Fundamental understanding of flotation of hexagonal pyrrhotite and millerite to improve the quality of ni-cu concentrates

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Nickel is one of important metals widely used in alloy, battery, catalyst, coin, and electronic device, just to name a few. The nickel sulphide minerals of economic interest include pentlandite ((NiFe)9S8) and millerite, which are associated with a greater abundance of pyrrhotite (Fe8S9). Chalcopyrite is typically associated with nickel sulphide minerals that must be separated to a copper bearing concentrate with low nickel grades to facilitate efficient copper smelting.****The selective separation of pyrrhotite from pentlandite and millerite is critically important for the economics and downstream nickel smelting and refining. The iron and sulphur levels in concentrate must be controlled to reduce the amount of Sulphur dioxide produced in smelting to avoid negative environmental impacts. The selective separation of monoclinic pyrrhotite from pentlandite has been effective by magnetic separation and low redox potential flotation. Recently, ores from the Sudbury Basin have contained a larger proportion of hexagonal pyrrhotite. This form of pyrrhotite has stronger flotation kinetics to that of the monoclinic variety and has not responded to the conventional pyrrhotite rejection techniques. Our objective in this part of research is to fundamentally understand the role of metal ions such as copper and nickel on the activation of hexagonal pyrrhotite or deactivation of hexagonal pyrrhotite in the presence of depressants such as diethylenetriamine (DETA), Dextrin, lignosulphonate, thiosulphate, and lime under controlled electrochemical conditions. The success of this project will strengthen Canada's leadership role in sustainable development and keep Canada in the forefront of new technology development that will not only benefit our society, our economy, but also our environment.