Printer toner cartridges must not be thrown in the bin. Since 2016, they are covered by the Waste Electrical and Electronic Equipment regulations, and so must be recycled.
However, that is easier said than done. The fine toner dust inside the cartridge is not only harmful to health, but it also tends to ignite when it is shredded. Explains Doppstadt project developer Leonhard Boscheinen: “There has been no complete recycling for this material so far. Although manufacturers and recycling enterprises refill empty cartridges, this does not include damaged and outdated cartridges.”
Many toner cartridges are either exported or incinerated, he states. “This will result in unnecessary costs and valuable raw materials will be wasted. The percentage of metals in the cartridges amounts to 50%. Furthermore, the plastics, mainly polystyrenes, are much in demand on the market.”
Instead, Doppstadt Systemtechnik has developed a patented processing concept to meet this challenge. Instead of removing the carcinogenic dusts via a special de-dusting plant, the cartridges are put into an oven, which melts the particulate matter. After that the melted toner is no longer explosive. “This thermal pre-treatment replaces the complicated ex-zone categorisation and de-dusting equipment,” Boscheinen says.
After the tempering process, a Doppstadt high-performance shredder combined with state-of-the-art separation technology can process the material. The aims are to recover the metals and to condition the plastics for further processing.
For both processes, Doppstadt prioritised health and safety. The risk assessment by the independent consulting firm INBUREX confirms that the dust emissions generated during the patented process are harmless. “As the expertise has demonstrated, there is no danger of explosion associated with the recycled toner cartridges,” Boscheinen says. Furthermore, Doppstadt is investigating the separation of different types of plastic in order to recycle them – this also applies to the agglomerated toner. The recovered re-granulates could for instance be used to produce new toner cartridges.