Abstract
In this study, Central Appalachian coal-derived fly ashes from two power plants were beneficiated in a pilot-scale facility in order to produce a product with a relatively consistent concentration of rare earth elements (REE). The <200-mesh final fly ash product was produced by removing the carbon-and Fe-rich particles prior to screening at 200 mesh (75 µm). The Plant D fly ash had high concentrations of CaO and SO3, which were diminished through the two months when the ash was being beneficiated, representing a consequence of the heat, humidity, and excessive rainfall in the Kentucky summer. The high CaO and SO3 concentrations through the early runs likely contributed to the lower REE in the <200-mesh products of those runs. Of the non-REE minor elements, Ba, V, Mn, Zn, and As showed the greatest between-run variations within the runs for each plant. The overall REE concentrations proved to be similar, both on a between-run basis for the individual fly ash sources and on a between-plant basis. Variations in fly ash quality will occur in larger-scale operations, so on-going attention to the fly ash quality and the response of the fly ash to beneficiation is necessary. Changes in the Plant D fly ash with time imply that both the freshness of the original ash and the length and conditions of its storage at the site of beneficiation could be factors in the quality and consistency of the processed fly ash.
Original language | English |
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Article number | 105 |
Journal | Minerals |
Volume | 10 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2020 |
Bibliographical note
Publisher Copyright:© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Funding
Funding: This study was completed as part of the U.S. Department of Energy contract DE-FE0027167. We thank our editors and reviewers for their constructive remarks.
Funders | Funder number |
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Michigan State University-U.S. Department of Energy (MSU-DOE) Plant Research Laboratory | DE-FE0027167 |
Keywords
- Coal combustion
- Critical elements
- Rare earth elements
ASJC Scopus subject areas
- Geotechnical Engineering and Engineering Geology
- Geology