The Main Components and Applications of Acid-Resistant Castables
Acid-resistant castable refers to a refractory castable that can resist corrosion by acidic media at a temperature of 800 to 1200°C. It is mainly prepared by using water glass as a binder, acidic or semi-acidic refractory materials as aggregate and powder, and a small amount of coagulant. The disadvantage of this castable is that it cannot be used where there is an alkaline corrosive medium. Next, let's learn more about the main components of acid-resistant castables and their applications.
Acid-Resistant Castable |
The main components of acid-resistant castables
The main components of acid-resistant castables are water glass, hardening accelerators, acid-resistant refractory aggregates, and powders. Acid-resistant refractory aggregates and powders mainly include particles such as silica, cast stone, wax stone, diabase, and fine powders of acid-resistant materials such as waste silica bricks, silica, waste porcelain, and cast stone. Water glass is generally used as a bonding agent. The modulus of water glass is 2.6~3.2, the density is 1.38~1.42g/cm3, and the dosage is generally 13%~16%. Sodium fluorosilicate is used as a coagulant, and the mixing amount is 10% to 12% of the mass of the water glass solution. This kind of acid-resistant castable has low cost and good acid resistance. It is used in metallurgy, the chemical industry, and other parts. However, it is less corrosive to phosphoric acid, hydrofluoric acid, and high fatty acids.
The proportion of main components of acid-resistant castable
In acid-resistant castables, acid-resistant aggregates account for 60%-70%, and powders account for 30%-40%. The density of the water glass solution is 1.38-1.42g/cm3, accounting for 13%-16%. A proper amount of coagulant, the addition amount is 10%-12% of the mass ratio of the water glass solution.
The acidic medium that the acid-resistant castable can resist
Acidic media generally include nitric acid, hydrochloric acid, sulfuric acid, and acetic acid.
Acid resistance of acid-resistant castable
The degree of acid resistance is a measure of the chemical attack of acid-resistant castables in acidic media. The acid resistance of water glass combined with acid-resistant castables is related to the acid resistance of the aggregates and powders used. The acid resistance of the raw materials of several commonly used acid-resistant castables is: cast stone is 98%, quartz stone is greater than 97%, clay clinker is 92%-97%, the wax stone is 92%-96%, andesite is greater than 94%.
Therefore, the acid resistance of the acid-resistant castable made of clay clinker as the main aggregate and quartz powder as the powder can reach 96.8%. Using clay clinker as the main aggregate and clay clinker powder as powder, the acid resistance of the acid-resistant castable reaches 97.2%. The acid-resistant castable made of wax stone as the main aggregate and quartz powder as the powder has an acid resistance of 93.5%. The acid-resistant castable made of wax stone as the main aggregate and wax stone powder as the powder has an acid resistance of 92.0%.
Characteristics and application of acid-resistant castable
Acid-resistant castables have better strength and stability when immersed in acid. As the immersion time increases, the compressive strength increases slightly. Acid-resistant castables are mainly used for anti-corrosion flue and chimney linings, acid storage tanks, pickling tank linings, nitric acid concentration tower linings, acid recovery furnace linings, and other acidic high-temperature gas corrosion vessel linings.
Acid-resistant castables are used in industrial kilns, and acid-resistant castables can be seen in other industrial applications. Since the acid-resistant castable is a monolithic refractory material product, its main application is not only in the repair of various industrial linings but also in new construction. It can make reasonable repairs on the damaged parts of the kiln to ensure the normal operation of the kiln. In addition, when repairing industrial kilns, acid-resistant castables can be used to repair certain linings. From the refractory manufacturer's side, this is enough to show that acid-resistant casting is one monolithic refractory product with a wide range of uses.
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