Low cement castable for waste incinerator

At present, the lining of waste incinerators has gradually evolved from traditional refractory bricks to refractory castables and sprayable plastics. The refractory castables used mainly include SiC low cement castables and high-strength wear-resistant castables. The quality of the refractory castable in the furnace is the key to whether the waste incinerator can be produced at long-term and full-load safety. Especially in the lower part of the wall of the waste incinerator, volatile gases, melts, fly ash, etc. are generated due to waste incineration. Fly slag, etc., so refractory materials are required to have good wear resistance, corrosion resistance, slag resistance, oxidation resistance and other properties. At present, the refractory materials used in waste incinerators at home and abroad are usually silicon carbide low cement castables, which are made of silicon carbide particles as aggregate and combined with low cement micropowder, which is used in actual use and construction. There are deficiencies, mainly in the following aspects:

First, the particle size of silicon carbide particles as aggregate is less than 5 mm, the critical dimension of the particles is difficult to exceed 5 mm, and there are more pseudo particles in the 3 to 5 mm silicon carbide particles, which easily leads to castables. The structure is loose and therefore the service life is not long.

Second, the volatile incineration temperature of the harmful gas in the waste incinerator is between 650 and 1 100. This temperature zone is the weak oxidation section of the silicon carbide castable, although the strength of the alumina and the sintering aid are added to the castable. Silica fume, but does not fundamentally improve the oxidation resistance of the castable.

Third, the silicon carbide low cement castable uses alumina cement as the binder. This single binder makes the use time of the castables not adjustable at will, and it is difficult to adapt to different occasions with large temperature difference and large difference in air humidity in China. Construction quality in various environments cannot be guaranteed.