Abstract
It is shown how a quantitative interpretation of the well known difference of particle size measurements (sedimentation and low angle laser light scattering) can be used to yield information on particle shape. Three kaolin types with different granulometry and composition were investigated. The concept of a median shape factor is introduced and a simple approximative equation is given to calculate it from results of routine size measurements. This median shape factor may be advantageously used as an index for the routine characterisation of powders with anisometric particles. For the kaolins investigated the value of the shape factor is shown to correlate well with the content of (more isometric) quartz grains. In contrast to the statistical method of shape determination by optical image analysis the ensemble method proposed here is less time consuming, does not require sophisticated sample preparation or specialised operators, and can be easily automated.
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