Chalmers researchers say carbon nanomaterials could replace scarce metals

Oct. 27, 2017

Scarce metals are found in a wide range of everyday objects, according to researchers at Chalmers University of Technology. They can be found in your computer, in your mobile phone, in almost all other electronic equipment, and in many plastics.

Society is dependent on the scarce metals, the researchers report, and this dependence has many disadvantages. The metals are complicated to extract, and several are so rare they have become “conflict minerals,” whose mining profits can perpetuate fighting among armies and rebel forces.

To try to limit profits from conflict mineral mining, the European Union Parliament voted earlier this year to adopt regulations regarding the sourcing of conflict minerals in high-risk zones. The regulations—which require supply-chain due-diligence self-certification of tin, tantalum, and tungsten; their ores; and gold originating in conflict-affected and high-risk areas—pose problems for businesses who use the minerals but may lack insight into their source. IPC-Association Connecting Electronic Industries has supported the EU regulations, which are mandatory for upstream smelters and importers of raw materials who are closest to the mines and thereby best able to assess whether the minerals are associated with the funding of violence, human-rights abuses, and environmental damage. The regulations are voluntary for downstream manufacturers whose products contain these minerals.1

The Dodd-Frank Wall Street Reform and Consumer Protection Act addresses similar concerns in the United States, and IPC earlier this year questioned the impact of the regulations on human rights abuses in the Democratic Republic of Congo (DRC). In a March 16 letter to the acting director of the U.S. Security and Exchange Commission, Fern Abrams, IPC director, regulatory affairs, wrote that that conflict minerals contribute to the violence, but mining them is also vital to the Congolese people’s survival. She concluded, “IPC appreciates the SEC’s reconsideration of the conflict minerals regulations and would welcome SEC efforts to reduce the burden they impose on industry.”

And extraction is only part of the problem with the metals, the Chalmers researchers report. They are difficult to recycle profitably since they are often present in small quantities in various components such as electronics.

However, potential technology-based solutions that can replace many of the metals may exist. Rickard Arvidsson and Björn Sandén, researchers in environmental systems analysis at the university, pose as an alternative solution the substitution of carbon nanomaterials for the scarce metals.

“Now technology development has allowed us to make greater use of the common element carbon,” said Sandén, in a press release. “Today there are many new carbon nanomaterials with similar properties to metals. It’s a welcome new track, and it’s important to invest in both the recycling and substitution of scarce metals from now on.”

Arvidsson and Sandén have studied the main applications of 14 different metals, and by reviewing patents and scientific literature have investigated the potential for replacing them by carbon nanomaterials (Table 1). They say a shift away from the use of scarce metals to carbon nanomaterials is already taking place.

Table 1. Scarce metal applications and potential substitutes
Courtesy of Chalmers University of Technology

“There are potential technology-based solutions for replacing 13 out of the 14 metals by carbon nanomaterials in their most common applications,” Arvidsson said. “The technology development is at different stages for different metals and applications, but in some cases such as indium and gallium, the results are very promising.”

“This offers hope,” said Sandén. “In the debate on resource constraints, circular economy, and society’s handling of materials, the focus has long been on recycling and reuse. Substitution is a potential alternative that has not been explored to the same extent, and as the resource issues become more pressing, we now have more tools to work with.”

The findings were recently published in the Journal of Cleaner Production.2 Arvidsson and Sandén stressed that there are significant potential benefits from reducing the use of scarce metals, and they hope to be able to strengthen the case for more research and development in the field.

They also point out that more research is needed in the field to deal with any new problems that may arise if the scarce metals are replaced.

“Carbon nanomaterials are only a relatively recent discovery, and so far knowledge is limited about their environmental impact from a life-cycle perspective,” Arvidsson said. “But generally there seems to be a potential for a low environmental impact.”


  1. IPC supports EU vote for voluntary conflict minerals requirements for manufacturers,” March 17, 2017, EE-Evaluation Engineering Online.
  2. Arvidsson, Rickard, and Sandén, Björn A., “Carbon nanomaterials as potential substitutes for scarce metals,” Journal of Cleaner Production, July 10, 2017.

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