Abstract: In a method according to the invention, a dispersion coming from a mixer part is conducted from downwards to the liquid part of the settler, into the middle part of the feed end, wherefrom it is set to be distributed to inside the settler part, in a closed channel-like space located in the immediate vicinity of the settler along the whole width of the settler and the flow therefrom mainly above the channel-like part towards the rear end of the settler. The method according to the invention is realized by means of an apparatus where an uptake shaft extending from the dispersion mixing tank to the settler opens into the feed end of the settler, from where there are further directed distribution channels towards the settler side edges. The distribution channels are placed in the bottom part of the settler.

Abstract: The invention relates to a method for adjusting the boundary surface between the two mutually separable solutions in liquid—liquid extraction at the discharge end of the separation part and for preventing the aeration of the solutions when discharging them from the separation part, so that the overflow height of the settled, lighter organic solution is maintained constant. In order to adjust the boundary surface in between the mutually separable solutions, the overflow height of the heavier aqueous solution is adjusted by conducting the settled aqueous solution from down upwards through tubular elements, in which case the height of these overflow pipes can be adjusted. The aeration of the solutions when discharging them from the separation part is prevented by conducting the solutions into transfer pipes through covered, shaft-like weir boxes that are deeper than the discharge end.

Abstract: The method and apparatus according to the invention relate to conducting the dispersion of two phases, created in the mixing unit (1) of liquid—liquid extraction, from the mixing unit to the separation part (2), in which case the flow direction of the dispersion discharged from the mixing unit asymmetrically with respect to the separation part is turned to be symmetrical with respect to the separation part. In the last mixer (4) of the mixing unit, the orientation of the dispersion is turned to be parallel to the lengthwise axis of the separation part, by means of flow-turning members (9), the dispersion flow is discharged from the mixing unit at the height of the mixer bottom (10) and conducted to an uptake shaft (11) parallel to the lengthwise axis of the separation part, where the dispersion flow is turned upwards and made to be discharged symmetrically into the separation part.

Abstract: The invention relates to a method for settling the dispersion formed in the mixing unit of liquid-liquid extraction, for controlling solution flows and for creating pure solutions in the separation part. According to the method, the flow speed of the organic solution phase is adjusted to be clearly higher than the flow speed of the aqueous solution phase, in which case in order to prevent border flow turbulence caused by the speed difference of the solution phases, the water drop dispersion layer left in between the separating solutions is adjusted to extend as far as the discharge end of the separation part.

Abstract: The invention relates to a method for recirculating the heavier solution from the separation part of liquid--liquid extraction to the mixing unit of the same extraction step, so that part of the recirculated solution is returned to the mixing unit from the overflow of the discharge end of the separation part. An essential feature of the invention is that the major part of the heavier solution recirculated into the mixing unit is obtained from the separation part proper, along the whole width thereof. The invention also relates to an apparatus based on said method, in which apparatus, in the bottom part of the settler (6) there is located a heavier solution collecting channel (13) extending over the whole width of the settler and being provided with suction pipes (15) which are oriented in an inclined fashion towards the solution to be collected from the channel.