JOIN USTime to save the 'rare earths'
Western capitals are suddenly worried over China’s near monopoly, which gives it a potential stranglehold on technologies of the future. In Washington, Congress is fretting about the US military’s dependence on Chinese rare earths, and has just ordered a study of potential alternatives. In Guyun village, a small community in southeastern China fringed by lush bamboo groves and banana trees, the environmental damage can be seen in the red-brown scars of barren clay that run down narrow valleys and the dead lands below, where emerald rice fields once grew.
Mining causing damage
Miners scrape off the topsoil and shovel golden-flecked clay into dirt pits, using acids to extract the rare earths. The acids ultimately wash into streams and rivers, destroying rice paddies and fish farms and tainting water supplies. On a recent rainy afternoon, Zeng Guohui, a 41-year-old labourer, walked to an abandoned mine where he used to shovel ore, and pointed out still-barren expanses of dirt and mud. The mine exhausted the local deposit of heavy rare earths in three years, but a decade after the mine closed, no one has tried to revive the rice fields downstream.
Small mines producing heavy rare earths like dysprosium and terbium still operate on nearby hills. “There are constant protests because it damages the farmland, people are always demanding compensation,” Zeng said. “In many places, the mining is abused,” said Wang Caifeng, the top rare-earths industry regulator at the ministry of industry and information technology in China. “This has caused great harm to the ecology and environment,” he added.
There are 17 rare-earth elements, some of which, despite the name, are not particularly rare, but two heavy rare earths, dysprosium and terbium, are in especially short supply. This is mainly because they have emerged as crucial ingredients of green energy products. China mines more than 99 per cent of the world’s dysprosium and terbium. Most of China’s production comes from about 200 mines in northern Guangdong and in neighbouring Jiangxi province.
Illegal practices
China is also the world’s dominant producer of lighter rare earth elements, valuable to a wide range of industries. But these are in less short supply, and the mining is more regulated. Western users of heavy rare earths say that they have no way of figuring out what proportion of the minerals they buy from China comes from responsibly operated mines. Licensed and illegal mines alike sell to itinerant traders. They buy the valuable material with sacks of cash, then sell it to processing centers in and around Guangzhou that separate the rare earths from each other.
Companies that buy these rare earths, including a few in Japan and the West, turn them into refined metal powders. “I don’t know if part of that feed, internal in China, came from an illegal mine and went in a legal separator,” said David Kennedy, the president of Great Western Technologies in Troy, Michigan, which imports Chinese rare earths and turns them into powders that are sold worldwide.
The biggest user of heavy rare earths in the years ahead could be large wind turbines, which need much lighter magnets for the five-ton generators at the top of ever-taller towers. Vestas, a Danish company that has become the world’s biggest wind turbine manufacturer, said that prototypes for its next generation used dysprosium, and that the company was studying the sustainability of the supply. Goldwind, the biggest Chinese turbine maker, has switched from conventional magnets to rare-earth magnets.
Executives in the $1.3 billion rare-earths mining industry say that less environmentally damaging mining is needed, given the importance of their product for green energy technologies. Developers hope to open mines in Canada, South Africa and Australia, but all are years from large-scale production that will produce sizable quantities of light rare earths. Their output of heavy rare earths will most likely be snapped up to meet rising demand from the wind turbine industry.