Infrastructure and Construction Materials Guide — Graphite

Commodity Description

Graphite has formed through metamorphosis of organic, carbonaceous material into a large, tabular mass of a soft, crystalline material. Graphite in its natural state can vary from a few percentage points to 90%+ carbon in small vein structures. Graphite has a specific gravity of 1.0-2.0 (a substance with specific gravity of 1.0 is buoyant in water; a substance with specific gravity greater than 1.0 will sink in water). Its specific gravity is similar to talc. Natural graphite is found in three forms, amorphous, flake (the most abundant source), and vein.

The term “amorphous graphite” is a contradiction in terms. All graphite is crystalline by definition; therefore, it is not “amorphous.” To the untrained eye a piece of amorphous graphite lacks a crystalline shape and simply looks like a lump of anthracite coal. However, it is much denser than anthracite, 2.2g/cc vs. 1.7g/cc for coal, and graphite is soft and smooth. A preferred descriptive term for this substance would be “microcrystalline graphite” or “cryptocrystalline graphite.” (https://asbury.com/resources/education/science-of-amorphous graphite)

Graphite sizes in flake range from a large size of +48 mesh (0.0177, inches, 0.300 millimeters) to fine a size at -200 (less than 200) mesh (0.0029 inches, 0.075 millimeters). Flake is the most common graphite form for use in batteries.

Market Details

Amorphous 50-70% graphite is not used for batteries. Amorphous less than 4 inch lumps to 3-micrometer powder is typical for use in mechanical motor seals, brake linings and electric motor brushes.

Vein or lump graphite is mined in the size range of 5-10 centimeters, and sold in powders in the range in size from 1-150 centimeters for use in brake linings.

Synthetic Graphite

Synthetic graphite is a growing market with the need for high purity graphite manufacturing to supply a number of growth industries. MarketWatch noted that the global synthetic graphite market was US$8,491 million in 2021 and expected grow to US$8,672 million by 2028.

Some of the uses of synthetic graphite are:
• Steel furnace electrodes
• Nuclear power plant neutron absorption protection
• Aluminum electrolytic cell anodes
• Lithium-ion battery anodes
• Magnesia-graphite refractories (materials that retain their strength at high temperatures) for basic oxygen and electric arc furnaces
• Alumina-graphite refractory for continuous metal castings production

The process for producing synthetic graphite uses petroleum coke (a solid produced in oil refining) as the carbon source which is heated in high temperature furnaces to approximately 3000 oC and results in anodes with 99% pure graphite.

China is the largest producer of natural and synthetic graphite, controlling approximately 25% of the world total, and the United States controls approximately 20%.

The USGS only reports natural graphite in its annual Commodity Summaries.

Production and Pricing

For U.S. production statistics and prices, “Graphite,” go to p. 84 of the USGS Commodity Summaries 2024.

For World Mine Production and Reserves, “Graphite,” go to p. 85 of the USGS Commodity Summaries 2024.

The United States imports virtually all its graphite. The flake, amorphous and vein species are produced in China, Sri Lanka Brazil, Madagascar, Mozambique and Ukraine.

Russia and Ukraine along with Russian ally, Uzbekistan, make short-term production questionable because of the political war among Eastern Europe and Central Asia countries. Brazil, Mozambique, and Madagascar will most likely be offering increased exports to North America and Europe.

Mining and Mineral Processing

The majority of mines in graphite producing countries utilize surface and underground mining methods. A truck-shovel method is generally used in surface mines and Load-Haul-Dump units are used in underground mines. Manual labor with low costs is used in developing countries and in China. Blasting is not required in graphite mines because of the soft character of the in-situ graphite deposits.

An example of mineral processing is the recovery of flake graphite from regolith (loose material lying over solid rock) and calcite-silicate. A flowsheet of the recovery of graphite typically includes:

• In pit screening.
• Rod mill grinds the material.
• Classifier screw removes sand from the material.
• Shaker table removes fine sand from the material .
• Re-grind the table middlings (remaining medium-sized rock).
• Flotation process brings low specific gravity, floating graphite concentrate to the top by using reagents (diesel fuel and Dowfroth frother) that attach to the particles.
• Froth de-watering (remove water from the froth).
• Belt dryer (materials is carried along on a belt through a gentle drying process).

