A influência de floculantes poliméricos na formação de pastas minerais

Abstract

In the last years, the disposal of tailings in the form of pastes or high-density slurries has gained importance as it may present significant advantages in comparison to more traditional disposal techniques. The knowledge of physical chemical characteristics of the material to be disposed, as well as the interactions that result from the use of polymeric flocculants on solid/liquid separation can lead to the formation of pastes and/or high-density slurries with adequate conditions for handling and final disposal.With the help of factorial design tool (22) and with pH and flocculant dosage as independent variables, the influence of three different flocculants was evaluated on the settling rate and final percent solids of a bauxite tailings flocculated material. Rheological aspects of the slurry were also investigated as they are of paramount importance for the subsequent handling of the paste and/or slurry produced.Regarding settling rate and final % solids of the flocculated material, a cationicpolymer presented the best results among the three reagents tested. With a dosage of 130 g/t and pH 5, a settling rate of 105.2 mm/minute was reached and the final % solid (by wt.) was 31.2%. In relation to the slurry rheology,employing Bingham and Darby models, optimized handling conditions would take place at 32% solids.