it is unqualified. 2. Setting time of refractory cement: in order to ensure that there is sufficient time to complete various processes such as mixing, transportation and molding during construction, the initial setting time of cement should not be too short; After construction, it is hoped that the cement can harden as soon as possible to produce strength, so the final setting time should not be too long. The initial setting time of refractory cement shall not be earlier than 45 minutes and the final setting time shall not be later than 390 minutes. 3. Volume stability of refractory cement: the uniformity of volume change of cement paste in the process of setting and hardening is called the volume stability of cement. If the volume changes unevenly, that is, the volume stability is poor, it is easy to produce warpage and cracking, reduce the project quality and even accidents.
When the refractory castable cement is used, an appropriate amount of water is added and stirred to form a slurry, which can harden in the air or better in the water, and can firmly bond other aggregates of the refractory castable with refractory materials such as powder.
Refractory cement has the characteristics of fast hardening speed, high bonding strength, strong plasticity and convenient construction. Refractory cement is different from common ordinary cement. In high temperature environment, as the binder of castable, refractory cement can quickly combine and harden, with good bonding performance, so as to improve the high-temperature service performance of refractory castable. Refractory cement is widely used, but it is mostly used as binder in the refractory industry to make refractory castables.