A novel approach to prevent bubble coalescence during measurement of bubble size in flotation

ZHANG Wei(张炜)^{1, 2}, Jan E. Nesset², James A. Finch²

(1. Mining and Mineral Resources Division, Department of Business Administration,
Chinalco China Copper Corporation Limited, Beijing 100082, China;
2. Department of Mining and Materials Engineering, McGill University, Montreal, H3A 0C5, Canada)

Abstract:Effect of frothers in preventing bubble coalescence during flotation of minerals has long been investigated. To evaluate the performance of a frother, an apparatus to measure the bubble size is a basic necessity. McGill Bubble Size Analyzer (MBSA) or bubble viewer that has been developed and completed by McGill University’s Mineral Processing Group during the last decade is a unique instrument to serve this purpose. Two parameters which are thought to influence the bubble size measurements by McGill bubble viewer include water quality and frother concentration in the chamber. Results show that there is no difference in Sauter mean (D₃₂) when tap or de-ionized water was used instead of process water. However, the frother concentration, in this research DowFroth 250 (DF250), inside the chamber exhibited a pronounced effect on bubble size. Frother concentration below a certain point can not prevent coalescence inside the chamber and therefore caution must be taken in plant applications. It was also noted that the frother concentration which has been so far practiced in plant measurements (CCC75-CCC95) is high enough to prevent coalescence with the bubble viewer.

Key words:flotation; frother; bubble size; bubble coalescence