Research On Influencing Factors Of Beneficiation Of Low-grade Bauxite By Hydrocyclone

In order to use Bayer process to produce alumina, centrifugal force field was used in separating diasporic bauxite of our country, to improve alumina-silica ratio. Low-grade diaspore bauxite was used as material, which distributes Zhongzhou of Henan Province. This paper is studying on influencing factors for beneficiation of hydrocyclone.Influencing factors of hydrocyclone include structural parameters and operation parameters. The main conclusions of this paper are as the following:Air-pillar and the path area of maximum tangential velocity in centrifugal force field were changed as apex diameter's changing. More diaspore and silicate minerals entered into underflow, which made alumina-silica ratio decreased and the results affected. Cone angle was another influencing factor, and it also changed the results. The separation results show that when cone angle is 11°, apex diameter is 6mm, alumina-silica ratio in underflow is 6.87, the recovery of Al2O3 in underflow is 69.88%, alumina-silica ratio in overflow is 2.32 and the recovery of SiO2 in overflow is 56.02%. At this time, the result of beneficiation is best.The results of beneficiation were improved as feed pressure was increasing. High feed pressure made tangential velocity of coarse particle was improved, and high tangential velocity made coarse particle enter into underflow. But it was not affecting fine particle. The results of beneficiation were improved as the results of classification were worse. The separation results show that when cone angle is 11°, feed pressure is 0.4MPa, alumina-silica ratio in underflow is 7.33, the recovery of Al2O3 in underflow is 70.52%, alumina-silica ratio in overflow is 2.30 and the recovery of SiO2 in overflow is 57.14%.The change of feed concentration changed ore pulp's density and viscosity. When cone angle is 15°, the results of beneficiation were decreased as feed concentration was increased. The results of 7°cone angle was as same as 15°cone angle, however, when feed concentration was 8%, the results was best. When cone angle is 15°, feed pressure is 10%, the recovery of Al2O3 in underflow is 75%, alumina-silica ratio in underflow is 6.54, the recovery of SiO2 in overflow is 49.01% and alumina-silica ratio in overflow is 2.27. When cone angle is 7°, feed pressure is 8%, the recovery of Al2O3 in underflow is 83.01%, alumina-silica ratio in underflow is 5.58, the recovery of SiO2 in overflow is 34.74% and alumina-silica ratio in overflow is 2.14.In the experiment of feed fineness, the result was bad as the amount of fine particles was more. While the result was also bad when coarse particles was too much in the ore-pulp. The best result is that when apex diameter is 6mm, feed fineness is 60%, the recovery of Al2O3 in underflow is 86.48%, alumina-silica ratio in underflow is 5.32, the recovery of SiO2 in overflow is 26.07% and alumina-silica ratio in overflow is 2.32.