Effects of galvanic interaction between galena and pyrite ontheir flotation in the presence of butyl xanthate
(School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China)
Abstract: The effects of galvanic interaction between galena and pyrite on their flotation and electrochemical characters were studied by electrochemical, adsorption, flotation and FTIR techniques, respectively. Electrochemical tests indicate that galena is electrochemically more active than pyrite and serves as an anode in galvanic combination with pyrite. The galvanic current density from a mixture of galena and pyrite is 4 times as high as the self corrosion current density of galena, which indicates that the corrosion rate of galena is accelerated. Adsorption tests show that the adsorption of butyl xanthate on galena surface is enhanced, and affected by a combination of pyrite-galena mixtures and conditioning time. Compared with individual mineral particles, galvanic interaction reduces the floatability difference between galena and pyrite. The flotation recovery of galena decreases while that of pyrite increases when two minerals are mixed together due to the influence of galvanic interaction on the formation of hydrophilic/hydrophobic product. The FTIR results show that the formation of dixanthogen on pyrite surface is depressed due to the galvanic interaction.
Key words: galvanic interaction; galena; pyrite; butyl xanthate; flotation