PMD sorting and purification for recycling
At the Indaver plant in Willebroek, we carefully sort selectively collected PMD (Plastic bottles and packaging, Metal and Drink cartons) into various fractions, which are ready to use as raw material for the recycling industry.
The PMD installation is continuously improved in order to separate more fractions with an even higher level of purity. That way, we can remove hazardous materials from the closed loop. The sorted fractions are used for all sorts of common products, such as fleece sweaters and toilet paper.
Municipalities and intermunicipal organisations, as well as companies (to a lesser degree), deliver their PMD waste to Indaver. The waste goes into a sophisticated PMD installation that sorts and purifies the waste.
- Via an automatic sack-opener and a conveyer belt, the PMD winds up in a rotating sieve. The initial separation occurs here, with an additional separation by size.
- A series of machines automatically sort the huge fraction of the PMD waste:
- a wind-sifter sucks out the paper residue and plastic bags, while an overhead magnet removes the metal;
- infrared light detects the drink cartons. Compressed air blows them out of the PMD waste. A non-ferrous separator selects the non-ferrous metals, such as aluminium;
- caps and covers are sent to a container. Large foils and bags are transported to the sorting hall;
- a ballistic separator separates soft and hard synthetics and thereby excludes bothersome foils from the sorting process;
- separation of synthetics occurs by means of a combined technique of material and colour recognition using the latest generation of optic separators. A first optic separation machine sorts PE, PET and the residual fraction based on an analysis of the reflected light spectrum. Compressed air blasts PE and PE to separate conveyer belts. The second machine separates clear PET from the coloured PET. The last machine further sorts the residues separated by the first and second machine according to material and colour. PET returns to the second separation machine in order to ensure optimal separation between clear and coloured PET.
- Ultimately, eight pre-sorted fractions end up in the sorting hall: aluminium, blue sacks, drink cartons, clear PET, blue and green PET, PE and residue. All these fractions are manually checked by the sorters.
Meticulous quality control
The purity of the sorted fractions must be high: not more than 5% of the input flow may be lost in the residue. To regulate the sorting process, Indaver carries out quality checks. All PMD deliveries are subject to a visual check. A quality assistant also carries out a process check of the end-products and/or the residue twice a day, on average.
Valuable raw materials
The sorted fractions are transported in sacks or in bulk for recycling. At this point these are valuable raw materials for the recycling industry. The end-products are used for industrial applications, such as building materials, but also for everyday products, such as fleece sweaters, mattress fillings, toilet paper and tins.
Every load of PMD can be identified – from collection up to final application. All the collection, sorting and recycling partners must register their data in a central database (Profost). The sacks with the sorted products are also labelled so that each sack can be traced back to its source.
Continuous improvement and innovation
In order not to contaminate the closed loop, no impure or hazardous substances may end up in the recycled fractions. Indaver continues to invest in ever better PMD sorting techniques in order to continue meeting the strictest requirements of the recycling industry. To achieve this, the PMD installation in Willebroek was optimised in 2013.