Abstract: The invention relates to a method for reversing the dispersion formed in the mixing section of liquid-liquid extraction and kept condensed in the separation section and the separated solutions from the rear end of the separation section to flow back towards the feed end of the separation section as two separate streams. The invention also refers to the extraction equipment for implementing the reversed flow.

Abstract: The invention relates to a method for reversing the dispersion formed in the mixing section of liquid-liquid extraction and kept condensed in the separation section and the separated solutions form the rear end of the separation section to flow back towards the feed end of the separation section. The invention also refers to the extraction equipment for implementing the reversed flow.

Abstract: The invention relates to a mixing apparatus and a method for mixing gas in a closed mixing reactor, which uses gas as a process chemical with a high efficiency and where the content of pulverous solids in the solution is great. The aim is to obtain a flow in the reactor which sucks gas from above the surface of the liquid using rotating mixing devices in the centre of the reactor, and to mix said gas throughout the reactor capacity. The mixing apparatus of the invention comprises at least two mixers located at different heights, and on the same shaft. The upper mixer is equipped with a central plate attached to the shaft, with essentially vertical inner blades rising upwards and downwards and outer vanes directed outwards from the central plate, which are inclined from the horizontal. The lower mixer is equipped with a central plate attached to the shaft with vertical blades located on the outer edge.

Abstract: The invention relates to a method for guiding a dispersion of two liquids formed in the mixing stage of liquid-liquid extraction along the longitudinal axis of the separation section in the feed end of an extraction separation section. In particular the method and equipment relate to the extraction process used in the recovery of metals. In accordance with the method the dispersion to be fed into the separation section is guided so that it spreads evenly over the cross-section of the separation section using a directional member placed so as to obtain a vertical flow. The equipment in accordance with the invention consists of a directional member, which is in turn made up of at least two separate parts.

Abstract: The invention relates to a method for the recovery of metals, in particular copper, from a copper-bearing raw material, whereby the material is leached into a chloride-containing solution. The leaching of the raw material is performed oxidatively and at a sufficiently high redox potential that the copper in the copper chloride solution from leaching is mainly divalent. The chloride solution obtained, which contains copper and potentially other valuable metals, is fed to liquid-liquid extraction. In the extraction the copper is first transferred to the organic phase with extraction and then to a sulphate solution in stripping, which is fed to copper electrowinning.

Abstract: The invention relates to a method for controlling and compressing a dispersion formed in the mixing stage of liquid-liquid extraction. The compression of the dispersion is achieved by reducing the cross-section of the separation section in the direction of flow and by equipping the separation section with a dispersion-damming member. The equipment according to the invention thus comprises a settler, which is essentially trapezoid in shape so that its cross-section is wider at the feed end of the settler and gets smaller towards the rear end of the settler, from whence the separated solutions are discharged from the settler, and the settler is equipped with at least one device to dam up the dispersion. In particular the method and equipment relate to the extraction process used in the recovery of metals.

Abstract: The invention relates to a method for the controlled separation of a dispersion of two liquids formed in the mixing stage of liquid-liquid extraction into their own phases in the separation section of the extraction. In particular the method and equipment relate to the extraction process used in the recovery of metals. In accordance with the method the dispersion band remaining between the separated phases is dammed up using at least one revert member for said purpose located in the separation section. The equipment according to the invention comprises at least one revert member, which is in turn made up of at least two separate parts.

Abstract: The invention relates to a method for the removal of metals from their aqueous solution with lime precipitation, in conditions where a precipitate of metal hydroxide and gypsum is formed, which settles well and is easy to filter. The metals are precipitated from their aqueous solutions at a high pH value and the slurry is recirculated several times in the precipitation space, whereby the gypsum is precipitated as separate crystals instead of a solid layer. The method is particularly suitable for neutralization of the aqueous solution from the pickling of refined steel. Using this method enables the removal of metals and fluoride from the water in question.

