Rare Earth Production In The US?
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If what is described in this article comes to fruition, it could allow the US to produce some of the rare earth metals it needs for electrical cars and renewable energy.
The Mountain Pass mine in California is the only rare-earth producing mine in the Western Hemisphere. Most rare earths are currently produced in China, which doesn’t mind environmental messes.
Refining rare earths has historically produced a lot of dangerous waste, partly because the rare earths are often found in combination with radioactive minerals. The process itself involves a variety of chemicals and a fair bit of water. MP Materials says that they plan, in the next quarter, to begin processing at Mountain Pass in a way that minimizes the waste and water usage. Previously, concentrates from the mine were processed in China and, for a short time, in Estonia, although the article doesn’t mention the latter.
The Silmet Plant in Sillamäe, Estonia, processed rare earths from the mid-1980s and uranium ore before that. The ores came from Central Asia and the Kola Peninsula. The wastes were deposited in an enormous tailings pond on the shore of the Baltic Sea.
That’s my photo from my first visit there in January 1998. The government of Estonia wanted the tailings pond made safe from sliding into the sea and from the infiltration of rainwater that carried metals into the sea. By 2009, an engineered cover had been installed on the tailings pond, and it was isolated from groundwater. But that meant that the plant had to produce less waste.
Silmet got a grant from the US government to redesign its process to produce less, and more handleable, waste. They hired a mining consulting firm in Denver and got a plan, which they put into effect.
In 2011, Molycorp, which owned the Mountain Pass mine at the time, acquired Silmet, including the improved process sheet. Molycorp went bankrupt in 2015 and was renamed Neo Materials, which still owns Silmet. The Mountain Pass mine is now owned by MP Materials.
It looks to me like the process at the Mountain Pass mine is similar to the improved process designed for Silmet. It likely differs in several ways because the ore is different, and MP could build the plant from scratch, rather than reworking what they had, as Silmet did. The MP Materials website has a nice photo (at top) of the facility with the various buildings identified if you mouse over it at the link.
I’m curious, of course, whether I have surmised the genealogy of the process correctly. There’s probably no issue relating to patents; the process steps are well known. I’d just like to know so that my Estonian colleagues can get proper credit. And I’m pleased if I helped to get to a less environmentally damaging way of getting the metals we need.
Cross-posted to Nuclear Diner