Silicic acid, aluminum magnesium sodium salt

Nanomaterial dustiness

Administrative data

Endpoint:

nanomaterial dustiness

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: DIN 55992-1:2006 ("Determination of a parameter for the dust formation of pigments and extenders - Part 1: Rotation method").

Deviations:

yes

Remarks:

see below

Principles of method if other than guideline:

With a regular Heubach dust meter alone, it is not possible to separate inhalable, thoracic and alveolar dust fractions as defined in DIN EN 481. Therefore, the Heubach dust meter was modified in a way that a seven-stage cascade impactor was inserted instead of the filter.
This interconnection of the rotating drum and the cascade impactor requires the following special approach:
Whereas the rotating drum requires an air flow rate of approx. 20 L/min in accordance with the manufacturer’s specifications, the cascade impactor requires an air flow rate of 40 L/min in order to work properly. Therefore, 20 L/min of additional air is fed into the system via the coarse dust separator.
By intruducing a glass tubing, the dust generated in the rotating drum is now directly conveyed into the cascade impactor. The vessel used as the coarse dust seperator in the original set-up now only serves as a tool to introduce additional air and for the purpose of visual inspection.

GLP compliance:

yes

Type of method:

rotating cylinder

Remarks:

according Heubach procedure

Details on methods and data evaluation:

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.
The “total dustiness” value was determined as the ratio of the mass of removed dust to the total sample mass initially weighed in.
Subsequently, the dustiness values for the inhalable, thoracic and alveolar fractions according to DIN EN 481 were determined.

Test material

Test material information

Constituent 1

Reference substance name:

Silicic acid, aluminum magnesium sodium salt

EC Number:

234-919-5

EC Name:

Silicic acid, aluminum magnesium sodium salt

Cas Number:

12040-43-6

Molecular formula:

Na(0.017-1.739)Mg(0.008-0.823)Al(0.002-0.2473)SiO(2.018-3.837)

IUPAC Name:

aluminium(3+) magnesium(2+) sodium tris(oxosilanebis(olate))

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Data gathering

Instruments:

Heubach dust meter
The substance to be investigated is kept in motion in a dust generation device consisting of a rotating drum (volume: 2.2 L, 30 rpm) with integrated baffle plates. After a short period of upwards transportation the substance subsequently falls down within the drum. The airborne part of the dust is taken out of the drum by an axial air current of 20 L/min. In the process, both the airborne dust already contained in the substance and the airborne dust which has been newly generated through abrasion within the drum are collected.

Results and discussion

Dustiness index

Key result

Mean:

177.62 other: mg/g

St. dev.:

2.6 other: µm

Any other information on results incl. tables

Total dustiness	[mg/g]	177.62
Inhalable fraction	[mg/g]	128.41
Thoracic fraction	[mg/g]	78.39
Respirable fraction	[mg/g]	26.00
Mass Median Aerodynamic Diameter (MMAD)	[µm]	13.5
Geometric Standard Deviation (GSD)	[µm]	2.6

Applicant's summary and conclusion

Conclusions:

Test item "Silic acid Aluminium Magnesium Sodium Salt" shows a (total) dustiness of 177.62 mg/g.