Abstract: A method of and apparatus for the flotation of mineral feedstock using the method of froth flotation. The method may be employed with flotation machines having their own air suction, or with flotation machines with subaeration. Pulps pretreated with flotation agents and having a density up to twice the normal density of ore pulps are submitted to a flotation process with a pulsed air flow by means of normal air supply periods alternating with periods wherein the quantity of air ranges from 1-90% of the normal air supply. The apparatus for carrying out said method makes use of known flotation machines with rotor-stator systems, which machines are modified to provide them with an air duct incorporating an air flow regulating member connected to an appropriate control means. With the existing methods of flotation there are obtained about 400 gr/l of solids in the pulp. With the present method with pulsing air supply there can be obtained about 800 gr/l of solids in the pulp.