EXPERIMENTS ON HIGH EFFICIENCY SEPARATION OF MIXED PLASTIC WASTES BY VORTEX-TUBE SEPARATOR

摘要

There are 200 shredder plants in the EU-region for the processing of the end-of-life vehicles and large obsolete household appliances. They annually produce 8 - 9 million tons of non-metallic fine by-product, which is land filled without recycling. The organic matter content of these-products is around 45 - 50 per cent, ie 4 - 4.5 million t/y. Another annual 1 - 2 million tons of organic matter comes from the WEEE (waste of electric and electronic equipment) residues, since these wastes are recycled at a minimal level. The increasing living standards and decreasing life cycle of the vehicles and appliances lead to their much faster obsolesce. This type of organic wastes generally consist of mixed plastics and rubber. Their energy content can be effectively utilised by pyrolysis, gasification or incineration. Thermal waste treatment needs a relatively simple preparation. However, once manufactured from crude oil, the plastic wastes should be recycled as a secondary raw material. For this purpose a clean and economically feasible technology is required, which would be able to produce plastic products separated by sort at a high recovery rate A heavy media vortex-tube separator could be a possibility. In such a separator particles finer than 10 mm can be separated effectively due to the centrifugal force, even if their density difference is not very high (for example, density difference between PBT’s with 10 or 20 per cent of glass reinforcement is 0.09 kg/dm~3). This paper presents the experimental setup and the results of experiments, which were carried out in the laboratory of the Institute of Raw Materials Preparation and Environmental Processing, University of Miskolc within the framework of the RECYTECH R&D ongoing project (TECH- 08-A4/2-2008-0142). A vortex-tube separator installation set up in the experimental was appropriate for the measuring the effect of the separation media density, the feed pressure, geometric parameters of the separator, as well as the feed rate and solid concentration. Measurements were carried out first on a model material. The results were then compared with those obtained for the real plastic wastes. Values of recoveries and yields were determined in all cases.