Silicon dioxide

PBT assessment

PBT assessment: overall result

Reference

Reference 1

Name:

synthetic amorphous silica, nanostructured material_Set 1

Type of composition:

boundary composition of the substance

State / form:

solid: nanoform

Reference substance:

synthetic amorphous silica, nanostructured material_Set 1

Type of information reported:

set of nanoforms

Name of set of nanoforms:

Snythetic amorphous silicon dioxide, nanostructured material_Set1

Reason / purpose:

justification for reporting set of similar nanoforms

Shape category:

spheroidal

Shape:

other: 3-dimensional branched fractal aggregates

Pure shape:

yes

Range:

>= 99 - <= 100 %

Shape category:

spheroidal

Percentile:

D10

Range:

>= 1 - <= 100 nm

Percentile:

D50

Range:

>= 1 - <= 100 nm

Percentile:

D90

Range:

>= 1 - <= 100 nm

Additional information:

The particle forming mechanism for each manufacturing process starts with the formation of liquid nuclei that grow to constituent particles that coagulate to aggregates and solidify. Constituent particles are therefore spherical in nature while aggregates (and agglomerates) show a high fractal structure.

Fraction of constituent particles in the size range 1-100 nm:

> 50 - <= 100 %

Structure:

amorphous

Name:

amorphous

Pure structure:

yes

Range:

> 99.7 - <= 100 %

Description:

X-ray diffraction diagrams of SAS, show only a broad halo, revealing an X-ray amorphous structure. The detection limit for crystallinity by X-ray is in the maximum order of 0.3% by weight or below.

Range of specific surface area:

>= 4 - <= 1 000 m²/g

Range of volume specific surface area:

>= 8.8 - <= 2 200 m²/cm³

Skeletal density:

>= 1.7 - <= 2.25 g/cm³

Surface treatment applied:

no

Reference 2

Name:

synthetic amorphous silicon dioxide gel precipitated [CAS-No. 112926-00-8]

Type of composition:

legal entity composition of the substance

State / form:

solid: nanoform

Related composition:

synthetic amorphous silica, nanostructured material_Set 1

Reference substance:

synthetic amorphous silicon dioxide gel precipitated [CAS-No. 112926-00-8]

Type of information reported:

set of nanoforms

Name of set of nanoforms:

Synthetic amorphous silicon dioxide, nanostructured material_Set 1

Shape category:

spheroidal

Shape:

spherical

Pure shape:

yes

Range:

>= 99 - <= 100 %

Shape category:

spheroidal

Percentile:

D10

Range:

>= 2 - <= 25 nm

Percentile:

D50

Range:

>= 2.5 - <= 50 nm

Percentile:

D90

Range:

>= 3.5 - <= 70 nm

Additional information:

The particle forming mechanism for each manufacturing process starts with the formation of liquid nuclei that grow to constituent particles that coagulate to aggregates and solidify. Constituent particles are therefore spherical in nature while aggregates (and agglomerates) show a high fractal structure.

Fraction of constituent particles in the size range 1-100 nm:

> 50 - <= 100 %

Structure:

amorphous

Name:

amorphous

Pure structure:

yes

Range:

> 99.7 - <= 100 %

Description:

X-ray diffraction diagrams of SAS, show only a broad halo, revealing an X-ray amorphous structure. The detection limit for crystallinity by X-ray is in the maximum order of 0.3% by weight or below.

Range of specific surface area:

>= 4 - <= 800 m²/g

Range of volume specific surface area:

>= 8.8 - <= 1 760 m²/cm³

Skeletal density:

ca. 2.2 g/cm³

Surface treatment applied:

no

Reference 3

Name:

synthetic amorphous silicon dioxide, fumed [CAS-No. 112945-52-5]

Type of composition:

legal entity composition of the substance

State / form:

solid: nanoform

Related composition:

synthetic amorphous silica, nanostructured material_Set 1

Reference substance:

synthetic amorphous silicon dioxide, fumed [CAS-No. 112945-52-5]

Type of information reported:

set of nanoforms

Name of set of nanoforms:

Synthetic amorphous silicon dioxide, nanostructured material_Set 1

Shape category:

spheroidal

Shape:

spherical

Pure shape:

yes

Range:

>= 99 - <= 100 %

Shape category:

spheroidal

Percentile:

D10

Range:

>= 2 - <= 25 nm

Percentile:

D50

Range:

>= 2.56 - <= 50 nm

Percentile:

D90

Range:

>= 3.5 - <= 70 nm

Additional information:

The particle forming mechanism for each manufacturing process starts with the formation of liquid nuclei that grow to constituent particles that coagulate to aggregates and solidify. Constituent particles are therefore spherical in nature while aggregates (and agglomerates) show a high fractal structure.

Fraction of constituent particles in the size range 1-100 nm:

> 50 - <= 100 %

Structure:

amorphous

Pure structure:

yes

Range:

> 99.7 - <= 100 %

Description:

X-ray diffraction diagrams of SAS, show only a broad halo, revealing an X-ray amorphous structure. The detection limit for crystallinity by X-ray is in the maximum order of 0.3% by weight or below.

Range of specific surface area:

>= 50 - <= 400 m²/g

Range of volume specific surface area:

>= 110 - <= 880 m²/cm³

Skeletal density:

ca. 2.2 g/cm³

Surface treatment applied:

no

PBT status:

the substance is not PBT / vPvB

Justification:

Annex XIII sets out the criteria for the identification of persistent, bioaccumulative and toxic (PBT) substances, and very persistent and very bioaccumulative (vPvB) substances; it does not apply to inorganic substances.