Effect of pyrite textures and composition on flotation performance: A review

Abstract

As high-grade ore deposits become depleted, there is an increasing demand to process marginal low-grade ores with complex metallurgical challenges. Orebodies can be rich in pyrite, which is the most abundant sulphide gangue mineral in ore deposits. Pyrite has been depressed to mining tailings for decades. Although these mine tails are an ongoing environmental liability, they also present an opportunity as they may contain valuable metals such as Au, Ag, Co and Ni.Pyrite-rich orebodies present challenges to current mining prospects as they tend to be non-responsive to traditional methods for pyrite depression. If not depressed, pyrite floats along with valuable minerals producing a low-quality concentrate that causes significant problems for smelting operations. Furthermore, the necessity for higher pyrite rejection causes projects and operations to resort to complicated and often inefficient processing flowsheets. These process developments can be economically, operationally, and environmentally challenging. Thus, understanding why pyrite's flotation performance varies within orebodies and the features affecting its floatability is critical for an efficient depression and possible reclamation of pyrite.Natural pyrite can exhibit different electrochemical properties, chemical composition, and texture depending on the ore genesis. These variations have been reported to affect pyrite's flotation response at different levels, though the mechanisms are not well understood. Different pyrite textures may influence flotation by altering the electrochemical properties of pyrite and the ways it interacts with the pulp, or they can introduce naturally floatable species within pyrite grains. This review examines why pyrite variations show differentiated flotation behaviour and identifies knowledge gaps from experimental and observational studies. The paper focuses on the effect of texture and composition of pyrite on electrochemical properties and floatability. The work investigates pyrite textures at Mount Isa Mines and their observed effect on flotation performance.