Study On The Stability And Sulfidation Mechanism Of The Sulfide Layer On The Surface Of The Smithsonite

Zinc oxide ore has an irreplaceable position in zinc resources,and the smithsonite is one of the most important types of zinc oxide ore.The demand for zinc resources is increasing with the development of science and technology.It is an urgent task to improving the recovery of zinc oxide ore.It is found that the rougher flotation recovery of zinc oxide ore is higher.However,with the increase of concentrating time,the recovery of concentrate decreases sharply and the midding increased obviously.The natural of this phenomenon may be that the sulfide layer on the surface of smithsonite is unstable.Therefore,it is of great significance to study the sulfidation mechanism of zinc oxide ore surface.The smithsonite is the main research object in this paper.the optimized flotation conditions of smithsonite was obtained using pure mineral flotation test.Then LEIS ICP-MS and XPS were used to study the electrochemical properties of smithsonite surface and the attenuation of sulfide layer on smithsonite surface.The sulfidation process of smithsonite surface was analyzed by ToF-SIMS and AFM.The atomic properties or the sulfidation mechanism of smithsonite were obtained by quantum chemical simulation of the sulfidation process of smithsonite surface.Finally,study on ammonium salt strengthening by ToF-SIMS XPS and ICP-MS.The results of flotation test show that the optimum dosage of butyl xanthate is 1×10^-3 mol/L when butyl xanthate is used as flotation collector and the recovery rate tends to be stable with the increase of collector.The optimum reagent consumption of sodium sulfide is 1×10^-4 mol/L and the recovery of smithsonite will be affected by too high or too low concentration of sodium sulfide.The experimental study of ammonium salt strengthened smithsonite shows that the recovery of smithsonite will be improved if ammonium chloride or ammonium sulfite is added before sulfurization of smithsonite and ammonium chloride has better strengthening effect on smithsonite than ammonium sulfite.The LEIS results show that the smithsonite surface impedance decreases from 8.44E+04 to7.05E+04 when the curing time continued for 10 minutes.It shows that the surface of smithsonite form some sulfides with good conductivity.The surface impedance of smithsonite first decreases and then increases with the increase of vulcanization time due to the instability of sulfide layer on the surface of smithsonite which leads to the increase of surface impedance.The ICP-MS analysis results show that the adsorption capacity of sulfur ion increases first and then decreases on the surface of smithsonite with the increase of curing time.It shows that the sulfide scale on the surface of smithsonite is unstable and easy to fall off.The adsorption capacity of sulfur ion on the surface of smithsonite is greater than on the surface of smithsonite without strengthening.The ToF-SIMS analysis results show that the CO₃^-strength of smithsonite surface is increasing and the strength of S^-increases first and then decreases with the increase of deep vulcanization time.The results of XPS analysis show that the 2p3 peak of S appeared on the surface of the smithsonite and the binding energy was 162.47 eV and the concentration was0.09%.It indicates that the sulfur component is adsorbed on the surface of smithsonite after sulfidation and the sulfur component is adsorbed on the surface of smithsonite to form zinc sulfide which provides the adsorption site for butyl xanthate and it can increase the thickness of sulfide layer on the surface of smithsoniteThe results of quantum chemistry calculation show that the S^2-interaction with the Zn on the surface of smithsonite.It indicates that S^2-is more easily adsorbed on the surface of smithsonite due to the absolute value of the adsorption energy of S^2-is larger.Density of state analysis shows that 4s 3p orbitals of Zn atoms move to low energy and 3d orbital forms a new orbital peaks near Fermi level.The 3S and 3P orbitals of S move to the left and forms a new peak.It indicates that S interacts with the Zn atom form a new S-Zn bond.It found that the presence of water molecules has a greater effect on the vulcanization of the diabase by calculating the adsorption of S^2-and HS^-on the surface of Zn site.It will affect the vulcanization of the smithsonite when the water molecules are in the sulfur component the middle of the Zn position of the smithsonite.