Recovery of valuable metals and plastics from end-of-life small home appliances by jig separation

Abstract

Jig separation, generally used for separating particles based on density differences, is one of the oldest and most widely used methods in mineral processing due to its operation simplicity, low cost, and high efficiency. This physical separation technique has been reported to be successfully applied in the recycling of electronic wastes like home appliances and computers. In this study, the RETAC® jig was utilized to recover valuable metals and plastics from actual crushed end-of-life small home appliances after removing large pieces of metals by magnetic and eddy current separation. The study found that separation efficiency dramatically decreased with the presence of copper wires. This is due to copper wires easily getting entangled in the separation chamber during separation, where plastic and PCB particles were trapped to prevent their motion in the chamber. However, it remains unclear which factors control this entanglement process of the copper wires. To further investigate this interesting phenomenon, effects of various factors like length and amount of copper wires were investigated by using model samples of plastics and copper wires. The results showed that the higher mass ratio as well as the longer copper wires caused the more entanglement. The copper wires removal by a mill pot pre-treatment prior jig separation was also investigated for possibility to increase the separation efficiency. It was found that copper having 93% purity was firstly obtained from the pre-treatment process and the recovery efficiency in the 6th layer of jig separation increased from 66% to 87% with this pre-treatment.