A comparison between two methods of shape-sorting particles

Two methods of shape-sorting powders have been compared using two very different feed materials (citric acid monohydrate and sodium perborate tetrahydrate). The particles in each shape-sorted fraction were characterised in terms of their length, width, thickness, surface area, volume, projected perimeter, projected area and density. These data were used to calculate a number of simple shape factors, the most useful of which proved to be the operational sphericity and the Heywood shape factor. Both the vibrating deck and the slotted sieving methods sorted each of the materials according to shape, but while the vibrating deck has a greater throughput, the sieving method gives greater sample homogeneity, is directly quantitative and is simpler to perform.