Application of Image Analysis Method for Particle Size Measurement in Salt

Abstract

The measurement of salt particle size should be employed with an alternative to the standard sieving method, to simplify and improve the efficiency of the process. With this in mind, we investigated ways to correct the data for particle size measurement of salt samples by applying image analysis method as an alternative. Initially, we classified tens of thousands of image analysis data according to the same particle size categories used in sieving, allowing for a comparison between the results obtained from both methods. The representative values （cumulative particle volume） for each category were calculated, thus aligning the number of data points with those of the test sieving. Subsequently, we developed a mathematical formula to correct for the particle variation caused by the angle at which the particles are captured in the image, a phenomenon unique to image analysis method, as well as the impacts various sieve types exert on the measurement results. Upon applying these correction formulas to the measurement of cubic and irregularly-shaped salt particle sizes, the relative error in the mean particle size（d₅₀）obtained from the sieving and image analysis methods was reduced from over 9 ％ to below 5 ％. These results confirmed that the applied corrections are practical and that the image analysis method has great potential as an alternative to the test sieving.