In the field of modern high-temperature industry, refractory plays an indispensable role, and refractory castable, as an important branch, has become the first choice material for many industrial furnaces and equipment because of its excellent performance and wide application range. This paper will deeply discuss the characteristics, classification, application and development trend of refractory castable, and reveal its important position and function in high temperature industry.

I. Overview of refractory castable

Refractory castable is an amorphous refractory material, which consists of refractory aggregate, powder, binder, admixture and water or other liquid materials. By optimizing the formula design, it has good fluidity and can be hardened at room temperature without high temperature sintering. This material can be molded by pouring, vibrating or ramming only by adding a proper amount of water or other liquid in the construction site, or it can be made into prefabricated parts for specific parts. Its unique properties make it a new type of refractory material, which is widely used in metallurgy, chemical industry, building materials and other industries.

II.the characteristics of refractory castable

Refractory castable has the following remarkable characteristics:

High working temperature: it can withstand extremely high temperature, and the highest service temperature of some high aluminum-based castables can reach above 1700 C.

High density and low porosity: high density gives it good corrosion resistance and wear resistance, while low porosity makes it more stable at high temperature.

Excellent corrosion resistance and erosion resistance: it can effectively resist chemical erosion and mechanical erosion and prolong service life.

Good thermal shock stability: when the temperature changes sharply, it can still maintain the integrity of the structure and reduce the occurrence of thermal cracks.

Convenient construction: easy to install and shape, can be poured on site according to specific needs, and has good integrity.

Customizability: according to different use environments and requirements, the chemical composition and physical properties can be adjusted to meet the needs of specific working conditions.

III. the classification of refractory castable

There are many kinds of refractory castables, which can be divided into the following categories according to different classification standards:

(1) Classification by chemical composition

High aluminum-based castable: bauxite, corundum, etc. are the main raw materials, with high aluminum content, suitable for high temperature environment.

Low-cement castable: by reducing the amount of cement, the content of CaO is reduced, and the fire resistance and corrosion resistance are improved.

Phosphate bonded castable: With phosphoric acid or phosphate as binder, it has good high temperature strength and chemical corrosion resistance.

Silicate bonded castable: sodium silicate is used as binder, which is suitable for medium and low temperature environment.

Steel fiber reinforced castable: adding steel fiber to ordinary castable can significantly improve impact resistance and wear resistance.

(2) Classification by purpose

Dense castable: used for parts that bear high temperature and mechanical load, such as ladle and tundish lining.

Thermal insulation castable: It has low thermal conductivity and is used as the thermal insulation layer of furnace lining to reduce heat loss.

Wear-resistant castable: it is specially used for the parts with serious high-temperature erosion and wear, such as the lining of circulating fluidized bed boiler.

Prefabricated castable: used to make prefabricated parts of various shapes, which is convenient for on-site installation and replacement.

(3) Classification by construction method

Vibrating castable: it is suitable for large-area pouring through vibration molding.

Self-flowing castable: It has good fluidity, can flow and form itself without vibration, and is suitable for parts with complex shapes.

Spraying castable: It is suitable for rapid repair and large-scale construction through spraying equipment construction.

IV. the application of refractory castable

Refractory castable has a wide range of applications, covering almost all high-temperature industrial fields:

(1) Metallurgical industry

In the process of iron and steel smelting, refractory castable is widely used in the lining of ladle, tundish, ladle and other containers, which can withstand the erosion and erosion of high-temperature molten steel and ensure the structural stability of the container. In addition, in blast furnace, converter, electric furnace and other equipment, refractory castable also plays an important role in protecting the furnace body from high temperature and chemical erosion.

(2) Building materials industry

In cement production, refractory castable is mostly used for lining of key equipment such as rotary kiln, preheater and calciner. These equipments need to run for a long time in high temperature and high dust environment. The high wear resistance and erosion resistance of refractory castable can effectively prolong the service life of the equipment and reduce the maintenance cost.

(3) Chemical industry

Various reaction furnaces, cracking furnaces, reforming furnaces and other equipment in the chemical industry have extremely high requirements for refractories because of their complex chemical reaction environment. Refractory castable can resist the corrosion of various chemical media, at the same time ensure the stability of equipment at high temperature and ensure the smooth progress of chemical production.

(4) electric power industry

In thermal power generation, the lining of circulating fluidized bed boiler, pulverized coal boiler and other equipment needs to use wear-resistant and heat-insulating refractory castable to reduce heat loss, improve combustion efficiency and protect the furnace body from high temperature erosion and wear.

(5) Other fields

In addition to the above-mentioned main industrial fields, refractory castables are widely used in glass kilns, ceramic kilns, garbage incinerators and other fields, providing reliable material guarantee for the development of high-temperature industries.

V. Development trend of refractory castable

With the continuous development of high-temperature industry, the performance requirements of refractory castable are getting higher and higher. In the future, the development of refractory castable will present the following trends:

High-performance: by optimizing the formula and production process, the high-temperature strength, corrosion resistance and wear resistance of refractory castable can be further improved to meet more demanding working conditions.

Environmental protection: reducing the emission of harmful substances and developing environment-friendly refractory castables such as chromium-free and low cement meet the requirements of sustainable development.

Intelligentization: combining modern sensing technology and intelligent monitoring system, develop refractory castable with self-diagnosis and self-repair functions, and realize intelligent maintenance of equipment.

Customization: according to the characteristics of different industrial furnaces and equipment, provide personalized refractory castable solutions to improve the adaptability and service life of materials.

VI. Case analysis

Take the ladle lining of a large iron and steel enterprise as an example. The traditional refractory bricks were originally used as the ladle lining in this enterprise. However, due to the high temperature erosion and erosion of molten steel, the service life of the lining is short and the production cost is increased due to frequent replacement. Later, the enterprise changed to high aluminum-based steel fiber reinforced refractory castable. After practical application test, the service life of the lining was increased by more than 50%, while the maintenance time and cost were reduced, and the production efficiency was significantly improved.

VII. Conclusion

As an important amorphous refractory, refractory castable plays an irreplaceable role in high temperature industry with its excellent performance and wide application range. With the continuous progress of technology and the increasing market demand, the future development of refractory castable will pay more attention to the direction of high performance, environmental protection and intelligence. Through continuous innovation and optimization, refractory castable will further enhance its application value in high-temperature industry and provide solid material guarantee for efficient, stable and sustainable development of industrial production.