Step change improvements in underflow rheology

Many thickening operations continue to be constrained by their ability to process consolidated underflows with high yield stress and associated rheological characteristics. The application of high molecular weight polymers (flocculants) is a prerequisite to maintain the operation integrity and dynamics of most gravity based solids/liquid separation processes. Such treatments are an effective means of consolidating solids and maximising clean water recovery. Unfortunately polymer/solids interaction at, and beyond, the gel point result in a significant increase the yield stress for a given solids content. BASF is developing a novel flocculant treatment (NFT) by which primary solid/liquid separation efficiency is maintained, and the subsequent consolidation process is enhanced, wherein higher underflow solids are associated with reduced yield stress. This paper will present application data to demonstrate the benefits associated with this NFT.