Bonded Again Fused Cast Alumina Block

Bonded again fused cast alumina block is a type of bonded again sintered refractories brick made of fused corundum clinker as the granular material and fused corundum or sintered

corundum powder as the matrix.

The batching of granular materials should be according to the principles of tightly packing, multilevel ratio, refractory company less intermediate particles and more fine powder. This can improve

the density and sintering of the products. The additives include aluminum phosphate, phosphoric acid, aluminum chromium phosphate, cellulose and pulp waste solution. Among them,

he most promising is active phosphate. Recently, ammonium phosphate is on the trial and achieves good magnesia carbon brick results. The mud should be mixed evenly with a moisture content of 3-4%.

After high pressure molding, high dense bricks are obtained.

There are a few harmful ingredients in the corundum which will cause poor sintering or cracking, firebrick refractory sale so corundum should be pre-calcined before use. The residual ferro-silicon alloy

is oxidized and decomposed into Fe2O3 and SiO2 at 500-1000℃ and Ti in the minerals can be oxidized into TiO2 (rutile), which can cause large volume expansion. After pre-

calcining, the stress caused by those decomposition reactions and oxidation reactions can be eliminated during the pre-calcining process and cracks caused by the volume

expansion of those impurities can be avoided during the sintering process.
Fused corundum block has large volume, so it should be smashed with drop hammers and other ways and then high insulating brick pulverized. The pulverized fused corundum is stored by size after

screened. Fused corundum is hard and difficult to grind. Therefore it is wet ground by ball mills or vibration ball mills. The grain size can be less than 40μm or even 10μm.

The iron in the granular material can be removed with electromagnets and the iron in the fine powder can be washed with acids.


When using fused brown corundum or white corundum as raw materials, the frits should be smashed and then processed by removing the ferro-silicon alloy and other impurities.

White corundum should be processed by removing the flaky sodium aluminate crystals and other low-melting substances. The impurities are easy to be identified since they have low

density and float in the surface of corundum frits.

The fused cast alumina block has high purity. It is difficult to sintere and should be sintered at 1800℃. The type of the kilns used depends on the production scale. For small

batch production, high-temperature batch kiln is better. For batch stable production, the small high-temperature tunnel kiln is used.

Henan Xinmi Changxing Refractory Material Co., Ltd. Located in Henan Province,China.ChangXing's product portfolio covers shaped products such as refractory materials,refractory

brick, refractory castable,refractory nozzle, ceramic fiber, slide gate, etc; unshaped products including repair, construction and casting mixes and mortars.exported to more

than 20 countries, such as Thailand, Indonesia, Pakistan, Saudi Arabia, South Africa, Turkey, Iran, Iraq and so on.