Improvement of jig efficiency by shape separation, and a novel method to estimate the separation efficiency of metal wires in crushed electronic wastes using bending behavior and entanglement factor

Jig separation, one of the oldest and most widely used methods in mineral processing that separates particles based on density differences, was applied to recover valuable materials from residues of an actual recycling plant treating small home appliances. hi this study, a modified TACUB jig called RETAC jig (R&E, Co., Ltd., Japan) was used to separate plastics and metals including copper (Cu) wires from real recycling plant residues. The results showed that the decrease in separation efficiency was largely because of Cu wire entanglement that trapped and prevented particle motion in the separation chamber. Jig separation of model samples and evaluation of bending behavior and entanglement factor of Cu wires were carried out to investigate this phenomenon. The results showed that higher Cu wire content and longer Cu wires (i.e., a higher entanglement factor) had lower separation efficiencies. To limit the effects of wire entanglement, two methods of shape separation were investigated. These shape separation techniques increased the recovery of Cu wires in the Cu concentrate from 64% (without shape separation) to 97% (with shape separation using probability of passage) and 95% (with shape separation using induced entanglement). In addition, estimation of jig separation efficiency using the entanglement factor is proposed.