A comprehensive technological approach for the selective recovery of aluminum oxide and rare earth elements from coal processing
Abstract
The primary aim of the research was the successful separation of both the aluminum oxide (Al2O3) and the rare earth elements (REEs) with the coal and the resulting coal fly ash (CFA). The issue in question was the selective recovery of valuable elements in CFA. It was suggested that the combination of gravity-flotation beneficiation, acid leaching, stage-wise precipitation with pH control, magnetic separation and flotation reagents was a comprehensive technological approach. The concentrations of aluminum and iron ions were found to be 7225 cps and 7000 cps, respectively. The results can be explained by the combination of selective chemical treatment and physical enrichment of coal fly ash. The main components were calculated as La, Ce, Sc, and Y. FTIR, UV-Vis, and SEM/EDS analyses indicated the presence of functional groups capable of binding REE in the flotation reagent. Using this method, it would be feasible to fully treat CFA while yielding a very pure Al2O3 and valuable REE products; thus, this method will also be environmentally friendly, low cost, and able to generate other types of waste materials. The findings can be implemented in the energy sector, metallurgy and chemical industries. In general, this method offers a modern and integrated answer to the issues of ecologically friendly and resource, saving utilization of coal fly ash, turning what could have been a beneficial industrial opportunity into a source of environmental pollution. In addition, the new methodology opens the way to the future of the further combination of the ion-exchange or membrane-based separation technologies, which will increase the possibility of even greater recovery yields of REE and the stability of the process