New LIBS sorting system developed for aluminium and other non-aluminium metals recycling

SMEs and research organisations in the EU-funded SHREDDERSORT project have developed and demonstrated a new industrial sorting system to separate non-ferrous shredder scrap into cast aluminium (Al), wrought Al, and non-Al categories. Compared to the unsorted material, the sorted categories are better suited for recycling into secondary metals, have a higher market value, and will reduce the use of raw materials.

End-of-life vehicles (ELV) generate around 10 million tonnes of waste per year in the EU. Around 75% of this waste is currently recycled or recovered, but this level still falls short of the 95 per cent target set by the European ELV Directive - 2000/53/EC.

The initial processing is of ELV metal scrap is carried out in shredder plants which chop the dismantled and depolluted vehicles into pieces around 5-20 cm in size to facilitate sorting and separation. Magnetic separators are used to separate out the ferrous metals (iron and steel), and eddy current separators are then used to separate the non-ferrous metals - aluminium (Al), copper (Cu), magnesium (Mg) etc. - from residual non-metals such as plastic and glass.

To improve the recycling of the high value metals present in ELV shredder scrap, for use in the production of secondary metals, and to reduce the demand on raw materials the SHREDDERSORT consortium is developing three sorting systems for use in shredder plants:

1) One which uses Laser Induced Breakdown Spectroscopy (LIBS) systems to distinguish and separate cast and wrought Al alloys.
2) One which uses LIBS to distinguish and separate Mg and individual Al alloys series.
3) One which uses magnetic induction and machine vision methods to identify and separate Cu alloys, Al alloys, and stainless steels.

The first LIBS sorting line became operational in April 2016. In that system, cast Al, wrought Al and non-Al metal fragments travel on a 1 m wide conveyor at a speed of 2 meters per second, with a target throughput of 1 tonne per hour.

The remaining two sorting systems, are under construction, and will be operational by September 2016, prior to the validation of all three systems in commercial shredder plants from Oct-Dec 2016.

The SME partners and end-users in the project aim to commercialize and use the systems in ELV and other recycling applications including demolition and construction waste, industrial scrap, and waste electronic and electrical equipment (WEEE).