Alternatives

• Author: Clemm, Christan; Löw, Clara; Baron, Yifaat; Moch, Katja; Möller, Martin; Köhler, Andreas R; Gensch, Carl-Otto; Deubzer, Otmar
• Pages: 30-31

RoHS Annex II Dossier, final

Five cobalt salts

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8. ALTERNATIVES

No information has been provided on possible alternatives during the first stakeholder consultation

on the grounds that cobalt dichloride and cobalt sulphate (as at this time, only these two cobalt

compounds were addressed) are not present in EEE and therefore substitution does not need to

be discussed.

Information on possible alternatives for cobalt dichloride and cobalt sulphate in the surface

treatment processes is scarce. Some information is available as detailed below but does not

indicate substitutes that can be considered to be practical in light of the hazardousness of such

substitutes.

8.1. Availability of substitutes / alternative technologies

During ECHA’s preliminary investigation into the conditions of use of the five cobalt salts

summarised in 2013,55 industry stated that “no valid alternatives to the cobalt salts have been

identified so far. In fact, it is remarked that the use of cobalt salts was developed by the automotive

industry as an alternative to the use of chromium VI in passivation processes. No feasible

alternatives are expected to be found in the near future.”

In the background document of ECHA in 2011, a cobalt-free passivation for zinc or zinc-alloy

plating was mentioned. In the ECHA report in 2013, it was noted that “one company did suggest

that the replacement of cobalt salts with nickel compounds could be a viable option in the longer

term, but no further information was provided on this.”

The (reverse) substitution by the following (more) hazardous substances is mentioned:56

• Substitution of zinc-cobalt plating by cadmium plating,

• Replacement of Cr(VI) in electroplating by Co(II); and though not mentioned in the ECHA report

vice versa.

In the background document of ECHA in 2011,57 with regards to alternatives, the interchangeability

within different cobalt salts was also discussed, which is however considered as a substitution with

an equally hazardous substance (see detail below). According to ECHA, industry argued that

“interchangeability between the cobalt salts included in ECHA’s recommendation is not expected to

occur at large-scale, and that case-by-case evaluation is deemed necessary.” ECHA

acknowledged that cobalt dichloride or cobalt sulphate may in some of its uses hardly be

replaceable by another cobalt(II) salt but concluded that “considering scientific knowledge in

chemistry and the principal chemical processes taking place it appears very improbable that it

would technically not be possible to replace cobalt dichloride [or cobalt sulphate] in at least some

of its uses by another cobalt salt or that cobalt dichloride [or cobalt sulphate] could not be used to

replace other cobalt salts.” However, taking into account the comparable human health and

environmental hazards of the five cobalt salts and the consequence that the five cobalt salts are

grouped for a joint restriction proposal, the approach of substitution of one cobalt salt by another or

by CR (VI) or cadmium does not seem to comprise a pragmatic solution as it is not expected to

lead to environmental and or health benefits.

55 Op. cit. ECHA (2017); from page 40 on as last part the following report is included: ECHA (2013): A preliminary

investigation into the conditions of use of five cobalt salts final report July 2013, public version.

56 Op. cit. ECHA (2011a and b)

57 Op. cit. ECHA (2011a and b)