Investigation about data reduction and sedimentation distance of sedimentation balance method

摘要

The Sedimentation balance type particle size analyzer is improved. The slurry supply device was automated and the height of peripheral wall of the detective tray was raised. As a result we can acquire data of the sedimentation mass change accurately. Moreover, the ratio of measured total sedimentation mass to the theoretical total sedimentation mass was kept constant ranging from 1.00 to 1.02 independent of particle size. By the above improvement, we can develop a more precious sedimentation balance. Twomey's non-linear iteration method was applied to retrieve a particle size distribution from the sedimentation curve measured with a sedimentation balance method. It is found that the non-linear iteration method can calculate size distributions accurately. Furthermore, the influence of the thickness at the base of the detective tray on the sedimentation distance was also investigated. As a result, it is clarified that the change in detected mass did not depend on thickness at the base of the tray. Therefore, it is concluded that the sedimentation distance in the sedimentation balance method should be defined as the distance between the lower surface of the base of the tray and suspension surface. [References: 6]