Study On Flotation Separation Process Of High Sulfur And High Silicon Bauxite

With the development of alumina industry,the high-quality bauxite resources are gradually depleted in China,and the guarantee degree of bauxite resources is getting lower.Therefore,it is important for the utilization of low quality bauxite.The high sulfur bauxite is abundant,but the sulfur in bauxite seriously endangers the alumina production and hinders the direct application in the of alumina production.The improvement on the quality of high sulfur and high silicon is of practical significance.In this paper,the physical and chemical composition and mineralogical characteristics of bauxite were studied by means of petrographic microscope,XRF and XRD.The flotation method was used to study the desulfurization and desilication of high sulphur bauxite,and The optimal flotation parameters were exploredinthe desulfurization and desilication process respectively.The physical and chemical properties of high sulfur bauxite show that the content of Al₂O₃ in the ores used in the laboratory is 54.32%,the ratio of aluminum to silicon?A/S?is 4.81,and the content of sulfur in bauxite is higher,which is 5.61%.The results of phase composition and morphology show that the main minerals in the ores used in the experiments are diaspore and pyrite.The diaspore is mostly massive and oolitic,and exists in the aggregate.Pyrite and diaspore are embedded complexly.Besides,there is a small amount of gangues including muscovite,quartz,hematite,anatase and other minerals in the bauxite.For high sulphur bauxite,the result of reverse flotation desulfurization technology shows that the sulfur in high sulfur bauxite can be effectively removed by one roughing,one cleaning,regrinding and flotation method,and the best test conditions are obtained as follows:content of particle less than 200 mesh 72.40%,pH value of 9.5,activator dosage of 90 g/t,collector dosage of 140 g/t,and the flotation stirring speed 2200 r/min,the 2/3 original dosage of collector in the cleaning and the 1/3 original dosage of collector in the second flotation.The sulfur content of bauxite is decreased to 0.54%,and the recovery of alumina is 73.79%.The main reason for the worse desulfurization of isopropyl methyl thiamine is that the interaction mechanism of isopropyl methyl thiamine with pyrite was mainly physical adsorption.In the positive flotation desilication of desulfurization concentrate of bauxite,the best conditions were obtained:the pulp pH value of 9,sulfonated humic acid dosage of 60 g/t,six sodium polyphosphate dosage of 30 g/t,the pulp temperature 31?C,sodium oleate dosage of 2200 g/t.The flotation desilication process by one roughing and one cleaning is adopted,and the depressant was added during the cleaning process.The results show that the ratio of A/S of bauxite concentrate increased 8.01,the total sulfur content is 0.49%,and the recovery of alumina is59.87%.The sulfur content and A/S meet the requirements of alumina production in the Bayer process.