Slurry viscosity modification effects on classifying cyclone performance

Efforts to reduce the amount of ultrafine bypass in classifying cyclones by decreasing water recovery increased the particle size cut point and negatively affected classification efficiency due to the impact on slurry rheology. The addition of a viscosity modifier to the feed stream of a classifying cyclone improved the classification performance and decreased the particle size cut point over a range of feed solids concentrations. The detailed test program investigated the use of the modifier in conjunction with varying apex diameters to identify conditions that minimize ultrafine bypass. With small apex sizes, roping conditions were readily eliminated by the addition of viscosity modifiers.