Abstract: The invention relates to a method for the stabilization of the production capacity of an extraction plant extracting metals in a process, where the metal content of the feed solution varies. For the stabilization of capacity, the extraction cells and their piping are constructed and situated in such a way, that the extraction stages can be connected in different combinations, either in parallel or in a series. The method is especially suitable for the copper extraction process.

Abstract: The invention relates to a mixing apparatus and a method for mixing gas in a closed mixing reactor, which uses gas as a process chemical with a high efficiency and where the content of pulverous solids in the solution is great. The aim is to obtain a flow in the reactor which sucks gas from above the surface of the liquid using rotating mixing devices in the centre of the reactor, and to mix said gas throughout the reactor capacity. The mixing apparatus of the invention comprises at least two mixers located at different heights, and on the same shaft. The upper mixer is equipped with a central plate attached to the shaft, with essentially vertical inner blades rising upwards and downwards and outer vanes directed outwards from the central plate, which are inclined from the horizontal. The lower mixer is equipped with a central plate attached to the shaft with vertical blades located on the outer edge.

Abstract: The invention relates to a method for extracting copper in liquid-liquid solvent extraction from aqueous solutions with a high sulphate content, by raising the viscosity of the extraction solution and by dispersing the aqueous solution into drops, achieving a dense drop aggregation. The viscosity of the extraction solution may be raised either by increasing the content of the actual extractant, the extraction reagent, in the extraction solution or by using a diluting agent with a higher viscosity than that of the diluting agent normally used. By raising the viscosity of the extraction solution the mixing durability of the extraction dispersion can be increased and resulting of that the amount of residual drops is decreased. Other advantages are that the extraction solution flow of the extraction process decreases in relation to the flow of the aqueous solution acting as the copper source and that the size of the extraction equipment needed is reduced.

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.

Abstract: The invention relates to a method for recovering nickel in one and the same process from two pyrometallurgically produced nickel mattes, one of which contains a remarkable percentage or iron. The leaching of iron-bearing nickel matte is carried out in one step by conducting solution from the leaching cycle of a less iron containing matte into the leaching of a more iron containing matte at a stage where the iron of the less iron containing matte is in soluble form. The iron contained in the mattes is advantageously precipitated as jarosite and the solution created in the leaching of the more iron containing matte is conducted back into the leaching cycle of the less iron containing matte.

Abstract: A method for preventing the formation of jarosite, ammonium and alkali metal double salts during solvent extraction and leaching of an acidic leaching process in which an aqueous solution containing at least two metals are separated selectively from each other, and ammonium and alkali salts in the solution are neutralized prior to separation of the metals from the solution, and the formation of harmful double salts are prevented by using an exchange ion, which includes separating a first metal of the at least two metals by solvent extraction after neutralizing the solvent extraction solution by means of ammonium or alkali base; contacting the extraction solution with an aqueous solution containing an exchange ion, and replacing the ammonium or alkali ions contained in the extraction solution with the metal exchange ion during a pre-extraction step, whereby the ammonium or alkali ions are transferred into the aqueous solution to prevent formation of ammonium and alkali based double salts in a leach process sol

Abstract: The invention relates to a process for leaching nickel and copper from nickel-copper matte formed in pyrometallurgical nickel production by means of a multi-stage process. It is essential of the invention that the leaching of nickel takes place in at least two stages in conditions where free sulfuric acid is essentially absent, and that in these stages, the leaching of the nickel content of the matte is mainly carried out with copper as the oxidizer.

Abstract: The invention relates to a method for maintaining a continuous mixing extending throughout the transversal section of the reactor space in a liquid containing solids and gas, and for simultaneously separating gas or gas and solids from the liquid. The invention also relates to an apparatus whereby the mixing is maintained, and simultaneously at least one phase is removed from the liquid under agitation. In a particularly advantageous fashion the method and apparatus of the present invention are suited for the stirring of bioreactors, as well as to removing gas and solids from the said reactors.