Study On The Harm And Removal Of Sulfur In Bauxite Grinding And Flotation Processing

With the continuous exploitation of bauxite resources in China,the reserves of high-quality bauxite has become less and less.The low-quality bauxite has been gradually used to produce alumina by“Mineralization-Bayer Process”.Sulfur-containing bauxite is a typical low-quality aluminum resource in China,but sulfur impurities are seriously harmful to the Bayer process.At present,there are many researches on the bauxite desulfurization process,but there are few systematic studies on the harm of sulfur in the grinding and flotation process of bauxite.Therefore,it is of great significance for the development and utilization of sulfur-containing bauxite resources to systematically study the harm of sulfur impurities of bauxite on the grinding process and remove it effectively.This paper used bauxite with different sulfur content provided by an alumina company in Henan.The samples were analyzed by XRF,polarized light microscopy and XRD,and then the physicochemical properties and mineralogical characteristics of them were fully studied.The hazards of sulfur in the bauxite flotation process were also explored.Reverse flotation process was used to optimize the desulfurization parameters of sulfur-containing bauxite.The main conclusions of this study are as follows:?1?Through the study of grinding of sulfur-bearing bauxite,it is found that with the increase of the sulfur content,the difficulty of bauxite grinding increases.As the sulfur content in the bauxite increases,the grinding time required to achieve the same grinding fineness increases;while the bauxite with different sulfur content is subjected to the coarse fractionation,the distribution of ore yield is similar,but the average ore particle size of fine fraction?-0.045mm?increases with the increase of sulfur content;?2?Mineralogy and solution chemistry studies show that the sulfur minerals in sulfur-bearing bauxite are pyrite.Sulfur-bearing bauxite grinding process causes the change of mineral properties and slurry properties in subsequent flotation process.After fine grinding,the pulp is acidic due to oxidation of pyrite in the bauxite.As the sulfur content increases,the pH of the ore slurry obtained by grinding gradually decreases;?3?Through the study on the grinding-flotation desiliconization process of sulfur-containing bauxite,it is found that the sulfur content has a significant effect on the index of desiliconization in bauxite flotation process.With the increase of sulfur content,the recovery of Al₂O₃ decreased;and under different pH and flotation temperature,the change of sulfur content in bauxite has significant difference on the recovery of Al₂O₃ and concentrate A/S;?4?Reverse flotation desulfurization research was made by using the imidazole collector TMBI,and the suitable desulfurization conditions were as follows:grinding fineness is 82.2%?-0.074 mm?;the pH of the ore slurry is 10;the optimum addition amount of the activator,collector and foaming agent was 20 g/t,80 g/t,and30 g/t.By designing one roughing and one cleaning open-circuit flotation experiment,the sulfur content of concentrate was finally reduced to 0.28%,and the recovery of Al₂O₃ was as high as 90.27%.