Lesson 1Dewatering and drying methods: centrifuges, thermal dryers, vacuum, target moisture levels prior to extrusionFocuses on removing water and drying washed flakes before melting. Compares centrifuges, mechanical water removal, heat and vacuum dryers, and sets target moisture for different plastics to avoid breakdown, gaps, and process issues.
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 steps after melting for top recyclates, including melt filtering, pellet cooling, and solid-state rebuilding for PET strength recovery. Explains conditions, quality checks, and rules 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 separation in recycling, including float-sink tanks and hydrocyclones. Describes gravity ranges for common plastics, water prep, and how settings affect separation quality and output.
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 receiving and early sorting of plastic waste. Covers feed checks, hand picking, trommels, and ballistic separators, stressing removal of bad items, handling volume, and prepping steady feed for auto 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 dealing with rejects and leftovers from sorting, washing, and melting. Addresses usual dirt, fines, and wastewater solids, with safe disposal, energy recovery, or reuse options meeting environment and rule needs.
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 cutting from rough shredding to fine granulating. Explains machine types, rotor and blade setups, and how size goals, volume, and energy use affect later washing, drying, and melting 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 auto sorting tech in plastic recycling, including NIR and VIS systems, float-sink, eddy current, and X-ray. Reviews usual efficiencies, limits, and how design affects purity, output, and running 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 for plastic flakes, including pre-wash, hot-wash, caustic and soap systems. Discusses heat, stay time, mechanical action, and how setup removes labels, glues, and organic leftovers.
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 mixing recycled plastics, focusing on stabilisers, smell control, strength boosters, and colourants. Discusses dosing tech, feed accuracy, mixing quality, and how additive mixes fit target uses and rule 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 melting in mechanical recycling, comparing single and twin screw designs, melt heat control, and air removal. Covers melt filter gear, pore size choice, and how these affect dirt 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
