TECHNOLOGY | WASHING
Below: Sorema has developed a de-inking module, an advanced washing system for the removal of inks
IMAGE: SOREMA
company Teknodepurazioni Aquae, Sorema can offer an integrated washing and recycling plant with wastewater treatment from the de-inking process. The wastewater treatment phase combines mechanical filtration processes with high-speed centrifuges, sedimentation with chemical adjuvants and purification with
ozone and activated carbon treatments. Cadel Deinking is a Spanish company dedi-
The de-inking module involves feeding incom-
ing material using volumetric or gravimetric dosing, controlled and independent dosage of chemical additives, and imparting high friction to the material in hot water with a defined residence time that is adjustable to specific inks and materi- als. This allows a single plant to be used to wash both rigid and flexible plastic materials. The recycling process is then completed by one or more rinsing and drying phases of the flakes, before extrusion into granules. According to Sorema, the de-inking process is mainly applied to post-industrial waste, but it is also being studied for use in post-consumer waste recycling plants. Good results have been achieved in many applications, however, not all types of printing inks are completely removable. For this reason, a pilot plant line in operation at the company’s laboratory, located in Alzate Brianza, Italy, has been optimised with all the necessary full-scale modules for de-inking. The laboratory is available for de-inking tests to validate processes and optimise chemical formulations and washing times. These tests can also be completed with in-house extrusion to verify results. Sorema adds that it can supply complete
turnkey washing and recycling plants, which can manage all stages of the process, including cleaning the chemical de-inking circuit and wastewater treatment. In collaboration with sister
cated to de-inking solutions for printed plastics waste. In December 2020, Erema subsidiary Keycycle became a major partner to Cadel, taking over exclusive worldwide sales and project implementation of its technology for ink removal. As part of the agreement, both companies will jointly operate the pilot system at Cadel’s facility in Sant Vicente del Raspeig, Spain. Cadel has also partnered Dow Packaging and Specialty Plastics – along with HP Indigo, Reifenhäu- ser and Karlville – in a project to develop a pouch- to-pouch mechanical recycling concept. Starting with a PE-based barrier food pouch designed for recyclability, the project team used mechanical recycling and de-inking to create a high-quality dishwasher MDO-PE pouch with 30% recycled content which is itself suitable for recycling. “To produce the recycled PE resins for the second pouch, we used our deinking technology to achieve the best outcome,” says Pablo Carta- gena, Business Development Manager at Cadel Deinking. “The deinking process is key because it effectively removes ink from the plastic surface to obtain a plastic with similar characteristics to the raw virgin material which helps to provide high- quality pouch-to-pouch recycling. We are very happy to collaborate closely with all these leading companies and to demonstrate that Cadel’s deinking technology is considered ‘crucial’ to achieve circularity in plastic.” In Japan, Toyo Ink has developed a plastic
Above: Flexible packaging waste-printed LDPE before (left) and after (right) Sorema’s de-inking process
32 PLASTICS RECYCLING WORLD | July/August 2022
recycling technology for multilayer flexible packag- ing, where a de-inking coating agent and a delaminating adhesive are applied to the plastic film surrounding the ink layers. After use, the packaging waste is subjected to an alkaline treatment in which the coating agent, adhesive and interlaying ink layers are cleanly released from the film substrate. Toyo Ink has a pilot plant demon- strating this technology. Herbold Meckesheim has developed a new washing plant for shredding and cleaning hard PP. The company says that the plant provides high purity recyclate and high throughput, as well as
www.plasticsrecyclingworld.com
IMAGE: SOREMA
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