Research On Extraction Of Iron And Alumina From High-iron-content Diaspore-type Bauxite Ore

Abstract:In order to realize comprehensive utilize of nontraditional refractory high iron content diaspore-type bauxite. The research takes undeveloped high iron content diaspore type bauxite ore as object, from Yunnan province in China. Study on the extraction technology of iron and alumina, and carried out following conclusions.Study on the mineralogy of crude ore show that the bauxite belong to iron aluminium compound resource with high iron content and low grade of alumina.The mineral of iron, alumina, silica appeared in the form of hematite, diaspore and silicate. And the hematite exist in aluminum and silicon minerals in the form of micro-fine particles packaged or intergrowth with complex disseminated relations, which makes it difficult to realize monomer dissociation.The reaserch on the alumina digestion of high iron diaspore-type bauxite by Bayer process indicate that, the actual dissolution rate of alumina is63.10%while relative dissolution rate is98.75%with yield of red mud78.19%were obtained. And the optimal condtions for leaching alumina list as following, the temperature is280℃with60minites, and the caustic ratio is4.0, caustic concentration is240g/L, liquid-solid ratio is4.0, additive dosage of lime is4%of sample.Study on the separation and recover iron from high iron diaspore bauxite, by sodium reduction roasting and magnetic separation, indicate that, the iron concentrate with iron grade of88.17%, recovery of92.51%can be acchived, and the optimal conditions were:reduction temperature at1050℃with60min, grinding finess is97.25%passing0.074mm, magnetic field intensity is1000Gs. By mix higher iron content bauxite as sample for intensify separation, the iron concentrate with iron grade of92.47%, recovery of92.43%were obtained, which can be meet the demand of raw material for steel-making.Take the magnetic separation residue as sample, research on the alumina digestion by Bayer process. The results show that, the actual dissolution rate of alumina is60.38%while relative dissolution rate is99.58%with yield of red mud56.59%can be acchived. The condition of digestion has been improved and red mud yield reduced dramaticly at the same time.