Iron Phases in Brown Coal Ashes

Iron-57 Mössbauer spectroscopy has been used in three areas of analysis of precipitator ash and deposits resulting from the combustion of Victorian brown coals. The principal iron-containing constituents identified in the samples were two mixed oxides (calcium aluminoferrite and magnesioaluminum ferrite). The changes occurring in some of the phases by altering the combustion conditions and during wet agglomeration are described. This work is aimed at developing a systematic description of relative phase stabilities for different flyash compositions, based on chemical analysis of the coal.