Galvanic Corrosion Between Galena And Pyrrhotite And Its Effect On Flotation Separation Effect On Mineral Flotation Separation

In the process of flotation of sulfide ore,desulfurization is the key link to improve the recycling level of non-ferrous metal resources.However,due to the different electrostatic potential on the surface of the semiconductor sulfide ore,it is easy to interact with the galvanic interaction in the pulp,which seriously affects the desulfurization effect.At present,scholars at home and abroad have carried out a lot of research on the flotation separation process of pyrite and other minerals,but there is a lack of systematic and in-depth study on the interaction mechanism of minerals.And most of these studies focus on pyrite,less research has been done on pyrrhotite,another source of sulphur.The galvanic corrosion between monoclinic pyrrhotite and galena and its effect on flotation behavior and surface properties were studied using monomineral flotation tests,ion leaching test,X-ray photoelectron spectroscopy（XPS）analysis and electrochemical test.The results of mineral flotation test showed that the natural floatability of monoclinic pyrrhotite increased and that of galena slightly decreased after galvanic corrosion in the range of pH=6～12without collector.With presence of butyl xanthate in pulp,the flotation recovery of monoclinic pyrrhotite increased at all pH conditions after galvanic corrosion.The flotation recovery of monoclinic pyrrhotite increased from 10.41%to 46.67%at pH=12,indicating that it was more difficult to inhibit monoclinic pyrrhotite in alkaline environment after the interaction.With lime as an inhibitor present in the pulp,galvanic corrosion weakened the inhibition effect of lime on monoclinic pyrrhotite.Even if the lime dosage was increased to twice the amount before galvanic corrosion,the inhibition effect was not the same,which increased the difficulty of lead-sulfur separation.The mechanism study showed that the electrostatic potential of galena is much lower than that of monoclinic pyrrhotite at all pH conditions.So when galvanic corrosion occurs,galena as anode and monoclinic pyrrhotite as cathode.The surface of galena was easy to lose electrons,the oxidation corrosion was intensified,the corrosion current density was significantly enhanced,the content of S and Pb on the surface was reduced,the content of O was increased,the oxidation degree was increased,so the floatability was weakened.Meanwhile,Pb²⁺can be dissolved from the surface of galena,and the dissolution amount is positively correlated with the addition amount of monoclinic pyrrhotite.The surface of monoclinic pyrrhotite was easy to obtain electrons,and the oxidation corrosion was inhibited.The hydrophilic oxidation products SO₄^2-and SO₃^2-of sulfur were reduced,while the hydrophobic products S⁰ were increased,so the floatability was enhanced.Meanwhile,Pb²⁺dissolved from galena surface was easy to adsorb on monoclinic pyrrhotite surface and generated Pb-S compound to activate monoclinic pyrrhotite,making it more difficult to inhibit.The addition of butyl xanthate and the decrease of the interaction distance between the two minerals would lead to the enhancement of galvanic corrosion.According to the mechanism study,it was found that EDTA-2Na could weaken the activation of Pb²⁺to monoclinic pyrrhotite by complexing it in slurry solution,so that Inhibitor lime could be normally adsorbed on the surface of monoclinic pyrrhotite.The combined use of 150 mg/L EDTA-2Na and 50 mg/L lime could reduce the floatation recovery of monoclinic pyrrhotite to 16.84%,while the flotation recovery of galena was maintained above 95%,and lead and sulfur separation can be realized under low alkali conditions.