Study On The Mechanism Of Vulcanization Intensified By Heating Of Zincite

With the decreasing of zinc sulfide resources to be treated easily,the exploitation and utlization of zinc oxide ores have become inevitable.Smithsonite is a typical reprensentative of zinc oxide ores,which is generally recovered through sulfurization with amine or xanthate.Compared to sulfurization-amine flotation,the more complete sulfurized surface is required to achieve the effective recovery of smithsonite by sulfurization-xanthate flotation.Therefore,how to effectively strengthen the sulfurization process and obtain more stable sulfurized surface is the key to recover smithsonite by sulfurization-xanthate flotation.Based on the current research achievements,we know that it is difficult to offer a perfect sulfurized surface for flotation with xanthate only using chemical methods to adjust and controll the surfurization process of smithsonite.Heating is still the most effective method to acquire sufficient sulfurized surface for recovering smithsonite with xanthate.Hence,it is necessary to clarify the effect of sulfurization under different tempreture on physicochemical properties of smithsonite flotation interface.This paper took smithsonite as the research object.The influence of heating sulfurization on the flotation behavior of smithsonite was studied,and the transformation about morphology,stability and thickness of sulfurization production on the surface of smithsonite after heating sulfurization were analyzed by modern analysis and testing tools.The results of pure mineral tests showed that the floatability of smithsonite could be significantly improved through heating-sulfurization.The highest flotation recovery rate of smithsonite was only 48.57%using opentyl xanthate as collector at normal tempreture,which corresponded to the flotation conditions as fallow:the pH was adjusted to 9.0,the dosage of sodium sulfide,copper sulfate and isopentyl xanthate was 2.0×10^-4 mol/L.The flotation recovery rate of smithsonite could by increased sharply through heating-sulfurization.When the sulfurization tempreture was increased form 20°C to 60°C,the flotation recovery rate had an increase of nearly 28 percentage points from 48.57%to 76.17%.The mechanism research results of the heating-sulfurization about smithsonite showed that sulfurization was a solid/liquid chemical reaction process,and mineral surface microstructure had a significant effect on sulfurization result.The incressing coverage area and longitudinal depth of the sulfurized product was formed on the surface of sulfurized smithsonite through heating-sulfurization.Besides,heating-sulfurization could change the morphology of sulfide products.The testing results of FESEM-EDS verified the formation of a new independent phase.The testing results of EPMA and XPS showed that the sulfurized product is not uniformly distributed on the surface of the mineral particles,and is preferentially formed on the surface of the mineral surface such as slits and sections.The atom concentration of sulfur on the surface of sulfurized smithsonite increased from 4.78%to 13.54%,22.48%with the increase of sulfurization tempreture（20°C→40°C→60°C）,and the morphology of the sulfurized product changed from a small distribution to a small particle,a denser sulphide-coated film with a slightly larger particle size eventually.And more,the analysis results showed of TOF-SIMS that the etching time corresponding to the equilibrium point of S^-and CO₃^-ion intensity increased from 9s to 12s,18s with the rise of sulfurization tempreture.That is to say,the thickness of the sulfurized product was increasing.