Slurry Viscosity Modification Effects on Classifying Cyclone Performance

Abstract

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.

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.

Les efforts pour réduire la quantité de dérivation de particules ultrafines dans les cyclones de classification en diminuant la récupération d'eau augmentaient la coupure de la taille de particule et affectaient négativement le rendement de classification à cause de l'impact sur la rhéologie de la pulpe. L'addition d'un modificateur de viscosité au circuit d'amenée d'un cyclone de classification a amélioré le rendement de classification et a diminué la coupure de la taille de particule sur une gamme de concentrations de solides d'alimentation. Le programe d'essai détaillé a étudié l'utilisation du modificateur en conjonction avec des diamètres variables de l'apex pour identifier les conditions qui minimisent la dérivation des particules ultrafines. Avec de petites tailles d'apex, on a éliminé sans difficulté les conditions de "cordage" par addition de modificateurs de viscosité.