Direct utilization - recovery of minerals from coal fly ash. Technical progress report, April 1-June 30, 1982. [HiChlor process]

Research on the chlorination of coal fly ash has included the evaluation of several reducing and chlorinating agents for use in the HiChlor process. Several additional coal fly ashes were chlorinated to demonstrate that processing is usable for a range of bituminous coal fly ash compositions. Aqueous separation research for purification of the mixed metal chloride products was initiated. Exploratory evaluation of the potential for using a fused salt media for coal fly ash chlorination coupled with a thermodynamic study of the possible reactions provided encouragement for pursuing this alternative chlorination procedure. The use of a fused salt should significantly improve the process reaction kinetics and the potential for more selective chlorination of specific oxides. Research was continued on the development of a desilication procedure to remove dissolved silica from lime-soda filtrates. Essentially all of the silica (less than 150 ppM) must be removed from solution before an alumina product suitable for aluminum metal production can be recovered. Further experiments were conducted on the magnetic separation of coal fly ash - water slurries. Counter-current air sparging was used to increase the agitation inside the magnetic grid volume but the separated products were still not of comparable quality to those obtainedmore » by dry separation using a moving-field electromagnet.« less