Revealing the influence of additional structure on the flow field characteristics in feedwell through PIV experiments
DOI:
https://doi.org/10.29393/ppudec-13fbrz70013Keywords:
Thickener feedwell, Particle image velocimetry, Additional structure, Flow fieldResumen
Cemented paste backfill (CPB) is a widely used method for resource utilization of tailings. The thickener feedwell is the key equipment for CPB in realizing solid-liquid separation. Flocculation is a significant process in treating tailings slurry thickening and dehydration. To reveal the flow field variation in the flocculation process, a range of feedwell with the additional structure were devised, containing the guide chute feedwell, the guide shelf feedwell, and the no-additional structure feedwell. To this purpose, the effects of hydrodynamics on flocculation performance in the feedwell were investigated with particle image velocimetry (PIV). The velocity and energy distribution were used to describe the variation of the flow field. The size and fractal dimension of aggregates for the flocculation reaction in the feedwell were studied. Furthermore, the turbidity was compared to evaluate the flocculation performance of these feedwells. The results of the PIV experiments indicated that the additional structure can effectively improve flocculation performance, ultimately achieving efficient solid-liquid separation efficiency. The flocculation process in the feedwell incorporates the mixing-collision section, and the settling-growth section along the flow direction, with bounding by additional structure. The ideal high-efficiency feedwell is to produce a symmetrical and uniform flow field, providing matched shear strength for the two flocculation sections. The guide shelf feedwell exhibited superior performance, resulting in significantly larger aggregate sizes while also experiencing remarkable compactness compared to the alternative additional structure. The reason is that the tailings slurry and flocculant obtain high mixing intensity and residence time in the mixing-collision section, causing the effective collision of micro aggregates, further increasing their size and compactness in the settling-growth section. Meanwhile, the gradually decaying energy distribution avoids fragmentation of the aggregates. This work is expected to provide the theoretical basis and technical support for the design and optimization of the feedwell, finally achieving deep dewatering and reducing solid waste pollution in mines.
Citas
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Derechos de autor 2026 Pengjie Wu, Aixiang Wu, Zhuen Ruan, Raimund Bürger, Shaoyong Wang, Chong Chen, Zhenqi Wang
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