Proposal for Phase II
Recovering REEs from coal ash is a fairly new concept. Numerous studies have been reported in available on REE extraction from conventional ore deposits; however, very few literature is available on chemical extraction of REE from coal ash. In recent years, several studies (Akdogan and Ghosh, 2014; Franus et al., 2015; Honaker et al., 2014; Miskovic, 2015; Sundararajan et al., 2015) have been reported on REE characterization of coal fly ash and physical separation studies to preconcentrate REE from coal fly ash. At this point we are 4 months into the Phase-I project. Within this short time, we have generated sufficiently encouraging results to move forward for ourPhase-II study. We are looking into ash samples generated from burning coal samples in a controlled laboratory environment. Our Phase II feedstock ash samples will be collected from the utility plant site(s).
Big-picture factors such as the project’s innovative aspects and its potential to challenge or shift current research or engineering paradigms, clear goals and technical soundness: So far, US’s REE needs have been met 75% by imports (mostly from China) and 25% by REEs extracted from conventional deposits in the US, like MolyCorp’s Mountain Pass Mine. However, for strategic reason, it is imperative to find alternative sources for rare earth elements, whose demand is rapidly increasing. Recent studies have indicated that coal and thus coal ash contains REE in small concentration, i.e., in the range of 50 to 1000 ppm. Bryan et al. (2015) estimates the presence of close to 11 million tons of REOs in coals from eastern and western States of the US in comparison to only 1.8 million tons of REE present in conventional ore deposits. Coal being so abundantly available in this country and losing its share in the energy portfolio, coal and coal ash could become the future source of REE if an economically viable and environmentally benign extraction flowsheet can be developed.
Project objectives, outputs and outcomes, and how they will be achieved and tracked/measured:
The overall goal of our P3-Phase II study is to investigate various extraction methods of REEs from coal combustion byproducts generating at the coal utilities and develop a sustainable process flowsheet(s) to produce REEs. The specific objectives to accomplish the overall goal are
- To characterize coal fly ash and bottom ash samples collected from two different sites and investigate the feasibility of extracting rare earth minerals and elements using combined physical and chemical separation techniques.
- To investigate environmentally benign bioleaching and biosorption techniques in a laboratory scale in place of conventional acid leaching step to reduce the environmental footprint of the REE extraction process.
- To investigate solvent impregnated resins/beads in contrast to conventional solvent extraction process to reduce the environmental footprint of the REE extraction process.
- To conduct an economic analysis to estimate the REO extraction cost in full-scale applications. According to a recent US DOE announcement (2015), the REE concentration in the final product should approach 2% to be of commercial interest. Therefore, 2% REE concentration in the final product will be our target to justify the achievement of our goal.
End users and how they are engaged: The end users of the processing scheme to be developed in the proposed study are the coal utility companies who are either producing fly ash and bottom ash or have a huge stockpile of it from the past. One such company has shown significant interest in our work as evident from the attached support letter.
Approach, procedures, and controls for ensuring awarded grant funds will be expended in a timely and efficient manner: Our lead faculty adviser has successfully supervised many large projects in the past. More importantly, he has also supervised a P3-Phase II grant, which completed about a year ago. Budget amount for each project year has been allocated for specific budget lines with justification for the budget items. Our university provides accounting help to keep track of individual project accounts on a monthly basis.
Approach for ensuring successful achievement of project objectives and project timeline: To achieve the above-mentioned project objectives, the entire project work to be completed over a 2 year period will be divided into following seven specific project tasks. The project timeline is listed within parenthesis, in terms of project month; for example, Task 1 will be completed during the project months 1st and 2nd .
Task 1: Sample collection and characterization (Months 1-2)
Task 2: Physical separation tests (Months 3-5)
Task 3: Chemical leaching tests (Months 6-12)
3.1: With acid
3.2: With alkali
3.3: Mild reagents, like Ammonium sulfate
Task 4: Bioleaching tests (Months 6-12)
Task 5: Solvent extraction, scrubbing, precipitation and calcination tests (Months 13-22)
5.1 Conventional approach
5.2 Use of solvent impregnated beads
Task 6: Economic Analysis (Month 23)
Task 7: REE extraction course development (Months 19-24)
Budget: $74,995 for the total project period of two years starting October 1, 2016.
Partnerships: Southern Illinois Power Co-Op (letter attached)
- Embodiment of sustainability as described in the sustainability primer: Sustainability primer classifies sustainability in terms of its three categories: environmental, social and economic. Each sustainability category has several subgroups. Our proposed study will address the “resource integrity” and “ecosystem service” aspects of the environmental sustainability category. For the social sustainability category, our project will address the “resource security” and “education” components. The “supply and demand” aspects of the economic sustainability category will also be addressed in the proposed study.
- Outcomes that benefit the intended users and/or society: The success of the proposed study may lead to the commercialization of the REE extraction concept from fly ash and bottom ash in future. This will make US less dependent on foreign imports of REEs, which has much strategic importance because of its use in defense and high technology applications.
- Potential for implementation, adoption, and long-term viability: The potential for implementation of the proposed conept will depend on the REE extraction cost and extraction process scheme’s environmental footprint. We have proposed specific tasks to reduce the environmental footprint of the process, for example by the use of bioleaching instead of conventional acid or alkali leaching.
Education and Teamwork
- The project’s potential as a tool for teaching sustainability principles: The project is about finding a critically needed resource (REE) in hundreds of millions of tons coal ash discarded in ash ponds at the utility sites all over the country. So the project is everything about sustainable utilization of natural resources in that coal has been mined primarily to meet our electricity need and the project proposes recycling and reuse of a valuable part of the the coal waste and treating the hazardous part of the waste in an envrionmetally safe manner. This will result in opening lesser new mines extracting REEs from conventional REE deposits in the US, but at the same time making us use REE from indigenous sources. The lead faculty adviser and the principal investigator for the project has already started the process of creating a graduate level course, which will attract undergraduate students as take elective. It may be noted that four undergraduate students, including two from mining and mineral engineering area and one from the biotechnology area will be involved in this project as student team members.
- Project design reflects interdisciplinary teamwork and student abilities: The proposed Phase II study will involve an interdisciplinary team of nine graduate students (five Ph.D. and four MS) and four undergraduate students under the supervision of six faculty advisers from five different disciplines, such as mining and mineral process engineering, civil and environmental engineering, geology, chemical and energy engineering and finally, biotechnology. There will be two Co-Student Team Leaders for smooth operation of the project. The principal investigator will meet the two student team leaders once a week. The team leaders meet all student participants once in two weeks and the entire project group will meet once a month to discuss the project progress and brain-storm the project needs.
- Phase II transition plan: The project team will change to some extent from the Phase- I to Phase-II study. However, the lead student members and the faculty advisers continue to be the same. The team will keep working on the remaining parts of the Phase I project until the Phase II projects are awarded.