Abstract: The present invention relates, generally, to a method and apparatus for electrowinning metals, and more particularly to a method and apparatus for copper electrowinning using the ferrous/ferric anode reaction. In general, the use of a flow-through anode—coupled with an effective electrolyte circulation system—enables the efficient and cost-effective operation of a copper electrowinning system employing the ferrous/ferric anode reaction at a total cell voltage of less than about 1.5 V and at current densities of greater than about 26 Amps per square foot (about 280 A/m2), and reduces acid mist generation. Furthermore, the use of such a system permits the use of low ferrous iron concentrations and optimized electrolyte flow rates as compared to prior art systems while producing high quality, commercially saleable product (i.e., LME Grade A copper cathode or equivalent), which is advantageous.

Abstract: This invention relates to a system and method for producing a metal powder product using conventional electrowinning chemistry (i.e., oxygen evolution at an anode) in a flow-through electrowinning cell. The present invention enables the production of high quality metal powders, including copper powder, from metal-containing solutions using conventional electrowinning processes and/or direct electrowinning.

Abstract: A method of producing high purity electrolytic copper through halide-bath electrowinning is provided. The method includes the steps of: growing copper in dendritic form to be deposited on a cathode; and recovering growth ends of 3.0 mm or shorter from the dendrites.

Abstract: A composite copper foil (10) comprises a carrier foil (12) formed by electrodeposition onto a cathode, the carrier foil (12) having a cathode side formed in contact with the cathode and an opposite electrolyte side. A very thin release layer (14) is on the electrolyte side of said carrier foil (12). A thin functional foil (16) formed by deposition of copper has a front side in contact with the release layer (14) and an opposite back side. The electrolyte side of the carrier foil (12) has a surface roughness Rz less than or equal to 3.5 ?m. There is also presented a method for manufacturing such a composite copper foil.

Abstract: A method of producing a higher purity metal comprising the step of electrolyzing a coarse metal material by a primary electrolysis to obtain a primary electrodeposited metal, the step of electrolyzing the material with the primary electrodeposited metal obtained in the primary electrolysis step used as an anode to obtain a higher purity electrolyte for secondary electrolysis, and the step of further performing secondary electrolysis by employing higher purity electrolytic solution than said electrolytic solution with said primary electrodeposited metal as an anode, whereby providing an electro-refining method that effectively uses electrodes and an electrolyte produced in a plurality of electro-refining steps, reuses the flow of an electrolyte in the system, reduces organic matter-caused oxygen content, and can effectively produce a high purity metal.

Abstract: The method for electrolytically refining copper makes use of crude copper as an anode and is characterized in that the temperature of the electrolyte in an electrolytic cell is maintained at a level of not less than 55° C.; that the electrolyte is continuously introduced into the electrolytic cell from the top of the cell, continuously discharged from the bottom of the cell along with slime, the slime is removed from the electrolyte discharged from the electrolytic cell and the electrolyte free of any slime is recirculated in the cell; and that the electrolyte is passed through the space between the electrodes at an average electrolyte velocity sufficient for allowing the electrolyte to flow on the whole surface of the cathode downward or in the direction opposite to that of the upward stream of the electrolyte generated on the cathode surface when the electrolysis is initiated while the electrolyte is in the stationary state.

Abstract: An electrochemical fabrication process for producing multi-layer three-dimensional structures includes selectively electrodepositing one or more building materials using contact masks. In some embodiments, a copper pyrophosphate plating solution is used and is formulated to allow simultaneous deposition to a large area (>=about 1.44 mm2) and to a small area (<=about 0.05 mm2) wherein the thickness of deposition to the smaller area is no less than ½ that to the large area when the deposition to the large area <=about 10 &mgr;m in thickness and where the solution contains >=about 30 g/L of copper. In other embodiments contact masks include a support structure that is treated with a corrosion inhibitor (e.g. BTA) prior to attaching or forming a patterned material on it and/or plating baths are operated at low temperature either of which may be useful in extending the life of the masks.

