Graphene: mining’s wonder material?

Graphene is a form of carbon that consists of a single-atom layer of graphite arranged in a hexagonal honeycomb-like lattice.

It is sometimes called a ‘wonder material’ due to its remarkable properties – it is the strongest, thinnest and most conductive material ever isolated – which means it could have many applications as a highly valuable additive to enhance a broad range of materials in industries such as electronics, aerospace and medicine.

The Graphene-Info website has this useful video about graphene, which also outlines some of its applications and some of the challenges that need to be overcome.

Scientists had theorised the potential existence and production of graphene for decades, but had assumed that a single atomic layer could not be obtained at room temperature.

It was first isolated and characterised by Andre Geim and Konstantin Novoselov at the University of Manchester in the UK in 2004, and in 2010 they received the Nobel Prize in Physics for their research.

Before graphene, Andre Geim was best known for a 1997 experiment to levitate a live frog using magnets. In 2000, he received an Ig Nobel prize for this work – the Ig Nobel prizes celebrate unusual or trivial achievements in scientific research that make people laugh, then think.

According to the organiser, “The prizes are intended to celebrate the unusual, honor the imaginative — and spur people’s interest in science, medicine, and technology.”

This makes Geim the first individual to win both a Nobel and Ig Nobel prize, an achievement recognised by the Guinness World Records.

This New Yorker article from 2014 has a great summary of how Geim and Novoselov first isolated graphene.

Potential applications in mining

Graphene could be used in the mining industry in a variety of ways. For example, Chinese OEM LiuGong is investing in the development of lubricants containing graphene.

Australia-based technology company Sparc Technologies has done test work on using graphene-enhanced adsorption material to remove gold and silver from tailings; earlier this month, it received a patent for its graphene-based remediation technology.

Puruvi Poddar, head of corporate and business development at graphite producer Tirupati Graphite, says: “Graphene can be used to improve the life of processing equipment using coatings, which may help to reduce damage and corrosion due to its mechanical properties.

“Furthermore, in high friction zones, it can help in increasing thermal conductivity and improve heat dissipation. It can also be used in lubrication formulations.”

Other technical applications could be in sensors of different kinds. Poddar says: “Apart from these general benefits from the use of graphene, we see that application-specific uses are also possible for different processes.”

Tirupati Graphite announced in May that it has developed a graphene-aluminium composite that it says exhibits significantly higher conductivity and strength properties when compared to aluminium.

The company says the graphene-aluminium composite, which was developed at its graphene and technology development unit in India, retains aluminium’s light weight while adding properties from graphene such as increased thermal and electrical conductivity and improved mechanical properties.

This means it could potentially substitute or displace the use of copper across various high-tech, weight sensitive, electrical and thermal conductivity applications.

The manufacturing process has already been used to produce batches of over 200g of the graphene-aluminium composite. Tirupati is now working with a FTSE 100 engineering company to optimise the material and look at commercialisation options.

Poddar says: “Graphene is now on the doorstep of commercialisation; we see it being used extensively across industries and sectors in multiple applications in bulk scales.”

Graphene production

Michael Bell, CEO at at Australia-based graphene producer First Graphene, says: “The properties of enhancing wear life plus fire resistance open the way for some obvious uses such as the wear liners and screen media panels that have been tested to date, as well as just about anything that is or could be made from elastomers/rubbers, composite materials high performance dry and grease-based lubricants.”

The company has also done some work with various PPE, including safety boots and face masks.

Bell notes that high-quality graphene proved to be surprisingly easy to isolate; however, the production of commercial volumes was hindered for many years due to difficulties producing consistent size product.

First Graphene developed a proprietary process, using high purity graphite, that it says enables precise control over production quality. The company markets a range of products for various applications under the PureGRAPH brand.

PureGRAPH is a range of graphene powders, aqueous pastes and a pelletised masterbatch product specifically for use in thermoplastics – the latter is the most recent addition to the range.

The company has the capability to produce 100t/y of its graphene products from a manufacturing facility in Western Australia, and has the capability to quickly scale up as demand increases.

“The different formats and platelet size options suit different applications – some are better for dispersing through composite materials for example, while others might suit concrete and cement applications,” says Bell.

“Manufacturers then incorporate the appropriate PureGRAPH format/size into their manufacturing processes to produce products such as the bucket wear liners that were tested at a Pilbara mine site recently – marketed as ArmourGRAPH by manufacturer newGen Group.”

Collaborative research

In March this year, First Graphene released the results of field tests of a PureGRAPH-enhanced bucket wear liner, which were installed at a major iron ore producer’s load-out facility in the Pilbara region of Western Australia for a 62-week trial from mid-2019.

A detailed abrasion analysis showed that the abrasion loss was significantly reduced in the PureGRAPH-enhanced ArmourGRAPH liner, with approximately six times reduction in average abrasion loss/improved resistance to wear.

First Graphene notes that since abrasion loss is the primary mechanism of failure, a six times increase in lifespan of the wear liner when compared to standard liners could be anticipated.

“All the specific mechanical properties aside, the ultimate outcome for miners – and all other industries – is far greater sustainability,” says Bell. “For example, longer wear life means less waste of consumables. But there are other more direct applications that can help from a sustainability perspective too.

“Graphene is highly conductive, making it a high-demand product for potential use in next generation battery-storage applications.”

In May, First Graphene also released results from a collaboration with Manchester Metropolitan University (MMU) in the UK on the use of metal oxide coated PureGRAPH materials as catalysts in polymer electrolyte membrane fuel cells (PEM-FC).

PEM-FCs are used to power hydrogen-fuelled vehicles, which could be an alternative to lithium-based battery-electric vehicles; however, expensive platinum catalysts are required for the oxygen reduction reactions that must take place in the cathode of the fuel cell.

First Graphene says that the research results mean that PureGRAPH has the potential to be used as a cheaper alternative to platinum in the next generation of fuel cells.

First Graphene and MMU have started another four-month collaboration to support the development of new products in hydrogen and fuel cell technology, focusing on further optimisation of the test devices and extended comparisons with current industrial catalysts.