Advanced research and technology: direct utilization, recovery of minerals from coal fly ash. Fossil energy program. Technical progress report, July 1-September 30, 1980

Abstract

This investigation is to develop methods for utilizing coal fly ash through processes for the extraction of alumina and titania, and for the separation and use of an iron-rich fraction. Research of the HiChlor process for the extraction of alumina and titania by high-temperature chlorination of a fly ash-reductant mixture is described. An engineering cost evaluation is presented for a centralized HiChlor processing facility to process the fly ash of several large coal-fueled power stations. Investigations for a high-temperature lime-soda process for extraction of alumina from fly ash included the use of several types of quarry limestones and waste materials to replace the limestone and/or soda ash. A breakthrough was made on the development of a limestone-fly ash process without soda. The addition of less than 5% by weight waste coal refuse to the sinter mixtures increased alumina recoveries from a 55 to 90%, at a much lower sintering temperature of 1200/sup 0/C. For the lime-soda sinter process, an engineering cost evaluation was prepared for a facility to process the fly ash from a 1000 MWe coal-fueled power station to produce alumina and Portland cement. This facility will process and dispose of the total generated fly ash volume as products rather than as waste, and the facility investment will be less than 10% of the cost of the corresponding power station. The magnetic fly ash fraction, separated before either HiChlor or sinter processing, was shown to have a market value as a heavy medium material for coal and ore beneficiation. Research was also conducted on the upgrading of magnetic fly ash to iron ore quality. Research of coal beneficiation using magnetic fly ash media was expanded.