Effect of suspension chemistry onto voltage drop: Application to electro-flotation

Electrochemical processes involving particle suspensions are still ill understood. Electro-flotation is process through which particles or ions can be selectively separated. Although the technique has been widely studied, not much is known about the effect of the chemistry of suspended particles on the process performance which constitutes the aim of the present research work.A column-type cell was designed to carry out electro-flotation experiments and standard air flotation experiments. Two minerals, Merensky reef and UG2, were tested.The classic air-flotation operation gave higher recoveries and grade of collected material compared to electro-flotation only when using Merensky reef ore. However, in the case of UG2 ore, the electro-flotation reached similar performance to that of the classic operation. It was found that the electrodes readily interact with the mineral pulp reducing the efficiency to generate bubbles. That efficiency depends significantly on the ore composition. Further electrochemical studies concerning how the voltage is used throughout the process was performed. The conductivity of the pulp formed using UG2 ore increased around 5 times compared to that observed when using Merensky reef ore. Under identical experimental conditions, the froth formed with Merensky reef ore was shallow and precarious compared to the thick and stable froth formed in the case of UG2 ore.

The interaction between pulp and different surfaces is still a subject not fully understood. For example, electro-flotation selectively separates valuable minerals using gas obtained from water hydrolysis. Costs of the process are proportional to the applied voltage which can be tailored by changing the ore type. This study explores the process optimisation by decoupling the applied voltage into its components.Figure optionsDownload as PowerPoint slide