Calcined alumina is a product obtained by calcining aluminum hydroxide at high temperature to partially or almost completely convert it into aAl2O2.
Calcined alumina powder for refractory material
Calcined alumina powder is a product obtained by calcining aluminum hydroxide at high temperature to partially or almost completely convert it into aAl2O2. Calcined alumina can be classified into many grades according to calcination (crystal size, specific surface area) and Na2O content (0.01%~0.5%). The so-called industrial alumina (or industrial alumina) in our country is a kind of calcined alumina, but its general calcination degree is poor.
The production methods of calcined alumina mainly include Bayer method, soda lime sintering method, and Bayer-sintering combined method.
The smaller the particle size of a-alumina micropowder, the higher the activity, the better the dispersibility, and the better the water reducing effect and dispersibility in the castable. In the case of the same ratio and the same amount of addition, the addition of alumina fine powder with small particle size improves the construction performance of the castable, the bulk density is large, and the flexural strength and compressive strength at room temperature and high temperature are higher than those with large particle size. Alumina micropowder castable. For the alumina powder with large particle size, the fluidity of the castable decays faster, and the working time of the castable becomes shorter.
The greater the amount of alumina powder added, the better the fluidity of the castable. This is because the alumina micropowder has a small particle size and can be filled into the gaps and flocculation structures between particles.
The higher the amount of alumina added, the higher the high temperature cold flexural strength of the castable, because a large number of staggered CA2 and CA6 crystals are formed in the matrix, forming a network-like structure in the matrix.
|
type |
Project |
Al2O3% |
SiO2% |
Fe2O3% |
Na2O3% |
burn |
true density(g/cm3) |
α-Al2O3 |
|
low sodium |
AN-03 |
99.5 |
0.06 |
0.03 |
0.03 |
0.10 |
3.97 |
95 |
|
AN-05 |
99.5 |
0.06 |
0.03 |
0.05 |
0.10 |
3.97 |
95 |
|
|
AN-10 |
99.3 |
0.08 |
0.04 |
0.10 |
0.10 |
3.96 |
95 |
|
|
AN-20 |
99.0 |
0.10 |
0.05 |
0.20 |
0.20 |
3.95 |
93 |
|
|
medium sodium |
AN-30 |
99.5 |
0.04 |
0.04 |
0.30 |
0.20 |
3.93 |
90 |
|
AN-40 |
99.0 |
0.10 |
0.05 |
0.40 |
0.20 |
3.90 |
85 |
|
|
AN-50 |
97.0 |
0.15 |
0.10 |
0.50 |
0.40 |
3.85 |
80 |
Advantages of a-alumina powder:
smaller particle size
higher activity
better dispersion
The better the water-reducing effect and dispersibility in the castable
The refractory ramming material is prepared from a high proportion of granular and powdery materials and a very low proportion of binders and other components, even all of which are composed of granules and powders, and are subject to strong ramming. Bulk materials for construction.
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In the blast furnace smelting process, blast furnace taphole clay, as a key plastic material, plays a vital role. This article will introduce in detail the product characteristics, working principle and innovation of blast furnace taphole clay in improving furnace stability and production efficiency.
The heavy part of the raw materials for the chrome zirconium corundum composite brick is sintered tabular corundum, high-purity chromium oxide, high-purity zircon, and Guangxi white cement.As the main raw material, the light part of the raw material is made of 47 mullite, kyanite, floating beads and coke gemstones as the main raw materials. During molding, a separator is set in the middle of the mold, and heavy materials and light materials are added at both ends. After high pressure molding , finished products made of high temperature sintering.
The unshaped refractory material used when repairing the lining of thermal equipment by spray construction method is called refractory gunning material. It is made of a refractory set with a certain particle gradation

