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2026 Vol.63, Issue 2 Preview Page

General Remarks

Mechanical Recycling of Plastic Waste: Recent Trends and Applicability

폐플라스틱 기계적 재활용 공정 기술의 동향과 적용성 고찰

Hansol Lee1
,
Hoon Lee12*
이 한솔1
,
이 훈12*
1Mineral Processing & Metallurgy Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon, Korea
2KIGAM School, University of Science & Technology, Daejeon, Korea
1한국지질자원연구원 자원회수연구센터
2과학가술연합대학원대학교 KIGAM스쿨
*Corresponding Author
30 April 2026. pp. 259-276
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Abstract

The rapid increase in global plastic consumption has made the sustainable management of plastic waste a critical challenge across industrial and environmental sectors. In response to growing demands for carbon neutrality and resource circularity, mechanical recycling has emerged as a practical and readily deployable strategy. Mechanical recycling typically consists of sequential physical processes—collection, sorting, size reduction, washing, drying, and pelletizing—requiring tailored technological solutions due to the diversity of polymer types, complex multilayer structures, and varying contamination levels in plastic waste streams. To address these challenges, both industry and academia have developed approaches incorporating automated optical and artificial intelligence (AI)-based sorting technologies, material- and structure-dependent comminution mechanisms, advanced washing and drying processes, and strategies to mitigate polymer degradation during reprocessing. This review systematically summarizes recent technological developments across the mechanical recycling chain and highlights key considerations and future directions for improving process efficiency and securing high-quality recycled feedstock.

Keywords
plastics waste
sorting
comminution
washing·drying
pelletizing

전 세계적인 플라스틱 사용량 증가는 폐플라스틱의 지속 가능한 처리를 산업·환경 분야의 핵심 과제로 부상시키고 있으며, 탄소 중립과 자원 순환 요구가 높아진 현 시점에서 기계적 재활용은 가장 현실적이고 즉각적인 대응 전략으로 평가된다. 기계적 재활용은 일반적으로 수거–선별–파·분쇄–세척–건조–펠릿화로 이어지는 일련의 물리적 처리 공정으로 구성되며, 각 단계는 재질의 다양성, 복합 구조, 오염 특성 등 실제 폐플라스틱이 지닌 복잡성에 따라 상이한 기술적 대응을 필요로 한다. 이러한 요구를 충족하기 위해 산업계와 학계에서는 자동화 기반 선별 기술, 재질·구조 특성을 반영한 파·분쇄 메커니즘, 고도화된 세척·건조 공정, 열화 억제를 위한 물성 안정화 기술 등 다양한 기술적 접근방식이 발전해 왔다. 본 총설은 기계적 재활용 전 공정의 최신 기술 동향을 체계적으로 정리하고, 각 단계별 핵심 고려 요소와 발전 방향을 제시함으로써 고품질 재생원료 확보와 재활용 공정 효율 향상을 위한 통합적 관점을 제시하고자 한다.

키워드
폐플라스틱
선별
파·분쇄
세척·건조
펠릿화
References
1

Alade, J. and Bada, S.O., 2023. Wind-sifting separation: a review, ACS omega, 8(38), p.34196-34205.

10.1021/acsomega.3c0108737780006PMC10536854
2

Ali, H., Kim, K.W., Bang, S.G., Chae, H.B., Shin, S.W., and Park, C.W., 2018. Numerical Analysis to Improve the Ballistic Trajectory of an Air-Based Material Density Separator System, Applied Sciences, 8(3), p.359.

10.3390/app8030359
3

Alrazen, H.A., Aminossadati, S.M., Mahmood, H.A., Hussein, A.K., Ahmad, K.A., Dol, S.S., Jabbar, S., Algayyim, S.J.M., Konarova, M., and Fattah, I., 2025. A review of the pathways, limitations, and perspectives of plastic waste recycling, Materials for Renewable and Sustainable Energy, 14(3), p.50.

10.1007/s40243-025-00328-4
4

Altieri, V.G., De Sanctis, M., Sgherza, D., Pentassuglia, S., Barca, E., and Di Iaconi, C., 2021. Treating and reusing wastewater generated by the washing operations in the non-hazardous plastic solid waste recycling process: Advanced method vs. conventional method, Journal of Environmental Management, 284(112011), p.1-11.

