Multiphase Flow In The Blast Furnace Sludge Cyclone Classification

The blast furnace (BF) sludge, containing iron and carbon, is valuable and necessary to be reclaimed and recycled. However, the impurity of zinc in BF sludge is too high so that the BF sludge could not be effectively recovered immediately. Some researches show that zinc is contained in fine particles mostly. Therefore, hydrocyclone can be used in decreasing zinc process.A simplified multiphase flow model and a Reynolds stress turbulent model are established to describe the classification of BF sludge particles in a hydrocyclone. Numerical simulations are based on SIMPLE algorithm. The outlets of hydrocyclone have been set on both pressure outlet boundary condition and mass flow outlet boundary condition. The multiphase flow field and particle classification efficiency curves are obtained.The diameter and the cone angle of hydrocyclone have little influence to the flow rate of the outlet. The inlet pressure has a little influence to it. The main factor that influences the flow rate is the diameter rate of underflow to overflow. The separate diameter will increase with the increase of hydrocyclone diameter and cone angle, and decrease with the increase of inlet pressure. The separate performance of the hydrocyclone will be worse and the separate diameter will decrease with the increase of underflow diameter, while the separate diameter will increase and outlet flow rate will decrease with the increase of overflow diameter. The simulation results agree well with experimental data.The separation experiments show that the outlet flow rate increase, the zinc removal rate decrease, the sludge recovery rate increase with the increase of the diameter rate of underflow to overflow under the condition of 25% inlet mass concentration, 27.5 psig pressure. This is coincident with the results of simulation.The microcosmic particle analysis shows that centrifugal force is the main one that urge the particle separate among the scope of the BF sludge concentration. The interaction between the particles has little influence to the separation in this scope. The velocity of the particle is proportioned to the square of the particle diameter on the whole and the different particles separate under the centrifugal force. So the simulation results in the low concentration can be used to instruct the operation of the BF sludge...