Germanium, germanium hydroxide oxides and amorphous silica, recovery products from germanium refining

Particle size distribution (Granulometry)

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

DIN 55992-1 (Determination of a parameter for the dust formation of pigments and extenders - Part 1: Rotation method)

Deviations:

yes

Remarks:

DMT modified the Heubach dust meter in a way that a seven-stage cascade impactor was inserted instead of the filter. This will allow to separate inhalable, thoracic and avleolar dust fractions as defined in DIN EN 481

GLP compliance:

no

Type of method:

rotating drum method

Type of particle tested:

agglomerate

Remarks:

dried filter cake

Type of distribution:

mass based distribution

Specific details on test material used for the study:

Due to wet sample, a preliminary drying was conducted for 24h according the recommendation of the sponsor (first stage drying) before starting the test. The remaining humidity of the substance was 5.89% as determined by drying the sample in a furnace in accordance with DIN 18121-1: a part of the sample (first stage dried) was weighed in a weighing glass and then dried in the drying cupboard at approx. 105°C until constancy of weight was attained. The sample was weighed after cooling in a desiccator for determing the residual moisture content.

Mass median aerodynamic diameter:

31.8 µm

Geometric standard deviation:

1.9

No.:

#1

Size:

< 100 µm

Distribution:

ca. 7 %

Remarks on result:

other: total dustiness

No.:

#2

Size:

< 100 other: aerodynamic diameter (µm)

Distribution:

ca. 4.04 %

Remarks on result:

other: inhalable fraction

No.:

#3

Size:

< 10 other: aerodynamic diameter (µm)

Distribution:

ca. 0.36 %

Remarks on result:

other: thoracic fraction

No.:

#4

Size:

< 4 other: aerodynamic diameter (µm)

Distribution:

ca. 0.08 %

Remarks on result:

other: respirable (alveolar) fraction

total dustiness 69.98 mg/g

inhalable fraction 40.42 mg/g (4.04%)

thoracic fraction 3.59 mg/g (0.36%)

respirable (alveolar) fraction 0.79 mg/g (0.08%)

Conclusions:

As a conclusion, for the sample "RESHS 316 REACH", the respirable fraction represent 0.08 % of used quantity of the substance under the modified Heubach procedure.

Executive summary:

Examinations were performed to determine the dustiness of a substance sample designated as "RESHS 316 REACH ". The objective of these examinations was to determine the dust fractions of this substance. These are the dust fractions which are defined in DIN EN 481 as the inhalable fraction, thoracic fraction and the respirable fraction.

The modified Heubach procedure was applied. In the process, the substance sample was mechanically stressed in a rotating drum (dust generation device), and both the dust already contained in this sample and the dust generated due to abrasion were removed from the dust generation device by an air current. The proportion of dust separated and considered as dust with the ability to become airborne was fed into a seven-stage cascade impactor connected to the dust generation device. Particle size classification was conducted by subsequent weighing of the respective dust masses deposited on the individual cascade stages reflecting certain particle size ranges.

As a conclusion, for the sample "RESHS 316 REACH", the respirable fraction represent 0.08 % of used quantity of the substance under the modified Heubach procedure.

Reference 2

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

ISO 13320 (Particle size analysis - Laser diffraction methods)

GLP compliance:

not specified

Type of method:

Laser scattering/diffraction

Type of particle tested:

primary particle

Type of distribution:

mass based distribution

Specific details on test material used for the study:

The substance was dried at 100°C until constat weight and aggregates were crushed to obtain primary particles.

Remarks on result:

not measured/tested

Key result

Percentile:

D90

Mean:

ca. 390.23 µm

St. dev.:

0

Remarks on result:

other: standard deviation not reported

Key result

Percentile:

D50

Mean:

ca. 142.5 µm

St. dev.:

0

Remarks on result:

other: standard deviation not reported

Key result

Percentile:

D10

Mean:

ca. 4.8 µm

St. dev.:

0

Remarks on result:

other: standard deviation not reported

Conclusions:

The test substance has the following particle size distribution: D10 = 4.80 μm; D50 = 142.50 μm; D90 = 390.23 μm.

Executive summary:

The particle size distribution of the test substance RESHS 316 REACH was determined via laser diffraction.

The test substance has the following particle size distribution: D10 = 4.80 μm; D50 = 142.50 μm; D90 = 390.23 μm.

Description of key information

The test substance has the following primary particle size distribution: D10 = 4.80 μm; D50 = 142.50 μm; D90 = 390.23 μm.

The total dustiness and the respirable fraction represent 7.00% and 0.08%, respectively, as determined with the modified Heubach procedure.