High-purity r-HDPE and r-PP granules achieved through triboelectricity.
Granuplast has successfully revolutionized the recycling of HDPE and PP plastics.
By collaborating with the CNRS and the PPRIME Institute, we have developed specialized equipment capable of selectively separating HDPE and PP flakes, allowing us to efficiently sort these plastics that were previously challenging to mechanically separate. This achievement was a significant breakthrough for the recycling industry.
The principle of triboelectrification is based on the electrostatic properties of materials. When different types of plastics are rubbed or brought into contact, they can develop opposite electrical charges. This difference in electrical charges between the plastics facilitates their separation.
Triboelectrification is a crucial technology used by Granuplast in its plastic recycling process. It plays a crucial role in separating different types of plastics to produce r-HDPE and r-PP granules of very high purity, closely resembling that of virgin resin.
A mechanical process for maximum quality
The entire process is monitored by our quality department to garantee a first class quality of our products.
Receipt
The plastics arrives in the form of bales, mainly HDPE and PP, from household and industrial waste collectors/sorters. The bales are first checked then stored in batches. To ensure the full traceability of the material, the pre-treatment is done in batches equivalent to a truck load.
Shredding
The bales are automatically loaded into the shredder. The shredder, with a capacity of 5t/hour, is capable to reduce all types and shapes of plastics into flakes of less than 50 mm.
Shredding, washing, sorting
The shredded material is crushed in water into flakes smaller than 14 mm. We then sort the material through decantation. Our washing water is reprocessed in a closed circuit and reused in our production line.
Electrostatic sorting
In order to improve the sorting and the quality of the finished product, our line is completed with a double electrostatic sorting system which ensures a purity rate of 98/99% close to the virgin resin.
Homogenization
After drying, the flakes are put into a mixing silo to obtain a perfect homogeneity.
Granulation
The flakes fill the extruders. Colorants can be added at the customer’s request. The extruders are equipped with two degassing zones each, and a 150μ sieve filtration to remove the last impurities.
Packaging
At the end of the granulation process, the granules pass through a mixing silo for a second homogenization. An automatic big bag packaging equipment finalizes the production process. Each big bag contains 1t - 1.2t of granules.
Sampling
The in-house laboratory, managed by qualified personnel, with the help of new DSC3 physical analysis equipment, allows continuous quality control of HDPE and PP samples in order to know precisely the levels of purity of the recycled granules.