Phosphogypsum: Another Russian rare earths pipe dream?

By IM Staff
Published: Monday, 22 August 2016

A plan to recycle waste from fertiliser plants to produce pure rare earths and gypsum is the latest to come out of Russia’s metallurgical science community, but this project is already facing many of the obstacles that have scuppered previous similar endeavors, Vladislav Vorotnikov, IM Correspondent, finds.

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Having announced plans to extract rare earths out of everything from Siberian mountains to moon rocks, Russia’s latest announcement that it plans to exploit yet another obscure source material for the lanthanide minerals is unlikely to set many tongues wagging in anticipation.

But the tirelessness with which both Russian private and state institutions fund and promote research into new ways of producing rare earths provides an engagingly abstract backdrop to rather miserable efforts elsewhere in the world to make a profit from simply mining the minerals from commonly-occurring ores like monazite and bastnaesite.

In the latest Russian project to come to the fore, a group of scientific and commercial bodies have collaborated to develop a process for extracting rare earths from phosphogypsum, a form of gypsum formed as a byproduct from treating phosphate ore with sulphuric acid to produce fertiliser. 

The project involved Russia’s National Research Technological University (MISA), the Institute of Chemical Technology, nuclear energy company Rosatom and chemical engineering firm, Skygrad. 

Rostec, Russia’s state-owned high tech company and the largest consumer of rare earths in Russia, has also expressed an interest in the project.

Estimates by the researchers suggest that Russia has accumulated 320m tonnes of phosphogypsum waste from mineral fertiliser production. This material typically consists of 80-98% gypsum and just 0.02% rare earths. In total, however, this means there are 800,000 tonnes rare earths lying in landfill around Russia.

At present, Russia consumes around 2,500 tpa rare earths of which 1,500 tpa is imported. Russia’s industry ministry forecasts that domestic rare earths demand will reach 5,000-7,000 tpa by 2020, while the most optimistic scenario projects consumption could rise to 13,000 tpa. Meanwhile, stocks of phosphogypsum are rising by 10-15m tpa.

According to MISA researchers, technology to recover rare earths from phosphogypsum has proved successful in laboratory scale tests and they are confident that the process will also work at an industrial level.

"We have developed a closed-loop technology for processing phosphogypsum using a sulphate leaching method to produce a high-purity rare earths concentrate, containing minerals including oxides of neodymium, dysprosium, terbium, cerium, lanthanum and didymium," says Alexander Medvedev, one of the leading researchers at MISA.

The rare earths concentrate is neutralised with ammonia and separated into individual elements using special centrifugal extractors. This step removes gypsum, phosphorus and fluorine impurities. Calcium phosphate and fluoride byproducts from this process can be recycled as components of chemical binders.

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Russian scientists hope to extract rare earths from
phosphogypsum.

Development history

Skygrad, which invented the phosphogypsum processing technology, has been working on the process for almost a decade. Five years ago, having produced its first batch of mixed rare earths concentrate, the company attempted to sell this material as a raw product.

Even though rare earths prices were at record levels in 2011, Skygrad’s efforts to commercialise the concentrate were not successful.

"In our early studies, we really thought the production of a rare earths concentrate was a good self-contained result," recalls Skygrad’s founder, Yuri Sobol. "However, it turned out there was no market for this type of product in Russia and foreign producers were setting the prices of rare earths, so we had no control over what we could ask for the material on the international market." 

Skygrad therefore had to decide whether to abandon the project or attempt to separate the rare earths from concentrate – an entirely new research project. "Many expert chemists, who had previously worked on rare earths processing, tried to discourage us from embarking on this scheme, telling us that it was impossible to extract rare earths using centrifuges," says Sobol.

"Every kind of rare earths separation technology is different, since it has to take into account the peculiarity and the composition of the concentrate. We initially succeeded in separating cerium, a low value abundant rare earth, but this encouraged us to try for more elements," explains Yuri Mikhailov, vice president of the Russian Academy of Science, who worked on the project.

Skygrad’s aim is to create a vertically-integrated business model which processes raw phosphogypsum into pure, saleable rare earth materials. Initial production capacity is targeted at 2,000-4,000 tpa from a new production facility, which the company hopes to build in the vicinity of the Volhovsky Chemical Plant, a fertiliser manufacturing facility in Moscow Oblast, close to large landfills of phosphogypsum. 

