The design of a feeding or pneumatic conveying system is heavily influenced by a bulk solid’s particle shape, size (aspect ratio) and particle size distribution as well as the particle’s roughness, hardness (abrasiveness), and density. In the case of calcium carbonate these characteristics vary widely depending on the source and production process for the individual samples. The sieve analysis below illustrates the difference in particle shape, particle size and particle size distribution for two samples of calcium carbonate.