Harvesting Rare Earths from Wastes

Rivalia Chemical Co. is pioneering new chemical extraction technology to solve two important problems: critical mineral scarcity and coal ash waste management. The U.S. has more than two billion metric tons of coal fly ash containing valuable rare earth elements; what is missing is a sustainable and scalable separation method. Rivalia harvests rare earths from ash, then transforms the residual for green concrete.

Critical Need for this Technology

Critical minerals, namely rare earth elements (REEs), have played invaluable roles in clean energy technology and high-tech manufacturing for decades. These technologies depend heavily on REEs’ unique properties, and to date, no adequate replacements for these high-performing elements have been developed. Important REEs include neodymium and praseodymium, used in permanent magnets in electric vehicles and wind turbines, and scandium, used in solid oxide fuel cells and high-strength aluminum alloys in aircraft. REE demand is anticipated to skyrocket, driven by green technologies and advancing electronics.

The U.S. lacks a stable domestic supply of rare earths and depends heavily on China for its supply. Given the long lead times needed for traditional mining (permitting, raising capital, exploration, to construction and operations), harvesting rare earths without mining becomes a necessity. Rivalia’s founder, Laura Stoy Ph.D., developed a patent-pending method that extracts rare earths from coal ash, a product of coal combustion for electricity generation that’s enriched in rare earths. With over 130 million metric tons of coal ash produced annually in the U.S., along with decades of accumulation in storage ponds, vast quantities of this material are available for rare earth element harvesting.

Ultimately Rivalia seeks to build a platform technology agnostic to input, processing any REE-rich material into an enriched REE product and useful byproducts.

Supplemental Need for this Technology

After harvesting rare earth elements, Rivalia will process the residual ash solid for use in concrete, where it substitutes for Portland cement. Cement production produces large amounts of CO2 (nearly three billion tons in 2021). Reclaimed ash can replace 20-40% of cement, thus creating an opportunity to decrease cement production.


  • Traditional mining (largely based in China, Malaysia,)
  • Recyclers (permanent magnets, tailings)

Potential Markets

  • Rivalia’s mixed rare earth element product will be sold to a rare earth element separations company for further purification before use in end products like permanent magnets used in wind turbines, electric vehicles, consumer electronics, and like catalysts and petroleum refining, among others.
  • The residual ash will be processed for use in concrete and other construction products (geopolymer feed, roofing, fill material, etc.).

Key Innovation

Rivalia’s key innovation is a patent-pending chemical extraction process for harvesting rare earths from coal ash and other industrial wastes.

R&D Status of Project

Rare earth harvesting process demonstrated at bench scale for representative coal ash samples. Optimization and scale up currently underway; exploration of additional ash classes and waste types also underway to determine feedstock viability.

Team Overview

Laura Stoy, Ph.D., CEO and Founder:  Stoy is an experienced entrepreneur, inventor, and scientist passionate about onshoring critical mineral supply chains. She earned a B.A. in Chemistry from Vanderbilt University and a Ph.D. in environmental engineering from the Georgia Institute of Technology, where she developed a now patent-pending rare earth element recovery technology. She founded Rivalia Chemical Co. to commercialize that technology and completed Energy Techstars in Birmingham, Alabama, in the fall of 2022. Prior to founding the company, she worked for the Environmental Protection Agency and with the Federation of American Scientists on critical mineral supply chains.

Technology Profile

Status: pre-seed
Primary industry: Mining, Advanced Manufacturing, Chemical
Category (i.e. tech keywords): critical minerals, rare earth elements, green concrete
Estimated annual revenue: n/a
Employs: n/a
Social challenge: n/a
R&D commercial collaborator: n/a