Biggest Breakthrough in Plastic Recycling

by Anjana Nair (Bio Market Insights) ... The recent research from the Aarhus University, Denmark, demonstrated for the first-time computer vision technology, which can be used to differentiate between a wide range of plastics according to their chemical composition. Applied on an industrial scale, this could enormously increase the rate of plastic recycling. This new technology, developed by researchers from the department of biological and chemical engineering at Aarhus in collaboration with Vestforbænding, Dansk Affaldsminimering ApS, and Plastix allows for differentiation between 12 different types of plastic which constitute many households’ plastic types. The plastics are PE, PP, PET, PS, PVC, PVDF, POM, PEEK, ABS, PMMA, PC, and PA12. Plastics that exist in the world today are combinations of many materials (polymers) with varying chemical compounds and additives, containing pigments or fibers, depending on their core application. This makes it extremely difficult to tell the difference between types of plastic, making it hard to separate and recycle them. More than 90% have not been recycled. With this technology, the camera allows for the separation of plastic-based litter on a purer chemical composition than what exists today. It, therefore, opens new opportunities for plastic recycling. It has already been piloted and will be implemented this year.

“With this technology, we can now see the difference between all types of consumer plastics and several high-performance plastics,” said Professor Mogens Hinge, who is heading this study. “We can even see the difference between plastics that consist of the same chemical building blocks, but which are structured slightly differently.” He further spoke of the hyperspectral camera being used, in the infrared area, which leverages machine learning to analyse and categorise the type of plastic to be directly loaded on the conveyor belt. The plastic then is separated into different types. The researchers believe that the breakthrough will have a huge impact on all plastic separation.

The separation of plastic from various types of waste streams remains one of the major problematic processes. The sorting of plastics is a very essential step in different waste management techniques. Manual sorting is suitable when plastic components are present in large amounts, but it is a labour-intensive process. In the automated sorting technique, NIR (near-infrared) offers a great advantage among all wave sorting techniques but is not suited for dark-coloured plastic and can be used on transparent bodies. In air sorting, lighter particles are separated from heavier ones based on specific gravity. In electrostatic sorting, method materials are separated based on electrostatic charge. In the float-sink separation technique, the plastics are in a fluid that has a density in between the materials making it possible for less dense material to float and heavier to sink. Plastics are currently separated using near-infrared technology or via density tests, that is they are tested based on floating or sinking in water. These methods can separate certain plastic fractions, like PE, PP, and PET but not with the same accuracy as this new technology, and therefore not with the chemical purity in the composition. This kind of technology is vital for boosting the recycling rate of plastic waste.

Plastix CEO Hans Axel Kristensen also commented: “The technology we’ve developed in collaboration with the university is nothing short of a breakthrough for our ability to recycle plastics. We look forward to installing the technology in our processing hall and starting in earnest on the long journey towards 100% utilisation of waste plastic.” Plastic must be at least 96% pure by polymer type to be recycled according to conventional industrial processes. This means that the plastic must be separated into an almost pure product in terms of chemical composition. Hinge says that bringing in new technology and adding it will enable the continuation of refined data to indicate it may soon be possible to differentiate even further between polymer and additive types.

The study has been published in the scientific journal Vibrational Spectroscopy. READ MORE