LSU Researcher Mines Red Mud for Critical Minerals

For more than a decade, LSU Professor of Research Amitava Roy has labored anonymously studying the contents of “red mud,” until recently considered a waste product from alumina processing.

“It was just my scientific curiosity. Many years ago, I was given some samples from the bauxite tailings at Gramercy. I wanted to see what was in them,” Roy said.

His job at the Center for Advanced Microstructures and Devices (CAMD), whichis in the process of being rebranded as Louisiana Light Source and positioned as a research core facility at LSU, gives him access to high-intensity X-ray “beamlines” that can identify and quantify elements and reveal their chemical environment. When the beamlines were available and Roy had spare time, he analyzed the samples’ content.

Among other things, he found the red mud contained high levels of gallium, which is listed by the U.S. Department of Energy as a high-risk, high-value critical mineral and used in semiconductors, microwave circuits, high-frequency transistors, and radiopharmaceuticals for medical imaging and diagnostics.

While Roy found the results interesting, his research didn’t attract much attention. But attitudes changed dramatically in the last few years as the viewpoint on red mud shifted from environmental headache to strategic resource.

Gallium is essential to modern electronics and technology, while China controls nearly all of the world’s gallium.

There are more than 30 million tons of red mud or bauxite residue on the grounds of the Atlantic Alumina (Atalco) plant in Gramercy, the only such U.S. facility.

In November, Texas-based ElementUSA announced a $29.9 million federal award for a demonstration plant in Gramercy that will tap Atalco’s stockpile to extract gallium and scandium, used in aerospace alloys. In December, ElementUSA announced it will build an $850 million commercial-scale extraction facility in Gramercy. In January, Atalco announced a $450 million strategic partnership with the federal government to create the country’s first large-scale gallium production plant. Atalco's plant will use the same method as other large facilities around the globe, removing gallium from the liquid produced when bauxite is processed, not the stored red mud.

Roy is not working with ElementUSA or Atalco but believes there could be commercial opportunity for his work.

A consultant for the Canadian mining industry has been using CAMD’s services for several years to consider similar questions. The consultant, who serves as one of CAMD’s scientific advisers, has been in touch with ElementUSA and visited the company’s facility.

“A confluence of interest is developing,” Roy said.

CAMD has some of the most powerful tools available for analyzing critical minerals. The synchrotron radiation facility is one of only seven in the United States and one of two university-owned centers.

State support makes it much easier for outside users to access services, Roy said. Going through a federally supported center requires a much lengthier process.

Roy said CAMD’s tools can help producers determine if critical minerals like gallium are economically recoverable. Gallium locked inside the mineral structure of a material requires a complicated and costly chemical extraction process. Gallium loosely bound to the material’s surface is much easier to extract.

“In red mud, the loosely bound elements are often arranged in messy, disordered clusters. They are not well crystallized,” Roy said.

That’s important because standard X-ray diffraction can’t “see” the disordered elements, meaning a potential reservoir of valuable resources remains invisible. CAMD’s X-ray absorption spectroscopy (XAS) beamline can analyze amorphous material sample sizes in the micrograms, roughly the weight of grain of sand.

“The techniques available here are very, very useful. They can be applied to any number of materials, not just red mud,” Roy said.

The United States has launched a number of initiatives to accelerate domestic critical minerals processing and production. Figuring out where the different elements are concentrated will take thousands or even millions of measurements.

“In every case, you need to know how they are there, what procedure you can use to extract them, and whether your process is working or not,” Roy said. “All of these questions can be answered here at LSU.”