Separating mixed plastic materials - by producing each type with its own markings, irradiating mixt., analysing characteristic emissions and using them to control sorting

摘要

Mixed plastic materials are separated by giving to each type one or more characteristic markings at the time of its production, subjecting the mixture to thermal neutrons or electromagnetic radiation, and analysing the characteristic energy emanating from the markings in a detector system which controls a sorting device. The mixed material is first washed, and sorted according to item size; this is followed by sorting by shape, colour and transparency and then by deformability. When the material is then irradiated e.g. by thermal neutrons etc. its markings become activated. They therefore emit characteristic energy levels, and these are analysed. Automatic sorting is controlled by the data collected. The final categories of material are then ready for use again. ADVANTAGE - The method can be cheaply mechanised so as to provide automatic separation and with a high degree of accuracy.