10.1016/j.jenvman.2021.112011
5

ASTM International, 2006. Standard Guide for Waste Reduction, Resource Recovery, and Use of Recycled Polymeric Materials and Products, ASTM D7209-06, West Conshohocken, PA.

6

Awaja, F. and Pavel, D., 2005. Recycling of PET, European Polymer Journal, 41(7), p.1453-1477.

10.1016/j.eurpolymj.2005.02.005
7

Awe, D.V., Asafa, T.B., Adeniran, T.A., Ohenhen, P.E., Alao, V.A., and Balogun, O.A., 2024. Development and performance evaluation of a mini plastic crushing machine, World Journal of Advanced Research and Reviews, 22(1), p.591-602.

10.30574/wjarr.2024.22.1.1126
8

Bauer, M., Lehner, M., Schwabl, D., Flachberger, H., Kranzinger, L., Pomberger, R., and Hofer, W., 2018. Sink-float density separation of post-consumer plastics for feedstock recycling, Journal of Material Cycles and Waste Management, 20(3), p.1781-1791.

10.1007/s10163-018-0748-z
9

Becker, W., Sachsenheimer, K., and Klemenz, M., 2017. Detection of black plastics in the middle infrared spectrum (MIR) using photon up-conversion technique for polymer recycling purposes, Polymers, 9(9), p.435.

10.3390/polym909043530965736PMC6418689
10

Berkane, I., Aracil, I., and Fullana, A., 2023. Evaluation of thermal drying for the recycling of flexible plastics, Waste Management, 168, p.116-125.

10.1016/j.wasman.2023.05.054
11

Bobulski, J. and Kubanek, M., 2021. Deep learning for plastic waste classification system, Applied Computational Intelligence and Soft Computing, 2021(1), p.1-7.

10.1155/2021/6626948
12

Campos, G., Morales, F., Alonso, Y., Costantino, A., and Pettarin, V., 2025. Beyond processing methods: the impact of the drying technique on PET performance, Discover Polymers, 2(1), p.1.

10.1007/s44347-025-00013-9
13

Damayanti, D., Saputri, D.R., Marpaung, D.S.S., Yusupandi, F., Sanjaya, A., Simbolon, Y.M., Asmarani, W., Ulfa, M., and Wu, H.-S., 2022. Current prospects for plastic waste treatment, Polymers, 14(15), p.1-29.

10.3390/polym1415313335956648PMC9370925
14

David, A. and Joel, O.O., 2018. Design and construction of a plastic shredder machine for recycling and management of plastic wastes, International Journal of Scientific & Engineering Research, 9(5), p.1379-1385.

15

Dodbiba, G., Shibayama, A., Sadaki, J., and Fujita, T., 2003. Combination of triboelectrostatic separation and air tabling for sorting plastics from a multi-component plastic mixture, Materials Transactions, 44(12), p.2427-2435.

10.2320/matertrans.44.2427
16

Fu, S., Hua, W., Yuan, H., Ling, J., and Shi, Q., 2019. Study on the light medium separation of waste plastics with hydrocyclones, Waste Management, 91, p.54-61.

10.1016/j.wasman.2019.04.043
17

Gent, M.R., Menendez, M., Toraño, J., and Diego, I., 2009. Recycling of plastic waste by density separation: prospects for optimization, Waste Management & Research, 27(2), p.175-187.

10.1177/0734242X08096950
18

Gente, V., La Marca, F., Lucci, F., Massacci, P., and Pani, E., 2004. Cryo-comminution of plastic waste, Waste Management, 24(7), p.663-672.

10.1016/j.wasman.2004.03.005
19

Gu, F., Guo, J., Zhang, W., Summers, P.A., and Hall, P., 2017. From waste plastics to industrial raw materials: A life cycle assessment of mechanical plastic recycling practice based on a real-world case study, Science of the Total Environment, 601, p.1192-1207.

10.1016/j.scitotenv.2017.05.278
20

Hopewell, J., Dvorak, R., and Kosior, E., 2009. Plastics recycling: challenges and opportunities, Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1526), p.2115-2126.

10.1098/rstb.2008.031119528059PMC2873020
21

Ikpe, A.E. and Ikechukwu, O., 2017. Design of used PET bottles crushing machine for small scale industrial applications, International Journal of Engineering Technologies IJET, 3(3), p.157-168.