Abstract: A process for the removal of primarily iron impurities from acidic aqueous electrolytic solutions used in the electro-winning of copper is described. Strong base Type 1 ion exchange resin is used to remove acid from the solution resulting in a treated solution that contains only a small amount the original acid but all of the dissolved salts. This low acid treated solution is then processed using standard processes such as adjustment of the pH or oxidation potential to remove the iron impurities and the solution containing valuable process cobalt is returned to the electrolyte solution to continue the extraction of copper.

Abstract: A method consists in measuring ac impedance spectrum using gold, platinum or carbon working ultramicroelectrodes (1). The direct current DC potential pulse which overlaps with alternating current AC signal of an amplitude in the range from 0.005 to 0.015 V and frequency in the range from 10−2 to 106, Hz is applied at the electrode. The value of said DC potential pulse for a process of copper electrorefining is in the range from −0.4 to −0.9 V in relation to a platinum reference electrode (2). Resistance values characteristic of a given electrolyte (E) are obtained from said AC impedance spectrum and compared with standard characteristic obtained by standard additions method. A measuring system consist of electrodes (1, 2, 3) placed inside a measuring cell (4) filled with flowing industrial electrolyte.

Abstract: A method of operating a cell for electrowinning of copper, the cell including a plurality of anodes and cathodes therein, the method including the steps of introducing fresh electrolyte and sparging gas to a manifold system in the cell, controlling flow of fresh electrolyte and sparging gas in the manifold system and providing outlet openings in the manifold system such that streams of fresh electrolyte and sparging gas from the outlet openings are directed relatively uniformly across the cathodes in the cell.

Abstract: An electrolytic copper foil is electrodeposited onto the cathodic drum surface of a rotating cathode drum by feeding an electrolytic solution between the cathode drum and an anode facing each other and applying direct current between them, while the initial formation of the crystal nuclei of the electrolytic copper foil is performed by providing an auxiliary anode, an electrolytic solution receiver and a flashboard above the anode and applying an electric current between the cathode drum and the auxiliary anode and feeding an electrolytic solution separately onto the cathodic drum surface from an electrolytic solution feeder placed near the auxiliary anode and discharging it through the gap between the cathodic drum surface and the edge of the electrolytic solution receiver, keeping an electrolytic solution holdup between the cathodic drum surface and the auxiliary anode by the electrolytic solution receiver and the flashboard.

Abstract: An improvement in the solvent extraction process for recovering metal values, i.e. copper, from acidic aqueous solutions containing copper and iron which may also include chloride, and more particularly to an improvement which provides for increased copper to iron ratios in the loaded organic extractant phase. The improvement comprises washing the loaded organic extractant phase prior to stripping of the copper values therefrom with an aqueous acidic wash solution containing at least a portion of electrolyte solution, wherein the wash solution or the electrolyte solution has been previously contacted with copper metal.

Abstract: Electrolytic solutions containing organic additive(s) selected from a described class of additives (e.g., 4,6-dihydroxypyrimidine) reduce overall applied electrical potential of electrolytic cells and/or reduce gas formation at the anode(s) or increase copper production rate. Benefits include reducing overall power consumption and reducing acid mist during electrolytic processes.

Abstract: Disclosed is a process for recovery of cyanide and metals from a liquor containing complexes of cyanide and metal typically generated by a metallurgical or industrial process. The process involves electrochemical dissociation of the metal-cyanide complex and electrowinning of the metal while free cyanide generated in the process is recovered in a membrane treatment step for re-use in a metallurgical process utilising it. An electrochemical apparatus, which may be used in the process, forms a further aspect of the invention. A membrane process alone, for separation of cyanide, from liquors containing cyanide complexes is a further aspect of the invention.

Abstract: The electrolyte is supplied from a reservoir through at least one supply line to an electrolysis area including anodes and cathodes and at least one electric d.c. voltage source, and used electrolyte is at least partly recirculated from the electrolysis area back to the reservoir through at least one discharge line. Between a first contact point in the electrolyte of the supply line and a second contact point in the electrolyte of the discharge line there is a bridge line containing electrolyte, where the ohmic resistance R1 of the electrolyte in the bridge line between the first and the second contact point is not more than 10% of the ohmic resistance R2 which exists between the first and the second contact point in the electrolyte flowing through the reservoir. The amount of electrolyte flowing through the bridge line per unit time is not more than 5% of the amount of electrolyte flowing in the supply line in the vicinity of the first contact point.

