Editing Graphite (section)

==Uses==
Natural graphite is mostly used for refractories, batteries, steelmaking, expanded graphite, brake linings, foundry facings, and lubricants.<ref name=usgs/>

===Refractories===
The use of graphite as a [[refractory]] (heat-resistant) material began before 1900 with graphite [[crucible]]s used to hold molten metal; this is now a minor part of [[Refractory|refractories]]. In the mid-1980s, the carbon-[[magnesite]] brick became important, and a bit later the alumina-graphite shape. {{As of | 2017}} the order of importance is: alumina-graphite shapes, carbon-magnesite brick, Monolithics (gunning and ramming mixes), and then crucibles.

Crucibles began using very large flake graphite, and carbon-magnesite bricks requiring not quite so large flake graphite; for these and others there is now much more flexibility in the size of flake required, and amorphous graphite is no longer restricted to low-end refractories. Alumina-graphite shapes are used as continuous casting ware, such as nozzles and troughs, to convey the molten steel from ladle to mold, and carbon magnesite bricks line steel converters and electric-arc furnaces to withstand extreme temperatures. Graphite blocks are also used in parts of [[blast furnace]] linings<ref>{{cite journal |last1=Almeida |first1=Bruno Vidal de |last2=Neves |first2=Elton Silva |last3=Silva |first3=Sidiney Nascimento |last4=Vernilli Junior |first4=Fernando |title=Blast Furnace Hearth Lining: Post Mortem Analysis |journal=Materials Research |date=15 May 2017 |volume=20 |issue=3 |pages=814–818 |doi=10.1590/1980-5373-mr-2016-0875|doi-access=free }}</ref> where the high thermal conductivity of the graphite is critical to ensuring adequate cooling of the bottom and hearth of the furnace.<ref>{{cite journal |last1=Li |first1=Yiwei |last2=Li |first2=Yawei |last3=Sang |first3=Shaobai |last4=Chen |first4=Xilai |last5=Zhao |first5=Lei |last6=Li |first6=Yuanbing |last7=Li |first7=Shujing |title=Preparation of Ceramic-Bonded Carbon Block for Blast Furnace |journal=Metallurgical and Materials Transactions A |date=January 2014 |volume=45 |issue=1 |pages=477–481 |doi=10.1007/s11661-013-1976-4|bibcode=2014MMTA...45..477L |s2cid=137571156 }}</ref> High-purity monolithics are often used as a continuous furnace lining instead of carbon-magnesite bricks.

The US and European refractories industry had a crisis in 2000–2003, with an indifferent market for steel and a declining refractory consumption per [[tonne]] of steel underlying firm buyouts and many plant closures.{{citation needed|date=January 2017}} Many of the plant closures resulted from the acquisition of Harbison-Walker Refractories by [[RHI AG]] and some plants had their equipment auctioned off. Since much of the lost capacity was for carbon-magnesite brick, graphite consumption within the refractories area moved towards alumina-graphite shapes and Monolithics, and away from the brick. The major source of carbon-magnesite brick is now China. Almost all of the above refractories are used to make steel and account for 75% of refractory consumption; the rest is used by a variety of industries, such as cement.

According to the [[United States Geological Survey|USGS]], US natural graphite consumption in refractories comprised 12,500 tonnes in 2010.<ref name=usgs/>

===Batteries===
The use of graphite in batteries has increased since the 1970s. Natural and synthetic graphite are used as an [[anode]] material to construct [[electrode]]s in major battery technologies.<ref>{{cite web | url=https://www.targray.com/li-ion-battery/anode-materials/graphite | title =Graphite Anode Materials | author =Targray | publisher=[[Targray]] | date =August 27, 2020}}</ref>

