Effect of Overflow Pipe on the Internal Flow Fields and Separation Performance of W-Shaped Hydrocyclones

Lanyue Jiang,Hui Wang,Xinghua Yang,Peikun Liu,Yulong Zhang,Xiaoyu Li,Yuekan Zhang

doi:10.3390/min10040329

Lanyue Jiang, Hui Wang + Show 5 more

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https://doi.org/10.3390/min10040329

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Journal: Minerals	Publication Date: Apr 7, 2020
Citations: 10	License type: CC BY 4.0

Affiliation: Shandong University of Science and Technology

Abstract

The entrainment of fine particles in underflow of a grinding-classification hydrocyclone can cause ore overgrinding, which will lead to reductions in both metal recovery and ball mill throughput. To address this problem, this paper proposed a W-shaped hydrocyclone that can effectively reduce underflow fine particle entrainment. Experimental tests and numerical simulations were employed to deeply investigate overflow pipe diameter influence on the separation performance and internal flow field of W-shaped hydrocyclones. The effects of overflow pipe diameter on air core shape, velocity field, pressure field, and separation performance were studied. The results revealed that as the diameter of the overflow pipe increased, air core gradually stabilized, and air core diameter gradually increased. The diameter of stabilized air core was approximately 45% to 55% of overflow pipe diameter. As overflow pipe diameter increased, hydrocyclone pressure drop decreased, energy consumption was reduced, the tangential velocity decreased, outer vortex axial velocity did not change significantly, and inner vortex axial velocity gradually increased. At the same time, zero-velocity points gradually moved outward, and the inner vortex region expanded. By the increase of overflow pipe diameter, both the underflow yield and split ratio gradually decreased, the coarse particle content in the overflow product increased, and the fine particle content in the underflow product gradually decreased.

Highlights

The hydrocyclone has been widely used as a classification and separation device in grinding-classification operations
Dueck [9,10,11] injected clean water at a certain location in the cone section at a specific speed to disperse the outer swirl, pushing the fine particles settled on cyclone wall towards its center, making them re-enter the inner swirl and discharge from the overflow port to reduce the amount of Minerals 2020, 10, 329; doi:10.3390/min10040329
Flow field distribution in W-shaped hydrocyclones, including air core, velocity field, and pressure obtained through numerical simulations

Summary

Introduction

The hydrocyclone has been widely used as a classification and separation device in grinding-classification operations. (fine particle entrainment in underflow) and coarse particles in overflow, a phenomenon known as derichment [1,2,3,4]. In the classification of high-concentration coarse-grained materials, the “fish-hook”. Depends on the settling velocity of multi-component particles in a swirling flow field. This derichment often causes ore over-grinding, which leads to further problems, such as reductions in the metal recovery and the ball mill throughput. Dueck [9,10,11] injected clean water at a certain location in the cone section at a specific speed to disperse the outer swirl, pushing the fine particles settled on cyclone wall towards its center, making them re-enter the inner swirl and discharge from the overflow port to reduce the amount of Minerals 2020, 10, 329; doi:10.3390/min10040329 www.mdpi.com/journal/minerals

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