Tomorrow, the European Commission will meet to significantly reduce the use of plastics in the coming years and even ban them in some cases. Humanity uses more plastic than ever and that leaves a mark worldwide. Especially single-use plastics will be severely restricted, because there are often more environmentally friendly alternatives. Although man produces huge quantities of plastic, only a small part of it is recycled. Until recently. With the latest innovative separation methods, the mountain of plastic can be strongly reduced.
Until recently, plastic recycling was downgraded; of high-quality recycled plastic, only inferior products could be made, such as roadside poles. But TU Delft has now tackled that problem.
‘Plastic is difficult to recycle and a lot of quality is lost when it comes to remodelling,’ Peter Rem, Professor of Civil Engineering at TU Delft, explains. ‘The packaging industry already uses around 250 different types of plastic, but every brand also has a different colour. The biggest differences are the technical compositions of a plastic. Until recently this was the bottleneck. ‘
TU Delft has now made plastic recycling considerably more efficient by selecting it for density with sensor separators and air blowers, but recently also with more efficient water jets. ‘One of the problems with these sensor separators was that it was rather expensive and inefficient,’ says Rem.
‘The camera that looks at such a stream of plastic flakes had trouble separating it. If a certain type of flake is very close to another piece with a different colour, it was also separated. That was because we used air nozzles of 5 mm, but that air flow was too thick for the flake. The solution we have found is to work with very thin water jets that can blow away the flakes very accurately. After plastic is separated for density, you still have the colour problem. By separating them you keep pure plastic. This bypasses a chemical step (compounding) that is normally always part of the plastic recycling method.’
The implementation of this innovation is already being applied in the new plastic mining plant of Rotterdam’s Umincorp. In addition, Umincorp also uses the revolutionary MDS technology (Magnetic Density Separation) consisting of ferromagnetic liquids and specially designed magnets. Jaap Vandehoek, one of the directors of Urban Mining Corp and raw materials technologist explains: ‘The technology of Urban Mining Corp is focused on selecting plastic, originating from waste streams, as much as possible on density. Because separating the different plastics into categories makes it easier to recycle them. The precision of this selection process is currently at 97%, which at the end of the operation is very close to the quality of new plastic. The plastic becomes a high-quality raw material from waste. ‘