The final step in the recycling process is separation using Post Shredder Technology (PST). The PST plant in Tiel separates the remaining shredder waste into reusable raw materials. The combination of technology is unique in the world and it is still developing. “We are continually working on innovations,” says Recycling Director Hans van de Greef.
Four waste streams are separated in the PST plant: plastics, minerals, fibres and metal scrap. The process is divided into various modules, each with their own colour at the plant. The blue module separates the materials into three main flows of minerals, plastics and fibres. Those groups are separated further in separate modules. The PST is responsible for recycling the final almost 16 per cent of the end-of-life cars.
The PST plant separates the various metals from other residual substances and from each other, so that in the end copper, aluminium, iron and stainless steel are left. PVC-containing plastic in particular, contains a lot of metal, mainly copper. Fibres from the textiles in the car contain copper wires. That copper is also recovered.
The separation process takes place using magnets and vibrating tables, among other things, which separate the various types of metal particles. The recovered metals finally go to smelting companies and then on to the metallurgy industry. The stainless steel is suitable for steel constructions. Copper has numerous applications, such as in cables for electricity companies. Aluminium goes to aluminium smelting companies for reuse, for example for cans. The recovered iron is used for applications including reinforced concrete in the construction of houses and offices.
The red module in the PST plant recovers metal scraps from the plastics and fibres. Metals such as copper, aluminium, iron and stainless steel are separated and sent to the metallurgy industry.
The orange module processes the fibres from the textile in the car into useable raw materials. The fibres are compacted into granules. One application, for instance, is as insulation material in construction.
The yellow module processes minerals. This regards mainly sand and glass, which is separated into three granule sizes. The minerals are used in road construction as a road bed under asphalt.
The green module at the PST plant separates plastics into similar weight categories. Light fractions are suitable for reuse in new cars. Some plastics are burned and generate electricity.
The recovered plastics can be used in a wide variety of applications. Light plastics, such as PP and PE, are reused in new cars, among other things. They are used in bumpers and in the interior. Through the Galloo company, ARN supplies Renault with materials for the bumpers, a third of which consists of recovered plastics. With this, Renault is taking on a pioneering role, but increasing numbers of car brands are following suit. And thereby returning plastics from end-of-life vehicles back to the automotive industry.
Heavier plastic fractions are given a new application as a reducing agent in the production of iron in blast furnaces. They are used instead of coke.
PVC-containing plastic is not suitable for reuse, but it can be used as fuel for power plants and supply energy. A notable application of plastics is in dam walls and shoring made by the Circore brand.
The PST plant separates the plastics into three different flows. The aim is to separate even more flows in the future. One of the most innovative processes with the PST plant, is separating plastic from a mix of plastic, rubber and wood. The process uses the differences in density of the materials. Using a so-called ‘sink-swim’ separator the hard plastic particles ‘swim’, and the softer rubber and wood ‘sink’. Resulting in hard plastics being left. “It sounds simple, but try building an installation like this. It’s great we have succeeded,” says Recycling Director Van de Greef.
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