M. A. Vera

Simultaneous determination of collection zone rate constant and froth zone recovery in a mechanical flotation environment

Abstract This paper presents the results of an investigation in which the new JKMRC Flotation Cell was used to determine the collection zone rate constant and froth zone recovery of a copper rougher ore simultaneously. The determination of these two parameters has been based on the straight line relationship that exists between the overall flotation rate constant and the froth depth [1]. Experimental work was conducted using a copper rougher ore with a P 80 of 200 μm. Operating variables such as air flow rate, impeller speed, feed percent solids, collector and frother dose, and wash water flow rate were investigated. Analysis for copper and iron minerals (chalcopyrite and pyrite, respectively) was carried out. The results indicate that the collection zone rate constant of both copper and iron minerals increased with increasing air flow. Froth zone recovery, on the other hand, decreased as air flow was increased, possibly as a result of increased detachment of particles from bubbles in the froth. Increasing the impeller speed also increased collection zone rate constant and decreased the froth zone recovery of both minerals. Experiments at different wash water flow rates have showed that events occurring in the froth zone do not affect the kinetics of the pulp zone. Moreover, and interestingly, the froth recovery of attached particles (wash water reduced entrainment to a minimum) was non-selective. The froth recovery curves for chalcopyrite and pyrite followed each other very closely in every instance studied. The work has proved that it is possible to measure both the collection zone rate constant and froth zone recovery simultaneously and continuously in a mechanical flotation environment. The results obtained to date are interesting and the work is continuing.

The modelling of froth zone recovery in batch and continuously operated laboratory flotation cells

This paper proposes an integrated methodology for modelling froth zone performance in batch and continuously operated laboratory flotation cells. The methodology is based on a semi-empirical approach which relates the overall flotation rate constant to the froth depth (FD) in the flotation cell; from this relationship, a froth zone recovery (R,) can be extracted. Froth zone recovery, in turn, may be related to the froth retention time (FRT), defined as the ratio of froth volume to the volumetric flow rate of concentrate from the cell. An expansion of this relationship to account for particles recovered both by true flotation and entrainment provides a simple model that may be used to predict the froth performance in continuous tests from the results of laboratory batch experiments. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved.

The JKMRC High Bubble Surface Area Flux Flotation Cell

The High Bubble Surface Area Flux Flotation Cell (HSbFC) is a 16-litre mechanical flotation cell with a bottom driven impeller, which is operated continuously. Bubble formation is carried out using an in-line mixer which enables the cell to achieve superficial gas velocities (J(g)) equivalent to those generated in industrial flotation cells (0.7-1.2 cm/s). At the same time, the cell produces considerably smaller bubble sizes, consequently, a high bubble surface area flux (Sb) Can be generated