Methods for improving the flotation recovery of the coarse fraction of a nickel ore

Coarse particle size fractions (100 - 150 μm) generally have a poor response to flotation. This is mainly due to the low prospect of the particle-bubble aggregates withstanding the shearing forces in the flotation cell. Since particle-bubble attachment and detachment are directly related to the hydrophobicity of the particle, the most practical way to improve the fl otation of coarse fractions is to enhance their hydrophobicity. In this study, diesel oil, in addition to Potassium Amyl Xanthate (PAX), was used as an extender collector to fl oat the coarse fraction of a nickel ore in a laboratory batch flotation cell. Two different methods of oil addition were explored: oil was either emulsified with water and added to the flotation cell, or emulsified together with water and xanthate and then added to the flotation cell. It was shown that in both cases the oil addition increased the nickel recovery compared to the base case, but at the expense of concentrate grade. A high degree of entrainment, which was associated with extremely high water recoveries, was typical for flotation tests with the oil addition. The addition of collector via aerosol was also tested, as a way of introducing the collector with the air phase. This improved the quality of concentrate in terms of the nickel grade, at the expense of the lower nickel recoveries. The flotation rates of particles from flotation tests using these different methods are compared and discussed