Impact and risk evaluation

• Author: Clemm, Christan; Löw, Clara; Baron, Yifaat; Moch, Katja; Möller, Martin; Köhler, Andreas R; Gensch, Carl-Otto; Deubzer, Otmar
• Pages: 46-48

RoHS Annex II Dossier, final

Diantimony trioxide (flame retardant)

46

7 IMPACT AND RISK EVALUATION

It should be noted that for halogenated flame retardants applied with ATO, the use of the latter allows

applying less halogenated flame retardants. From the human health and environmental perspective,

the application of ATO should not be assessed alone but together with the halogenated flame

retardant. However, as such a combined/cumulative assessment is not in scope of this dossier, these

considerations cannot be further explored.

Impacts on WEEE management as specified by Article 6 (1)a

Article 6 (1)a of the RoHS Directive stipulates that specific account should be taken on whether a

substance selected for a review “could have a negative impact during EEE waste management

operations, including on the possibilities for preparing for the reuse of waste EEE or for recycling of

materials from waste EEE”.

As diantimony trioxide is solely used in combination with halogenated flame retardants, diantimony

trioxide is used in the plastic waste stream as one sound parameter to sort out plastic containing

brominated flame retardant.104 As described in the stakeholder contribution by KU Leuven,105 the

presence of ATO in plastics is commonly used to sort out the plastic for incineration. Post-shredder

sorting techniques separate plastics containing diantimony trioxide-based flame-retardant systems

with a high efficiency from other non-flame-retardant plastic types, because of the high density of

antimony trioxide ( = 5,7 g/cm3). According to the KU Leuven,106 also X-ray fluorescent-based

optical sorting techniques are used alternatively or in combination with density-based sink-float

sorting techniques after size reduction by shredding as state-of-the-art recycling processes in

Europe. This fraction is as of today’s state of the art not recycled but is sent to incineration with

energy recovery. The reasons are that there is no further post-shredder sorting of different plastic

materials to obtain a required purity, e.g. to separate the plastic material ABS and HIPS both

containing brominated flame retardants.

To conclude, ATO used as synergist together with brominated flame retardants does not have a

negative impact on the recycling of materials from waste EEE because ATO is used as a sound

parameter to sort out plastic containing brominated flame retardants; ATO in this process has to be

recognised as supporting the sorting technique based on sink-float that is the commonly applied

process. In this sense, ATO supports to separate plastic fractions where the fraction not containing

ATO might be recycled.

The plastic fraction containing ATO (and brominated flame retardants) is often not recycled but

incinerated. The recovery of antimony from the ashes of the incinerated plastics is so far not common

practice according to the KU Leuven. Campine (2018) also states that “the recovery of antimony out

of plastics is not yet implemented on a broader scale because the operation is not economically

viable yet and rather complex (due to pop’s in FR plastics).” i2a (2018) explains that “in a number of

countries, bottom ash is used for road and other constructions, unless the concentration of ATO in

the ash exceeds a particular limit, in which case it must be treated as a hazardous waste (i.e.

landfilled).”

104 It has to be noted that here (soft) PVC containing ATO is excepted as PVC cable insulation containing ATO is partly

recycled by e.g. industry initiatives as mentioned in section 5.

105 Op. cit. KU Leuven-University of Leuven (2018)

106 Op. cit. KU Leuven-University of Leuven (2018)