The rise of home shopping and especially during COVID times has seen a huge rise in OCC, especially small pieces of OCC coming into co-mingled MRFs across the UK. Recovery of large OCC is well established but the small OCC can travel through the MRF process and can often end up in the plastic container line causing overloading of picking belts and optical sorters.
In a MRF using ONP screens the screens will be arranged in series, screening materials at A4 and A5 (paper sizes) in order to remove News and Pams and Mixed paper grades, respectively, for further clean up. Materials less than A5 size falling through the screen, such as small paper and plastic containers, normally go on to a ballistic separator to separate 2-dimensional (2D) paper from 3 dimensional (3D) plastic containers and then optical sorters for separation into polymer types.However, we have seen that the small OCC less than A5 size often comprises of box lids or parts of boxes which has often been crushed as part of the collection process and therefore have a 3-dimensional cross section and end up in the plastic container fraction, causing overloading these optical sorters and potential loss of valuable OCC into residue.
In order to recover more of this 3D card, Turmec along with Bollegraaf/LUBO designed new A6 stars to retrofit into an existing ONP screen and as a result 30% more of this smaller card and paper was recovered onto the paper sorting line without affecting the recovery of plastics. As a result the first optical sorter in the 3D line received a material stream composition of between 82-87%plastics containers, to improve both the recovery of 3D card by approximately 400-600kgs/hr and overall efficiency of the container line by 15%.