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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:
2016
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail
Qualifier:
according to
Guideline:
other: CIPAC MT 59 Sieve Analysis; CIPAC MT 170 Dry Sieve Analysis of Water Dispersible Granules; CIPAC MT 169 Tap Density of Water Dispersible Granules
Deviations:
no
Principles of method if other than guideline:
Sieve analysis consisting of the quantitative separation of the test item into fractions of different particle size ranges by using of machine sieving method.
GLP compliance:
yes (incl. certificate)
Type of method:
sieving
Type of particle tested:
primary particle
Type of distribution:
mass based distribution
Remarks on result:
not determinable because of methodological limitations
Key result
Percentile:
D10
Mean:
63 µm
Remarks on result:
other: Not the D10, but the sieve size (µm) which passes less than 10 % of the charged substance is presented.
Key result
Percentile:
D90
Mean:
500 µm
Remarks on result:
other: Not the D90, but the sieve size (µm) which passes more than 90 % of the charged substance is presented.

Determination of Tap Density:

A sample of 80 ± 2 g was prepared by appropriate division of the bulk sample. The sample was weighed into a beaker (W g) and poured into the measuring cylinder. The rubber bung was fitted into the cylinder without jolting. It was carefully put in the dropping box and the timing device was started. With the thumb and forefinger of one hand the upper part of the cylinder was held and, during 1 second it was lifted up to 25 mm height . At the beginning of the next second, the cylinder was smartly released by quickly and completely withdrawing the thumb and forefinger. 50 counted drops was completed. Then the cylinder was removed immediately from the dropping box, the volume was noted to the nearest 1 ml (V ml).

Sieve Test:

The mass of the sample needed (m) was calculated with the following formula: m = n * D * 20 [g] where:

n = number of sieves used

D = tap density of the test item (g/mL)

The nest of 8 sieves was assembled in the correct order with the coarsest at the top and the finest at the bottom and was mounted on the receiver pan. The test item of specified mass was weighed and transferred to the coarsest sieve. The sieves with the covering lid were put in the sieving machine. The machine was started and was running for a period of 5 min.

The nest of sieves was removed from the machine after allowing time for airborne particles to settle (about 2 min). The lid was taken off carefully and each sieve was inverted over a separate sheet of paper. The side of the sieve frame was tapped and the uppermost surface was brushed. The sieve was reversed and this process was repeated to dislodge any loose particle remaining. This procedure was followed for each sieve.

Conclusions:
The sieve size (µm) which passes less than 10 % of the charged substance is 63 µm.
The sieve size (µm) which passes more than 90 % of the charged substance is 500 µm.
The mean particle size (by mass) is between 100 and 250 µm.
Executive summary:

Machine sieving test was carried out using the following test sieves 4, 2, 1 mm, 500, 250, 100, 63 and 45 μm.

The sieve size (µm) which passes less than 10 % of the charged substance is 63 µm.

The sieve size (µm) which passes more than 90 % of the charged substance is 500 µm.

The mean particle size (by mass) is between 100 and 250 µm.

Description of key information

Results of the more recent study:

The mean particle size (by mass) is between 100 and 250 µm.

Additional information