Tailings flocculation and sedimentation in a lab-scale gravity thickener by CFD modelling--颗粒学报PARTICUOLOGY

Wang, X., Shao, Y., Mao, Z., Wang, Y., Cui, B., & Bayly, A. (2026). Tailings flocculation and sedimentation in a lab-scale gravity thickener by CFD modelling. Particuology, 108, 183-195. https://doi.org/10.1016/j.partic.2025.10.023

Tailings flocculation and sedimentation in a lab-scale gravity thickener by CFD modelling

Xuetao Wang^{a *}, Yuchen Shao^a *, Zhiran Mao^a, Yulian Wang^a, Baoyu Cui^b, Andrew Bayly^c

a School of Materials Science and Engineering, Shenyang Ligong University, Shenyang, 110159, China
b School of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, China
c School of Chemical and Processing Engineering, University of Leeds, Leeds, LS29JT, UK

10.1016/j.partic.2025.10.023

Volume 108, January 2026, Pages 183-195

Received 26 June 2025, Revised 29 July 2025, Accepted 28 October 2025, Available online 7 November 2025, Version of Record 3 December 2025.

E-mail: wangxuetao@sylu.edu.cn; yuchenshao2025@126.com

Highlights

• A novel CFD-PBM-KTGF framework was proposed to simulate flocculation-sedimentation process by steps.

• A visualization analysis of particle behavior inside the thickener was conducted.

• Effects of turbulent characteristics on particle aggregation and floc breakage are systematically analyzed.

• Thickening efficiency was improved through the feeding parameters intensification.

Abstract

This study employed coupled the Computational Fluid Dynamics-Population Balance Model (CFD-PBM) framework and Kinetic Theory of Granular Flow (KTGF) to investigate the flocculation and sedimentation dynamics of polymodal tailings particles in a lab-scale gravity thickener. The Euler-Euler multiphase model and RNG k-ε turbulence model are integrated to simulate solid-liquid interactions and turbulent flow characteristics, while flocculation kinetics, including aggregation and breakage mechanisms, are incorporated to quantify particle size evolution. The influence of feed velocity on flow field characteristics and particle flocculation-sedimentation efficiency was analyzed through visualization. The results indicated that the turbulent energy distribution is highly sensitive to the feed velocity. The optimal velocity range (2.0–2.5 m/s) promotes a balanced aggregation-breakage dynamics of particles, stabilizing the formation of larger flocs and enhancing sedimentation. Excessively high feed velocities (>3.0 m/s) induce stronger turbulence, reducing floc size and impairing sedimentation efficiency. Spatial analysis reveals that fine particles (<50 μm) are widely dispersed, while large flocs (>100 μm) dominate the underflow solid concentration. The impact of floc size and density on sedimentation was also examined. This study identifies a critical threshold for feed velocity to optimize thickener performance, providing a theoretical basis for process intensification in industrial thickeners.

Graphical abstract

Keywords

Gravity thickener; Particle flocculation; Flocs sedimentation; Numerical simulation

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