Old king coal: The next rare earths rush?

By IM Staff
Published: Monday, 22 October 2018

With trade wars once again exacerbating concerns over critical mineral supplies, Fastmarkets correspondent Rose Pengelly looks at whether new technologies can make coal a viable alternative source of rare earths.

The latest flaring of trade tensions between the United States and China has set alarm bells ringing about the security of rare earths supplies – and not for the first time.

China has dominated the global supply of rare earths since the 1990s, and was responsible for more than 80% of global output in 2017.

This dominance has allowed China to flex its trade muscles, at different times, over Japan, Europe and the US. All of them rely on the Asian giant for shipments of such elements, which are essential for everything from hydrocarbon catalysts to missile systems to magnets for electronic devices.

The latest major trade dispute between China and US President Donald Trump’s administration has highlighted how significant the East Asian country’s monopoly of rare earths supply continues to be.

In September, the US government revealed that it had decided to exclude rare earths from its final list of tariffs against $200 billion-worth of Chinese imports.

China supplies around 75% of US imports of rare earth compounds (which totaled more than 17,000 tonnes imported in 2017), according to data from the US Geological Survey (USGS), as well as a considerable proportion of its imports of rare-earth magnets – products which were also removed from the government’s list of designated tariff rises.

Industry observers have noted that finding alternative sources of these minerals at short notice would be difficult for US rare-earths consumers, given the lack of active mines outside China.


RareEarths1  
Lynas Corp’s rare-earths processing facility in Malaysia
is being scrutinized by the country’s authorities,
despite being given a clean bill of health by national
and international monitoring bodies. 
IAEA Image Bank, via Flickr 

Lynas back under pressure

The front-running alternative supplier, Australia’s Lynas Corp, is being investigated by the Malaysian government over the management of radioactive waste produced at the company’s rare-earths processing facility in Kuantan, in eastern Malaysia.

Lynas, which extracts rare earths from its Mount Weld mine in Western Australia, has faced several years of opposition from Malaysian campaigners to its Lynas Advanced Materials Plant (LAMP). The commissioning of the facility was delayed by more than a year while the company fought a series of legal battles to obtain an operating license.

The reassessment of Lynas’ facility is at the behest of Malaysia’s ruling political coalition, led by the Alliance of Hope. This came to power unexpectedly in May, on a manifesto of promises to review several major domestic industrial projects.

If the plant should be closed, Lynas may have to send its rare earths from Australia to China to be processed, which would further tighten China’s grip on exports.

China has retaliated to US protectionist measures by increasing tariffs on many imported US-origin products – worth about $16 billion – including coal, oil and chemicals. So far, however, it has refrained from restricting the supply of any products to the US.

Although this would undoubtedly hit the US where it hurts – in its high tech, energy and defense industries – sector analysts have suggested that even small obstructions to the sales of Chinese rare earths to US buyers could quickly lead to a situation of severe oversupply in China, causing prices to crash.

Nevertheless, a total ban on exports of Chinese rare earths to the US is not unthinkable. In September 2010, China cut off supply of rare earths to Japan for several weeks, after a Chinese fishing captain was detained in disputed waters in the East China Sea (although it is unclear whether the embargo was ever actually enforced).

In the event of an all-out export ban, US importers would have limited options. These include domestic mines, suppliers in Australia and South East Asia and, perhaps less likely, exporters in Russia.

But while new projects scramble to get into production everywhere from Alaska to Burundi, new technologies could make it easier for the US to source rare earths closer to home – including from coal waste, which the US has in abundance.

RareEarths2  
Coal ash, a waste by-product from electricity generation,
is typically stored in ponds and dumps, and is an
environmental problem in many countries, including
the United States.
Waterkeeper Alliance Inc, via Flickr 

Getting more from coal

A team at the National Energy Technology Laboratory (NETL), a part of the US Department of Energy (DoE) which is based at several sites across the US, has developed a miniaturized laser technology which they claim can accurately quantify concentrations of rare earths in various source materials, including coal and coal-related by-products.

For the past five years, NETL has been running a program looking at alternative sources and separation techniques for rare earths.

"Our primary goal is to study unconventional sources, such as acid mine effluent and sludge, and fly-ash ponds, and to determine if the rare earths can be extracted by more economical means with methods that have less of an environmental effect," the program’s lead researcher, Dustin McIntyre, said.

NETL’s laser is versatile and can be used in a range of environments, not just on coal and carbon-based materials, he added.

"Our technology uses a miniaturized laser head that is all-optical and is both driven by, and delivers data through, an optical fiber," he told Fastmarkets.

"This architecture allows for a small probe to be either handheld, mounted on a robotic manipulator, deployed into fluid systems or lowered down into a test bore hole," he added. "Our system can make laser-induced sparks in water and on the surface of solids, and has produced limits of quantification of rare-earth elements under 10 parts per million [ppm] in solution."

Understandably, NETL prefers not to go into detail about the amount of funding it has received from the DoE to develop its technology.

One of the criticisms leveled at expensive new technologies for exploiting rare earths is that prices for these minerals are notoriously volatile, with the most abundant elements worth just few dollars per kilogram at low points in the pricing cycle. Spending millions of dollars to find new ways to produce them is therefore economically difficult to justify.

On the other hand, investing to reduce dependence on China has obvious benefits, and new technologies could very quickly pay for themselves, politically as well as financially, if they become successful.

Without commenting on the costs of research and development, NETL’s McIntyre points out that his team’s laser technology can yield efficiency savings in the rare earths production process, theoretically making it commercially viable even with low rare-earths prices.

