Preliminary Study On The Surface Morphology And Crystal Structure Of The Sulfide Film In The Flotation Of White Lead Sulfide

Lead is an important non-ferrous metal and plays an irreplaceable role in the national economic construction.China's lead ore resources are abundant,but with the rapid advancement of modernization,the continuous consumption of lead sulfide ore makes the development and utilization of lead oxide orebecomes increasingly important.The direct flotation reaction of lead oxide is relatively poor,and sulfide-xanthate flotation method is the main method for recovering lead oxide ore.So the sulfidization process determines the quality of the lead oxide ore flotation.Understanding the sulfidization process is important for understanding lead oxide ore.The predecessors have done a lot of research work on the cerussite of sulfide-xanthate flotation method.However,due to the limitations of analytical testing methods,the microstructure,crystal phase and other chemical properties research are limited.Therefore,this thesischoose cerussite as the research object,and studies thesulfidization mechanism of cerussitesulfide-xanthate flotation by micro-flotation test and modern analytical testing methods,aiming to further understand the sulfidizationreaction of cerussite.The effects of sulfurizing reagent,pH value,and excess sulfur ion and sulfidization time on the flotation behavior of cerussite were investigated by flotation experiments.The results show:the direct flotation of cerussite is poor in floatability and low in recovery rate;after sulfidization,the flotation becomes better,the recovery rate of cerussite is clearly improved,and the recovery rate increases with the increase of the concentration of sulfurizing reagent.When it exceeds 75 mg/L,the recovery rate begins to decrease again.At the same time,excess sulfur ions affect the flotation of cerussite.The main reason is that the excess sulfur ion in the slurry solution affects the flotation.The lead sulfide film formed on the surface of the cerussite is relatively stable.Finally,the flotation pH was determined to be 10,the amount of sodium sulfide was 75 mg/L,the sulfidization time was 5 minutes,and the butyl xanthate was30 mg/L.With the surface analysis methods such as OM,SEM-EDS and AFM,the surface morphology of sulfided and unsulfided cerussite was observed from different scales using different imaging principles.The results show:after cerussitesulfided,spheroid ball of sulfide?sulfide film?will form on the cerussite surface,and the sulfide film changes cerussite's color,optical properties.The SEM,XPS,TOF-SIMS and other test methods are used to discuss the changes of cerussie surface.The results show:the cerussite ore concentrate is pure,EDS semi-quantitative analysis only has Pb,C,O elements;after appropriate sulfidization have S element production,TOF-SIMS surface analysis,CO₃^2-and PbO₂^-ions decline,S^2-and PbS^2-ionsrise,PbS is formed on the surface of cerussite after sulfidization;after excessive sulfidization,EDS semi-quantitative analysis of S element increases and content is limited.TOF-SIMS surface analysis,CO₃^2-and PbO₂^-ions continue to decline,S^2-and PbS^2-ions rise,surface lead sulfide component increases.The flotation recovery rate of cerussite after appropriate sulfidization is clearly higher than direct flotation.This is related to the PbS filmoncerussite surface,so the appropriate sulfidization contributes to the flotation of the cerussite;although the production of S element continue increases after excessive sulfidization,the flotation recovery rate does not continue to rise but decreases,which is also related to the slurry solution environment.Only appropriate sulfidizationis beneficial to flotation,we shouldnot only considercerussite itself,but also the slurry solution environment.In addition,the sulfide formed under the regular flotation of sodium sulfide dosage is lower than the XRD detection limit,so the sulfurized product cannot be directly detected.In order to detect the sulfurized product under the regular flotation of sodium sulfide dosage,in this paper use the selective of acetic acid to purifythe sulfurized product,and XRD results show that the sulfurized product of cerussite is galena phase PbS.This is the first time that we found galena phase under the regular cerussite flotation of sodium sulfide dosage.The results show:after usingsodium sulfide on the surface of cerussite will form spheroid ball of PbS with a high coverage density,suggesting that the cerussite aftersulfidization has a core-shell structure.The cross-section EPMA surface scan of the sulfidization cerussite particles shows that S is distributed on the surface of cerussite particles and the inner surface is O.It is indicated that the sulfided cerussite has a PbS?galena phase?shell and a PbCO3?cerussite?core.Based on the experimental results and discussion,the viewpoint of thesulfidization mechanism is a solid-liquid heterogeneous chemical reaction is proposed.When the sulfurizing reagent is added,the sulfur ions are rapidly adsorbed on the surface of the mineral,and then the adsorbed sulfur ions replace the CO₃^2-ions to form PbS on the surface of cerussite.This reaction belongs to the field of solid-liquid heterogeneous chemical reaction,and the reason for this reaction is the different solubility between PbCO₃ and PbS.