10.19072/ijet.327166
22

Jekel, L. and Tam, E., 2007. Plastics waste processing: comminution size distribution and prediction, Journal of Environmental Engineering, 133(2), p.245-254.

10.1061/(ASCE)0733-9372(2007)133:2(245)
23

Karpenko, M., Ževžikov, P., Stosiak, M., Skačkauskas, P., Borucka, A., and Delembovskyi, M., 2024. Vibration research on centrifugal loop dryer machines used in plastic recycling processes, Machines, 12(1), p.29.

10.3390/machines12010029
24

Kokate, D., Kale, D., Korpale, V., Shinde, Y., Panse, S., Deshmukh, S., and Pandit, A., 2014. Energy conservation through solar energy assisted dryer for plastic processing industry, Energy Procedia, 54, p.376-388.

10.1016/j.egypro.2014.07.281
25

Lee, H., Park, Y., Kim, K., and Lee, H., 2025. Development of a deep learning-based object recognition system for pre-stage separation to improve the recycling rate of major general-purpose plastics, Separation Science and Technology, 60(1), p.121-132.

10.1080/01496395.2024.2418289
26

Li, J., Wu, G., and Xu, Z., 2015. Tribo-charging properties of waste plastic granules in process of tribo-electrostatic separation, Waste Management, 35, p.36-41.

10.1016/j.wasman.2014.10.001
27

Lubongo, C. and Alexandridis, P., 2022. Assessment of performance and challenges in use of commercial automated sorting technology for plastic waste, Recycling, 7(2), p.11.

10.3390/recycling7020011
28

Maisel, F., Chancerel, P., Dimitrova, G., Emmerich, J., Nissen, N.F., and Schneider-Ramelow, M., 2020. Preparing WEEE plastics for recycling-How optimal particle sizes in pre-processing can improve the separation efficiency of high quality plastics, Resources, Conservation and Recycling, 154(104619) p.1-10.

10.1016/j.resconrec.2019.104619
29

Masoumi, H., Safavi, S.M., and Khani, Z., 2012. Identification and classification of plastic resins using near infrared reflectance, International Journal of Mechanical and Industrial Engineering, 6, p.213-220.

30

Meneses Quelal, W.O., Velázquez-Martí, B., and Ferrer Gisbert, A., 2022. Separation of virgin plastic polymers and post-consumer mixed plastic waste by sinking-flotation technique, Environmental Science and Pollution Research, 29(1), p.1364-1374.

10.1007/s11356-021-15611-w34350580PMC8724085
31

Mi, D., Wang, Y., Kuzmanovic, M., Delva, L., Jiang, Y., Cardon, L., Zhang, J., and Ragaert, K., 2019. Effects of phase morphology on mechanical properties: oriented/unoriented PP crystal combination with spherical/microfibrillar PET phase, Polymers, 11(2), p.248.

10.3390/polym1102024830960231PMC6419086
32

Möllnitz, S., Khodier, K., Pomberger, R., and Sarc, R., 2020. Grain size dependent distribution of different plastic types in coarse shredded mixed commercial and municipal waste, Waste Management, 103, p.388-398.

10.1016/j.wasman.2019.12.037
33

Molnar, B. and Ronkay, F., 2019. Effect of solid-state polycondensation on crystalline structure and mechanical properties of recycled polyethylene-terephthalate, Polymer Bulletin, 76(5), p.2387-2398.

10.1007/s00289-018-2504-x
34

Mustafa, D., 2023. Optimization of Drying Process of Plastic Granules Based on Stochastic Method with Neuro Regression Approach, MS Thesis, Izmir Katip Celebi University, Türkiye, 95p.

35

Negoro, T., Thodsaratpreeyakul, W., Takada, Y., Thumsorn, S., Inoya, H., and Hamada, H., 2016. Role of crystallinity on moisture absorption and mechanical performance of recycled PET compounds, Energy Procedia, 89, p.323-327.

10.1016/j.egypro.2016.05.042
36

Neo, E.R.K., Yeo, Z., Low, J.S.C., Goodship, V., and Debattista, K., 2022. A review on chemometric techniques with infrared, Raman and laser-induced breakdown spectroscopy for sorting plastic waste in the recycling industry, Resources, Conservation and Recycling, 180(106217), p.1-15.

