湿式サイクロンの性能に及ぼすアンダフロー・ノズル口径の影響

抄録

The effects of the diameter of underflow nozzle(d_u)upon various performances of a wet cyclone were experimentally investigated using quartz pulp and 60-mm rubber-lined wetcyclone unit at the Mineral Dressing Laboratory, University of Tokyo. The results obtained are summarized as follows:
1)The underflow discharge observed was of vortex spray type when the underflow nozzle larger than 16-mm was used, whilst the rope type underflow was obtained for the nozzle diameter of less than 14-mm (Fig.2 and Fig.3), indicating that the transition point about nozzle diameter lay between 14 and 16-mm under the conditions applied.
2) For a particular diameter of underflow nozzle, flow ratio(Q_u/Q₀)was independent of feed inlet pressure (P)(Fig. 4), and the relationship between flow ratio and the ratio of discharge area(d_u²/d₀²)was different with the types of underflow (Fig. 5).
3) The ratio of underflow discharge velocity (v_u) to inlei velocity(v_i)in relation to nozzle diameter(d_u)took its minimum value around the transition point of underflow type (Fig. 8).
4) The thickening ratio (δ_u/δ_f)decreased linearly with increasing nozzle diameter (Fig. 9)
5) Solid-liquid separation was best around the transition point (Fig. 12).
6) The classification performance of a wet cyclone was highly dependent of underflow nozzle diameter. It was shown by Tromp distribution curves obtained that the separation size(d_T)and Terra index (ècart probable)(E_T)became larger with reducing diameter of nozzle (Fig. 13 and Pig. 14). Generally speaking the vortex-spray type underflow was superior to the rope type one from the viewpoint of classification operation.