The demand for batteries, primarily [[Nickel–metal hydride battery|nickel–metal hydride]] and [[lithium-ion batteries]], caused a growth in demand for graphite in the late 1980s and early 1990s – a growth driven by portable electronics, such as portable [[CD player]]s and [[power tool]]s. [[Laptop]]s, [[mobile phone]]s, [[tablet computer|tablet]]s, and smartphone products have increased the demand for batteries. Electric-vehicle batteries are anticipated to increase graphite demand. As an example, a lithium-ion battery in a fully electric [[Nissan Leaf]] contains nearly 40&nbsp;kg of graphite.{{citation needed|date=November 2022}}

Radioactive graphite removed from nuclear reactors has been investigated as a source of electricity for low-power applications. This waste is rich in [[carbon-14]], which emits electrons through [[beta decay]], so it could potentially be used as the basis for a [[betavoltaic device]]. This concept is known as the [[diamond battery]].

=== Graphite anode materials ===
Graphite is the "predominant anode material used today in lithium-ion batteries".<ref>{{cite journal |last1=Zhang |first1=Hao |last2=Yang |first2=Yang |last3=Ren |first3=Dongsheng |last4=Wang |first4=Li |last5=He |first5=Xiangming |title=Graphite as anode materials: Fundamental mechanism, recent progress and advances |journal=Energy Storage Materials |date=April 2021 |volume=36 |pages=147–170 |doi=10.1016/j.ensm.2020.12.027 |bibcode=2021EneSM..36..147Z }}</ref> Electric-vehicle (EV) batteries contain four basic components: anode, cathode, electrolyte, and separator. While there is much focus on the cathode materials{{emdash}}lithium, nickel, cobalt, manganese, etc., the anode material used in virtually all EV batteries is graphite.<ref>{{Cite web |url=https://electrek.co/2022/06/09/ev-batteries-need-graphite-heres-whats-forecast-for-the-vital-minerals-supply/ |title=EV batteries need graphite – here's what's forecast for supply |website=Electrek}}</ref>

===Steelmaking===
Natural graphite in [[steelmaking]] mostly goes into raising the carbon content in molten steel; it can also serve to lubricate the dies used to extrude hot steel. Carbon additives face competitive pricing from alternatives such as synthetic graphite powder, petroleum coke, and other forms of carbon. A carbon raiser is added to increase the carbon content of the steel to a specified level. An estimate based on [[USGS]]'s graphite consumption statistics indicates that [[steelmaker]]s in the US used 10,500 tonnes in this fashion in 2005.<ref name=usgs/>

===Brake linings===
Natural amorphous and fine flake graphite are used in brake linings or [[brake shoes]] for heavier (nonautomotive) vehicles, and became important with the need to substitute for [[asbestos]]. This use has been important for quite some time, but nonasbestos organic (NAO) compositions are beginning to reduce graphite's market share. A brake-lining industry shake-out with some plant closures has not been beneficial, nor has an indifferent automotive market. According to the [[USGS]], US natural graphite consumption in brake linings was 6,510 tonnes in 2005.<ref name=usgs/>

===Foundry facings and lubricants===
A foundry-facing mold wash is a water-based paint of amorphous or fine flake graphite. Painting the inside of a mold with it and letting it dry leaves a fine graphite coat that will ease the separation of the object cast after the hot metal has cooled. Graphite [[lubricants]] are specialty items for use at very high or very low temperatures, as forging die lubricant, an antiseize agent, a gear lubricant for mining machinery, and to lubricate locks. Having low-grit graphite, or even better, no-grit graphite (ultra high purity), is highly desirable. It can be used as a dry powder, in water or oil, or as colloidal graphite (a permanent suspension in a liquid). An estimate based on [[USGS]] graphite consumption statistics indicates that 2,200 tonnes were used in this fashion in 2005.<ref name=usgs/>  Metal can also be impregnated into graphite to create a self-lubricating alloy for application in extreme conditions, such as bearings for machines exposed to high or low temperatures.<ref>{{Cite web|url=https://www.foundrymag.com/feature/graphitemetal-alloy-extends-material-life-high-temperature-processes|title=Graphite/Metal Alloy Extends Material Life in High-Temperature Processes|date=2004-06-04|website=Foundry Management & Technology|access-date=2019-06-20}}</ref>

