Electric vehicles, smartphones, nuclear reactors, refractories, lubricants, pencils. What do they all have in common? Graphite. The element is an incredibly versatile component in many essential manufacturing processes and products, and its uses are only growing.
At Coidan Graphite, we’re leading machined graphite specialists with over two decades of experience in the industry, supplying top-quality carbon and graphite products globally. It’s our lifeblood and something we’re proud to call ourselves experts on. Several of our team members have worked with graphite for over 40 years, with a diverse spread of applications and industries. This experience gives us unrivalled knowledge – to share with our customers, which is exactly what we’re aiming to do.
So we’re breaking down graphite (figuratively). Here’s what you need to know.
What is carbon graphite?
Graphite is the crystalline form of carbon that has been used since the Stone Age. Primitive men used graphite to draw on cave walls, and its artistic prowess extends through history. The actual word ‘graphite’ derives from graphein, which was an ancient Greek word that means to write or to draw.
Graphite is a naturally occurring form of carbon with its atoms arranged in a hexagonal pattern and forming a lattice. It has a value of 1-2 on the Mohs hardness scale and is grey to black in colour. It’s odourless, tasteless, and non-toxic.
Due to its chemical structure, carbon graphite is durable and able to withstand high temperatures. You can find out more about the composition and properties of graphite here.
What’s the difference between synthetic and natural graphite?
Natural graphite
Natural graphite is primarily mined in deposits in metamorphic rock in countries such as China, Brazil, Mozambique, and Madagascar. It occurs in three distinct forms: flake, amorphous, and vein (otherwise known as lump) – each with different usages. For example, flake can be processed into spherical graphite for anodes, whilst amorphous graphite is the primary form used for steelmaking.
Synthetic graphite
In industrial applications, graphite usually refers to synthetic graphite, however. This is a manufactured material (also comprised of carbon in a crystalline solid form) that is extremely resistant to high temperature, making it perfect for machining.
How is carbon graphite made?
- Raw material preparation
- Mixing and moulding
- Baking
- Graphitisation
- Machining
Petroleum coke is heated to incandesce, crushed, and ground before being mixed with binders such as coal tar pitch. This is then moulded as needed. Extrusion, compression moulding, and isostatic moulding allow producers to dictate the final needed shape of the graphite. They are then carefully baked into carbon over the course of months, which requires close observation and monitoring in a graphitisation process. It is an energy-intensive process that yields a durable, high-purity, long-lasting material.
It’s ideal for energy storage applications and steel manufacturing, and is usually created in two forms – electrodes and graphite blocks. However, secondary synthetic graphite can also be produced as a byproduct and can be available in powder form.
Is synthetic graphite better than natural graphite?
The two materials can offer different primary usages and require different levels of production, with synthetic graphite utilising much higher energy in order to create the desired outcome. However, it is purer in terms of carbon content and behaves more predictably, making it better suited for applications such as lithium-ion batteries for electric cars.
The energy-intensive process and environmental costs for manufacturing synthetic graphite mean many manufacturers are choosing natural graphite as a suitable alternative. Synthetic graphite generates around 20 to 40 kg CO₂ per kilogram compared to just around 2 to 6 kg CO₂ per kilogram of natural graphite.
Both graphite varieties have comparable thermal and electrical conductivity, but the natural variety is more resilient to corrosion, oxidation, and high temperatures due to its longer crystallisation time.
What is graphite used for?
The common uses of graphite in everyday life
- Pencils: This may be the first thing that comes into your mind when you think about the uses of graphite. While many people may refer to the material in pencils as ‘lead,’ this is a misconception that came from the misidentification of graphite deposits in England in the 1500s. The soft nature of graphite makes it perfect for pencils.
- Art supplies: One of the first usages of graphite was for art, with the primordial man, Romans, and even Egyptians all adopting the material in their art.
- Lithium-ion batteries: This is a leading usage for graphite that continues to soar in popularity with the growing need for laptops, mobile phones, and electric cars. Graphite anodes help lithium batteries retain their shape and improve electrical conductivity. Graphite anodes act as a host for lithium ions, making them necessary to their construction.
- Dry lubricants: While the everyday person may not come into contact with dry lubricants used in machining, it’s a necessary part of the process of creating many of the items we do encounter in our lives. Tiny slivers of graphite help ensure there’s no friction in machinery to prevent the breakdown of equipment. In this case, graphite in the form of a powder or a film is usually recruited.
Other uses for graphite
- Graphite electrodes: Primarily used in electric arc furnaces, these electrodes play a major role in the production of steel, iron, and other metals.
- Refractories: Due to the properties of carbon graphite (including its high thermal conductivity, graphite is often used for the production of refractory materials. This can include linings for kilns, furnaces, and reactors.
- Carbon fibre: Lighter than many conventional materials, carbon fibre and fibre composites are used in the automotive industry for a variety of applications, including the brake system. Their lightweight properties make vehicles lighter, reducing CO2 emissions.
The sectors Coidan provides graphite for:
As leading machined graphite experts, Coidan provides carbon graphite solutions for a wide range of sectors and industries. We work with clients in aerospace, engineering, defence, and steelworks, as well as creating bespoke graphite solutions. We’re continuing to innovate, creating new usages for the material, and seeking new applications.
We even recycle scrap electrodes into green graphite electrodes – helping to reduce emissions and aid the environment.
Coidan Graphite: Your leading graphite experts
Looking to learn more about graphite? Here are our must-know facts about graphite you’ll love to learn if you enjoy this article, including the link between graphite and diamonds. Read our nine interesting facts about graphite here.
If you’d like to discuss graphite solutions and our carbon and graphite-focused services, you can get in touch with a member of our team at 01423 330 492 or explore more on our website here.