Editing Graphite (section)

== Types and varieties ==
Graphite can occur naturally or be produced synthetically. Natural graphite is obtained from naturally occurring geologic deposits and synthetic graphite is produced through human activity.<ref name="USGS_PP1802J"/><ref name="BanekEtAl_GR1">{{cite journal|vauthors=Banek NA, Abele DT, McKenzie, Jr KR, Wagner MJ|date=2018|title=Sustainable Conversion of Lignocellulose to High-Purity, Highly Crystalline Flake Potato Graphite|url=https://doi.org/10.1021/acssuschemeng.8b02799|journal=ACS Sustainable Chemistry and Engineering|volume=6|issue=10|pages=13199–13207|doi=10.1021/acssuschemeng.8b02799}}</ref>

=== Natural ===
Graphite occurs naturally in [[ore]]s that can be classified as either ''amorphous'' (microcrystalline) or ''crystalline'' (flake or lump/chip) which is determined by the ore [[Polymorphism (materials science)|morphology]], [[crystallinity]], and [[grain size]].<ref name="USGS_PP1802J"/> All naturally occurring graphite deposits are formed from the [[metamorphism]] of [[carbonaceous]] [[sedimentary rocks]], and the ore type is due to its geologic setting. [[Coal]] that has been thermally metamorphosed is the typical source of amorphous graphite. Crystalline flake graphite is mined from [[carbonaceous]] [[metamorphic rocks]], while lump or chip graphite is mined from veins which occur in high-grade [[metamorphic]] regions.<ref name="USGS_PP1802J"/> There are serious negative environmental impacts to graphite mining.

=== Synthetic===
Synthetic graphite has high purity and is usually produced by the thermal [[graphitization]] of [[hydrocarbon]] materials at temperatures in excess of 2,100&nbsp;°C, most commonly through the [[Acheson process]].<ref name="USGS_PP1802J"/><ref name="Acheson_1906">{{cite patent |country=US |number=836355 |title=Production of Graphite |pubdate=1906-11-20 |fdate=1906-10-22 |inventor=Acheson, E. G.}}</ref> The high temperatures are maintained for weeks, and are required not only to form the graphite from the precursor carbons but also to [[vaporize]] any impurities that may be present, including hydrogen, nitrogen, sulfur, organics, and metals.<ref name="USGS_PP1802J"/> The resulting synthetic graphite is highly pure{{emdash}}in excess of 99.9% C purity{{emdash}}but typically has lower density, conductivity and a higher porosity than its natural equivalent.<ref name="USGS_PP1802J"/> Synthetic graphite can be formed into very large (centimeter-scale) flakes while maintaining its high purity, unlike almost all sources of natural graphite.<ref name="USGS_PP1802J"/> Synthetic graphite can also be formed by other methods including by [[chemical vapor deposition]] from hydrocarbons at temperatures above {{convert|2500|K|C}}, by decomposition of thermally unstable [[carbide]]s, or by [[crystallization]] from metal melts [[supersaturated]] with [[carbon]].<ref>{{cite book |doi=10.1016/B978-008044463-5/50023-6 |chapter=Production and Reference Material |title=Activated Carbon |date=2006 |last1=Marsh |first1=Harry |last2=Rodríguez-Reinoso |first2=Francisco |pages=454–508 |isbn=978-0-08-044463-5 }}</ref>

=== Research ===
Research and development efforts continue into new methods for the industrial production of graphite for a variety of applications, including [[lithium-ion batteries]], refractories, and foundries, among others. Significant work has been done on graphitizing of traditionally non-graphitizable carbons. A company in [[New Zealand]] utilizes forestry waste to produce what they have termed 'biographite' through a process referred to as thermo-catalytic [[graphitization]].<ref>{{Cite web|url=https://www.euronews.com/green/2024/02/26/cars-powered-by-woodchips-biographite-makes-ev-batteries-sustainable|title=Batteries made from woodchips could clean up the EV industry|date=February 26, 2024|website=euronews}}</ref><ref>{{Cite web|url=https://www.batterytechonline.com/materials/carbonscape-s-renewable-biographite-anode-material-ready-to-scale|title=CarbonScape Renewable Biographite Anode Material Ready to Scale|website=www.batterytechonline.com}}</ref> Another group in the [[United States]] uses a method referred to as [[photocatalytic]] graphitization to produce highly crystalline highly pure graphite for lithium-ion batteries and other applications from a variety of carbon sources.<ref name="BanekEtAl_GR1"/><ref name="BanekEtAl_GR2">{{cite journal|vauthors=Banek NA, McKenzie, Jr KR, Abele DT, Wagner MJ |date= 2022 |title=Sustainable conversion of biomass to rationally designed lithium-ion battery graphite |url=https://doi.org/10.1038/s41598-022-11853-x |journal=Scientific Reports|volume= 12 |issue= 1 |page= 8080 |doi= 10.1038/s41598-022-11853-x |pmid= 35577817 |bibcode= 2022NatSR..12.8080B |pmc= 9110727 }}</ref>