Control method of a flotation machine that is used in metallurgical processes

A control method of a flotation machine that is used in metallurgical processes. The flotation machine includes a flotation cell (1), and a rotor (2) that is inside the flotation cell. The amount of solid matter accumulated on the bottom of the cell is determined, and the rotation speed of the rotor is adjusted on the basis of the determined amount of solid matter. The rotor is rotated at the lowest possible first rotation speed which, in terms of metallurgy, is selected so as to have an adequate mixing power to maintain a suspension and form foam and, at the same time, to be small enough to allow the accumulation of solid matter on the bottom of the cell. The rotation speed of the rotor is periodically increased from the first rotation speed to a higher second rotation speed to remove the solid matter accumulated on the bottom of the cell. The second rotation speed is maintained for a predetermined period of time, after which the rotation speed of the rotor is reduced to the said first rotation speed.