10.1016/j.resconrec.2022.106217
37

Niaounakis, M., 2019. Recycling of biopolymers-the patent perspective, European Polymer Journal, 114, p.464-475.

10.1016/j.eurpolymj.2019.02.027
38

Nordahl, S.L., Baral, N.R., Helms, B.A., and Scown, C.D., 2023. Complementary roles for mechanical and solvent-based recycling in low-carbon, circular polypropylene, Proceedings of the National Academy of Sciences, 120(46), p.1-8.

10.1073/pnas.230690212037934823PMC10655212
39

OECD. 2022. Global plastics outlook: Economic drivers, Environmental Impacts and Policy Options. OECD Publishing.

40

Okubo, H., Kaneyasu, H., Kimura, T., Phanthong, P., and Yao, S., 2021. Effects of a twin-screw extruder equipped with a molten resin reservoir on the mechanical properties and microstructure of recycled waste plastic polyethylene pellet moldings, Polymers, 13(7), p.1-11.

10.3390/polym1307105833801778PMC8037719
41

Okusanya, M.A., Ogunlade, C.B., and Oluwagbayıde, S.D., 2023. Development and Performance Evaluation of Double Shaft Plastic Bottle Crusher for Small Scale Industrial Application, Turkish Journal of Agricultural Engineering Research, 4(2), p.151-177.

10.46592/turkager.1260521
42

Oliver Wyman Energy and Natural Resources Journal, 2026.01.02., https://www.oliverwyman.com/our-expertise/journals/energy-and-natural-resources-journal/2024/the-industry-that-created-plastic-may-fix-its-waste-problem.html

43

Park, C.-H., Jeon, H.-S., Yu, H.-S., Han, O.-H., and Park, J.-K., 2008a. Application of electrostatic separation to the recycling of plastic wastes: separation of PVC, PET, and ABS, Environmental Science & Technology, 42(1), p.249-255.

10.1021/es070698h
44

Park, C.H., Park, J.K., Jeon, H.S., and Chun, B.C., 2008b. Triboelectric series and charging properties of plastics using the designed vertical-reciprocation charger, Journal of Electrostatics, 66(11-12), p.578-583.

10.1016/j.elstat.2008.07.001
45

Pongstabodee, S., Kunachitpimol, N., and Damronglerd, S., 2008. Combination of three-stage sink-float method and selective flotation technique for separation of mixed post-consumer plastic waste, Waste Management, 28(3), p.475-483.

10.1016/j.wasman.2007.03.005
46

Richard, G.M., Mario, M., Javier, T., and Susana, T., 2011. Optimization of the recovery of plastics for recycling by density media separation cyclones, Resources, Conservation and Recycling, 55(4), p.472-482.

10.1016/j.resconrec.2010.12.010
47

Rojek, I., Macko, M., and Mikołajewski, D., 2024. Machine Learning in the Analysis of the Mechanical Shredding Process of Polymer Recyclates, Polymers, 16(13), p.1852.

10.3390/polym1613185239000709PMC11244512
48

Roosen, M., De Somer, T., Demets, R., Ügdüler, S., Meesseman, V., Van Gorp, B., Ragaert, K., Van Geem, K.M., Walgraeve, C., and Dumoulin, A., 2021. Towards a better understanding of odor removal from post-consumer plastic film waste: A kinetic study on deodorization efficiencies with different washing media, Waste Management, 120, p.564-575.

10.1016/j.wasman.2020.10.021
49

Roosen, M., Harinck, L., Ügdüler, S., De Somer, T., Hucks, A.-G., Belé, T.G., Buettner, A., Ragaert, K., Van Geem, K.M., and Dumoulin, A., 2022. Deodorization of post-consumer plastic waste fractions: a comparison of different washing media, Science of The Total Environment, 812(152467), p.1-11.

10.1016/j.scitotenv.2021.152467
50

Ruj, B., Pandey, V., Jash, P., and Srivastava, V., 2015. Sorting of plastic waste for effective recycling, International Journal of Applied Sciences and Engineering Research, 4(4), p.564-571.

