Alumina Powder Al2O3


  1. Aluminum hydroxide minerals are the main component of bauxite, the principal ore of aluminum. The bauxite ore is made up of a mixture of the minerals gibbsite (Al (OH)3 ), boehmite (?-AlO(OH)), and Diaspora (a-AlO(OH)) along with iron oxides and hydroxides, quartz and clay minerals.
  2. Bauxite is purified by the Bayer process: Al2O3 + 3 H2O + 2 NaOH ? 2NaAl (OH)4
  3. The other components of bauxite do not dissolve. The SiO2 dissolves as silicate Si(OH)62-. Upon filtering, Fe2O3 is removed. When the Bayer liquor is cooled, Al(OH)3 precipitates, leaving the silicates in solution. The mixture is then calcined (heated strongly) to give aluminum oxide: 2 Al(OH)3 ? Al2O3 + 3 H2O
  4. The formed Al2O3 from bauxite is alumina. The alumina formed tends to be multi-phase; i.e., constituting several of the alumina phases rather than solely corundum. The production process can therefore be optimized to produce a tailored product.

Alumina / Aluminum Oxide Chemical Formula:  Al2O3

Chemical Properties:

  1. Purities available from 95% (industrial grade) to 99.999% (high purity grade)
  2. Product is also available to MIL-A-22262B

Physical Properties:

Sintered pieces, targets, single crystals, tumbling media (1 1/2″ x 2″ down to 24 x 240 mesh), coarse grit, hollow bubbles, fine powder, in a colloidal dispersion, and nanoparticles

Typical Applications:

  1. Abrasive applications, blasting applications, lapping & polishing compounds, and fillers
  2. Ceramic injection molding


Molecular Weight (g/mol.) 101.96
Apparent Density (g/cm3) 3.4- 3.9
Odor odorless
Melting Point (°C) 2072
Boiling Point (°C) 2980
Solubility insoluble in water
Thermal Conductivity (cal/s-cm-°C) 1500- 1900
Mohs Hardness @20°C 9.0
Particle Shape irregular & sharp edged
Specific Gravity 3.78- 3.94
Apparent Porosity 2.5- 3.94
Ph 7.0- 9.5