Study On Separation Performance Of Hydrocyclone With Composite Curved Conical Section

The conventional hydrocyclone is characterized by linear cone section and it is always accompanied by the phenomenon of "overflow mixed with coarse particle" and "underflow mixed with fine particle" during the production process.The separation accuracy and efficiency need to be improved.In order to improve the separation performance of the hydrocyclone,a hydrocyclone with composite curved conical section is proposed and designed in this paper.Its structural characteristics is that the upper cone segment is concave curve while the lower cone segment is convex curve.The separation performance is studied by theoretical analysis,numerical simulation and experimental methods.Firstly,the separation performance of hydrocyclone with conventional linear cone and hydrocyclone with composite curved conical section is compared and analyzed.The results show that compared with the fluid velocity inside the conventional hydrocyclone,the tangential velocity and the axial velocity of outer spiral flow inside the new hydrocyclone increased in the upper cone,but decrease in the lower cone.The velocity change promotes the extension of zero-velocity axial envelope and the formation of a high-density suspension layer,making the coarse and fine particle distribution more reasonable.The effects of the curvature index n on the flow field characteristics and separation performance of the hydrocyclone are comprehensively studied.Under the research range,the optimal curvature index n=3 is determined.Here,the underflow recovery rate of 5?m particles is reduced from 5.74%to 2.54%,and the underflow recovery rate of 50?m particles is increased from 90.75%to 92.97%,showing that the separation accuracy has been improved.The accuracy of the numerical simulation results is proved by later experiments.The phenomenon of "overflow mixed with coarse particle" and "underflow mixed with fine particle" is improved obviously and the classification efficiency of each size particle increases.Subsequently,in order to guide the application of the hydrocyclone with composite curved conical section,the influence rules of different apex diameters,feed pressure and feed concentration on the separation performance are explored.The results show that as the apex diameter increases,the zero-velocity axial envelope surface moves upward,weakening the high-density suspension layer.The underflow recovery rate of each size particle increases,but the cut size decreases.With the increase of feed pressure,the tangential velocity in the hydrocyclone increases,making the particles tend to move toward the underflow,therefore the underflow recovery of each size particle increases,but the cut-size decreases.With the increase of feed concentration,the tangential velocity in the hydrocyclone decreases,as a result the high-density suspension layer is further extended,the underflow recovery of each particle size decreases,but the cut-size increases.Combining the indicators of product concentration,particle size composition,solid phase yield and comprehensive efficiency,the paper presents the production operation applicable to each process parameter,which has certain guiding significance for practical application.Finally,a desliming process is designed by using the hydrocyclones with composite curved conical section,and successfully applied to the beneficiation operation of a scheelite mine in Gansu Province.Through this process,6.65%of the non-floatable fine mud of the original ore is thrown away.The particles smaller than 10 ?m account for 91.67%and the particles smaller than 20 ?m account for 100%in the fine mud,achieving the goal of exact discarding.After the whole process test,the WO3 recovery rate of tungsten concentrate increases by 3.88 percentage points,and the grade increases by 6.80 percentage points.The consumption of beneficiating agents has been reduced,and the production has been promoted,increasing the economic benefits for the entreprise.This study is of great significance for enriching the structure of the hydrocyclone,increasing the separation accuracy and efficiency,improving the operation technical indicators such as classification and sorting,and improving production efficiency and resource utilization.