As the name suggested, Al2O3-SiC-C castable is composed of corundum or high alumina clinker, silicon carbide, carbon, binder and additives. Alumina silicon carbide carbon castable is mainly used to cast the inner lining of blast furnace tapping spout, so it is also called tapping spout refractory castable. When main aggregate material is corundum, it is called corundum silicon carbide carbon castable. When high alumina clinker is main aggregate, it is called high alumina silicon carbide carbon castable.
Corundum used to prepare this kind of castable is mainly fused corundum, which’s carbon content is less than 0.10%. Because carbon in corundum usually exists in the form of Al4C3, which will react with water and produce methane and Al(OH)3 and make corundum pulverized. So the lower the carbon content is, the better the quality is, or the lining will crack or spall during heating.
Al2O3-SiC-C castable has weak permeability, and is apt to crack during heating due to drastic water vaporization. So antidetonant such as aluminum powder, antidetonant fibers, aluminum lactate and so on. But the quantity of antidetonant should be strictly controlled to avoid the decrease of bulk density, strength, corrosion resistance ability and scouring resistance ability.
Large Scale Blast Furnace Tapping Spout Castable Index
Item
Main channel slag line
Main channel iron line
Branch iron channel
Slag trough
Al2O3 %
56~60
70~75
70~72
65~68
SiC %
15~30
12~15
12~15
15~18
Bulk Density(110℃,24h) g/cm3
2.9~3.0
2.9~3.0
2.75~2.80
2.65~2.70
Compression strength(110℃, 24h) Mpa
35~40
35~40
30~35
25~30
Linear change rate(1450℃,3h) %
+0.1~0.2
+0.1~0.3
+0.1~0.2
+0.1~0.2
Rupture strength (1450℃,2h) Mpa
>1.5
>2.5
>3.0
>1.5
Al2O3-SiC-C Castable Applications
Alumina silicon carbide carbon castable can not only be casted in spot but also can be made into precast block for use. The service life of alumina silicon carbide carbon castable varies largely due to the grade of raw material. Corundum silicon carbide carbon castable is mainly used to cast main channel lining of large scale blast furnace, one time iron output is about 100,000~150,000 t, after casting patch or gunning patch, iron output can reach to more than 300,000 t. For middle and small size of blast furnaces, high alumina silicon carbide carbon castable is usually used.
