The Study Of Surface Complexation With Zinc Carbonate,Zinc Oxide And Zinc Sulfide

With the development of industry and the application range of the zinc mineral,mineral resources is rapidly exhausted, which becomes one of the most seriousproblem we must face. Therefore, how to improve flotation efficiency of the zincoxide mineral and zinc carbonate mineral is a challenge. The flotation process ofoxide mineral is influenced by many factors, for example, the redox potential andsolublility in the mineral suspension, the concentration and types of inorganiccomponents, the propertoes of collector, solution pH, ionic strength and temperature.The results show that the three parameters i.e. collector concentration, pulp pH valueand pulp potential, have very important impacts on flotation.In this article, zinc carbonate and ZnO were successfully synthesised by thesolution chemical method, the ZnS were synthesised at normal temperature, zinccarbonate and ZnO were successfully surface sulfidized using xanthate. The five kindsof samples were characterized using a series of advanced techniques including XRD,FT-IR analysis, N2adsorption/desorption （BET） and contact angle measurements. Theresults show that the samples of zinc carbonate, zinc carbonate after surfacesulfiphidization of ZnO is nano particle, the decomposition temperature of zinccarbonate is280℃, the contact angles show that zinc carbonate and ZnO after surfacesulfiphidization are more hydrophobic, which is fevorabe to the mineral flotation.We found in exploring the acid-base properties of samples, that the buffer rangeof zinc carbonate and zinc carbonate after surface sulfidization is between pH=7.5-10.5,8.5-10.5for ZnO and ZnO/ZnS and3.5-10.5for ZnS. According to theconstant capacitance model （CCM） of surface complexation model, we used thecomputer software WinSGW calculated the acid-base equilibrium constant of zinccarbonate, zinc carbonate after surface sulfidization, ZnO, ZnO/ZnS and ZnS, bycomparing the equilibrium constants, we can see the diversity between surfaces beforeand after sulfidization.The adsorption ability of minerals to xanthate is the key factor for mineralflotation. The results show that the adsorption quantity of xanthate on zinc carbonatebefore and after sulfidization ZnO, ZnO/ZnS and ZnS for are all increasing withincreasing residual concentration of xanthate. The numbers of xanthate adsorbed areproved to belong to a multilayer adsorption isotherm instead of a monolayer type,which follows BET absorption isotherms. We found when exploring the influence of the solution pH value on mineral adsorbed xanthate, along with increasing solutionpH value, the octyl xanthate adsorption of the five samples all gradually reduced. Weuse the WinSGW software calculated the equilibrium constants of relevant xanthatecomplexation to be respectively as follws.≡ZnOH+X^-≡ZnOHX^-log K＝3.77,5.13,4.43,4.51,3.75,Here≡ZnOH respectively represents zinc carbonate, zinc carbonate after surfacesulfided, ZnO, ZnO/ZnS and ZnS and X-represents octyl xanthate. The resullts showthat among these samples the complexation order of xanthate on the mineral surface isZn₄CO₃（OH）₆/ZnS> ZnO/ZnS> ZnO> Zn₄CO₃（OH）₆> ZnS.The innovation of this study is to introduce the surface complexation theory tothe surface sulphidization of zinc oxide and zinc carbonate mineral system and usingthe computer software WinSGW to calculate the surface acid-base equilibriumconstant and surface complexation equilibrium constant of octyl xanthate at themineral surfaces. The results may not only provide a theoretical basis for studying thesurface speciation, but also for the surface modification of zinc oxide and carbonatemineral material.