The new expression of the effectiveness of powder classification

In this paper, the authors try to propose a new index—‘the classification size ratio (CSR)’ —which is defined as CSR = (Dv(10) of the coarse part)/(Dv(90) of the fine part). The CSR can be used to judge effectiveness of separation between coarse and fine powder. If CSR ≥ 1, it represents the classification to be considerably good in separating into two groups of powder; however, if CSR << 1, it represents poor separation of powder. After careful discussions, Dv(10) and Dv(90) are suitable for describing the classification effectiveness because most optical instruments will report these data. Results also show that the new expression, i.e. CSR, is a good index for describing the effectiveness of powder classification and this idea deserves to be promoted for future utilization.