Canadian Breakthrough: Use of Industrial Strength Absorbents to ‘Soak up’ Lanthanum from Mine Waste

Highlights

• Researchers at Toronto Metropolitan University develop chemical adsorbents to extract lanthanum from industrial mine waste.
• The ‘fancy sponges’ can filter lanthanum from contaminated water, enabling metal reuse in new electronics.
• The growing rare earth element market is projected to expand from $6.2 billion to $16.1 billion by 2034.
• Highlighting the importance of sustainable recovery methods.

Most readers here at Rare Earth Exchanges understand the global market for rare earth elements (REE) to be growing not the billions—now at according to some estimates $6.2 billion (USD), heading north to $16.1 billion (USD) by 2034.  We know the products that require these inputs—from cellphones and computers to electric vehicles and even defense systems. High concentrations of one particular REE — lanthanum — are often in find in mine tailings. Runoff from this waste can make its way into nearby bodies of water where it poses a risk to human health and the environment. As a result, researchers are on the hunt for ways to recover the material.

Lanthanum (La) is a soft, silvery-white, ductile metal classified as a rare earth element with atomic number 57 on the periodic table; it is considered the first element in the lanthanide series, meaning it is highly reactive and readily oxidizes when exposed to air; commonly used in nickel-metal hydride batteries and as a component in certain types of optical glass due to its refractive properties; discovered by Carl Gustaf Mosander in 183

Michael Chan (opens in a new tab), working under the supervision of Dr. Huu Doan (opens in a new tab) in the Department of Chemical Engineering at Toronto Metropolitan University (TMU), and their recent discovery that industrial-strength chemical adsorbents can be used to “soak up” lanthanum from that mine waste.

Chan went on the record for Canadian Light Source (opens in a new tab) “These ‘fancy sponges’ are about the size of a grain of salt,” says Chan, who is completing his Masters degree at TMU. Working in a lab, Chan and his colleagues found that the metal ions present in a sample of contaminated water trade places with the hydrogen ions present on the surface of adsorbent.

When they filtered the adsorbent out of the water, they were left with cleaner water and recovered lanthanum that could be reformed and reused in new electronics.

Some of the Science

Using a scanning electron microscope at TMU to better understand the ion exchange process, the team then used the Canadian Light Source at the University of Saskatchewan (opens in a new tab) to get even more detailed images and to confirm their findings.

“The exciting part about these findings is that this is something that we can do now, today,” says Chan. “We can use what we have. We can really give it a shot and apply it to real-life situations and industry.”

Chan and his team collaborated with Dr. Trong Dang-Vu from SNF Canada (opens in a new tab), a company specializing in water treatment solutions. “They were able to guide us in terms of what industry is looking for,” says Chan. “They also provided us with tailings samples from mines, so in further research we’ll see if we can use those samples and see just how effective this approach really is.”

Source:  Chan, Michael, Huu Doan, and Trong Dang-Vu. "An Investigation of Lanthanum Recovery from an Aqueous Solution by Adsorption (Ion Exchange)." Inorganics 12, no. 9 (2024): 255. https://doi.org/10.3390/inorganics12090255 (opens in a new tab)