Mineral flotation is a process whereby valuable hydrophobic mineral particles are recovered from low grade mineral pulp by means of attachment to air bubbles. Particles smaller than 10 mu m have a low probability of collision with bubbles, due to their tendency to be caught in streamlines created by a rising bubble. This review focuses on the techniques aimed at increasing the effective size of ultrafine mineral particles through aggregation, as an aid in improving flotation performance. These techniques are: shear flocculation, selective polymer flocculation and temperature responsive flocculation. Each technique is evaluated in terms of its mechanisms and its efficacy at improving the flotation of fine mineral particles. (C) 2011 Elsevier B.V. All rights reserved.