The Utilization of Fly Ash from Hungarian Coal-Firing Power Stations

摘要

The fly ash from coal-firing power stations can be utilised in many ways in accordance with international R&D reports and industrial experience. The great amount of fly ash is utilised in the cement and concrete industry. It can be used for the recovery of valuable by-components. rnSeveral research projects were carried out at University of Miskolc on the investigation of the possibility of utilising the Hungarian fly ashes. rnThe Ajka fly ash was investigated for the sake to enrich its uranium-content. It was revealed by XRD and scanning microscope with micro probe that the uranium has no defined crystalline phase, although the chemical assay of bi-dimensional fractions showed a significant concentration of the uranium in the finest heavy fraction. The zeta-potential of the separated U-rich and U-poor fractions was determined in a wide pH-range, without and with surfactants parallel with the flotation tests to establish the flotation technology for the preconcentration of uranium prior to the leaching unit. rnSeveral Hungarian fly ashes were investigated to classify them in accordance with their chemical and phase composition, alkalinity, mechanical properties, and potential utilisation as a cement substitute. The special chemical activation technology by fine grinding was elaborated to enhance the puzzolanic activity.