Calcined alumina is an alpha-alumina produced to consistently achieve the chemical purity and crystal structure necessary to meet individual ceramic application needs. Almatis offers a large product range of calcined aluminas classified by soda content, particle size, and degree of calcination.

Calcined Alumina Applications

Calcined aluminas are utilized in the production of a wide range of industrial and products:

  • Technical & engineered ceramics, such as:
    • Thread and wire guides
    • Faucet valves
    • Wear resistant engine and pump parts
    • Sealing rings and bearings
    • Armor
  • Electronic ceramics:
    • Metallized thick and thin film substrates
    • High Alumina (+99%) ceramic insulators
    • Electrical housings
    • Resistor rods and tubes
    • Electrical insulation parts
  • High voltage insulators
  • Spark plugs
  • Catalyst supports
  • Filter Ceramics
  • Chinaware
  • Sanitary ware
  • Wear resistant ceramics, including grinding media
  • Ceramic tiles, frits and glazes

Benefits of Almatis Calcined Aluminas

Processing properties such as:

  • Typical high fired densities of typical 3.90 g/cm 3 in finished ceramics parts
  • Consistent pressing and slip casting behavior
  • Very good green machining properties
  • Low sintering temperatures and decreased polishing times reduce customer processing costs
  • Tightly controlled shrinkage

Final ceramic product properties such as:

  • Defined uniform microstructure
  • Very good corrosion resistance
  • Excellent mechanical wear resistance and strength
  • High dielectric strength
  • Good thermal shock resistance

Why Almatis Calcined Aluminas are Premium

  • Ensured supply with largest global capacity
  • Excellent lot-to-lot consistency for producing highly reliable ceramic products
  • All products produced to tight product specifications for optimized processing to guarantee excellent physical, electrical and thermal properties of the advanced ceramics components:
    • chemistry
    • particle size distribution
    • specific surface area/BET
    • primary crystal size
    • green density
    • firing shrinkage
    • fired density
  • Contaminant-free ground products ensure high performance of ceramic products
  • Global technical support offering consulting, troubleshooting and application assessment to optimize ceramic performance
  • Products are globally available through expansive worldwide manufacturing, sales and supply


Calcined Alumina Products

Low Soda Calcined Alumina - Na2O ‹ 0.10%


Features: dense ceramic metrics, consistent shrinkage, high electrical resistance and high thermal conductivity.

CT 1200 Surface area from 0.9 - 1.1m2/g
Crystal size 1.5-2.3 µ
CL 2500 Surface area from 0.85 - 1.00 m2/g
Crystal size 1.5-2.3 µ
CL 3000 Surface area from 0.55 - 0.70 m2/g
Crystal size 2.0-2.7µ
CL 4400 Surface area from 0.25 - 0.40 m2/g
Crystal size 2.6-5.1 µ
CL 5000 Surface area from 0.20 - 0.35 m2/g
Crystal size 3.1-5.1 µ
CT 19 Surface area between 0.20 - 0.45 m2/g; also available fine ground (‹45µm)
A10 Typical surface area of 0.20 m2/g
Crystal size 4.5-5.3 µ
A14 Typical surface area of 0.55 m2/g
Crystal size 2.4-3.2 µ

Intermediate Soda Calcined Alumina - Na2O ‹ 0.15%


Features: High dielectric strength, high mechanical strength, high thermal conductivity and consistent shrinkage.

WRA Surface area between 0.5 - 0.7 m2/g
CT 700 Unground
Surface area between 0.60 - 0.80 m2/g
Low chemical impurities and tight specification
CT 800 For use in ceramics and refractories
Surface area between 0.65 - 0.85 m2/g
Also available fine ground (‹45 µm) and SG (<20 µm)
HVA Surface area between 0.40 - 0.55 m2/g
Also available fine ground (‹45 µm)

Medium Soda Calcined Alumina - Na2O ‹ 0.25%


Features: High dielectric strength, high mechanical strength, high thermal conductivity and consistent shrinkage.

A13 -325 mesh Medium surface area from 8.0 to 15.0 m2/g, high purity
A13 LS High purity, medium surface area from 6.5 to 15.0 m2/g
A35 Unground Low surface area (‹0.6 - 1.5 max m2/g), available ground or unground
A35 -325

Normal Soda Calcined Alumina - Na2O ‹ 0.45%


Features: Provides for consistent surface properties and color. Good grindability guarantees consistent process behavior and defined ceramic properties.

A2 Low surface area (‹0.6 - 1.5 max m2/g) available ground or unground
A2 -325
A2 -325CR
SC 13 High purity, medium surface area 9 - 16 m2/g