Refractory castables with special properties include wear-resistant castables, acid-resistant castables, alkali-resistant castables, anti-seepage castables, and high thermal conductivity refractory castables.
Wear-resistant castables
Wear-resistant castables are dense and hard, using multi-grade particle grading and high bulk density. They use excellent binders, ultrafine powders, and admixtures, with high compressive strength and strong wear resistance. They are used for rolling furnace slides and boiler linings in the power industry. There are many different methods for testing the wear resistance of wear-resistant castables, and there is no comparison between them. When the quality of the process raw materials and the test methods are the same, the size and quality of the wear resistance can be judged.
Acid-resistant refractory castables are made of water glass and cement as binders, and are prepared with siliceous materials and a small amount of aluminum silicate materials. Their characteristics are that they have good use effects in medium and low temperature acidic medium atmospheres. Acidic refractory castables are mostly used for the protective layer of blast furnaces and hot blast furnaces, and are more commonly used for steel chimneys and flue linings.
For acid-resistant castables combined with water glass, when the acid solution concentration is small, the connection between aggregates will be destroyed, resulting in reduced strength. When the acid solution viscosity is high, it is not easy to penetrate, and the chemical strength is enhanced. Silicate gel can promote the growth of castable strength. After soaking, the acid solution is added to the castable, and the strength of the acid-resistant castable does not decrease.
Acid-resistant castables combined with cement are mostly used for chimney linings, and can also be used as acid-resistant spray coatings for spraying.
Description of alkali-resistant castables
Alkali-resistant castables are made of aluminum-silicon series raw materials and aluminate cement. They are divided into heavy and light types. They are mostly used in preheaters and pipelines of large and medium-sized cement rotary kilns. Alkali-resistant castables combined with water glass also have alkali resistance and can effectively resist the erosion of sodium salt melts. They are mostly used in alkali recovery furnace linings in the papermaking industry, and the effect is also quite good. Alkali-resistant castables also include magnesium series castables, which can be used in high-temperature parts of alkaline furnace linings.
Anti-seepage castables
Anti-seepage castables are used in aluminum electrolytic cells and belong to medium and low-grade castables.
High thermal conductivity refractory castables
High thermal conductivity refractory castables are silicon carbide castables, which are characterized by high thermal conductivity and small expansion coefficient, but also good thermal shock stability, high strength, and good wear resistance.
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