Diiron trioxide

Particle size distribution (Granulometry)

Link to relevant study record(s)

Reference

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:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

according to guideline

Guideline:

OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions)

Deviations:

yes

Remarks:

The particle size distribution was determined by Image Analysis

Principles of method if other than guideline:

The particle size distribution was determined by Image Analysis in accordance with the Council Regulation (EC JRC73260, nanomaterial). The test method is in all essential part identical with the OECD Guideline, Test no. 110, method B.
The pigment was dispersed in about 10 ml of distilled water by means of ultrasound for 1min with the power of 100W. Thus, agglomerates are destroyed forming single or aggregated particles. The particles are placed on a TEM grid and tested by high resolution scanning transmission electron microscopy (HR STEM Company: FEI, QS- No.: 02464; SOP 00013 Vers.2; Reference Material: UER3 922.00).

GLP compliance:

no

Type of method:

microscopic examination

Type of distribution:

counted distribution

Percentile:

D50

Mean:

118 nm

Remarks on result:

other: Migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.

Percentile:

other: 39%

Mean:

1 - <= 100 nm

St. dev.:

2.8

Remarks on result:

other: The quantity of 39 ± 2.8% of all particles with an ECD (equivalent circle diameter; Q0 ECD) are between 1 nm and 100 nm.

Statistical Data Number of particles 1002 Median ECD [nm] 118 +/- 83   Q0 ECD </= 100 nm [%] 39 +/- 2.8 Median aspect ratio 1.4 +/- 0.4

Conclusions:

39 +/- 2.8% of all particles of the measured test material diiron trioxide based on the equivalent circle diameter are between 1 nm and 100 nm. The test material is not a nanomaterial.

Executive summary:

According to the EU definition diiron trioxide is not a nanomaterial. 39 +/- 2.8% of all particles of the measured test material diiron trioxide based on the equivalent circle diameter are between 1 nm and 100 nm.

Definition:

"Nanomaterials means a natural, incidential or manufactured material containing prticles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range of 1 nm - 100 nm."

Description of key information

The particle number size distribution Q0 </= 100 nm of the test material was: 39 +/- 2.8%

D50: 118nm

Additional information

Based on the particle size distribution measurements diiron trioxide is a pigment which consists of nanomaterial and powder forms, according to the Commission recommendation 2011/696/EU on the definition of nanomaterials.

Nanomaterial means a natural, incidental or manufactured materials containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimension is in the range 1 nm - 100 nm. The cut of value is 100 nm for 50 % or more of the particles (number size distribution).

To distinguish between nano and not nano formed materials, the different forms of diiron trioxide, the particle size distribution of mean equivalent circle diameter (ECD) is taken as criterion. The sample distribution of two representative grades of diiron trioxide were analysed by electron microscopy (HR STEM). The particle size distribution was determined by Image Analysis in accordance with the Council Regulation (EC JRC73260, nanomaterial). The test method is in all essential parts identical with the OECD Guideline, Test no. 110, method B. With regard to ECD particle size distribution one of the tested grades fulfils the criteria of nano. One tested grade of diiron trioxide is not nanomaterial.

Diiron trioxide produced by roasting in steel plants is not a nano material and typically has particle size 0.1 mm to 1 mm when produced by the Lurgi process and > 0.4 μm when produced by the Ruthner process.

Iron Oxide containing catalysts are generally formed as shaped solids rather than powders. Granulometry data for catalyst products is therefore considered to be a measure of the propensity of a catalyst to produce fines in the course of transportation, handling and use. Test data for catalysts is based on Particle Size Distribution analysis of fines produced in the ASTM D4058 - 96(2011)e1 Standard Test Method for Attrition and Abrasion of Catalysts and Catalyst Carriers. These fines do not typically fall into the definition of nanomaterials according to Commission recommendation 2011/696/EU.