Abstract: The invention relates to a method and an apparatus for monitoring the quality of an ore delivered to flotation concentration and the state of a slurry prepared from said ore. In the method, two or more working electrodes (6, 7, 8) featuring a cross sensitivity are immersed in the slurry to be monitored and the differences of potentials between each pair of electrodes is measured, whereby no reference electrodes are needed. The working electrodes (6, 7, 8) may comprise an argentite electrode, a platinum electrode and a molybdenum electrode, in which case the following differences of potentials between electrodes are being measured: ?(Ag—Pt), ?(Ag—Mo) and ?(Pt—Mo).

Abstract: Method and apparatus for controlling the flotation process of sulphide ores including separation of sulphide minerals from pyrite in an alkaline environment created by lime. The method comprises measuring the molybdenum electrode potential of an aqueous slurry of the ore and adjusting the addition of lime based on the measured molybdenum electrode potential to maintain the molybdenum electrode potential of the slurry in a preselected range. The apparatus comprises means (6) for measuring the molybdenum electrode potential and a control unit (7) for controlling the addition of lime to the slurry based on the measured molybdenum electrode potential of the slurry.

Abstract: A method and an apparatus for the separation of the mineral components of a pyrite containing copper-molybdenum ore by flotation. The method comprises grinding the ore in the presence of soda ash in an open circuit to produce an aqueous ore slurry; subjecting the slurry to a collective flash flotation step (10) in the presence of soda ash and sodium sulphide to recover a first part of metal sulphides of the ore in the form of a first concentrate (C1); subjecting the tailings (T1) of the collective flash flotation step (10) to a grinding step (13) and to a collective rougher flotation step (14) to recover a second part of metal sulphides of the ore in the form of a second concentrate (C3); and subjecting the concentrate (C1) of the collective flash flotation step (10) and the concentrate (C3) of the collective rougher flotation step (14) to a selection step (12) to separate molybdenite from the other metal sulphides of the concentrate.