The effect of sieve loading and particles shape on the results of polymer sieve kinetics

Abstract

An experimental investigation has been made into the effects of different factors on the results of screening efficiency of polymer samples. The used polyvinyl chloride (PVC) samples have equal content of `small`, `large` and `small-to large` particles and filled the whole area of the sieve in one, two and four characteristic layers during the screening. Visual examination showed that the particle shape was similar in whole particle size distribution in the one sample tested. In addition to the aforementioned variable, the other factors studied included samples shape, vibrating amplitude and the duration of screening. Analysis of the obtained results of the screening rate in laboratory conditions was performed by applying the classical and modified model of the first order screening kinetics. The results showed that high loading of the sieve requires a larger vibrating amplitude for good classification and that the high layer reduction of sample is a more effective remedy for good efficiency than prolongation of sieving time. It has also been shown that the particles shape has a significant impact on the screening rate. The modified kinetics model (Magdalinović–Trumić) of the first order describes polymer screening kinetics with very good correlation coefficient in all cases. The application of the classical model is not adequate for determining a screening rate constant since the correlation coefficients are smaller than the minimum correlation coefficient.