Optimising the activity of acrylamide-based polymer solutions used to flocculate mineral processing tailings suspensions – A review
Claudia Castillo, Phillip Fawell, Allan Costine
Abstract
The polymer flocculants applied to mineral tailings suspensions to aggregate fine particles and thereby enhance solid-liquid separation are also used in a range of other industrial applications. As a consequence, their synthesis, degradation and general solution properties have been extensively reviewed. The polymer’s state in solution can vary substantially, and given flocculation activity is closely related to this property, it is surprising there is no systematic review of the many factors at play in maximising flocculant solution activity in tailings applications. At the simplest level these factors influence applied dosages and thereby reagent consumption, but sub-optimal activity can impose performance limits on solid-liquid separation unit operations, with potential adverse effects on downstream tailings properties and both the volume and quality of returned process water. All aspects impacting upon likely polymer flocculant activity are considered, including physical forms, stock solution preparation (dissolution and ageing), water chemistry, mechanical forces in mixing and transport, dilution prior to dosing, temperature effects and dosing locations. Special attention is given to insights gained from studies on industrial tailings suspensions, noting how these may vary due to different operational priorities and conditions. Finally, potential opportunities for research that could contribute to more effective flocculant utilization are discussed.