Editing Recycling (section)

=== Plastic recycling ===
{{Main|Plastic recycling}}

[[File:Spoon recycling 3d printing.jpg|thumb|upright|A container for recycling used plastic spoons into material for [[3D printing]]]]

Plastic recycling is the process of recovering scrap or waste plastic and reprocessing the material into useful products, sometimes completely different in form from their original state. For instance, this could mean melting down soft drink bottles and then casting them as plastic chairs and tables.<ref>{{cite web |last = Layton |first = Julia |url = http://science.howstuffworks.com/environmental/green-tech/sustainable/eco-plastic1.htm |title = "Eco"-plastic: recycled plastic |publisher = Science.howstuffworks.com |date = 22 April 2009 |access-date = 9 June 2014 |archive-date = 27 May 2020 |archive-url = https://web.archive.org/web/20200527085737/https://science.howstuffworks.com/environmental/green-tech/sustainable/eco-plastic1.htm |url-status = live }}</ref> For some types of plastic, the same piece of plastic can only be recycled about 2–3 times before its quality decreases to the point where it can no longer be used.<ref name="NG" />

==== Physical recycling ====
Some plastics are remelted to form new plastic objects; for example, PET water bottles can be converted into polyester destined for clothing. A disadvantage of this type of recycling is that the molecular weight of the polymer can change further and the levels of unwanted substances in the plastic can increase with each remelt.<ref name="SilvaGouveia2019">{{cite book | author1 = Francisco José Gomes da Silva | author2 = Ronny Miguel Gouveia | date = 18 July 2019 | title = Cleaner Production: Toward a Better Future | publisher = Springer | page = 180 | isbn = 978-3-03-023165-1 | url = https://books.google.com/books?id=ouijDwAAQBAJ | access-date = 30 August 2022 | archive-date = 20 February 2023 | archive-url = https://web.archive.org/web/20230220183216/https://books.google.com/books?id=ouijDwAAQBAJ | url-status = live }}</ref><ref name="LongScheirs2005">{{cite book | author1 = Timothy E. Long | author2 = John Scheirs | date = 1 September 2005 | title = Modern Polyesters: Chemistry and Technology of Polyesters and Copolyesters | publisher = John Wiley & Sons | page = 459 | isbn = 978-0-470-09067-1 | url = https://books.google.com/books?id=ZgxgZ5vfxTkC | access-date = 30 August 2022 | archive-date = 20 February 2023 | archive-url = https://web.archive.org/web/20230220183215/https://books.google.com/books?id=ZgxgZ5vfxTkC | url-status = live }}</ref>

A commercial-built recycling facility was sent to the [[International Space Station]] in late 2019. The facility takes in [[plastic waste]] and unneeded plastic parts and physically converts them into spools of feedstock for the space station [[additive manufacturing]] facility used for in-space [[3D printing]].<ref name=sn20191021>{{cite news |last=Werner |first=Debra |url=https://spacenews.com/made-in-space-to-launch-commercial-recycler-to-space-station/ |title=Made in Space to launch commercial recycler to space station |work=[[SpaceNews]] |date=21 October 2019 |access-date=22 October 2019 |archive-date=20 February 2023 |archive-url=https://web.archive.org/web/20230220183223/https://spacenews.com/made-in-space-to-launch-commercial-recycler-to-space-station/ |url-status=live }}</ref>

==== Chemical recycling ====
For some polymers, it is possible to convert them back into monomers, for example, PET can be treated with an alcohol and a catalyst to form a dialkyl terephthalate. The terephthalate diester can be used with ethylene glycol to form a new polyester polymer, thus making it possible to use the pure polymer again. In 2019, [[Eastman Chemical Company]] announced initiatives of [[Transesterification|methanolysis]] and [[syngas]] designed to handle a greater variety of used material.<ref>{{Cite web|url=https://www.greenbiz.com/article/eastman-advances-two-chemical-recycling-options|title=Eastman advances two chemical recycling options|last=Siegel|first=R. P.|date=7 August 2019|website=GreenBiz|language=en|access-date=29 August 2019|archive-date=29 August 2019|archive-url=https://web.archive.org/web/20190829070614/https://www.greenbiz.com/article/eastman-advances-two-chemical-recycling-options|url-status=live}}</ref>

==== Waste plastic pyrolysis to fuel oil ====
Another process involves the conversion of assorted polymers into petroleum by a much less precise thermal [[depolymerization]] process. Such a process would be able to accept almost any polymer or mix of polymers, including [[thermoset]] materials such as vulcanized rubber tires and the [[biopolymer]]s in feathers and other agricultural waste. Like natural petroleum, the chemicals produced can be used as fuels or as feedstock. A RESEM Technology<ref>{{cite web |title = RESEM A Leading Pyrolysis Plant Manufacturer |url = http://www.pyrolysisoil.net |publisher = RESEM Pyrolysis Plant |access-date = 20 August 2012 |archive-url = https://web.archive.org/web/20130218171416/http://www.pyrolysisoil.net/ |archive-date = 18 February 2013 |url-status = dead }}</ref> plant of this type in [[Carthage, Missouri]], US, uses turkey waste as input material. Gasification is a similar process but is not technically recycling since polymers are not likely to become the result.
Plastic Pyrolysis can convert petroleum based waste streams such as plastics into quality fuels, carbons. Given below is the list of suitable plastic raw materials for [[pyrolysis]]:
* Mixed plastic ([[HDPE]], [[LDPE]], [[polyethylene|PE]], [[polypropylene|PP]], [[Nylon]], [[Teflon]], [[polystyrene|PS]], [[ABS plastic|ABS]], [[Fibre-reinforced plastic|FRP]], [[Polyethylene terephthalate|PET]] etc.)
* Mixed waste plastic from waste paper mill
* Multi-layered plastic