===Everyday use===

====Pencils====
[[File:Pencils hb.jpg|Graphite pencils|thumb|alt=Graphite pencils]]
The ability to leave marks on paper and other objects gave graphite its name, given in 1789 by German mineralogist [[Abraham Gottlob Werner]]. It stems from ''γράφειν ("graphein")'', meaning ''to write'' or ''draw'' in [[Ancient Greek]].<ref name="Brit">[https://www.britannica.com/EBchecked/topic/242042/graphite graphite]. Encyclopædia Britannica Online.</ref><ref>{{OEtymD|graphite}}</ref>

From the 16th century, all pencils were made with leads of English natural graphite, but modern pencil lead is most commonly a mix of powdered graphite and clay; it was invented by [[Nicolas-Jacques Conté]] in 1795.<ref>{{cite web | url=http://pubs.acs.org/cen/whatstuff/print/7942sci4.html | title =Pencils & Pencil Lead | author =Ritter, Steve | publisher=[[American Chemical Society]] | date =October 15, 2001}}</ref><ref>{{cite web | url=http://lrs.ed.uiuc.edu/students/kzage/ithistory.html | title=The History of the Pencil | publisher=[[University of Illinois at Urbana–Champaign]] | access-date=2013-02-15 | archive-url=https://web.archive.org/web/20150317005153/http://lrs.ed.uiuc.edu/students/kzage/ithistory.html | archive-date=2015-03-17 | url-status=dead }}</ref> It is chemically unrelated to the metal [[lead]], whose ores had a similar appearance, hence the continuation of the name. '''Plumbago''' is another older term for natural graphite used for [[drawing]], typically as a lump of the mineral without a wood casing. The term [[plumbago drawing]] is normally restricted to 17th and 18th-century works, mostly portraits.

Today, pencils are still a small but significant market for natural graphite. Around 7% of the 1.1&nbsp;million tonnes produced in 2011 was used to make pencils.<ref name="galaxycapital">{{cite web | url =http://www.galaxycapitalcorp.com/sites/default/files/110720%20-%20Electric%20Graphite%20-%20Initiating%20Coverage.pdf | title =Electric Graphite Growing Demand From Electric Vehicles & Mobile Electronics | publisher =galaxycapitalcorp.com | date =July 20, 2011 | access-date =February 15, 2013 | archive-date =October 4, 2013 | archive-url =https://web.archive.org/web/20131004215128/http://www.galaxycapitalcorp.com/sites/default/files/110720%20-%20Electric%20Graphite%20-%20Initiating%20Coverage.pdf | url-status =dead }}</ref> Low-quality amorphous graphite is used and sourced mainly from China.<ref name=usgs/>

In art, graphite is typically used to create detailed and precise drawings, as it allows for a wide range of values (light to dark) to be achieved. It can also be used to create softer, more subtle lines and shading. Graphite is popular among artists because it is easy to control, easy to erase, and produces a clean, professional look. It is also relatively inexpensive and widely available. Many artists use graphite in conjunction with other media, such as charcoal or ink, to create a range of effects and textures in their work.<ref>{{cite web | url=https://www.sybariscollection.com/art-technique-graphite-medium/ | title = ART TECHNIQUE-GRAPHITE AS A MEDIUM | author =Not known | publisher=[[Sybaris]] | date =January 29, 2018}}</ref> Graphite of various hardness or softness results in different qualities and tones when used as an [[artistic medium]].<ref name="SBTCModule6">{{cite web|title=Module 6: Media for 2-D Art|url=http://www.saylor.org/site/wp-content/uploads/2011/12/Module-6.pdf |archive-url=https://web.archive.org/web/20120809171125/http://www.saylor.org/site/wp-content/uploads/2011/12/Module-6.pdf |archive-date=2012-08-09 |url-status=live|publisher=Saylor.org|access-date=2 April 2012}}</ref>

