An interim report on a project investigating the waste management options for mixed waste electrical and electronic equipment (WEEE) polymers containing brominated flame retardants (BFRs) has found that separation and treatment to remove the additives is probably more commercially and environmentally beneficial than disposal or incineration with energy recovery.

The work was undertaken by Axion Recycling Ltd, and is being carried out in light of the impending European WEEE Directive, which is set to encourage the closed loop recycling of WEEE polymers in the future.

This latest report covers the second stage of the four-phase project, which is designed to address one of the technical barriers to recycling – the removal of potentially hazardous BFR compounds.

The project aims to find a complete solution for the removal of BFRs from the variety of different waste streams which fall within the WEEE category.

The whole recovery and recycling process is included, from WEEE polymer identification and mechanical sorting in order to separate non-BFR polymers for direct recycling, through to the technologies that could be employed to remove BFRs.

Practical trials have shown that the identification of BFR-containing polymers by both BFR content and polymer type at WEEE dismantling facilities is technically feasible using relatively low cost, fast-acting hand-held instruments.

They have also demonstrated separation of polymers should be commercially viable for WEEE items over about 0.5kg and bulk separation of a clean mixed polymer fraction from mixed WEEE polymer by density is technically feasible and should be commercially viable in the UK.

However, further separation of the clean fraction and also bulk separation of BFR-containing from BFR-free polymer is difficult with currently available technologies.

X-ray based polymer chip sorting is extremely promising as a commercially viable technique for bulk separation of polymers containing bromine, and other elements such as chlorine, lead and cadmium – and it also has potential for separation of styrenic polymers by type.

Two solvent-based BFR removal processes – Creasolv and Centrevap – appear at this stage to offer the best commercial and environmental potential.

Creasolv has produced high quality, almost BFR-free recycled polymer in the course of the project from waste TV casings.

Paul Davidson, material sector manager for plastics at WRAP, said: “This report is a product of some highly significant progress in the field of WEEE plastic recycling, but also could have wider implications for solvent based plastic recycling processing in general.”

By Sam Bond

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