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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:
January 28, 2020
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions - Method A: Particle Size Distribution (effective hydrodynamic radius)
Deviations:
no
Qualifier:
according to
Guideline:
ISO 13320 (Particle size analysis - Laser diffraction methods)
Deviations:
no
GLP compliance:
no
Type of method:
Laser scattering/diffraction
Type of particle tested:
agglomerate
Type of distribution:
volumetric distribution
Key result
Percentile:
D10
Mean:
147 µm
Remarks on result:
other: SD not determined
Key result
Percentile:
D50
Mean:
504 µm
Remarks on result:
other: SD not determined
Key result
Percentile:
D90
Mean:
1 082 µm
Remarks on result:
other: SD not determined

The test item consisted of transparent, irregular-shaped particles with which appeared flaked-shaped.

As some larger agglomerates were observed in the sample of the test item, the latter was sieved with a mesh size of 1000 µm. 97.7% (w/w) of the test item passed the sieve and only this fraction was measured with laser diffraction.

The test item was tested as a liquid dispersion in demineralized water (with 1 % detergent). Before the measurement the test item was mixed with demineralized water (with 1% detergent) and homogenised. This homogenised dispersion was fed to the sample unit. Subsequently the diluted dispersion was pumped to the optical system. After passing the spectrometer the sample was pumped back into the small volume sample dispersion unit.

After adjusting the laser, measuring the background (demineralized water with 1 % detergent) and adjusting the correct particle concentration (obscuration) the measurement was started. The control software automatically performed three measurements. The average of these three measurements was given as result. Two test series of three measurements each were performed. The measurement time was12s.

The particle size distributions determined in the first and second test series are shown in Figure 1 (page 8) and Figure 2 (page 9), respectively. For each test series fractions (left axis of the ordinate) and the siftings (right axis of the ordinate) are presented in percent by volume as a function of the particle size. Median values were calculated from unrounded values.

 

The median particle size L50(D (v, 0.5): 50 % of particle volume or particle mass with lower particle diameter) deduced from these distributions were:

1st test series: L50 = 485 μm

2nd test series: L50 = 523 μm

The average of the median particle size L50 was: L50 = 504 μm

 

The particle size L10 (D (v, 0.1 ): 10 % of particle volume or particle mass with lower particle diameter) deduced from these distributions were:

1st test series: L10 = 126 μm

2nd test series: L10 = 168 μm

The average of the particle size L10 was: L10 = 147 μm

 

The particle size L90 (D (v, 0.9): 90 % of particle volume or particle mass with lower particle diameter) deduced from these distributions were:

1st test series: L90 = 1041 μm

2nd test series: L90 = 1123 μm

The average of the particle size L90 was: L90 = 1082 μm

 

A maximum was observed at approximately 600 μm. Additionally, a shoulder was observed between 100 µm and 200 µm.

 

Conclusions:
The median particle size L50 of the test item deduced from the particle size distributions was 504 µm.
Executive summary:

The determination of the particle size distribution by laser diffraction of the test item was performed according tothe OECD Guideline 110 by laser diffraction. The median particle size L50 of the test item deduced from the particle size distributions was 504 µm.

Description of key information

The determination of the particle size distribution by laser diffraction of the test item was performed according to the OECD Guideline 110 by laser diffraction. The median particle size L50 of the test item deduced from the particle size distributions was 504 µm.

Additional information