Cryogenic recycling of valuable, industrially underused materials as industrial research

The recyclability of a material is only as good as the combined components can be separated and cleaned. The KryoReIF project is working on a new way of processing material composites through cryogenic grinding. The project partner SYNRON has patented a process based on the embrittlement of the components by liquid nitrogen ( 196 °C at normal pressure). Due to the different coefficients of thermal expansion, combined materials can be ground down to a desired fineness by the action of friction and pressure in a drum. If this results in different particle sizes, the fractions can be separated from each other by sieving and recycled without any loss of quality. If there is a difference in density, further separation can be carried out using the float-sink process. In this way, valuable raw materials can be recovered in an energy-efficient process, thus production costs are reduced. In addition, otherwise necessary chemical or thermal processes for separation are avoided.

In the KryoReIF project, the advantages for the circular economy are demonstrated with two exemplarily selected types of plastic composites (e.g.: multi-layer films - evaluated by TCKT) and metal waste (mainly cooling lubricant emulsion-contaminated chips - evaluated by the project partner LKR). This synergetic research into the cryo-recycling process for the utilisation of industrial waste and end-of-life waste is carried out across materials and sectors. Not only the physical separation with the experimental plant at SYNRON, but also the recyclability of the cryogenically separated/purified main fractions are demonstrated on a laboratory scale for a metal and a plastic grade by LKR and TCKT respectively. Further orientation tests on selected end-of-life/post-consumer waste types from different industries complete the scope of work.