Grinding of Coriander Seeds: Modeling of Particle Size Distribution and Energy Studies

Coriander seeds were ground in an impact type hammer mill and a pin mill to study the pattern of particle size distribution and their relationship with energy consumption. The particle size distribution for all samples was best described by the Rosin-Rammler-Bennett (RRB) and model with high degree of correlation coefficient compared to the Gaudin-Shumann (GS) model and Log-normal function. Particle size distribution was also characterized by various size parameters such as: uniformity index, size range variation coefficient, mass relative span, skewness, kurtosis, size guide number, coefficient of uniformity, and the coefficient of gradation and geometric standard deviation. Energy consumption for grinding was studied based on classical grinding laws, namely, Bond's, Rittenger's and Kick's law. Bond's Work index varied from 0.5 to 4.3kJkg(-1) depending on the size reduction ratio. Energy consumption followed a linear relationship with size reduction ratio.