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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:
2 February 2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Within this study, the sedimentation rate of suspended particles was examined using the Sedigraph 5100 which provides results based on Stokes law in the form of a distribution of additive percentage as a function of spherical equivalent diameters. The number and size of the suspended particles were also determined using the Multisizer 3.
GLP compliance:
not specified
Type of method:
sedimentation (gravitational settling)
Remarks:
additionally, electrical sensing zone method was applied
Remarks on result:
not measured/tested
Remarks:
Not calculated
Key result
Percentile:
D10
Mean:
>= 0.8 - <= 1 µm
Remarks on result:
other: Based on Sedigraph 5100
Key result
Percentile:
D10
Mean:
>= 1.1 - <= 1.3 µm
Remarks on result:
other: Based on Multisizer 3
Key result
Percentile:
D50
Mean:
>= 1.3 - <= 2.3 µm
Remarks on result:
other: Based on Sedigraph 5100
Key result
Percentile:
D50
Mean:
>= 1.8 - <= 2.5 µm
Remarks on result:
other: Based on Multisizer 3
Key result
Percentile:
D90
Mean:
>= 3.3 - <= 3.5 µm
Remarks on result:
other: Based on Sedigraph 5100
Key result
Percentile:
D90
Mean:
>= 3.4 - <= 3.6 µm
Remarks on result:
other: Based on Multisizer 3

The results of the Sedigraph 5100 obtained for the different test item particle diameters are rounded as follows:

 Round  Diameter
 0.01  <0.8 µm
 0.02  Between 0.8 and 1 µm
 0.05  Between 1 and 3.5 µm
 0.1  Between 3.5 and 8 µm
 0.2  Between 8 and 10 µm
 0.5  Between 10 and 35 µm
 1  Between 35 and 100 µm
Conclusions:
The d10, d50 and d90 of a representative sample of gadolinium oxide were determined to be 0.8-1.0 μm, 1.3-2.3 µm, and 3.3-3.5 µm, respectively, using a Sedigraph 5100, and 1.1-1.3 µm, 1.8-2.5 µm, and 3.4-3.6 µm, respectively, using a Multisizer 3.


Description of key information

The key study determined the particle size distribution of a representative sample for gadolinium oxide (Klimisch 2, Solvay, 2017). The d10, d50 and d90 of a representative sample of gadolinium oxide were determined to be 0.8-1.0 μm, 1.3-2.3 µm, and 3.3-3.5 µm, respectively, using a Sedigraph 5100, and 1.1-1.3 µm, 1.8-2.5 µm, and 3.4-3.6 µm, respectively, using a Multisizer 3.

Additional information

All co-registrants provide particle size distribution information on their products in their individual dossiers. A d10 range of 0.587-1.3 µm, a d50 range of 1.3-3.10 µm, and a d90 range of 3.4-8.76 µm seems to be roughly representative for what is manufactured.