Effect of changes in the feed duct on hydrocyclone performance

Enhancement of the classification and recovery process of fine mineral particles via a newly developed volute feed hydrocyclone

Ore resources in the mining process form a large number of unmanageable tailings, mostly inhalable fine mineral particles, into the environment will cause serious pollution, and recycling is a precious resource. The cyclone classification provides the possibility for the recovery and exploitation of fine particles, but the recovery and utilization rate of conventional cyclone separation is seriously low, and the performance urgently should be optimized. In the present study, a new type of volute feed was proposed to strengthen the classification and recovery process of fine mineral particles. Combined with numerical simulation and experimental research, the effects of various structural parameters and operating parameters on the flow field distribution, particle motion, and classification performance were systematically examined. The obtained results reveal that the new volute feed structure can effectively reduce the internal turbulence and improve the flow field stability and particle classification efficiency. Compared with the traditional hydrocyclone, the classification efficiency of fine particles with new feed structure increases by 10-18%. Increasing underflow diameter and feed pressure and reducing overflow diameter and feed concentration are also beneficial to lessening classification particle size and enhancing classification performance. The currently achieved outcomes can provide valuable guidelines for further development of novel hydrocyclones.

A novel hydrocyclone for use in underground DNAPL phase separation

Halogenated organic solvents are the most commonly detected pollutants in groundwater and are particularly toxic and harmful. How to separate these dense nonaqueous phase liquid (DNAPL) pollutants efficiently from groundwater has become an important research question. Here, a novel hydrocyclone with annular overflow structure was designed, which eliminated the short-circuit flow of the traditional hydrocyclone and solved the problem of overflow entrainment caused by the enrichment of droplets near the locus of zero vertical velocities (LZVV) into turbulence. The flow field characteristics of this novel hydrocyclone were studied using Computational Fluid Dynamics (CFD) simulation and compared with the traditional hydrocyclone. It was found that the annular gap structure of the novel hydrocyclone increased the tangential velocity of the outer vortex. Moreover, the radius of the LZVV was expanded outward by 0.17 mm, which reduced the possibility of droplets with small particle sizes in the second phase escaping from the overflow pipe. The collective effect was to eliminate the short-circuit flow. This novel hydrocyclone was able to separate DNAPL pollutants with low consumption and high efficiency, across a range of inlet velocity from 4 to 6 m/s. The maximum separation efficiency was 99.91 %. In addition, with trichloroethylene (TCE) as the target pollutant, the maximum volume fraction of the dispersed phase in the hydrocyclone was located on the side wall of the hydrocyclone. Taken together, we believe that this work will provide a low-cost, efficient separation method for the separation of groundwater- contaminated liquid mixtures. Furthermore, it has broad application prospects in the field of heterotopic remediation of groundwater.

Influence of Vortex Finder Structure on Separation Performance of Double-Overflow Three-Product Hydrocyclones

In view of the difficulty of traditional hydrocyclones to meet the requirements of fine classification, a double-overflow three-product (internal overflow, external overflow and underflow) hydrocyclone was designed in this study. Numerical simulation and experimental research methods were used to investigate the effects of double-overflow flow field characteristics and structural parameters (i.e., internal vortex finder diameter and insertion depth) on separation performance. The research results showed that the larger the diameter of the internal vortex finder, the greater the overflow yield and the larger the cut size. The finest internal overflow product can be obtained when the internal vortex finder is 30 mm longer than the external vortex finder. The separation efficiency is highest when the internal vortex finder is 30 mm shorter than the external vortex finder.