The effect of saline water on copper activation of pyrite in chalcopyrite flotation

Saline water has been widely used in the flotation of copper sulfide minerals against pyrite where pyrite may be activated by copper ions emanating from copper sulfide minerals. The effect of saline water on copper activation on pyrite surface has not been studied before. In this study, the effect of seawater with a high ionic strength on the flotation of chalcopyrite against pyrite was investigated. Compared to fresh water, seawater significantly increased pyrite recovery in flotation and made the separation of chalcopyrite from pyrite more difficult. The significant increase in pyrite recovery in flotation using seawater mainly resulted from the increased copper activation on pyrite surface. Polarization analysis and EDTA extraction show that the use of seawater enhanced chalcopyrite oxidation and dissolution leading to the formation of a larger amount of copper ions available for copper activation. The flotation of pyrite in the presence of copper ions together with cyclic voltammetry (CV) measurements indicates that the copper activation process on pyrite surface was facilitated in seawater owning to the lower potential of seawater.