Particle flocculation and thickening by multiscale <scp>CFD</scp> modeling: A focus on wide solid concentration field

Abstract Flocculation–thickening is widely used in mineral processing and various chemical engineering fields. The flocculation in the thickener feedwell plays a key role in the tailings slurry thickening process. Hydrodynamic conditions directly affect particle flocculation kinetics and subsequent settling rates, thus determining the overall performance of the thickener. This study employs a multiscale modeling approach to investigate how feed solid concentration affects flow characteristics and flocculation–settling performance in a pilot‐scale deep cone thickener, in which Computational Fluid Dynamics‐Population Balance Model (CFD‐PBM) and a Two‐Fluid Model with Kinetic Theory of Granular Flow (TFM‐KTGF) were applied to simulate flocculation and settling behavior, respectively. Results show that medium solid concentration promotes particle aggregation via optimal turbulence dissipation. Increasing concentration reduces both the initial settling rate ratio of flocs and the settling differential between particle sizes. These findings enhance the understanding of flocculation–thickening mechanisms and support process optimization in solid–liquid separation fields.