The invention relates to a turbine-type high-power impeller, to be used for mixing slurry in hydrometallurgical process reactors. The impeller is formed of at least five blades, each of which blades comprises a front edge, trailing edge, root and tip; the roots of the impeller blades are permanently attached by a joint to the hub or axis of the impeller, so that the front edge of the impeller blade is straight, and the trailing edge is chamfered, in which case the blade is narrowed towards the tip, and the blade is provided with two longitudinal folds arranged in parallel with the front edge of the blade.