Phenomenological Study on Fine Particle Misplacement Behavior in Hydrocyclone

  • Chandranath Banerjee
  • Rakesh Kumar Dubey
  • Arun Kumar MajumderEmail author
Technical Paper


In spite of widespread applications of hydrocyclone, imprecise particle separation is an inherent limitation associated with it and led to a significant effect on the grinding operation. Such inefficiency is primarily attributable to the misplacement of significant amount of fine particles in the coarser product stream and commonly known as “bypass” in literature. Concerted research efforts are still continuing at various directions to rationalize the occurrence of such phenomenon in a quantifiable manner. This study reveals a fundamental basis towards the genesis and occurrence of bypass in hydrocyclone based on the hydrodynamic of particulate suspension within the turbulent field. Through a series of experiments, we generated carefully controlled experimental data in a 50.8 mm hydrocyclone to analyse the physical response of different parameters (design and operating) on the bypass. Proceeding with the experimental observations we disclose that fines recovery is not equal to that of water split in the underflow. Following this lead, we concluded that the bypass is principally driven by the hydrodynamic condition and the turbulent dispersion of the suspended particle in the prevailing centrifugal force field. Detailed calculations are presented on the basis of solid–fluid two-phase turbulent model to describe the above phenomenological incident. Although our analysis presented here confined to the small diameter hydrocyclone, we are optimistic that the acquired knowledge will be rationale towards the perception of a physical meaning to bypass even for larger classifying cyclones.


Hydrocyclone Bypass Hydrodynamics Turbulent dispersions 

List of symbols


Vortex finder diameter (mm)


Spigot diameter (mm)


Particle diameter (m)


Particle density (kg/m3)


Fluid density (kg/m3)


Fluid viscosity (kg/m3)


Feed inlet pressure (kPa)


Solid concentration (%w/w)


Specific gravity of mixture


Particle radial velocity (m/s)


Tangential velocity (m/s)


Settling velocity (m/s)

\( u^{*} \)

Shear velocity (m/s)


Dispersion length scale (m)


Dispersion index (dimensionless)


G force (dimensionless)


Centrifugal acceleration (m/s2)


Particle relation time (s)


Mass of pulp water in underflow (kg)


Mass of pulp water in feed (kg)


Mass flow rates of solids in underflow (kg/s)


Mass flow rates of solids in feed (kg/s)


Mass fraction of ith size particle in underflow


Mass fraction of ith size particle in feed


Selectivity index


Classification function


Bypass fraction


Volumetric water recovery in underflow (dimensionless)


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Copyright information

© The Indian Institute of Metals - IIM 2016

Authors and Affiliations

  • Chandranath Banerjee
    • 1
  • Rakesh Kumar Dubey
    • 1
  • Arun Kumar Majumder
    • 1
    Email author
  1. 1.Department of Mining EngineeringIndian Institute of Technology KharagpurKharagpurIndia

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