Slags, nickel smelting

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The nickel slag is a complex metal containing substance. It mainly contains iron silicate and silicates of aluminum and calcium. Traces of metals are present in metal forms, mineral form or included in silicate phases

Classification derived based on rules for mixtures:

Skin sensitization: Not classified

Results from calculated classification are further supported (WoE) by consideration of physical chemical properties of the UVCB substance.

Chemistry and mineralogy of the slag (see IUCLID section 4.23 chemical and mineralogical characterization) were taken into account.

Water solubility (IUCLID section 4.8) and Sequential dissolutions (IUCLID 4.23 Chemical assays) furthermore confirmed species present and their solubility behavior.

Copper slag contains only minor constituents classified as skin sensitisers ( Ni, Co) but their actual levels are lower than < 1% thus nickel slag is not classified for skin sensitization.

Ni presents at concentration up to 0.44 % and Co present in concentrations up to 0.27% in nickel slags (see IUCLID section 1.2 and 4.3).

Therefore to further confirm the conclusions the solubility of Ni was assessed during an in-vitro bio-accessibility test in artificial sweat fluid in accordance with standardized test method (EN 1811). Results interpreted in the regulatory context of the EU Nickel Directive (94/27/EC) which sets threshold for nickel release in artificial sweat of less than 0.5 µg Ni/cm2/week for products intended to come into direct and prolonged contact with the skin.

The amount of Ni released during the sweat test of typical nickel slag is below 1.3 or below 0.018 µg Ni/cm2/week. This information thus provides further evidence that there is no need to classify the nickel slag substance for skin sensitisation

Migrated from Short description of key information:
Complex metal containing substance
Solubility of constituents in water is poor
Classification based on rules for mixtures
In vitro bio-accessibility test in artificial sweat fluid in accordance with EN 1811 (skin sensitisation)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The nickel slag is a complex metal containing substance. It mainly contains iron silicate and silicates of aluminum and calcium. Traces of metals exist in metal, mineral form or included in silicate phases.

Classification derived based on rules for mixtures:

Respiratory sensitization: Not classified

Results from calculated classification are further supported (WoE) by consideration of physical chemical properties of the UVCB substance.

Chemistry and mineralogy of the slag (see IUCLID section 4.23 chemical and mineralogical characterization) were taken into account.

Water solubility (IUCLID section 4.8) and Sequential dissolutions (IUCLID 4.23 Chemical assays) furthermore confirmed species present and their solubility behavior.

Copper slag contains only minor constituents classified as respiratory sensitisers( Co) but their actual levels are lower than < 1% thus nickel slag is not classified for respiratory sensitization.

Migrated from Short description of key information:
Complex metal containing substance
Solubility of constituents in water is poor
Classification based on rules for mixtures

Justification for classification or non-classification

Nickel slag contains only minor constituents classified as skin or respiratory sensitisers but their actual levels are lower than < 1% thus nickel slag is not classified for skin or respiratory sensitization.

The classification derived is applicable to all nickel slags.See end-point record and discussion above for detailed justifications. 

The assessed samples and derived classifications are representative for typical nickel slags , across the industry, and defined within the concentration ranges outlined under IUCLID section 1.2.

Self-classification of the UVCB substance (IUCLID Section 2.1 & 2.2) was performed based on the following outline:

1. Characterization

The substance is accurately described with elemental composition (typical concentrations and concentration ranges–IUCLID Section 1.2), and specific speciation data (mineralogical composition) obtained from the respective representative samples (IUCLID Section 4, in particular 4.23). This detailed information on the substance identity is used as a basis for the classification.

2. Classification by the rules for mixtures

The UVCB is considered as complex metal containing substance with number of discrete constituents (metals, metal compounds, non-metal inorganic compounds).

The classification is based on concentration thresholds referring to the classified constituents present in the UVCB substance. Specific concentration limits are taken into account.

This concept and classification rules are incorporated in easy to use IT tool which is used to classify the UVCB substance.

3. Bridging or Read-Across

Toxicological data are not available for the specific UVCB being evaluated. Considering variability in composition, read-across and bridging is applied by using representative mineralogical/speciation composition combined withthe metal concentration ranges (see composition in section 1.2)as a basis for the classification of the UVCB substance (chemical and mineralogical surrogates with similar origin/production process and physical/chemical properties –see IUCLID 1.4 for information on Sampling procedure).

 4. Bioavailability consideration

Data from in-vitro bio-accessibility test in artificial sweat fluid further confirm the classification.

SeeArche Complex Metal Mixture classification calculator (copper version June 2010); MeCLAS webpage: www. meclas. Eu