What Is a Lightweight Refractory Castable

Lightweight refractory castables are made of powder and refractory aggregate, admixture and binder. General provisions: the volume density is less than 1800kg/m, did not make requirements for the refractoriness, or the total porosity is more than 45%, in the specified temperature of the shrinkage rate is less than 1.5% of the castable, called light refractory castable.

Lightweight refractory castable has the following characteristics: small volume density, low thermal conductivity, so it has a good heat insulation performance. There are many varieties of light refractory castables, which are generally classified according to light aggregate varieties, binder types, production methods and performance grades. The most commonly used varieties of light aggregate are light refractory castable such as light sand brick, porous clinker, hollow ball, ceramsite and expanded perlite.

Saving energy is one of the most concerned topics in the world at present. In this general trend, light refractory castable can be developed rapidly, varieties expanded, output increased, quality improved, widely used. In the past, in kilns with temperatures over 1000°C, lightweight refractory castable can only be used as insulation layer, and it is difficult to contact the flame directly. At present, light refractory castables used in flame kilns below 1800°C can be normally produced, and some can be used as working linings.

In the petrochemical industry, metallurgy, electric power and building materials and other industrial sectors, such as furnace and thermal equipment, light refractory castable is widely used, generally used as heat insulation layer, can also be used as its working layer or load-bearing components, have obtained good results and evaluation. In contact with liquid metal or slag, only tundish is covered with insulation board, and good results have been achieved. The performance test of light refractory castable is basically the same as that of heavy refractory castable. One of the differences is that the test of softening temperature under load is 0.1MPa under added load.

It should be pointed out here that with the demand of energy saving of industrial kilns, lightweight refractory castable is sure to get a greater development prospect, its direction is high strength, light weight, low thermal conductivity, low price and easy to use. In addition, light aggregate and binder are generally used in combination, and admixture can develop excellent lightweight refractory castable.

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