Lesson 1Dewatering and drying methods: centrifuges, thermal dryers, vacuum, target moisture levels prior to extrusionFocuses on dewatering and drying of washed flakes before extrusion. Compares centrifuges, mechanical dewatering, thermal and vacuum dryers, and defines target moisture levels for different polymers to prevent hydrolysis, voids, and processing instability.
Mechanical dewatering: screw presses and centrifugesThermal dryers: hot air, infrared, and contact typesVacuum drying for hygroscopic polymers like PETTarget moisture levels for PET, PA, and othersEnergy optimization and dryer performance controlLesson 2Solid-state cleaning and post-extrusion steps: melt filtration, solid-state polycondensation (SSP) for IV recovery in PETCovers post-extrusion steps for high-performance recyclates, including melt filtration polishing, pellet cooling, and solid-state polycondensation for PET IV recovery. Explains process conditions, quality control, and regulatory considerations for food-contact use.
Melt filtration polishing and fine contaminant removalStrand and underwater pelletizing system choicesSolid-state polycondensation principles for PETIV monitoring, residence time, and temperatureFood-contact compliance and decontamination testsLesson 3Separation and density-based processes: float-sink tanks, hydrocyclones, specific gravity windows for PET/PE separationExplains density-based separation used in recycling, including float-sink tanks and hydrocyclones. Describes specific gravity windows for common polymers, process water conditioning, and how operating parameters affect separation sharpness and yield.
Principles of density separation in water mediaFloat-sink tank design and operating parametersHydrocyclone configuration and cut-point controlSpecific gravity windows for PET, PE, and PPWater chemistry, surfactants, and contaminationLesson 4Reception and pre-sorting: manual sorting, trommels, ballistic separators, size and throughput considerationsIntroduces reception and pre-sorting of incoming plastic waste. Covers feed inspection, manual picking, trommels, and ballistic separators, with emphasis on removing non-conformities, managing throughput, and preparing a stable feed for automated sorting.
Incoming load inspection and quality checksManual sorting stations and ergonomicsTrommel screens for size classificationBallistic separators for 2D and 3D separationBalancing throughput, staffing, and safetyLesson 5Reject handling and residue processing: contaminants, fines, wastewater solids, and safe disposal or valorization optionsCovers handling of rejects and residues from sorting, washing, and extrusion. Addresses typical contaminants, fines, and wastewater solids, with options for safe disposal, energy recovery, or material valorisation while meeting environmental and regulatory requirements.
Typical contaminants and off-spec plastic streamsCollection and treatment of fines and dustWastewater solids thickening and dewateringSafe landfill, co-processing, and incineration routesValorization options: RDF, co-processing, and reuseLesson 6Sizing and shredder options: coarse shredding, granulators, knife mills, particle size targets and energy useDetails size reduction strategies from coarse shredding to fine granulation. Explains equipment types, rotor and knife configurations, and how particle size targets, throughput, and energy consumption influence downstream washing, drying, and extrusion performance.
Coarse shredders for bulky plastic feedstocksGranulator design, rotor types, and screen selectionKnife mill applications and wear managementParticle size targets for film, rigid, and fiberEnergy use, throughput, and maintenance trade-offsLesson 7Automated sorting technologies: NIR, VIS cameras, float-sink, eddy current, X-ray and typical sorting efficienciesDescribes automated sorting technologies used in plastic recycling, including NIR and VIS systems, float-sink, eddy current, and X-ray. Reviews typical sorting efficiencies, limitations, and how system design affects purity, yield, and operating costs.
NIR sorting for polymer type identificationVIS cameras for color and label detectionEddy current separators for non-ferrous metalsX-ray systems for PVC and metal contaminationSorting efficiency, purity, and yield metricsLesson 8Washing and cleaning stages: hot-wash, counter-current washers, caustic washes, surfactant use, temperatures and residence timesDetails washing and cleaning stages for plastic flakes, including pre-wash, hot-wash, caustic and surfactant systems. Discusses temperature, residence time, mechanical action, and how process design removes labels, adhesives, and organic residues.
Pre-wash and friction washer configurationsHot-wash conditions for label and glue removalCaustic washing chemistry and controlSurfactant selection and foaming managementResidence time, agitation, and soil loadingLesson 9Compounding and additive dosing: stabilizers, odor absorbers, impact modifiers, dosing system considerationsExamines compounding of recycled plastics, focusing on stabilisers, odour control, impact modifiers, and colourants. Discusses dosing technologies, feeding accuracy, dispersion quality, and how additive packages are tailored to target applications and regulatory limits.
Thermal and UV stabilizers for recycled resinsOdor absorbers and deodorization approachesImpact modifiers and toughness enhancementColor masterbatches and pigment selectionGravimetric and volumetric dosing system designLesson 10Extrusion, filtration and degassing: single-screw vs twin-screw, melt filtration (screen changers, pore sizes), melt temperature rangesExplores extrusion in mechanical recycling, comparing single-screw and twin-screw designs, melt temperature control, and degassing. Covers melt filtration hardware, pore size selection, and how these factors influence contaminant removal and pellet quality.
Single-screw extruder design and operating windowsTwin-screw extruders for compounding and devolatilizationMelt temperature control and residence time effectsMelt filtration hardware, screen changers, pore sizesVacuum degassing, vent design, and volatile removal
