Upgrading nickel in laterite ores by flotation

Nickel is sourced from sulphide and laterite ores. While 70% of the nickel resources are contained in laterites, these ores are often complex and expensive to treat using conventional methods. Therefore, upgrading the nickel content in laterite ores ahead of any recovery processes is economically desirable. Flotation has not been successful to recover nickel from laterite ores because of the fare-grain and low grade nickel. Nickel laterite deposits are generally divided into limonite (oxide), nontronite (clay) and saprolite (silicate) zones. A systematic study was conducted on the ore samples sourced from these three categories to see the effect of different mineralogies on the flotation behaviour of laterite ores. Pre-concentration of laterite ores by flotation was found to be possible, but it is highly determined by the ore mineralogy. In this study, no or minor upgrade in the nickel content was found for the limonite and nontronite samples. However, it was possible to obtain 40% upgrade in the nickel content (at 70% recovery) for the saprolite ore sample using flotation.