With the improvement of the operating temperature and service life of various high-temperature kilns and thermal equipment, refractory castables are widely used as unshaped refractory materials in production and use. There are many types of refractory castables. What are the refractory castables commonly used in high-temperature kilns? In the modern era of rapid industrial technology, the advantages of the use of refractory castables compared with refractory bricks are simple to process, energy-saving, low cost, and convenient mechanized construction. It has been widely used in various types of thermal equipment such as cement, steel, glass, and electric power.
Refractory castables for cement rotary kiln
In the new dry process cement rotary kiln, refractory castables have been widely used. According to the different working environments of the kiln, the refractory castables used include ordinary refractory castables, low cement refractory castables, ultra-low cement refractory castables, and cement-free refractory castables. Steel fiber refractory castables, anti-burst refractory castables, anti-skinning refractory castables, phosphate refractory castables, alkali-resistant castables, and heat insulation castables. In addition, there are new castables such as self-flowing refractory castables.
Refractory castables for glass-melting furnaces
Due to the requirements of the working environment of the glass melting furnace itself, the applied refractory castable should have the characteristics of good high-temperature resistance, strong resistance to glass liquid erosion, and low porosity. The refractory castables mainly used include fused silica castables, corundum castables, lightweight mullite castables, zircon ramming materials, etc.
Application of Refractory Castables in the Metallurgical Industry
(1) Refractory castables for the ironmaking system
In the ironmaking system, there are many refractory castables for blast furnace tapping troughs, and ASC refractory castables are generally used. ASC castables are generally low-cement or ultra-low-cement castables, which are mainly composed of Al2O3 aggregates, SiC, carbon, refractory cement and various admixtures. Different parts use different materials, such as main ditch, slag ditch, branch ditch, etc.
(2) Refractory castables for molten iron pretreatment
In the application of refractory castables in the ladle, aluminum silicon carbide carbon castables are mainly used in the furnace bottom, molten pool, and slag line. The spray gun is an important device for the pretreatment of molten iron. At present, the refractory materials for spray guns are mostly castable as a whole, and their materials are mainly Al2O3-SiO2 series. The overall spray gun made of this castable has the characteristics of uniform structure, no joints, good thermal shock resistance, and long service life.
Refractory castables for electric furnace steelmaking
The application of refractory castables in electric furnaces is mainly concentrated in the furnace cover of electric furnaces. The overall prefabrication technology of castables is generally used in the electric triangle area. Integral castable furnace cover may become a development trend of electric furnace cover materials in the future. The material of the prefabricated block is divided into corundum, high alumina, and mullite. The user provides the drawing, the location of use, and the temperature, and the manufacturer uses a suitable refractory castable to cast it into a prefabricated part according to the drawing. After curing and baking, it will be delivered and delivered to the user’s site for on-site splicing.
Refractory castables for refining outside the furnace
(1) Refractory castables for RH furnaces. A small amount of high-alumina castables and aluminum-magnesium castables are used in the RH furnace lining. The upper part of the RH vacuum chamber adopts Al2O3-MgO·Al2O3 castable integral lining or gunning integral lining. Integral aluminum-magnesium castables are used for the outer wall of the dip tube in the RH furnace.
(2) Refractory castables for LF furnace. The materials used for the curtain wall of the LF furnace cover are mainly high-alumina or corundum series castables. High alumina-spinel refractory castables are often used to cast large bricks in the impact area of the bottom of the package.
(3) Refractory castables for CAS refining units. The CAS refining unit is divided into upper and lower parts, and the refractory materials used are all castables. The upper part mostly uses low-expansion Al2O3-SiO2 castables. The lower part mostly uses corundum-spinel series castables with fused corundum added with MgO fine powder. In the later stage, in order to prolong the service life of the device, magnesium-aluminum gunning materials are mostly used.
(4) Refractory castables for ladles. The types of refractory castables for ladles are mainly aluminum-magnesium castables and aluminum-magnesium spinel castables.
Refractory castables for continuous casting
Castables for tundish include lightweight castables (mainly used for the heat insulation layer), high alumina or mullite self-flowing castables corundum, and magnesium castables (used for the bottom working layer).
