Effect of Reagents on the Rheological Behavior of an Iron Ore Concentrate Slurry

The influence of dosages of flocculants, dispersants and coagulants on the rheological behavior and state of aggregation and dispersion of an iron ore concentrate slurry was evaluated by determining the degree of dispersion using a settling tube, together with the analysis of flow curves obtained in a concentric cylinder rheometer. These curves were fitted according to models of Herschel-Bulkley and Bingham. The objective was to select reagents that promote a higher slurry thermodynamic stability, at pH 10 (pH used at SAMARCO’s regrinding circuit). These reagents would be evaluated later as grinding aids. None of the evaluated twenty reagents caused significant increases in the slurry’s degree of dispersion. Of the twenty selected reagents, six reduced the fluid consistency index (k coefficient) and apparent viscosity, at the dosage 300 g/t: three polyacrylic acids, silicone acrylate copolymer, citric acid and sodium hexametaphosphate.