Induction time measurements for the quartz—amine flotation system

Abstract An induction time apparatus which has a sensitivity limit of 100–150 μs has been constructed in the present work. The basic unit is similar to the one used by Eigeles and Volova and Trahar, but it operates with a microcomputer and has a greater sensitivity. Using this apparatus, the flotation chemistry of the quartz—amine system has been studied. It has been found that at a given dodecylaniminium hydrochloride concentration, the induction time is at a minimum at approximately pH 10.5. At this pH, the collector hydrolizes to form neutral amine and the flotation recovery reaches a maximum, suggesting that ionomolecular species are the surface-active species responsible for flotation. This finding confirms the earlier conclusions obtained using the surface tension and contact angle techniques. Induction time measurements have also been conducted as a function of particle size, collector concentration, indifferent electrolyte concentration, bubble change, and temperature. The results are compared with flotation data, and the activation energy for the bubble—particle adhesion has been calculated.