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Particle size distribution (Granulometry)

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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:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail
Remarks:
Well documented, scientifically sound study that used appropriate measurement instrumentation. Work performed following cGMP. Report was reviewed by the laboratory's Quality Assurance department.
Qualifier:
equivalent or similar to
Guideline:
ISO 13320 (Particle size analysis - Laser diffraction methods)
Version / remarks:
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)
Deviations:
no
GLP compliance:
not specified
Type of method:
Laser scattering/diffraction
Type of particle tested:
primary particle
Type of distribution:
volumetric distribution
Key result
Percentile:
D50
Mean:
6.58 µm
Remarks on result:
other: Migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.
Percentile:
D10
Mean:
2.64 µm
St. dev.:
0
Percentile:
D50
Mean:
6.58 µm
St. dev.:
0
Percentile:
D90
Mean:
15.23 µm
St. dev.:
0

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 0.13 m^2/g.

Endpoint:
particle size distribution (granulometry)
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Data from peer-reviewed handbook or collection of data.
Reason / purpose:
reference to same study
Principles of method if other than guideline:
Measured by Fisher subsieve sizer (FSSS)(ASTM B 330 and MPIF 32 standards)
GLP compliance:
not specified
Percentile:
D50
Remarks on result:
other: Migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.
Percentile:
other: sample #1
Mean:
0.6 µm
St. dev.:
0.1
Percentile:
other: sample #2
Mean:
1 µm
St. dev.:
0.1
Percentile:
other: sample #3
Mean:
1.5 µm
St. dev.:
0.2
Percentile:
other: sample #4
Mean:
2.5 µm
St. dev.:
0.3
Percentile:
other: sample #5
Mean:
3.5 µm
St. dev.:
0.3

     Standard grades  2 -5 um  W 06 W 10   W 15  W 25  W 35  W 45  W 65
  unit                  
  Particle sizes (measured via FSSS)                     
  As supplied  um    3.27  0.6 +/- 0.1  1.0 +/- 0.1   1.5 +/- 0.2   2.5 +/- 0.3   3.5 +/- 0.3   4.5 +/- 0.3  6.5 +/- 1.0 
  Lab milled  um    2.93   0.5 +/- 0.1   0.8 +/- 0.1   1.4 +/- 0.2   2.4 +/- 0.3  3.3 +/- 0.3    4.2 +/- 0.3   3.5 +/- 1.0

All tungsten powder sizes, from ultrafine to hundreds of microns, are produced on an industrial scale, but the bulk of the powder used presently is in the size range 2-5 um.

Conclusions:
All tungsten powder sizes, from ultrafine to hundreds of microns, are produced on an industrial scale, but the bulk of the powder used presently is in the size range 2-5 um.

Description of key information

Mean D10, D50, and D90 = 2.64, 6.58, and 15.23 µm, respectively. The specific surface area of the test substance sample (as determined by B.E.T.) was found to be 0.13 m2/g.

Additional information