51

Serebryanyk, A., Zisler, M., and Schnörr, C., 2018. Generic Paper and Plastic Recognition by Fusion of NIR and VIS Data and Redundancy-Aware Feature Ranking, Proceedings of the Future Technologies Conference, p.30-45.

10.1007/978-3-030-02686-8_3
52

Signoret, C., Caro-Bretelle, A.-S., Lopez-Cuesta, J.-M., Ienny, P., and Perrin, D., 2019. MIR spectral characterization of plastic to enable discrimination in an industrial recycling context: I. Specific case of styrenic polymers, Waste Management, 95, p.513-525.

10.1016/j.wasman.2019.05.050
53

Skoczinski, P., Carus, M., Tweddle, G., Ruiz, P., de Guzman, D., Ravenstijn, J., Käb, H., Hark, N., Dammer, L., and Raschka, A., 2023. Bio-based building blocks and polymers: global capacities, production and trends 2022-2027, Industrial Biotechnology, 19(4), p.185-194.

10.52548/CMZD8323
54

Stavinski, N., Maheshkar, V., Thomas, S., Dantu, K., and Velarde, L., 2023. Mid-infrared spectroscopy and machine learning for postconsumer plastics recycling, Environmental Science: Advances, 2(8), p.1099-1109.

10.1039/D3VA00111C
55

Stegmann, P., Daioglou, V., Londo, M., van Vuuren, D.P., and Junginger, M., 2022. Plastic futures and their CO2 emissions, Nature, 612(7939), p.272-276.

10.1038/s41586-022-05422-5
56

Tamin, O., Moung, E.G., Dargham, J.A., Yahya, F., and Omatu, S., 2023. A review of hyperspectral imaging-based plastic waste detection state-of-the-arts, International Journal of Electrical and Computer Engineering (IJECE), 13(3), p.3407-3419.

10.11591/ijece.v13i3.pp3407-3419
57

Valente, C., Tellnes, L.G., and Callewaert, P., 2021. Waste 2 Power (W2P) - high value energy recovery of plastic waste, OR 46.21, Krakerøy, Norway, 30p.

58

van den Brink, P., Bontekoe, S., Genuino, H.C., and van Eijk, M.C., 2025. Quantification of moisture in household plastic packaging waste using near-infrared hyperspectral imaging (NIR-HSI), Clean Technologies and Recycling, 5(1), p.44-63.

10.3934/ctr.2025003
59

Vírseda, I.B., Beltrán, F., De la Orden, M., and Urreaga, J.M., 2024. Effects of solid-state polymerization on the structure and properties of degraded poly (3-hydroxybutyrate-co-3-hydroxyvalerate), Polymer Degradation and Stability, 220(110630), p.1-11.

10.1016/j.polymdegradstab.2023.110630
60

Xia, D. and Zhang, F.-S., 2018. A novel dry cleaning system for contaminated waste plastic purification in gas-solid media, Journal of Cleaner Production, 171, p.1472-1480.

10.1016/j.jclepro.2017.10.028
61

Xiong, X., Zhou, S., Liang, Q., Ren, G., Zhang, Y., Li, S., Qu, Z., Ren, X., and Wang, J., 2025. Application of AI in the whole process of WEEE recycling and reuse, Environment, Development and Sustainability, p.1-오늘은44.

10.1007/s10668-024-05955-x
62

Zheng, Y., Bai, J., Xu, J., Li, X., and Zhang, Y., 2018. A discrimination model in waste plastics sorting using NIR hyperspectral imaging system, Waste Management, 72, p.87-98.

10.1016/j.wasman.2017.10.015
63

Zimniak, J., 2010. Importance of comminution in plastics processing, Journal of Polish CIMAC, 5(3), p.257-265.

Information
  • Publisher :The Korean Society of Mineral and Energy Resources Engineers
  • Publisher(Ko) :한국자원공학회
  • Journal Title :Journal of the Korean Society of Mineral and Energy Resources Engineers
  • Journal Title(Ko) :한국자원공학회지
  • Volume : 63
  • No :2
  • Pages :259-276
  • Received Date : 2025-12-15
  • Revised Date : 2026-01-02
  • Accepted Date : 2026-01-05
  • DOI :https://doi.org/10.32390/ksmer.2026.63.2.259
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