London - Axion Consulting has recently completed a series of trials of the most promising techniques for difficult WEEE separations. The full report is now available to download. The trials were commissioned by WRAP (Waste & Resources Action Programme) following an earlier Defra funded study in to new and emerging separation techniques.

The new study focused on techniques that have emerged over the past three to four years since the UK began to reprocess significant volumes of WEEE materials. Techniques with the potential to improve the effectiveness and commercial viability of WEEE recycling processes were selected for the project. The trials demonstrated techniques that could be used to separate and process mixed WEEE plastics and evaluated the techniques in terms of their ability to sort material by polymer type, colour and/or remove impurities. The suitability and economic performance of the techniques was assessed.

Axion trialled four categories of techniques:
* Sensor based separators;
* Shape and density separators;
* Separation by impact milling; and
* Effect of particle size distribution.

Following extensive trials, five techniques were identified as producing good quality separations of their target WEEE materials.
* TITECH Near Infrared (NIR) ‘Polysort’ sorter;
* Visys laser sorter;
* Delft University Kinetic Gravity Separator;
* Holma Wilfley wet shaking table; and
* Allmineral ‘Allflux’ upflow classifier.

Axion evaluated the economic potential of the five techniques and estimated that, (with certain conditions), the TITECH NIR sorter would recoup its initial investment within three years, and the Delft University Kinetic Gravity Separator, the Holman Wilfley wet shaking table and the Allmineral Allflux upflow separator would pay back their initial investment within two years. The Visys laser sorter, whilst producing a concentrated circuit board fraction with good separation efficiency, was found to be not economically viable at the present time, given the low current market value of circuit boards.

Axion Director, Roger Morton, comments on the trials: “We expect the results of these trials will be of great use to both primary and secondary WEEE processors facing the technical and economic challenges of reprocessing WEEE materials. The information on the demonstrated techniques will help to improve the efficient and effective reprocessing of this potentially ‘difficult to handle’ waste stream”.

Quelle: Axion Consulting

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