"Our system can be used as a sensor for the separations process and, in this capacity, would provide a valuable tool to increase the efficiency of separations," he said.

"When applied to acid mine or fly-ash pond effluent, it could potentially allow for the identification and characterization of rare-earth elements in unconventional deposits," he added. "By providing an online quantitative measurement tool capable of high-resolution measurements, it could reduce analytical time during the various separation processes."

Further development

McIntyre admits that the technology still has "some way to go" before it can compete with the handheld laser-induced breakdown spectrometry (HH-LIBS) units used in traditional prospecting.

But by pushing the limits at which rare-earth concentrations can be detected in solids and liquids, more convenient, everyday and environmentally friendly sources of rare earths could become accessible.

Although it has not been specifically tested for this by NETL, McIntyre believes that the laser technology could easily be adapted for use in recycling to quantify rare-earth elements in waste streams, especially because similar LIBS systems are already being used in recycling processes to recover other kinds of metal alloys.

NETL’s miniaturized system is designed to be "relatively" portable, with the ability to deploy one or more optical probes for long periods of time.

"We concentrated on making the high-energy laser head as small as possible and without any electronics, to provide us with distinct advantages over other systems," McIntyre told Fastmarkets.

"Our system currently relies on lab-scale equipment that could be further miniaturized to fit the application," he added. "Since the deployable component is all-optical, we believe that it will be amenable to harsh environments, more so than other downhole tools where electronics are the limiting factor, due to their sensitivity to heat."

According to McIntyre, there has been commercial interest in enhancing and scaling-up NETL’s laser.

"We are currently partnered with a company that provides benchtop LIBS analysis units to the analytical market. We are also in talks with a well services company to further develop our technology," he said.

"LIBS systems such as ours have been taken to the sea floor and are currently zapping rocks on Mars. We are currently preparing our field-capable prototype and are looking for additional industrial or academic partners to further develop the device," he added.

Ash to cash

Another method of extracting rare earths from secondary sources, also partly funded by the US DoE through NETL, involves using carbon dioxide (CO2) to separate minute amounts of the elements from coal ash.

Coal ash is a by-product of burning thermal coal to make electricity. The US produces nearly 80 million tons per year (72.6 million tonnes per year) of coal ash, about 43% of which is used in cement and to enrich soil.

A team from the Rochester Institute of Technology (RIT) Golisano Institute for Sustainability, based in New York State, US, examined the use of compressed CO2 to selectively dissolve and extract rare-earth elements from coal ash, to produce pure, saleable elemental compounds.

The concentration of rare earths in coal ash or electronic wastes is in the range of 30-1,700ppm, about 100 times lower than that of rare-earth ores, which have concentrations of 3,000-132,000ppm. Consequently, the cost of extracting rare earths from these secondary sources, even on a large scale, would be much more expensive than extracting them from ores.

Saptarshi Das, a research scientist at RIT who worked on the coal ash study, argues that, costs aside, there are good reasons for extracting the elements in this way.

"Coal ash and electronic wastes can contain rare earths such as scandium and neodymium that are not readily available in ore form. In such cases, it might be useful to look at coal ash as an alternative source," he told Fastmarkets.

"Rare earths have very specific properties that can’t be easily replicated or substituted. This process is meant primarily to help the rare earths industry in the US," he added. "While it does re-use waste from the coal industry, based on our calculations, extracting rare earths from US coal ash is unlikely to be financially viable, and therefore unlikely to improve the economics of the coal mining industry."

Another factor to consider is that coal is no longer king. Notwithstanding US President Donald Trump’s efforts to revive the country’s coal industry, the overriding trend is toward phasing out thermal coal in favor of "cleaner" methods of generating electricity.

But according to Das, even a 50% reduction in thermal coal consumption in the US would still produce enough rare earths-rich coal ash to satisfy a large part of current domestic demand.

"The US generates about 80 million tons per year of coal ash. Assuming a low average of 300ppm rare-earths concentration, theoretically this contains 24,000 tons [21,800 tonnes] of rare earths," he said. "Moreover, the US has several millions tons of ash [stored in] in more than 310 active landfill sites and 735 surface impoundments."

Surmountable barriers?

The form of CO2 used by RIT’s researchers is called "super-critical" and has several applications, including in the food industry, such as for removing caffeine from coffee beans.

In the summer of 2018, supplies of this kind of CO2 in Europe ran short – to the surprise of many – due to cutbacks in fertilizer production, of which CO2 is a by-product. This was partly in response to high gas prices coinciding with maintenance closures at CO2 compressing facilities, and high seasonal demand.

This highlights another vulnerability to disruption of the coal ash process, although Das points out that perennially low prices for natural gas in North America mean that such a situation is unlikely to occur there.

Although super-critical CO2 extraction is widely used in the food industry, it is not currently used in the metallurgical industry, and this represents a further major barrier to the adoption of RIT’s process for rare-earths production.

"The processes we discussed… are all in the experimental phase at this point, and I am not aware of any groups looking to commercialize this process yet," Das said. "Our paper was the first attempt to produce a financial analysis of the technique."

Like McIntyre, Das believes strongly that such research, however financially challenged the results turn out to be, is a worthwhile investment for the future of the rare earths industry.

Such proof for novel methods of extracting rare earths may yet be useful, if geopolitical tensions escalate to a point where vital natural resources are held to ransom, while technological progress could yet make expensive lab-scale processes economical, if not indispensable.