Alkali-resistant refractory castables are castable refractory materials that can resist the corrosion of alkali metal oxides (such as K2O and Na2O) at medium and high temperatures. The composition of alkali-resistant refractory castables is similar to that of ordinary calcium aluminate cement-bonded castables. It is a mixture of alkali-resistant refractory aggregates and powders, binders, and admixtures. According to different use environments and conditions, alkali-resistant refractory castables are divided into light and heavy, and heavy alkali-resistant refractory castables can be divided into medium-temperature alkali-resistant castables and high-temperature alkali-resistant castables.

Classification of Alkali-Resistant Refractory Castables

(1) Aggregates used in lightweight alkali-resistant refractory castables include alkali-resistant ceramsite, clay porous clinker, waste porcelain material, high-strength expanded perlite, etc. Ordinary calcium aluminate cement is used as the binder. High-silica refractory powder can be added to the matrix of the castable to enable it to react with alkali metal oxides at high temperatures to form a glaze-like dense layer on its surface. This prevents further penetration and corrosion of alkali metal oxide melts.

Chemical composition of ordinary lightweight alkali-resistant castables: Al2O3 is 35%~65%, SiO2 is 25%1~45%, and the bulk density (drying) is 1.5~1.6 g/cm3.

(2) The aggregates used in heavy medium temperature alkali-resistant refractory castables include high alumina clinker, clay clinker, etc. The binder is calcium aluminate cement plus silica powder (smoke silica). The addition of silica powder not only helps to improve the medium-temperature bonding strength of the castable but also helps to form an anti-permeability layer on the surface of the castable lining during use. Its characteristics are that the strength after medium temperature (1000~1200℃) firing is equivalent to the strength after drying (110℃). It has good alkali corrosion resistance.

Chemical composition of ordinary heavy medium temperature alkali-resistant castables: Al2O3 is 45%~65%, SiO2 is 25%~35%.

Physical and Chemical Properties of Ordinary Alkali-Resistant Refractory Castables

Heavy High-Temperature Alkali-Resistant Castable

The alkali-resistant refractory aggregates (aggregates and powders) used in heavy high-temperature alkali-resistant castables include fused spinel, chrome corundum, aluminum chrome slag, sintered or fused zirconium corundum, and zircon. The binder uses calcium aluminate cement plus silica powder, and water glass solution is also used as the binder, which is selected according to the actual use requirements.

Application of Alkali-Resistant Refractory Castables

Alkali-resistant refractory castables are mainly used in places with alkali metal oxides and their vapor corrosion. Such as the lining of the cement rotary kiln tail and kiln decomposition cyclone separator outside the kiln, the lining of the roasting alumina rotary kiln tail, etc. As well as the lining of industrial furnaces and their flues and smoke windows with alkali vapor corrosion in steel, nonferrous metals, glass, papermaking, and other industries.

Rongsheng Alkali-Resistant Refractory Castable Manufacturer

Rongsheng Refractory Material Manufacturer has an environmentally friendly and advanced fully automatic amorphous refractory material production workshop, specializing in providing high-quality amorphous refractory products for high-temperature industrial furnaces. Rongsheng manufacturers can customize alkali-resistant refractory castable lining materials for customers according to the actual working conditions of high-temperature industrial furnaces. Save production costs for enterprises and improve economic benefits. Contact Rongsheng to get free samples and refractory lining solutions.