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

Abstract

The purpose of this investigation is to develop methods to utilize coal fly ashes through processes for the extraction of alumina and titania, and for the separation and utilization 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 has involved comparative calculations for several fly ashes, and the design of a bench-scale fluidized chlorination system. The initial chlorination research of the high-volume fly ashes from western coals was begun. Process development of the sinter process for alumina recovery has included the investigation of several variables for improving the quantity and quality of the alumina extracted from sintered materials. As a result of this work, it is clear that further optimization of the sintering and extraction variables is required for commercialization of the fly ash sinter process. Iron-rich, magnetically separated coal fly ash particles were beneficiated to a quality equal to high grade, naturally mined iron ore by a high-temperature pressurized caustic treatment. About 95% of the contained silica and 65% of the alumina was extracted. Work was begun on the assembly of equipment for a detailed comparison of magnetically separated iron-rich fly ashes and commercialmore » magnetities for use in heavy media coal beneficiation. Characterization of the particles, ad stability and rheological properties of media solutions prepared with these materials will provide data for further evaluating magnetic fly ash as a heavy media material. A circuit is also being built for long-term flow tests of the media suspensions for measurement of construction material erosion and solid medium particle friability.« less