Reclaim pelletizing

In the Reclaimator, a high pressure extmder, fiber-free mbber is heated to 175—205°C with oils and other ingredients. High pressure and shear between the mbber mixture and the extmder barrel walls effectively devulcanize the mixture in one to three minutes. In the Lancaster-Banbury method, high temperature, pressure, and shear are appHed to the mbber in a batch process that is otherwise similar to the Reclaimator process. In another high pressure process, scrap mbber is devulcanized at 5.5—6.9 MPa (54—68 atm) for ca five minutes. The product is milled, baled, or pelletized as in other processes. 

Table 4.3 Typical specifications for reclaimed flakes, recycled PET pellets and virgin PET pellets...

Figure 11.6 Photographs of foreign contamination in pellets of a re-pelletized reclaim stream a) photomicrograph of discolored PE pellets containing dark defects, and b) transmitted polarized light micrograph of a pellet cross section containing a defect. Photographs were provided by E. Garcia-Meitin of The Dow Chemical Company...

Chemical synthesis can include chlorination, alkylation, nitration, and many other substitution reactions. Separation processes include filtration, decantation, extraction, and centrifugation. Recovery and purification are used to reclaim solvents or excess reactants as well as to purify intermediates and final products. Evaporation and distillation are common recovery and purification processes. Product finishing may involve blending, dilution, pelletizing, packaging, and canning. Examples of production facilities for three groups of pesticides foUow. 

An extruder pumps melt through a straining head into the die. It passes through round holes in its die plate where a wet atmosphere exists. Upon exiting the plate, a spinning knife blade cuts the extrudate into pellets. The pellet/water slurry is pumped into a dryer where the pellets separate from the water. Water is reclaimed for repeat use. 

The products are recovered from the MS W stream via curbside collection, separated/ sorted at MRFs, and then cleaned and ground into chips at plastic reclaiming facilities to be remelted into recycled resin pellets. The recycled resin is used, mixed with virgin plastics, in the fabrication of plastic products. Mechanical recycling works best when applied to source-separated streams of waste plastics products. 

Pellet size is a major consideration of the material suppliers in the manufacture of hygroscopic polymers. It should also be a major consideration when reclaiming scrap regrind materials. 

Slitting, Winding, and Recovery. The film in and close to the clips is very thick and cannot be wound into film. This is slit off as the film exits the stenter and reclaimed for reprocessing into film. It is combined with scrap film and is either cut up into flake and compacted into particnlate form or is reextruded and formed into pellets. This reclaimed polymer either is fed back in with the virgin poljuner at the start of the film process or is fed into the CP process. 

Successful recycling requires an adequate supply of a reasonably clean feedstock. Items such as PET soft drink bottles or natural HDPE milk bottles are abundant in the United States, where curbside collection and drop-off centers are common, and thus make ideal feedstocks. The collected plastics are sorted, ground, reclaimed as flakes or pellets, and sold to fabricators of new products. In Germany,... 

Reclaim Reclaim (Flake/Pellet) (Flake/Pellet)Pyrolyze ... 

Most polymers can be analysed as received, as pellets, powders, films, fibres, in solution, or even as whole articles such as mouldings. Fine fibres can present some difficulties if a Raman microscope is not available. Raman spectroscopy has found applications in the identification of polymers in which additives obscure the polymer peaks in the IR spectrum. Reclaimed polymer is more prone to fluorescence than virgin material, causing problems for Raman analysis [394], Laser-Raman spectroscopy often allows polymer identification (e.g. in recycled material) only in conjunction with IR spectroscopy. Raman spectroscopy has been used to examine weathered PVC plasticised with DOP, DOA and BBP for dehydrochlorination [395], Laser-Raman spectroscopy has also been proposed as a suitable method for precise detection of ageing deterioration of vinyl chloride resins containing plasticisers and fillers used as electrical wire and cable coatings [396]. 

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