Acid-resistant castables are divided into heavy, semi-light, and light. Their main function is to be used for furnace linings that resist acid erosion. Acid-resistant castables are generally combined with acid-resistant cement and are applicable to acid-resistant chimneys and liquid sulfur pool linings in the petrochemical industry.
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| Acid-Resistant Castables for Lining of Acid-Resistant Chimneys |
The acid-resistant castable for acid-resistant chimneys is similar to and different from other refractory castables. It belongs to an acidic medium. During production, the raw materials are also processed into granules and fine powder in an acidic medium, and a certain proportion of ultra-fine powder and additives are added. However, the acid-resistant castable used for lining the liquid sulfur pool cannot be used in atmospheres with large temperature differences, nor can it be used in construction in places that are too humid. If the temperature is not suitable, it will reduce the later use strength and acid resistance of the acid-resistant castable, and it will peel off.
Application of acid-resistant castables
Chimneys are made of acid-resistant castables, generally semi-lightweight. It can not only be used for thermal insulation but also be resistant to erosion and acid gas erosion. Because semi-lightweight acid-resistant castables can save energy and improve the operation rate and service life of the chimney. At the same time, the weight of the chimney body is not too heavy.
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| Application of acid-resistant castables |
Acid-resistant refractory castables are all used in furnace linings that resist acidic atmospheres and cannot be used in neutral or alkaline furnace-lining atmospheres. Due to the high-temperature resistance of acid-resistant castables, it is not as good as high-aluminum series castables used in neutral atmospheres. In an alkaline atmosphere, use castables inferior to the magnesium series. It is mainly used in acidic atmosphere chimneys, flues, nitric acid shrink tower linings, and acid gas container linings. The high-temperature resistance of acidic refractory castables is not as good as that of the high aluminum series and magnesium series.
However, acid-resistant castables can be used as separate lining materials. When used in a furnace with a consistent atmosphere, the castable's own acid resistance will be exerted, and it cannot be used as a furnace lining in other atmospheres. First, there is a gap in high-temperature resistance, and then there is a gap in resistance to erosion by other atmospheres.
In other words, acid-resistant castables, whether heavy, semi-light, or light, can only be used as furnace linings for acid gases.
Lightweight acid-resistant castable for anti-corrosion flue
Lightweight acid-resistant castable is mainly used in anti-corrosion flue and chimney linings, acid storage tanks, pickling tank linings, and nitric acid shrinkage tower linings. Acid recovery furnace lining and other refractory castables corroded by acidic high-temperature gases. It can improve the air tightness and integrity of the lining wall and the corrosion resistance of the lining. It is a kind of refractory material that is widely used at present.
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| Lightweight acid-resistant castable |
Characteristics of lightweight acid-resistant castables for chimney lining
1. It has the characteristics of light volume and high compressive strength.
2. It is resistant to acid and acid gas corrosion.
3. It has the characteristics of heat insulation, heat preservation, and low water absorption.
4. It can significantly improve the air tightness, integrity, and anti-corrosion ability of the lining.
Characteristics of lightweight acid-resistant castables for lining pickling tanks
1. Low thermal conductivity. The thermal conductivity of lightweight acid-resistant castable is only 0.12-0.16W/(m·k), which is about 1/10 of ordinary concrete. Therefore, the thermal insulation effect can be better exerted.
2. High temperature resistance. The castable can be used for a long time in a high-temperature environment of 1000°C without cracking or falling off. Excellent fire resistance.
3. Strong corrosion resistance. Lightweight acid-resistant castable has good acid and alkali corrosion resistance. It can be used for a long time in corrosive environments such as strong acids and alkalis without causing damage or destruction.
4. Simple construction. The castable is easy to construct and uses water as a diluent. It can be mixed with water on-site to form a slurry and then poured directly on the surface of the equipment. No special construction equipment or technology is required. The labor intensity and construction difficulty of workers are greatly reduced.
The characteristics of the lightweight acid-resistant castable used for lining the acid recovery furnace enable it to be widely used as a lightweight acid-resistant castable. At the same time, as an unshaped refractory castable, it can also be made into prefabricated parts of various shapes for use. It is a refractory product that is widely used and ideal at present.
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