Particle size distribution analysis by sedimentation distance measurement in sedimentation tube

Abstract

Tangent line method and Twomey’s non-linear iteration method are applied to retrieve a particle size distribution from the sedimentation curve measured with a sedimentation distance in sedimentation tube. It is found that it is difficult to calculate the particle size distribution by the tangent line method using the sedimentation curve drawn from visual observation of the interface. On the other hand, the particle size distribution can be predicted numerically by Twomey method although the reliability is low. In order to improve the measurement accuracy, improved method to define the sedimentation interface using image analysis is investigated. Furthermore, introduction of correction term to Twomey method improves the reliability of the particle size distribution. As a results, this calculation method can be applied to measure particle size distribution not only for glass beads but also suspension concentrate of agricultural fungicide penthiopyrad.