A review is presented here outlining design improvements for agitated tanks as developed in CSIRO’s laboratories,
which have solved practical problems in minerals processing operations involving viscous slurries.
Depending on Reynolds number, there are a range of design options which can be employed to
improve the mixing technology in general. These include optimizing impeller spacing and pitch angle.
Swirl flow via removal of baffles can be employed for Re > 500, even for viscous non-Newtonian slurries
with a yield stress. These agitator design improvements could be used to reduce stagnant zones, increase
wall velocity and reduce sedimentation depth, with the same power input as original designs. Significant
industrial benefits include reduced growth of scale, reduced agitator sedimentation bogging risk and
improved reagent mixing. These improvements have been demonstrated by many full-scale implementations
in large minerals processing tanks over the last 20 years. Radical design concepts including shafts
installed at an angle or offset have also been suggested for mixing high viscosity fluids more efficiently