DEVELOPMENT OF A FROTH DROPBACK MEASUREMENT DEVICE

摘要

This paper presents the development of a new device which can collect the detached particles fromrnthe froth phase directly as they fall out of the froth. The device consists of two concentric tubesrnseparated by 10 mm gap and attached to a flotation column. The bubbles are loaded in the columnrnand rise through the gap between two tubes where a stable froth is formed. The particles that detachrnfrom the froth phase are collected in the inner tube, known as dropback chamber. Both dropback andrnconcentrate particles are collected, weighed and froth recovery is measured as fraction of particlesrnentering froth phase attached to air bubbles transferred as concentrate. Experiments have beenrnperformed using mixture of fine (60 G, d_(90) = 110 μm) and coarse (50 N, d_(90) = 370 μm) silica. Therninfluence of froth depth and the gap between the pulp froth interface and dropback catcher on frothrnrecovery has been investigated. Experiments have also been carried out varying the percentage ofrncoarse particles in the feed. Results have shown that the presence of coarse particles has a detrimentalrneffect on the froth recovery as well as on the froth stability.