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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:
N/A to 2009-05-08
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
ISO 13320 (Particle size analysis - Laser diffraction methods)
Version / remarks:
2009
Principles of method if other than guideline:
The particle size was analyzed by the Malvern MasterSizer LASER diffracter. This instrument is an ensemble analyzer that calculates a volume distribution from the LASER diffraction pattern of a cloud of particles. This raw scatter data is then processed using a complex algorithm and presented on the basis of an equivalent spherical diameter. This instrumentation is approved by ECHA Guidance, 2008 (Chapter R.7a, pg. 148)
GLP compliance:
not specified
Type of method:
Laser scattering/diffraction
Type of particle tested:
primary particle
Type of distribution:
volumetric distribution
Specific details on test material used for the study:
Identification: tungstic acid
Chemical formula: H2WO4
CAS No.: 7783-03-1
Sponsor: H.C. Starck Tungsten GmbH
Batch No.: TA17NF0054
Key result
Percentile:
D10
Mean:
1.3 µm
St. dev.:
0
Remarks on result:
other: Distribution type: volume
Key result
Percentile:
D50
Mean:
7.93 µm
St. dev.:
0
Remarks on result:
other: Distribution type: volume
Key result
Percentile:
D90
Mean:
13.2 µm
St. dev.:
0
Remarks on result:
other: Distribution type: volume
Key result
Percentile:
D10
Mean:
0.11 µm
St. dev.:
0
Remarks on result:
other: Distribution type: number
Key result
Percentile:
D50
Mean:
0.19 µm
St. dev.:
0
Remarks on result:
other: Distribution type: number
Key result
Percentile:
D90
Mean:
0.53 µm
St. dev.:
0
Remarks on result:
other: Distribution type: number

No specific standard deviation were identified for the particle distribution data although significant robust data was presented in the laboratory report.

The B.E.T. Surface Area of the test substance sample was determined to be 15.21 m^2/g.

Conclusions:
This tungstic acid registraion covers a highly pure (>99.9%) monoconstituent substance with a particle size distribution on the microsized region.

Description of key information

Mean (based on volume) D10, D50, and D90 = 1.30, 7.93 and 13.20 um, respectively.

The specific surface area of the test substance sample (as determined by B.E.T.) was found to be 15.21 m2/g.

Additional information