Study On Concentration Of Dense Medium Suspensions By Thickening Cyclone

With the continuous expansion of the application of heavy-medium separation technology in mineral processing fields,in the face of some minerals with easy to be turnified and high slime content,how to efficiently recover a large amount of suspension carried out by each product and ensure the stability of the heavy medium suspension system become the problem that needs to be solved.In this paper,we are using ferrosilicon powder and silicate mud slurry to make up dense medium suspensions with different particle size,using the thickening cyclone to exploring the influencing law of the particle composition,the particle size and the content of the sludge on the viscosity and stability of the medium suspension was investigated under the condition of 2.8-2.9 g/cm³ density.Studies have shown that the content of ferrosilicon powder particles containing an appropriate amount of 74um or more particle size can make the pure dense medium suspension low viscosity and stability,and after the incorporation of slime,the stability enhancement of ferrosilicate powder preparation heavy medium suspension is more pronounced.Comparing the slime with the median diameter of 9.1um and 9.1um,the viscosity and stability of the former heavy media suspension are higher than those of the latter,and with the increase of the amount of slime contents,the absolute difference between the viscosity and stability of the two kinds of heavy media suspensions increases gradually,when the slime contents exceeds 6%,the viscosity of the former heavy media suspension increases significantly faster.The viscosity of the two-peak and narrow-grade pure medium suspension was 58mpa·s and 124mpa·s.In 2.8g/cm³ density level heavy medium suspension,the limit content of fine grained slime?D50=9.1um?is 8%,and the limit content of coarse grained sludge?D50=23um?is 12%.The results of the thickening cyclone system shows that with the increase of the slime content in the feeding suspension,the thickening effect is reduced,and the ratio of the slime content in the overflow and the input is gradually reduced as a whole;with the increase of feeding pressure,the thickening effect has been improved to some extent.The ratio of the slime content in the overflow and the feeding has gradually increased;as the diameter of the central pipe is 1#and 2#,the overall effect of the thickening effect has not changed substantially.However,with the increase of pipe diameter,the thickening effect has been weakened.Among the above factors,the diameter of the center pipe has the greatest influence on the density and concentration of the overflow suspension.The model of concentration effect was obtained by system optimization test.The underflow concentration C₁=0.969-0.011A+0.006B,The overflow concentration model is C₂=1.932-0.081A+0.004B-0.031C,and The enrichment efficiency model is E_th=-1.607+0.027A+0.096B+0.078C-0.002AB-0.001BC-0.001B²-0.016C²,and the density differences between underflow and overflow suspension model is??=-2.140-0.190A+0.228B+0.351C+0.001AC-0.007BC-0.003B²-0.051C²,The overflow clarify coefficient is?=49.777-4.669A+0.559B-10.472C-0.031AB+0.897BC?The results of the optimized system test shows that the slime content is a significant factor affecting the thickening effect.The interactions between slime content and feeding pressure,feeding pressure and center pipe diameter,slime content and center pipe diameter have the most significant effects on the concentration efficiency,bottom flood density difference,and overflow clarification coefficient respectively.When the optimal concentration efficiency is realized,the enrichment concentration efficiency is 0.262,which is between 2#heavy medium suspension,40Hz input pump frequency,and central pipe diameter between 1#and 2#.In order to realize the characteristics of optimal overflow suspension?low density,low concentration,low magnetic content?,we choose 2#heavy medium suspension,40Hz input pump frequency and 1#tube diameter.