New process recycles rare earth elements from wastewater


October 31, 2013

Scientists have had success at capturing rare earth elements diluted in industrial wastewater

Scientists have had success at capturing rare earth elements diluted in industrial wastewater

Rare earth elements are an integral part of many of today's electronic devices, serving as magnets, catalysts and superconductors. Unfortunately, these minerals are also ... well, rare, and thus very pricey. Recently, however, scientists discovered that some of them can be reclaimed from industrial wastewater, instead of being mined from the earth.

The researchers, from the Chinese Academy of Sciences, already knew that a nanomaterial known as nano-magnesium hydroxide (nano-Mg(OH)2) could remove some metals and dyes from wastewater. It was also known that the rare earth elements in wastewater tend to be very diluted, and thus quite difficult to remove in a practical, inexpensive fashion.

After studying the manner in which nano-Mg(OH)2 works, the scientists proceeded to produce special flower-shaped nanoparticles of the material. In lab tests that replicated real-world conditions, these particles were able to capture over 85 percent of the rare earth elements diluted in water samples. By subsequently adjusting the pH, it was possible to then separate the captured minerals from the nano-Mg(OH)2.

“Recycling REEs from wastewater not only saves rare earth resources and protects the environment, but also brings considerable economic benefits,” the team stated in a paper on the research, which was recently published in the journal ACS Applied Materials and Interfaces.

Source: American Chemical Society

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away. All articles by Ben Coxworth

"Unfortunately, these minerals are also ... well, rare, and thus very pricey."

Rare Earth is a misnomer. These minerals are not rare at all. The price is governed by the fact that the majority of the functioning supply comes from China and over the last few years they've been restricting supply for 'strategic' reasons. There are plenty of known reserves in other countries that haven't been touched up until now because the Chinese price was low. That is now changing.


Wastewater is also contaminated with lots of other common elements such as sodium, magnesium, iron and such. I think these non rare elements will be preferentially absorbed by the sponge, leaving little space for the rare elements..


@nicho - Interesting. I imagine the offshore mining being worked on now will change that monopoly even more.


There's a lot of junk hard drives with rare earth magnets. I take them apart and collect them.

Captain Obvious

The sea is earth's waste-water. The air purifies the water and distributes it over the land. Nature does it best. If something can be extracted from the water before it hits the better be more profitable than nature.

Unless it's subsidised. Subsidised is corruption.


according to the thorium energy assoc. thorium is associated with REE's in monzanite gravels. if the thorium reactors ever get built, then we also have a source for REE's. kind of a win/win situation that is being stopped by both politicians and public opinion on nuclear reactors. too bad, they appear to be safer for energy production than our present reactors.


As my Geology professor said, "The problem with rare earth metals is't that they are rare, which compared to most other elements in the earths crust they are, but that they are dispersed so finely across the planet." If we could design efficient ways of concentrating them everything would be easier. This seems like a good idea.

Darius Vons
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