Upgrading of Low-Grade Colombian Coals via Low-Cost and Sustainable Calcium Nitrate Dense Media Separation

Williams, Orla Sioned Aine; Daley, Patrick; Perkins, Joseph; Martinez-Mendoza, Karen Lorena; Guerrero-Perrez, Juan; Mazabuel, Lyna Maria Sabogal; Saavedra, Edward Andres Garcia; Trujillo, Maria; Barraza-Burgos, Juan; Barajas, Maribel; Romero, Manuel Hernando; Lester, Edward Henry

Abstract

Wet coal beneficiation in Colombia is prohibitive due to the high cost and scarcity of commonly used dense media. The practical value of this study is that it demonstrates for the first time that a common fertilizer, calcium nitrate, can be used in the beneficiation of low-grade Colombian coals. Three high-ash low-grade Colombian coals (Valle, Cundinamarca, and Antioquia) commonly used in Colombian sugar mill stoker furnaces were tested. Coal mineralogy and prevalence were analyzed before and after washing using mineral liberation analysis. The swelling potential of the coals was assessed using a novel application of thermal mechanical analysis (TMA) and an ash fusion oven (AFO). Calcium nitrate reduced ash levels across all size fractions, even for high-ash coals like Valle (29% to below 7%) to acceptable levels for coke manufacturing or pulverized fuel combustion. The novel use of TMA and AFO to analyze coal swelling demonstrated that swelling varies under constrained and unconstrained conditions and the small sample size allows for rapid testing of coal swelling. This study has demonstrated that the use of common fertilizers can allow beneficiation to become a processing option for low-grade coals in Official Development Assistance countries where conventional dense media is prohibitively expensive.

Citation

Williams, O. S. A., Daley, P., Perkins, J., Martinez-Mendoza, K. L., Guerrero-Perrez, J., Mazabuel, L. M. S., …Lester, E. H. (2022). Upgrading of Low-Grade Colombian Coals via Low-Cost and Sustainable Calcium Nitrate Dense Media Separation. ACS Omega, 7(4), 3348-3358. https://doi.org/10.1021/acsomega.1c05346

• Journal Article Type: Article
• Acceptance Date: Jan 4, 2022
• Online Publication Date: Jan 19, 2022
• Publication Date: Feb 1, 2022
• Deposit Date: Jan 12, 2022
• Publicly Available Date: Jan 19, 2022
• Journal: ACS Omega
• Electronic ISSN: 2470-1343
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 4
• Pages: 3348-3358
• DOI: https://doi.org/10.1021/acsomega.1c05346
• Keywords: General Chemical Engineering; General Chemistry
• Public URL: https://nottingham-repository.worktribe.com/output/7224185
• Publisher URL: https://pubs.acs.org/doi/abs/10.1021/acsomega.1c05346