====Pinewood derby====
Graphite is probably the most-used lubricant in [[Pinewood derby|pinewood derbies]].<ref>{{cite web | url=https://www.pinewoodderbycars.com/Top-5-Speed-Tips-for-Your-Pinewood-Derby-Car-a/277.htm | title=Top 5 Speed Tips for Your Pinewood Derby Car | publisher=S&W Crafts Mfg. | access-date=July 28, 2022 }}</ref>

===Other uses===
Natural graphite has found uses in [[Zinc–carbon battery|zinc-carbon batteries]], [[electric motor]] brushes, and various specialized applications. Railroads would often mix powdered graphite with [[waste oil]] or linseed oil to create a heat-resistant protective coating for the exposed portions of a steam locomotive's boiler, such as the [[smokebox]] or lower part of the [[firebox (steam engine)|firebox]].<ref>[http://list.nwhs.org/pipermail/nw-modeling-list/Week-of-Mon-20080623/002828.html True color/appearance of the "Graphite, or Smokebox colors]. List.nwhs.org. Retrieved on 2013-04-15.</ref> The [[Scope soldering iron]] uses a graphite tip as its heating element.

===Expanded graphite===
Expanded graphite is made by immersing natural flake graphite in a bath of [[chromic acid]], then concentrated [[sulfuric acid]], which forces the crystal lattice planes apart, thus expanding the graphite. The expanded graphite can be used to make graphite foil or used directly as a "hot top" compound to insulate molten metal in a ladle or red-hot steel ingots and decrease heat loss, or as [[firestop]]s fitted around a [[fire door]] or in sheet metal collars surrounding plastic pipe (during a fire, the graphite expands and chars to resist fire penetration and spread), or to make high-performance gasket material for high-temperature use. After being made into graphite foil, the foil is machined and assembled into the bipolar plates in [[fuel cells]].
The foil is made into heat sinks for [[laptop computers]] which keeps them cool while saving weight, and is made into a foil laminate that can be used in valve packings or made into gaskets. Old-style packings are now a minor member of this grouping: fine flake graphite in oils or greases for uses requiring heat resistance. A GAN estimate of current US natural graphite consumption in this end-use is 7,500&nbsp;tonnes.<ref name=usgs/>

===Intercalated graphite===
{{main|Graphite intercalation compound}}
[[Image:CaC6structure.jpg|thumb|Structure of CaC<sub>6</sub>]]
Graphite forms [[graphite intercalation compound|intercalation compounds]] with some metals and small molecules. In these compounds, the host molecule or atom gets "sandwiched" between the graphite layers, resulting in a type of compound with variable stoichiometry. A prominent example of an intercalation compound is potassium graphite, denoted by the formula KC<sub>8</sub>. Some graphite intercalation compounds are [[superconductors]]. The highest transition temperature (by June 2009) ''T''<sub>c</sub> = 11.5&nbsp;K is achieved in CaC<sub>6</sub>, and it further increases under applied pressure (15.1&nbsp;K at 8&nbsp;GPa).<ref name="cac6">{{cite journal|pmc=5099629|author1=Emery, Nicolas |author2=Hérold, Claire |author3=Marêché, Jean-François |author4=Lagrange, Philippe |title =Synthesis and superconducting properties of CaC<sub>6</sub>| journal = Sci. Technol. Adv. Mater.|volume = 9| issue = 4|year =2008| page =044102|doi = 10.1088/1468-6996/9/4/044102| bibcode=2008STAdM...9d4102E | pmid=27878015}}</ref>  Graphite's ability to intercalate lithium ions without significant damage from swelling is what makes it the dominant anode material in lithium-ion batteries.