An examination of pulp viscosity in tubes at higher shear rates.

Deficiencies in the description of pulp properties is a major factor limiting improvements in the modelling of the flow within many mineral processing separation devices such as jigs and cyclones. Two factors severely hamper the development of accurate descriptions of pulp rheology: the large number of variables which influence pulp behaviour and the difficulty of making accurate measurements of pulp viscosity. Many factors make measurements of pulp viscosity difficult, including wall effects, turbulence, settling and the physical size of particles, particularly at high shear rates. An examination is presented of the measurement of pulp viscocity using capillary viscometers and in particular the high shear rate regions for which turbulent flow (or the transition to turbulent flow) occurs. The results show a marked difference in the behaviour of the pulps in this regime compared to Newtonian fluids. This is significant for hydrodynamic simulations of pulps at high shear rates.
Deficiencies in the description of pulp properties is a major factor limiting improvements in the modelling of the flow within many mineral processing separation devices such as jigs and cyclones. Two factors severely hamper the development of accurate descriptions of pulp rheology: the large number of variables which influence pulp behaviour and the difficulty of making accurate measurements of pulp viscosity. Many factors make measurements of pulp viscosity difficult, including wall effects, turbulence, settling and the physical size of particles, particularly at high shear rates. An examination is presented of the measurement of pulp viscocity using capillary viscometers and in particular the high shear rate regions for which turbulent flow (or the transition to turbulent flow) occurs. The results show a marked difference in the behaviour of the pulps in this regime compared to Newtonian fluids. This is significant for hydrodynamic simulations of pulps at high shear rates.