Decoupling separation accuracy and flow partitioning in industrial hydrocyclones: CFD investigation of axial installation angle effect

The impact of the industrial hydrocyclone installation axial angle on separation performance remains a subject of practical debate, with limited full-scale validation. This study employs advanced computational fluid dynamics to bridge this gap, simulating two industrial hydrocyclones used in iron concentrate production across a range of axial angles (15°–105°). Utilizing an Eulerian–Lagrangian approach with Reynolds stress turbulence modeling, we quantitatively deconvolute the effects on separation accuracy (K80 cut-size) and separation efficiency (overflow-to-feed mass ratio). The results demonstrated that while the centrifugal force dominance renders separation accuracy insensitive to inclination (K80 variation < 3 μm), the axial angle critically governs separation efficiency by modulating flow partitioning. Near-vertical installations (75°–105°) reduce overflow yield by up to 43%, significantly increasing the recirculating load to the mill without altering product fineness. This study presents a validated operational paradigm: the installation angle is a key lever for managing hydraulic capacity and resilience during flow fluctuations, rather than for product quality control. These findings provide concrete strategies for optimizing design and operation in the mining and steel industries, striking a balance between product quality and circuit stability.