Calcined alumina powder is made from industrial aluminum hydroxide or industrial alumina as raw materials, calcined at an appropriate temperature to produce a crystalline stable α-alumina product; alumina micro powder is made from calcined α-alumina as raw material, processed through ball milling. Calcined alumina powder is generally used in shaped refractory products such as skateboards, three major components, and corundum bricks, or in combination with activated alumina for unshaped refractory materials.
When using calcined alumina powder to produce resin-bonded products, its low moisture content allows for easy and uniform mixing, and it has high volume stability. When combined with activated alumina micro powder or silica fume for amorphous refractory materials, it can form a particle gradation with finer micro powders to achieve the closest packing, reduce water addition and porosity, decrease linear change rate, and increase strength.