ASTM C326 Drying and Firing Shrinkage of Ceramic Whiteware Clays

Scope:

The shrinkage values of the ceramic whitewares should be known prior to their shipping as they affect the structure or the thickness of the material. Drying the ceramic makes it more durable and avoids any problems in the firing step. In ASTM C326, granules obtained after firing are analyzed to get the desired type of ceramics.

Test Procedure:

In ASTM C326, the clay sample is dry-pressed. Prior to pressing, the ceramic clay sample is granulated to form a free-flowing powder and is dried by spray-drying. Hot gasses inject the slurry into a drying chamber. Spray dryers particularly work best at temperatures of 70° to 570°C. During spray drying, the moisture content of the granules should be in the range of 35-40%. After drying, the sample undergoes firing (making dense, compact, and uniform clay granules).

Specimen Size : 

For ASTM C326, the sample is taken in the range of milligrams to kilograms, as per the need.

Data:

The chromatogram obtained in ASTM C326 testing after spray drying is interpreted for checking the shrinkage in the given clay sample.

Conclusion:

ASTM C326 measures the shrinkage of the ceramic whiteware after firing and drying the clay sample.