Mineral composition of atmospheric particulates around a large coal-fired power station

The present work is a mineralogical study of atmospheric particulates around a large coal-fired power station in NE Spain. After a mineralogical study of the fly ash sampled in the electrostatic precipitators of the power station, several chemical and mineralogical patterns of the fly ash were employed as tracers of the power station emissions. At the same time, the study focused on the downwind evolution of secondary particulate matter, especially particulate sulphate. The studies on the mineralogy of air borne dust allowed us to distinguish between natural and anthropogenic particles. The major mineral phases identified in the samples studied were: gypsum, calcite, clay minerals (kaolinite, clinochlore and illite), quartz, talc and hematite. In addition to these mineral phases which are frequently present in the atmospheric particulate matter of the studied area, other mineral phases, such as feldspars, mullite, and copper sulphates, were detected in minor proportions. The results show that some mineralogical and morphological characteristics of the atmospheric particulate matter may be used as tracers of the influence of coal-fired power plant emissions. These characteristics include spherical morphologies, aluminosilicate glass, mullite, hematite and sulphate-fly ash associations. The possible buffering effect of atmospheric Ca-bearing minerals to neutralize the sulphate deposition is investigated.