Research On The Direct And Reverse-flotation Process Of Haikou Phosphate Ore

At present,the Yunnan Phosphate Chemical Group mainly uses a simple,low cost reverse flotation process for production,only carbonate impurities of dolomite is removed from its phosphate rock.With the gradual depletion of this calcareous phosphate rock in Haikou phosphate mine,most of the remaining ores are siliceous and calcareous mixed phosphate rock,which can no longer be treated by the simple single reverse flotation process to produce a phosphate concentrate meeting the downstream requirements.Therefore,it is urgent to seek new and economical mineral processing technologies.In this paper,the siliceous and calcareous mixed phosphate rock in Haikou phosphate mine is taken as the research sample.The optimization of the direct-reverse flotation process and the study of the rational application of the new collector YP2-1 are presented.The optimal dosage of direct-reverse flotation reagent,flotation time and pulp density were determined to produce a phosphate concentrate satisfying downstream users’requirements.For a feed of P₂O₅ grade of 22.71%,MgO content of 3.21%,SiO₂content of 22.17%,under grinding fineness of-0.076mm 94.4%,a combined concentrate of reverse concentrate and scavenger concentrate of 29.99%P₂O₅,0.85%MgO can be obtained when using a direct-reverse flotation flowsheet of one roughing,one scavenging and one cleaning in the direct flotation stage and one roughing for reverse flotation stage.The content of MgO in concentrate is comparatively good.When the cleaning concentrate were mixed with the scavenging concentrate in direct flotation and subjected to reverse floatation,a final concentrate of 30.02%P₂O₅,0.63%MgO could be obtained.The yield of concentrate is 66.24%,and the recovery rate is 87.68%.P₂O₅ in the concentrate is more than 30%and MgO is less than 1%,which is in line with the standard requirements of phosphorus chemical products.The structure of the tested flotation process is simple,and the middlings（scavenging concentrate in direct flotation stage）is no longer recycled back to the direct flotation operation,which avoids the loss of phosphorus minerals and improves the yield and recovery of the concentrate to the greatest extent.In addition,the final product phosphate concentrate is above the national standard for wet process phosphoric acid,and the experimental results are significantly enhanced,and the cost of flotation has been greatly reduced.A series of tests were carried out to elucidate the flotation mechanism.Zeta potential test shows that the adsorption of YP2-1 by phosphorite and dolomite are mainly through chemical adsorption.The Zeta potential of these minerals moves to more negative position after YP2-1 adsorption;YP2-1 cannot be adsorbed on the quartz surface in pure water.But in actual flotation,YP2-1 is attached to quartz due to the activation of Ca²⁺.The surface tension test shows that the surface tension of YP2-1 solution is closely related to the composition and concentration of the solution.