Influences of the Physical Properties of Powders upon the Mixing Degree and Mixing Speed of Several Types of Mixers

Abstract

In our previous papers, we reported on the optimum operating conditions of several types of mixers, [twin-shell (V-), double-cone (DC-), cubic (C-) and horizontal-cylinder (HC-) types] for one pair of dry powders, Na2CO3-polyvinyl chloride.In this paper, we make reports of our examination of the influences of the physical properties of powders upon the mixing degree and mixing speed of several types of mixers, as to several powders shown in Table 2 and several pairs of powders shown in Table 1.What were made clear by our experimental results are:1) With the same type and size of mixers, the optimum rotational speed of the mixer Nop(=Ns, σ) and the charged volume of the powder (Fb/V)op are constant for all pairs of powders having the same particle size distribution (as shown in Table 1).2) The influences of the physical properties of powders upon the mixing degree and mixing speed are described by the difference of characteristic constant CR (obtained by Equation 7 or Fig.3) of both powdersa) As ΔCR increased, the values of σs increased as shown in Fig. 7.b) As to the mixing degree, V- & C-type mixers are not suited to the mixing of the powders whose ΔCR is big, while HC- & DC-type mixers are recommendable for the mixing of the powders whose ΔCR is big.c) As to the mixing speed, a good mixing speed is expected of V- & C-type mixers for the mixing of the powders whose ΔCR is big, as shown in Fig. 7 and Table 3.