At a glance
Heathland sought a sustainable way to recycle high-quality PMMA plastics and reuse them in the chain.
Together with Lybover, a solution was developed that combines mechanical separation and innovative technology to guarantee pure material flows.
Lybover supplied a customised installation that efficiently processes PMMA waste into valuable raw materials, ready for reuse in new applications.
In order to establish a new and comprehensive PMMA recycling value chain in Europe, Heathland wants to develop a process for converting PMMA waste into a high-quality end product. Heathland chose Lybover RECYCLING to analyse and implement the first phase. Its many years of experience with various recycling processes in a wide range of sectors makes all the difference.
The Lybover way
The Dutch company Heathland is a collector and processor of post-production plastic waste. The focus is mainly on PMMA (poly methyl methacrylate) plastic. Most of the waste comes from Europe. Heathland collects the waste and then sorts 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 start processing the production waste itself now that China has stopped accepting certain types of waste since 2018. Today, Heathland is increasingly focusing on the post-consumer PMMA waste stream. These are plastic materials that have already been used, as opposed to the pure (post-production) waste stream, which consists of production waste.
Great recycling potential
In total, we produce 300,000 tonnes of PMMA waste in Europe every year. Until recently, all this waste was sent to incinerators, as current recycling techniques and processes in Europe are not suitable for recycling end-of-life PMMA. However, PMMA is highly recyclable, even more so than other plastics. The properties of recycled PMMA material are of the same quality as the raw material that would otherwise be used for a new product. The loss incurred in recycling this waste is only 10 to 15%, so if 100 kg is processed, 85 to 90 kg remains that can be reused as raw material.
MMAtwo: international and innovative research project
Since October 2018, Heathland has been the initiator and coordinator of the MMAtwo project. This project is part of the European Union’s Horizon 2020 programme for research and innovation. It is an innovative project to develop a new process for recycling post-industrial, end-of-life and discarded PMMA waste. A total of thirteen partners from six countries are participating.
PMMA, or polymethyl methacrylate, is a transparent thermoplastic better known under the trade names Perspex, Plexiglas, Altuglas and Oroglas, but also simply as acrylic. In the midst of the coronavirus crisis, this Plexiglas is frequently used for all kinds of screens. But PMMA has many applications, including car lights, illuminated advertising, noise barriers, skylights, balustrades, shop fittings, bus windows, insulated refrigerated doors in department stores, 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. The industry needs to be made aware of this so that discarded PMMA waste is brought in instead of being sent to the incinerator. The MMAtwo process consists of two phases. In the first phase, the PMMA post-consumer waste is pre-treated and then further processed using a chemical process (depolymerisation). 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 will not work. In other words, the entire project stands or falls with the pre-treatment of the plastic waste.
Various techniques in the pre-treatment phase
The pre-treatment of the waste consists of two lines, namely a clean (post-production) and a dirty (post-consumer) line. The dirty line contains more other materials, such as dust, films and paper, while the clean line mainly contains different types of plastic. As a pre-treatment for the clean line, Lybover RECYCLING recommended installing a Windshifter from partner TrennSo Technik. For the dirty line, an electrostatic separator from partner Hamos was chosen. Both installations were custom designed and built by Lybover RECYCLING.
Separating the plastic mix
The Hamos EKS is an electrostatic separator that utilises the different triboelectric behaviour of the individual plastics. Through friction and collision, two different plastics acquire a negative or positive charge respectively. These are then separated by 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 negatively charged.
Separation based on air
The TrennSo Technik Windshifter (ZigZag) uses a constant, regulated and controlled air flow to separate materials into a light and heavy fraction based on specific weight, shape and size. A fan blows the light material (PE film) upwards, away from the falling heavier material (PMMA waste). The light material is then separated from the recirculated air via a cyclone. The whole system is adjusted in various ways by Lybover RECYCLING’s service engineers to achieve a good separation result. ‘We are very satisfied with the collaboration. We chose Lybover RECYCLING because of their good service and high-quality installations,’ says Simon van der Heijden, Director of Heathland. “In consultation with them, we opted for a TrennSo Technik Windshifter because it is a system that does not use false air from outside, has a high capacity and performed very well in the test centre. Quality is very important in this project.” The pre-treatment process is currently being tested to determine whether the material is already sufficiently clean to continue working with. If not, the process will need to be further optimised. The aim of this project is to process 22,000 tonnes per year. Once this result has been achieved and the research project has been successful, a large production line will be built.