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Polypropylene recovery of post-industrial carpet. In association with Carpet Recycling UK Funded by Envirolink Northwest Andy Mail. Summary. Project aims Method of recovery Trial results Project conclusions Next steps. Project aim.
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Polypropylene recovery of post-industrial carpet In association with Carpet Recycling UK Funded by Envirolink Northwest Andy Mail
Summary • Project aims • Method of recovery • Trial results • Project conclusions • Next steps
Project aim • 10,000 tpa of post-industrial carpet enters UK waste stream. • Approx 50% is PP. • Can this carpet be recycled on a commercial scale?
Two research tasks • Post-consumer - identification and preparation for extrusion • Post-industrial – bulk feeding and extrusion
TIPPED CARPETS Post-consumer identification REJECT Yes RUG? WOVEN? No BACKING - JUTE? Yes Yes No No REJECT REJECT FOR NIR SORTING No PILE - PP? REJECT Yes No Yes PRODUCT BACKING - PP? REJECT
Size reduction and screening of post-consumer carpet • Granulator sizes; 10, 15 and 20mm • Screen sizes; 2, 4, 5.6, 8 and 11.2mm • 80% yield when granulate at 20mm and screen at 2mm • Work is currently ongoing • Next stages include aggressive screening and air classification
Post-industrial recovery • Baled post-industrial carpet • 1.2m x 0.5m strips • Tufted, PP with small contamination of PET Extrusion Shredding Feed extruder
Size reduction and feeding the extruder • 4 shaft shredder used with 25mm screen • Approximately 150 kg/h • Small particle size = easier to extrude • Material ‘fluffs-up’ once shredded • Caused bridging inside the feed hopper of extruder
Solutions • Increased shredder screen size • Compact material before extrusion within hopper • Pelletising mills Increased operating costs
Extrusion • Extruded material was weak when transferring to pelletiser Possible cause: • Blowing within the extruder • Vacuum extraction should improve this
Trial results • Few surface defects • Physical properties match lab scale trial
Trial conclusions and next steps • Successful recovery of PP at large scale • Closely matches lab scale results • Potential feedstock for injection moulding Next steps: • Compact material in feed hopper • Pelletise fibre prior to extrusion • Vacuum extraction during extrusion
Axion Consulting Tudor House Meadway Bramhall SK2 2DG 0161 426 7731 info@axionconsulting.co.uk