| Gold is sulfur-loving and iron-loving,so sulfide ore can be used as the most common gold-bearing mineral.Sulfide ores generally have the characteristics of good floatability and easy oxidation.This subject takes gold-bearing sulfide ores as the research object to explore the influence of mineral surface oxidation on mineral flotation and study its mechanism.Through oxidation,flotation test and contact angle detection test of two samples（lead-zinc ore and pyrite）,the influence of different oxidation conditions on mineral floatability was explored,and the law of surface oxidation behavior of sulfide minerals was obtained.By means of infrared detection and electrochemical techniques,the adsorption of collectors on the surface of lead-zinc ore and pyrite was investigated to find out the reaction mechanism between collectors and mineral surfaces.In the experiments of oxidation and flotation of lead-zinc ore and pyrite in water,the effects of stirring time,pulp concentration,p H,temperature and stirring speed on the oxidation characteristics and floatability of the two samples were investigated.The results show that when the pulp concentration is 30%,it plays a positive role in improving the flotation rate of lead-zinc ore,but the increase of pulp concentration is not conducive to the flotation of pyrite.Lead-zinc ore in acidic environment（p H=4）has good floatability,while pyrite is similar to lead-zinc ore.When the slurry temperature is 48℃,the floating rate of lead-zinc ore and pyrite can reach about 80%,If the slurry temperature continues to rise,it is not conducive to the floating of the two samples.Increasing stirring time and stirring speed are beneficial to the flotation of lead-zinc ore,but unfavorable to the flotation of pyrite.In the oxidation and flotation experiments of lead-zinc ore and pyrite,four common oxidants,H2SO4,HNO3,H2O2 and KMn O4,were used to investigate the effects of oxidation time and oxidant dosage on the oxidation characteristics and floatability of the two samples.The results show that KMn O4 has a significant inhibitory effect on lead-zinc deposits.H2SO4,HNO3 and H2O2 have no obvious inhibition effect on the flotation of lead-zinc ore.H2SO4,H2O2 and KMn O4 can inhibit the floatability of pyrite,among which KMn O4 can inhibit pyrite significantly.Increasing the amount of HNO3 will inhibit the flotation of pyrite.The infrared spectrum study of the interaction between xanthate and two minerals shows that the characteristic absorption peaks of lead xanthate and dixanthogen appear after the interaction between lead-zinc ore and pyrite and xanthate.After the lead-zinc ore is oxidized by H2SO4 and reacts with xanthate,the characteristic peak of lead xanthate in infrared spectrum has no obvious change,and no other substances are generated.However,KMn O4 destroyed the formation of lead xanthate on the surface of lead-zinc ore,and inhibited the floatability of lead-zinc ore to some extent.After pyrite is oxidized by H2SO4 and H2O2,it reacts with xanthate.The characteristic peak of dixanthogen in infrared spectrum is slightly weakened,but no new substance is formed.However,HNO3 and KMn O4 both destroyed the formation of xanthate on the surface of pyrite,and new substances were produced in the infrared spectrum of KMn O4,which inhibited the floatability of pyrite.Based on electrochemical workstation,the electrochemical reaction of microelectrode in oxidant solution with or without collector was investigated.The results showed that with the increase of oxidant solution concentration,the electrochemical reaction on the surface of two minerals intensified.The lead xanthate formed on the surface after the reaction with xanthate will be oxidized by KMn O4,resulting in the reduction of its output and the inhibition of the floatability of lead-zinc ore.The dixanthogen formed on the surface of pyrite will be oxidized by H2O2 and KMn O4 solution,and its hydrophobic layer will be destroyed,so the hydrophobicity of pyrite surface will be weakened,resulting in the decrease of floatability. |
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