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Physical & Chemical properties

Particle size distribution (Granulometry)

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Description of key information

Ferrous slag particles are of irregular shape
Ferrous slags are virtually free of fibres according to the fibre definitions of OECD and WHO
Ferrous slags are virtually free of asbestos
The marketed products contain particles of a grain size of less than 0.1 mm. The exact amount of these particles depends on the chemical composition, the slag production, the treatment and the use of the slags.

Additional information

Particle size distribution

Typical granulated blast furnace slag consists of small particles (Euroslag 2003) with a sieve size < 0.5 mm: 3.6 - 78.6 (wt.-%) and a sieve size < 3.2 mm: 81.1 - 100.0 (wt.-% ).

Particle size of marketed air-cooled and granulated blast furnace slag (ABS and GBS) was analyzed according to US ASTM method D422. The fraction of slag with a particle size smaller than 0.005 mm is small (less than 2 %). Due to particle size D10 (10percentile of diameter) of approximately 0.17 mm, only a very small portion of the marketed slag material has the potential for aerial transport and inhalative exposure.

Ground GBS (for production of cement) has a particle size distribution with the D50 of approximately 10 µm diameter with approximately 15 % w/w in the range of 1-5 µm (for comparison, for typical cement clinker approximately 15 to 50 % w/w are in the 1-5 µm fraction).

Ground GBS has the potential for aerial transport and inhalative exposure, and fine particles may enter the alveoles of the lungs.

Particle shape

ABS: Particles of ferrous slag are of irregular shape with sharp edges and occasionally with elongated needle-shaped forms. ABS may contain traces of fibrous structures (0.139 % w/w) according to OECD 110 definition (water solubility not tested).

GBS: There is no evidence that GBS (including GGBS) may contain fibrous particles.

GBS has no potential for deleterious effects caused by fibres.

Conclusions

Ferrous slag particles, including fine dust, are of irregular shape.

Ferrous slags are virtually free of fibres according to the fibre definitions of OECD and WHO

Ferrous slags are virtually free of asbestos

The marketed products contain particles of a grain size of less than 0.1 mm. The exact amount of these particles depends on the chemical composition, the slag production, the treatment and the use of the slag.