However, according to Sobol, it has been difficult to negotiate waste supply agreements with Russian fertiliser companies. 

"We once offered our technology to the CEO of a fertiliser plant to recycle its waste. We asked if we could build our facility on land belonging to the plant, which would save him the headache of disposing of the waste, but all he was interested in was profiting from the agreement – we can’t do business with people who are only interested in that," Sobol says.

Sobol claims that, once built, Skygrad’s facility would be the first in Russia capable of separating rare earths concentrate on an industrial scale. At present, all Russia’s domestic rare earths supply is mined from JSC Lovozero’s Lovozero mine on the Kola Peninsula in northwest Russia. The mine produces 6,000 tpa loparite ore, which is then processed at the OJSC Solikamsk Magnesium Plant in Russia’s Perm region. This facility yields around 1,500 tpa rare earth
concentrate, which is sent to be separated at JSC Silmet in Estonia and LLP Irtysh Rare-Earth Co. in Kazakhstan.

"No matter how hard we’ve tried to produce large amounts of separated rare earths domestically, without establishing modern separation facilities in the country, the industry will not be able to move forward," warns Sobol.

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Detractors say that logistics costs may undermine the profitability of the venture if it is built in Moscow.

State support

MISA’s Medvedev is optimistic that the venture with Skygrad will be eligible for subsidies from the Russian government, since it offers both waste recycling and import substitution. From 1 January 2017, the government will introduce a new environmental tax on pollution-generating businesses, which will be used to help fund clean technology initiatives.

"Each application for subsidies is considered individually and the [Skygrad project] has a good chance of qualifying for support," says Sergei Sysoev, a spokesperson for Russia’s Industry Ministry. 

Additionally, the project could receive some support from a Russian rouble (R) 145bn ($2.18bn*) government fund set up for "special purposes", including providing backing for several proposed rare earths mines in Russia.

This scheme is designed to encourage public-private participation in Russian industry, however the country’s faltering economy has so far scuppered the implementation of this plan, since potential financiers are wary of what are perceived as risky investments. 

"There is no point embarking upon large-scale mining projects in Republic of Yakutia, or in Murmansk Oblast in the Arctic Circle where largest Russian rare earths deposits are located, simply because they will require huge sums of money which will take too long to repay," says Kirill Arhipov, a Russian geologist and a member of Russian Academy of Science. "I think the government should shift its focus to processing projects, since these at the moment these appear much more promising." 

Skygrad’s Sobol also believes that state cash should be targeted at the science behind rare earths separation, to foster the development of new skills and technology in Russia. 

He suggests that the government can also help innovative startup businesses by offering to lease them empty government buildings, which could be converted into laboratories and test centres. 

Piloting phosphogypsum processing

A pilot project for processing phosphogypsum for rare earths was launched earlier this year and the first batch of commercial product should be received by the end of 2016. After that, the team behind the project will work to optimise costs and evaluate the potential for a large scale processing plant.

"The pilot plant was designed to process 60 tpa phosphogypsum, to produce rare earths concentrate and construction-grade gypsum," explains Sobol. "The main advantages of the proposed flowsheet are that it is a wasteless technology and consumes relatively small amounts of reagents and water, compared to existing technologies."

However, there are still a number of complications in implementing the project. Several scientific observers have warned that the new technology could be harmful to human health, particularly for staff employed at the processing facility, since rare earths waste can generate excessive levels of radiation. 

Other detractors have said that logistics costs are likely to undermine the profitability of the venture if it is built in Moscow Oblast, because once the area’s reserves of phosphogypsum have been used up, large quantities will need to be brought in from other parts of Russia.

The project’s supporters are nevertheless determined to take their phosphogypsum processing technology forward. The first batches of high-purity cerium oxide (CeO ≥99.5%) have been obtained and the researchers are working to produce batches of other rare earth oxides which can be offered to downstream consumers for testing. 

Until this happens, however, Skygrad and MISA’s ambitious scheme to turn mineral waste into a valuable secondary source of rare earths is likely to be chalked up among Russia’s growing list of metallurgical curiosities.

*Conversion made July 2016