About one-third of the US electric power comes from coal-driven power plants generating a huge amount of ash. The advancement and increasing interests in green energy production and environmental protection technologies have spurred the demand for the use of fly ash in concrete and rare earth elements (REEs) extraction. As fly ash is considered a hazardous material, the reuse and recycling in the construction sector and extraction of REEs are considered promising applications of coal combustion fly ash. The high demand for REEs in defense and national security sectors intrigues the use of fly ash for the extraction of REEs that suppresses the environmental issues associated with mining and processing. This paper aims to derive a comparative life cycle assessment (LCA) of coal fly ash as recycled material in the construction and extraction of REEs. The gate-to-gate approach is considered in this paper in LCA of fly ash, with the system boundary being defined as fly ash used in concrete and extraction of REEs. After the generation of coal fly ash, the collection, transportation, disposal, reuse, and recycling are considered for the LCA analysis. The functional unit (FU) is the amount of fly ash reused or recycled in REEs extraction or concrete. Global warming potential, mineral resource use, and energy use are considered for the comparative LCA for reuse in concrete and REEs extraction. Although no cost-benefit analysis has been carried out in this study, we depict the broad area of fly ash recycling and reuse potential in different beneficial uses to reduce landfill and quarry disposal burden.

Comparative life cycle assessment (LCA) of coal fly ash recycling or reuse

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.