Environmentally Friendly Economical Sequestration of Rare Earth Metals from Geothermal Waters
- Tusaar Corp., Lafayette, CO (United States)
The purpose of this work was to complete a proof of concept study to apply and validate a novel method developed by Tusaar for the capture and recovery of rare earth elements (known as REEs) and other critical and valuable elements from geothermal waters produced from deep within the earth. Geothermal water provides heat for power production at many geothermal power plants in the western United States. The target elements, the REEs, are vital to modern day electronics, batteries, motors, automobiles and many other consumer favorites and necessities. Currently there are no domestic sources of REEs while domestic and international demand for the products they are used in continues to rise. Many of the REEs are considered “strategically” important. A secure supply of REEs in the USA would benefit consumers and the country at large. A new method to recover these REEs from geothermal waters used at existing geothermal power plants around the country is a high priority and would benefit consumers and the USA. The result of this project was the successful development and demonstration of an integrated process for removal and recovery of the REEs from synthetic geothermal brines on a small laboratory scale. The work included preparation of model geothermal brines to test, selection of the most effective proprietary sorbent media to capture the REEs and testing of the media under a variety of potential operating conditions. Geothermal brines are generally very high in salt content and contain a wide range of elements and anions associated with the rock layers from which they are produced. Processing the geothermal water is difficult because it is corrosive and the dissolved minerals in the water precipitate easily once the temperature and pressure change. No commercial technologies have been shown to be effective or robust enough under these geothermal brine conditions to be commercially viable for removal of REEs. Technologies including ion exchange, traditional sorptive media and membrane concentration are too expensive, difficult or impossible to regenerate and easily rendered ineffective under these working conditions. The work completed during this project has demonstrated that a selective media that is robust and durable under the conditions associated with geothermal brines is possible. The initial economic analysis indicates that the process would not be financially viable at current market prices for REEs. The world market price for REEs has been turbulent over the past several years and are currently near historical lows. Historical trends and market forces suggest that the world price is stabilizing and will rise. At the same time, further development has the potential to reduce the costs associated with the technology. This work opened the door to the idea that a large scale process for removal and recovery of REEs from geothermal brines is possible. Upward price pressures coupled with technology improvements suggest that this process has the opportunity to be commercially successful at a point in the future.
- Research Organization:
- Tusaar Corp., Lafayette, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Geothermal Technologies Office
- DOE Contract Number:
- EE0006751
- OSTI ID:
- 1373883
- Report Number(s):
- DOE-Tusaar-EE0006751
- Country of Publication:
- United States
- Language:
- English
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