Calcined Alumina

Alpha calcined alumina is product after reactive alumina powder is calcined under high temperature. Main phase is α-Al₂O₃.

Alpha Calcined alumina could be 1 μm after grinding, with great activity value. It is widely used as ultra fine powder for monolithic refractories to increase the liquidity of the castable. With Alpha calcined alumina added, refractory blocks also have higher strength, better corrosion resistance and better thermal resistance.

During sintering process from Alumina powder to calcined alumina, the γ-Al₂O₃ begins to turn into α-Al₂O₃ phase since 1000 ℃,and it needs time to get Alpha Calcined alumina completely. There is large volume decrease during this process. So alumina powder is seldom used directly as raw materials for refractory products. Calcined alumina powder has stable performance after this sintering process, so mostly it's used instead of alumina powder.

In recent years, because of bad influence to castable from CaO (bring from high alumina cement), more and more companies develop ultra-low cement castable or no cement castable. In such product, Alpha alumina powder is added as binding agent instead of high alumina cement. Maintenance is more easier, and liquidity is better.

Refractory materials refer to inorganic non-metallic materials with refractoriness over 1580℃.

Refractory raw materials are raw materials used to produce refractory bricks and monolithic refractories.

Types: There are main aggregates, binding agents, additives, anti-oxidants etc.

For different applications, there are dense raw materials and light weight insulation materials

Long Keter is supplying a comprehensive dense raw materials, including high alumina bauxite, Kaolin flint clay, tabular alumina, alumina powder, brown fused alumina, white fused alumina, magnesia spinel, mullite etc.