Potential of electrochemical techniques (macro and microelectrodes) in fronth flotation concentration of sulfide minerals

ABSTRACT

The interactions between sulfide minerals and the chemistry of the exposure medium, from the grinding process to the flotation pulp, can be electrochemical and/or galvanic and influence the hydrophobicity of their surfaces, resulting in different levels of recovery. In the literature, most works are related to the electrochemistry of galena (lead sulfide), sphalerite (zinc sulfide), pyrite (iron sulfide), chalcopyrite (copper and iron sulfide), and pentlandite (iron and nickel sulfide). Potential measurements in the pulp are widely used to control and optimize recovery. However, some limitations exist as they do not allow understanding the electrochemical mechanisms involved. This review presents and discusses the electrochemical concepts involved in these processes, bibliometric research on the topic, and emphasizes the potential of applying studies using macro and microelectrodes to understand the electrochemistry of sulfide minerals. From the bibliometric search, 85 articles were obtained; the first was published in 1969, thus being an underexplored area with a maximum peak of 5 articles in 1984, 1989, and 2014. Australia, South Africa, Turkey, and Canada, the four countries that publish most, total 50% of the identified documents. The nature of the reactions, the activation or the presence of layers of oxides/hydroxides, and the adsorption of collectors on the surface of sulfide minerals have been investigated by electrochemical techniques to elucidate the efficiencies of flotation processes. The use of the cavity microelectrode (CME), in addition to the ease of preparation, may allow the analyses of mineral particulate samples.

Keywords
Flotation; Sulfide minerals; Electrochemistry; Microelectrodes