Jigging has been a well-known gravity technique for concentrating ores and minerals for centuries. Now it is adapted to process shredded post-consumer plastic mixtures, too. As the density of water is within the density range of plastics, two distinct jig designs are needed to process all types of plastic mixtures. For plastics that are heavier than water, such as mixtures of ABS and PMMA, a jigging process similar to that employed in minerals processing can be used. However, when the components of the plastic mixture to be separated are lighter than water, e.g. mixtures of PE and PP, a novel inverse jigging process has to be applied. In both types of plastics jig, a separate discharge of the segregated layers can best be achieved using a ragging. Ragging action is here different from known types of mineral jig, because ragging in plastics jigs greatly influences the segregation process. This paper describes basic designs of plastics jigs. In addition, the settling behaviour of plastic particles and ragging bodies during jigging is discussed.
