Detailed Application Range of Monomorphic Refractory Castables

Refractory castable is the most widely produced and used type of unshaped refractory. Today, with the rapid advancement of industrial technology, the types of refractory castables are ever-changing. Refractory castables are simpler in application than refractory bricks, save energy, have low costs, and are convenient for mechanized construction. It has been widely used in various types of thermal equipment such as cement, steel, glass, and electric power.

1. Application of refractory castable in cement rotary kiln.

In the new dry process cement rotary kiln, refractory castables have been widely used. There are many types of refractory castables used in the kiln. 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, cement-free refractory castables, steel fiber refractory castables, anti-burst refractory castables, anti-skinning refractory castables, phosphate refractory castables, alkali-resistant castables, heat-insulating castables, in addition, there are new types of castables such as self-flowing refractory castables.

2. Application of refractory castables in 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, etc.

3. 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, cement, and various additives.

(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. Since the middle and late 1980s in my country, the spray gun refractory material has gradually developed into a castable integral pouring spray gun, and its material is mainly an Al2O3-SiO2 system. The overall spray gun made of this castable has the characteristics of uniform structure, no joints, good thermal shock resistance, and long service life.

(3) Refractory castables for electric furnace steelmaking

The application of refractory castables in electric furnaces is mainly concentrated in the furnace cover of electric furnaces. In the late 1990s, the full water-cooled furnace roof technology was widely used, and the integral prefabrication technology of castables was generally used in the electrode triangle area. On the whole, the integral castable furnace cover may become a development trend of electric furnace cover materials in the future. Table 1 lists the physical and chemical indicators of several castables for electric furnace covers.

(4) Refractory castables for refining outside the furnace

Refractory castables for RH furnaces: A small number of high alumina castables and aluminum-magnesium castables are used in the lining of RH furnaces. 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.

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 pour large bricks in the impact area of the bottom of the package;

Refractory castables for CAS refining unit: 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 ultrafine powder. In order to prolong the service life of the device in the later stage, magnesium-aluminum gunning materials are mostly used.

Refractory castables for steel ladles: The varieties of refractory castables for steel ladles are mainly aluminum-magnesium castables and aluminum-magnesium spinel castables.

According to the type of ladle, the refractory castables used are divided into three grades. The castables used for large ladles are high-grade castables, generally using tabular corundum and spinel as the main raw materials. The castables for neutral ladles are medium-grade castables and generally use fused brown corundum and spinel as the main raw materials. The castables used in small ladles are resistant castables, and generally use super-grade bauxite and mid-grade sintered magnesia as the main raw materials.

(5) Refractory castables for continuous casting

Castables for tundish: lightweight castables (mainly used for the insulation layer), high alumina or mullite self-flowing castables (used for the permanent layer), corundum, and magnesium castables (used for the bottom working layer).