Products and Uses

Batteries

Graphite’s unique physical characteristics are important in the current growth of lithium ion battery power use as a renewable power. Graphite is an excellent electrical conductor because of the presence of free electrons in its crystal form where the fourth valence electron of each carbon atom is free. These free moving electrons are responsible for the conduction of electricity in a graphite crystal used in the battery anode. The negative lithium ion battery cathode terminal is made from a metal oxide such as lithium cobalt oxide, lithium iron phosphate, or lithium manganese oxide.

A typical lithium ion battery anode contains 50% of natural flake and 50% synthetic graphite. The 50-50 graphite combined make up 95% of the anode with the remainder being silicon and aluminum to improve electrical transmission in the battery cell.

Figure 1 Schematic of a Lithium-Ion Battery

Source: https://commons.wikimedia.org/wiki/File:Schematic_of_a_Li-ion_battery.jpg

Tesla/Panasonic typically uses a 50/50% natural graphite/synthetic graphite and the “in-development” 4680 battery is expected to comprise 55-60% natural graphite/40-45% synthetic graphite.

Graphite Demand

Consultancy Benchmark Mineral Intelligence (BMI) sees a roughly 20,000 tonne (metric ton) graphite deficit in 2022, versus a similar-sized surplus the previous year. About 20,000 tonnes of graphite is enough to make batteries for roughly 250,000 EVs. (Reuters Dec 2021).

EV demand drives anode demand

Source: https://www.ecograf.com.au/wp-content/uploads/2021/11/2307390.pdf

Graphite in metallurgical applications:
• Refractories including brick components and furnace construction material
• Electric steel furnace – anodes to melt scrap steel
• Foundries – crucibles for melting iron
• Due to its high tolerance to heat and resistance to change, graphite is commonly used as a refractory material.

Other applications:
• Brake linings – graphite has replaced asbestos
• Vehicle internal engine gaskets
• Graphite is the “lead” in pencils

Substitutes

Graphite has unique properties not common to other materials with suitable substitutes of artificial graphite and graphene.

Environmental Considerations

What is decarbonization? Generally, decarbonization is an economic and political process of reducing carbon dioxide emissions caused primarily from the use of fossils fuels.

Some environmental advocates oppose the use of graphite in electrical vehicles due to an assumed large carbon footprint for materials, manufacturing labor and energy costs.

Some organizations see graphite in electrical vehicles as the answer to improving the climate in relation to carbon dioxide.

The two arguments:

Oppose graphite use in lithium ion battery anodes

Opponents contend that the use of carbon-based products with the improvement of technical grade graphite involves carbon dioxide either for mining and processing natural graphite ores or petroleum products and energy to produce synthetic graphite. These generated “pollutants” appear to be detrimental but are not included in a carbon balance when projecting the future of electric vehicles.

Favor graphite use in lithium ion battery anodes

Supporters in favor of graphite’s use in lithium ion battery anodes tend to see the overall benefits of use of electric vehicles eliminating internal combustion engines as consistent with the move to renewable energy.

References

Asbury Carbons, https://asbury.com/resources/education/science-of-amorphous graphite

Farm Forum, https://www.farmforum.net/story/news/agriculture/2021/03/11/ocean-freight-rates

Graphite.com

Market Watch, www.marketwatch.pressrelease/synthetic-graphite.market.size. 2022

SME Industrial Minerals & Rocks 7th Edition.  SME Books. Editors: Jessica Elzea Kogel, Nikhil C. Trivedi, James M. Barker, Stanley T. Krukowski, 2006.

SME Mining Engineering, Industrial Minerals Review 2022 (primarily based on USGS commodity data)

Statista.com/graphite

United States Geological Survey (USGS) Commodity Summaries 2023.  https://pubs.usgs.gov/publication/mcs2023. NOTE:  2023 version reports 2022 statistics. 

United States Geological Survey (USGS) Commodity Summaries 2024.  https://pubs.usgs.gov/publication/mcs2024. NOTE:  2024 version reports 2023 statistics.