Being able to predict solid distribution in a mixing tank, as a function of operating conditions, is of upmost importance to several processes, having acted as the motivation for this work. It is widely accepted that operating above the critical impeller speed is usually unfavorable, since the increase of transfer rate will be slight when compared with the increase on the dissipated power. Thus, a concentration gradient normally exists in the tank. Nevertheless, predicting those distributions requires the development of constitutive models leading to accurate design procedures. The thesis of this paper is that those profiles can be explained by the settling/dispersion model, which states that suspension of the particles is due to random turbuent bursts being opposed by the settling tendency of the solids. Estimates of the concentration profiles developed in a mixing tank with an axial flow impeller, for several operating conditions, are presented and compared with experimental measurements from the literature. The results obtained suggest that the model proposed is a sufficient basis for assessment of suspension quality.