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Physical & Chemical properties

Particle size distribution (Granulometry)

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Reference
Endpoint:
particle size distribution (granulometry)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2009-05-27
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: A well documented study conducted to good scientific standards.
Qualifier:
according to
Guideline:
other: Lafarge test method A5-0038-LG
Principles of method if other than guideline:
FGD (Flue Gas Desulphurization Gypsum) sample taken from the Lafarge Gypsum plant of Lippendorf (Germany) during a standard quality control procedure. Particle size distribution was determined with a laser analyzer to the Lafrage test method A5-0038-LG.
GLP compliance:
not specified
Type of method:
other: Laser analyzer
Type of distribution:
volumetric distribution
Percentile:
D50
Mean:
63.2 µm
Remarks on result:
other: Particle size with wet way
Percentile:
D10
Mean:
26.2 µm
Remarks on result:
other: Particle size with wet way
Percentile:
D90
Mean:
124 µm
Remarks on result:
other: Particle size with wet way
Conclusions:
For calcium sulfate dihydrate the D10, D50, and D90 for particle size with wet way in µm were 26.2 63.2 and 124 respectively.

Description of key information

For calcium sulfate dihydrate, the D10, D50, and D90 for particle size with wet way in µm were 26.2 63.2 and 124 respectively.

Additional information

There is no "standard particle size distribution for calcium sulfate. Calcium sulfates can exist in a variety of granulometries. In some cases , the particle size distribution  is given by a grinding process , in others , it is a crystallisation process
- natural gypsum is often a mixture of blocs ( sometimes 10 -100 cm size) and powder witha very broad distribution difficult to characterize
- synthetix gypsum such as  FGD has usually a nearly monogranular particle size distribu tion centered somewhere between 30 and 100 microns
- after grinding , stucco can show very different particle size distributions , from very fine with an average particle size of 10 micron or less such as the stucco used for bandages to coarser products used for bonding compounds with usually average particle sizes of 100 microns or more
The study included is a typical distribution of what can be obtained with a synthetic gypsum