Abstract
Low grade sulfide ores are difficult to process due to their composite mineralogy and their fine grained dissemination with gangue minerals. Therefore, fine grinding of such ores becomes essential to liberate valuable minerals. In this research, selective flotation was carried out using two pitched blade turbine impellers with diameters of 6 cm and 7 cm to float copper and nickel. The main focus of this research was to generate optimum hydrodynamic conditions that can effectively separate nickel and copper from gangue minerals. In addition, we investigated the effects of superficial gas velocity, impeller speed, bubble size distribution, and bubble surface area flux on the flotation recovery and rate constant. The results demonstrated that a 7 cm impeller comparatively produced optimum hydrodynamic conditions that improved Cu-Ni recovery and the rate constant. The maximum copper and nickel recoveries in the 7 cm impeller tests were observed at 93.1% and 72.5%, respectively. However, a significant decrease in the flotation rate of nickel was observed, due to entrainment of nickel in copper concentrate and the slime coating of gangue minerals on the nickel particle surfaces.
Highlights
Our aim was to evaluate the effect of the impeller size, impeller speed, and aeration rate on the hydrodynamic parameters and how these parameters can affect the flotation performance of copper and nickel
The overall results suggested that the bubble size decreased as the rotation speed of both impellers increased
The maximum copper recovery of 93.1% was achieved at a superficial gas velocity of 0.17 cm/s and a rotation speed of rpm for the 6 cm impeller
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Complex and low grade sulfide ores are difficult to process due to their fine-grained and disseminated nature. In order to process such ores, a high degree of liberation is required prior to the flotation process. Processing low grade sulfide ores is seldom/rarely done using selective separation due to its processing difficulty and higher cost [1]. The flotation behavior of complex sulfide ore tends to vary due to differences in mineralogy [2]. The presence of varying amounts of gangue minerals such as talc, serpentine, and amphibole poses a challenge to maintain the targeted concentrate grade [3]
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