Objective
An automatic system using fluorescent tracer technology has been developed to enable articles made from different plastics to be identified and sorted. The performance of the system has been exemplified using plastics packaging (bottles and cartons).
The system comprises three components:
- The tracer system. The tracers are fluorescent compounds which emit characteristic fluorescent 'signatures' when illuminated by UV light. The tracers may be used either singly, or - when large numbers of plastics are required to be identified - in binary combinations of two or more tracers. The tracers are incorporated into the plastics either during polymer manufacture or by means of masterbatches which are added during conversion;
- The sensor system. The sensor system comprises a filtered UV light source; a collimator for projecting UV radiation onto the articles to be identified; an optical system for collecting the emitted fluorescent light; dedicated filtering and photomultiplier combinations tuned to detect emissions from specific tracers; and a data processor, which provides signals corresponding to the identified plastics materials to activate a sortation machine; and - The sortation machine. This machine singulates the stream of unidentified articles (e.g. containers) so that the latter traverse the sensor one at a time. When a signal is received from the sensor, an air jet is activated to eject the identified article into the appropriate storage bin.
The main benefits of this system over existing ones are that it is fully automatic, fast, accurate and capable of identifying a large variety of different plastics. A variable voting system ensures that the optimal balance between sorting efficiency and purity of sorted fractions is maintained, even under conditions where the articles are contaminated e.g. by labels on bottles. Unique features are that the system can discriminate between grades of the same polymer, and if required can reject materials (such as plastics containing certain additives) that must be kept out of the sorted streams.
A single lane process can sort at throughputs in excess of 1 tonne/h and at a cost substantially lower than is possible with manual sorting. The tracer system - if adopted by the industry - could therefore provide operators in the waste collection, recycling and disposal chain with significant economic and quality benefits.
The system has the potential to be developed for sorting shredder wastes and coloured plastics. This has significant implications for industry sectors other than packaging, for instance the automobile and electrical/electronics industries.
The proposed research is directed at developing of different plastics in mixed waste. The identification of the plastics will be effected by detecting fluorescent emission 'fingerprints' from traces of 'dopants' in the plastics. By using combinations of materials can be positively identified, thus it will be possible to not sort several different generic plastics, but also different grades of them.
The major research tasks are:
- development of a sey of dopants containing combinations of dyes which fluoresce at wavelengths greater than 500 nm and which are compatible with the polymers (polar and non polar)
- development of a low cost detector comprising a robust light source (laser diode or wide band source such as Xenon arc), light collecting system and detector (wavelengths greater than 500 nm)
- signal processing so that combinations of fluorescent emission signals can be used to allow positive identification of the dopants.
- development of sorting mechanism and integration with the detector system.
- proving trial of system using 3D products (bottles etc).
Successful operation of the system will help to increase the amount of plastics materials recovered for recycling from the post user waste stream from the current level of 7% to about 20%. Each 1% increase in the amount of plastics recycled will save the European Community about 150000 tonnes of oil equivalent. These savings will assist European industry to become more competitive in the global market.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- engineering and technologyenvironmental engineeringwaste management
- engineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringsignal processing
- natural scienceschemical sciencespolymer sciences
- engineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringsensors
- natural sciencesphysical sciencesopticslaser physics
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Topic(s)
Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
KT22 7RU Leatherhead
United Kingdom