Chapter 2 - Particle Size Estimation and Distributions

Abstract

This chapter is mainly based on particle size estimation and distribution. Particles in a mineral processing plant are of many different shapes and sizes, which make the characterization of the quantity and size very difficult. There are many ways to characterize the size of an irregular particle, with none being absolutely right. Main methods are microscopic method, particle size estimation in terms of volume and surface area, gravity sedimentation method, and centrifugal sedimentation method. The chapter describes all these techniques while emphasizing that all of these methods do not necessarily give the same measure of size for the same sample of particles. Hence, it is necessary to mention the measurement method when quoting particle size. Because sizing by different methods, such as sieving, cyclosizer and laser sizing, covers different size ranges, size distributions from different methods may need to be combined to give a complete size distribution. To determine particle size distribution main methods used are sieve analysis, log-normal distribution, Gaudin-Schuhmann distribution, and Rosin-Rammler distribution. Different methods of size measurement will give different size distributions. Generally, it is expected that irregular shaped particles will yield different sizing results when measured by different techniques.