In order to realise a new and comprehensive PMMA recycling value chain in Europe, Heathland wants to develop a process to handle PMMA waste into a high-quality end product. For the analysis and implementation of the first phase , Heathland chose Lybover RECYCLING. Years of experience with various recycling processes in the most diverse sectors makes all the difference.
The Dutch company Heathland is a collector and processor of post-production plastic waste. The focus is mainly on PMMA (PolyMethylMethAcrylate) plastic. Most of the waste comes from Europe. Heathland collects the waste and then sorts it and mechanically or chemically recycles it into raw materials for various types of acrylic products. The processing centres are located in the Netherlands and Poland. Heathland decided to process the production waste itself now that China has not accepted certain waste materials since 2018.
Today, Heathland is increasingly focusing on the post-consumer PMMA waste stream. These are already used plastic materials, as opposed to the pure (post-production) waste stream consisting of production waste.
High recycling potential
In total, we produce 300 000 tonnes of PMMA waste annually in Europe. Until recently, all that waste was taken to the incinerator, as current recycling techniques and processes in Europe are not suitable for the recycling of end-of-life PMMA. Nevertheless, PMMA is very recyclable, even better than other plastics. The properties of the recycled PMMA material are as qualitative as the raw material that would otherwise be used for a new product. The loss to recycle this waste is only 10 to 15%, so if one processes 100 kg, 85 to 90 kg remain, which can be reused as a raw material.
MMAtwo: international and innovative research project
Heathland has been initiator and coordinator of the MMAtwo project since October 2018. This project is part of the European Union’s Horizon 2020 programme for research and innovation. It is an innovative project developing a new process for recycling post-industrial, end-of-life and discarded PMMA waste. A total of thirteen partners from six countries are taking part. PMMA, or Polymethyl methacrylate, is a transparent thermoplastic which is better known under the trade names Perspex, Plexiglass, Altuglas and Oroglas, but also as acrylate. In the full corona crisis, this Plexiglass is frequently used for screens of all kinds. But PMMA has many applications including car lamps, illuminated advertising, sound walls, roof domes, balustrades, shop fittings, bus windows, insulated cooling doors in department shops, etc.
From collection to processing
It is estimated that only 30,000 tonnes of PMMA waste are currently collected for recycling in Europe each year, which is only about 10% of annual production. Industry must be made aware of this in order to bring in the discarded PMMA waste instead of going to the incinerator. The MMAtwo process consists of two stages. In the first phase, post-consumer PMMA waste is pre-treated (= pre-treatment) and then further processed with a chemical process (depolymerization). The pre-treatment of the material is a necessary and important step in the process. If the waste is not sufficiently pure and stable, the chemical process does not work either. In other words, the entire project stands or falls with the pre-treatment of the plastic waste.
Different techniques in pre-treatment phase
The pre-treatment of the waste consists of two lines, a clean (post-production) and a dirty (post-consumer) line. The dirty line contains more other materials, such as fabric, foils and paper, while the clean line mainly contains different types of plastic.
As a pre-treatment for the pure line, Lybover RECYCLING advised to install a Windshifter from partner TrennSo Technik. For the dirty line, Lybover opted for an electrostatic separator from partner Hamos. Both installations were custom designed and built by Lybover RECYCLING. “Via Lybover RECYCLING we had a test carried out with the Hamos EKS. We were very satisfied with the good results”, says Nikolaj Garnitsch, Director Heathland.
Separation of the plastic mix
The Hamos EKS is an electrostatic separator that uses the different triboelectric behaviour of the individual plastics. By means of friction and collision, two different plastics receive a negative or positive charge respectively. These are then separated via attraction or repulsion in a high voltage field (electrode with specific polarity). In this case, the PMMA particles are positively charged and the PVC particles are negatively charged.
The TrennSo Technik Windshifter (ZigZag) uses a constant regulated and controlled airflow to separate materials into a light and heavy fraction based on a specific weight, shape and size. A fan blows the light material (PE film) away from the falling heavier material (PMMA waste) from bottom to top. The light material is then separated from the recirculated air via a cyclone. The Lybover RECYCLING service engineers adjust the unit in various ways to achieve good separation as a result. “We are very satisfied with the cooperation. We chose Lybover RECYCLING because of the good service and the qualitative installations,” says Simon van der Heijden, Director Heathland. “In consultation with them, we chose a TrennSo Technik Windshifter because this is a system that does not use false air from the outside, it has a high capacity and the tests at the test centre were very positive. Quality is very important in this project”. The pre-treatment process is currently being tested in order to check whether the material is already sufficiently pure for further cooperation. If not, the process will have to be further optimised. The goal of this project is to process 22,000 tonnes per year. Once this result has been achieved and the research project is successful, a large production line will be built.