Performance of High-Quality Alumina Bubble Castable
As we all know about the alumina bubble bricks. Have you ever heard about the alumina bubble castable? The answer is Yes! Alumina Bubble Castable is a lightweight refractory castable prepared with alumina hollow balls as aggregate and industrial alumina or corundum powder as powder. The binders used in this kind of lightweight refractory castables are mainly CAC (CA-70C, CA-80C) cement, aluminum phosphate, and aluminum sulfate. The particle size of the alumina hollow ball aggregate in the castable is 5mm, and the natural particle size or graded gradation is usually used. At the same time, additives are also added to improve the Performance of High-Quality Alumina Bubble Castable.
The bulk density of alumina hollow spheres is 0.5~0.8g/cm-³. The true density is 3.94g/cm-³. The melting point temperature is 2040°C. The thermal conductivity is 0.46W·(m·k)-1 at 1100℃. The crystal form is α-AL2O3. The content of AL2O3 is greater than 99%. So is the Alumina Bubble Castable’s performance index as the following:
Items
CA-70C
Low Cement
Aluminum Sulfate
Crushing Strength (MPa)
110 ℃
27.1
19.0
15.9
9.7
7.4
1500 ℃
32.2
22(1000℃)
13.3
26.6
21.2
Bending Strength (MPa)
110 ℃
9.1
5.4
8.0
4.0
1500 ℃
10.8
Refractoriness Under Load (℃)
0.2MPa, 0.6%
＞ 1600
Thermal Conductivity (W/m·k)
1000 ℃
0.80
0.82
0.82
0.65
1.76
Chemical Composition (%)
Al2O3
94.8
80.8
93.7
95.4
95.8
Fe2O3
0.6
2.66(Cr2O3)
0.13
CaO
3.4
3.3
3.17
2.18
Bulk Density (g/cm3)
1.6
1.46
1.64
1.58
＜1.3
Working Temperature (℃)
1800
1600
1800
＞1600
＞1600
Silicon Carbide Alumina Bubble Castable
(1) Adding silicon carbide in an appropriate amount is beneficial to increase the volume density, room temperature compressive strength, and thermal shock stability of low cement combined alumina bubble castable. The excessive addition of silicon carbide will destroy the matrix structure of the castable. When the amount of silicon carbide added is 6%, the bulk density of the alumina bubble castable sample reaches 1.5g/cm3, and the retention rate of normal temperature compressive strength is 92.3%. At this time, the alumina hollow ball castable exhibited the best thermal shock stability.
(2) As the firing temperature increases, the bulk density of this kind of castable and the normal-temperature compressive strength before and after thermal shock increase gradually. When the firing temperature is 1 450 ℃, the bulk density of the sample reaches 1.48g/cm3, and the retention rate of compressive strength at room temperature is the highest, reaching 95.3%. The ability of the alumina bubble castables to resist temperature changes is enhanced.
Features and Applications of Alumina Bubble Castable
The characteristics of alumina bubble castable are high load softening temperature, high strength, and good heat insulation performance. The operating temperature is generally 1600℃~1700℃. It is an ideal thermal insulation material for carbon black reaction furnace and special high-temp permanent layer lining. Alumina bubble refractory castables are mainly used in thermal furnaces such as metallurgy, ceramics, refractory, petrochemical, and carbon black. It can meet the development needs of new processes and technologies, save energy, and has outstanding economic and social benefits.
RS Refractory Materials Manufacturer
As one of the refractory manufacturers, RS has more than 10 years of experience, and the refractory materials have been delivered to more than 60 counties and areas. Such as Malaysia, South Africa, India, Indonesia, Pakistan, Netherlands, Kuwait, Kenya, Russia, United States, etc. If you are looking for the alumina hollow ball bricks and the alumina bubble castables, please leave us your detailed requirements, so that we can according to your furnaces’ working conditions to provide you the suitable refractory materials.
