Characterisation of dusts from cement plants with respect to parameters relevant for storage and transport

In cement plants, large amounts of dust are generated and these have to be separated from various off-gases before discharge. The physical and flow properties of these dusts are important for the design and operation of the dust separation process and handling and storage facilities. In this study, five cement kiln dusts and three dusts from other sources in cement production were investigated. Shear tests showed that the flowability of most dust is very poor. Furthermore, the flowability depends on the consolidation stress: the higher the consolidation stress, the better the flowability. Three flowability indicators – the angle of repose, the Hausner ratio and Carr's compressibility – were also determined, but these indicators produced very inconsistent results. In most cases, the flowability of the dust was overestimated. Therefore, shear tests are strongly recommended for reliable categorisation of the flowability of dusts from cement plants.