Abstract: Various systems and methods for protecting electrowinning anodes having electrocatalytically active coatings in a bank of electrolytic cells from being damaged by reverse currents. In the first embodiment, one or more auxiliary power sources are provided that, when triggered by one or more predetermined conditions being met, keep the bank of electrolytic cells in an electrical state that is relatively harmless to the anodes having electrocatalytically active coatings. In a second embodiment, the invention is directed to a method of maintaining the polarization of anodes in an electrowinning cell positive of the cathodes (i.e. in a potential region where the anode coating is not susceptible to significant damage). In a final embodiment, the invention is directed to various methods for the installation of replacement anodes and maintenance of electrowinning cells.

Abstract: An electrolytic process for the production of metallic copper in an electrolytic cell including anode and cathode chambers separated from each other by a porous member, an anode disposed in the anode chamber, and a cathode disposed in the cathode chamber. The process comprises providing an ammoniacal alkaline electrolyte solution containing diammine cuprous ions in each of the anode and cathode chambers, and applying direct current to the anode and cathode to produce metallic copper on the cathode and to produce tetrammine cupric ions on the anode. An electrolytic cell apparatus including anode and cathode chambers separated from each other by a porous member, an anode disposed in the anode chamber, a cathode disposed in the cathode chamber, and a DC current source connected to the anode and cathode, wherein each of the anode and cathode chambers contains an ammoniacal alkaline electrolyte solution containing diammine cuprous ions.

Abstract: A method and apparatus are described for removing a chemical product species produced by electrochemical action at an electrode or by a chemical reaction which occurs at the surface of a solid catalyst. The method involves providing a flow of a host solution generally parallel to a surface at which a chemical reaction occurs. The flow of the host solution causes the products from the chemical reaction to be entrained in a thin boundary layer which moves along the surface. These products can be removed from a cell by withdrawing the boundary layer from the cell as it reaches the trailing edge of the surface.

Abstract: The present invention is directed to an improved process for the recovery of metal ions from metal-containing aqueous solutions using a supported liquid membrane (SLM) whereby the pH of the metal-containing solution is preferably adjusted to between 5.5 and 8 and ammonia or other weak base is present in the metal-containing solution in a concentration sufficient to form a complex between the weak base and metal ions present in the solution. The present invention permits enhanced recovery of metal in the solution without any need to adjust the pH of the solution during the SLM process.

Abstract: The present invention concerns a method for the prevention of anode passivation in the electrolytic refining of copper, when periodic reversal current technology is used in electrolysis. The method is particularly suitable for the electrolytic refining of copper at high current densities. Irregular periodic reversal current technology is used in the present method, whereby current reversal is adjusted on the basis of an increase in electrolysis cell voltage.

Abstract: A copper electroplating composition for integrated circuit interconnection is proposed, including a copper salt, an inorganic acid containing same anion as the copper salt, a suppressing agent and a polishing agent. This electroplating composition helps deposit copper into fine trenches with a high aspect ratio on a substrate, so as to form a surface-flat and void-free plated copper layer over the substrate by electroplating. It can therefore reduce the usage of polishing slurry and polishing time in a subsequent chemical mechanical polishing process, and also improve surface planarity of the copper later after being polished.

Abstract: An electrowinning cell, having a tank with an opened upper end defined by a tank edge, electrolyte within the tank and a plurality of flat, metallic electrode plates disposed within the tank in side-by-side, spaced-apart, parallel relationship. Adjacent electrode plates define an electrode gap therebetween. An injector manifold is disposed at the bottom of the tank for feeding electrolyte into the tank at locations below the electrode plates. A collector grid, comprised of a plurality of collectors having ports, define an upper level of electrolyte by collecting the electrolyte from the tank. The ports are disposed in spaced-apart relationship within the open upper end defined by the tank edge. The collector grid and the injector creating a flow of electrolyte upward between the plates as the electrolyte flows from the manifold locations below the plates to the ports.

Abstract: A method and apparatus is disclosed for reclaiming a metal from the effluent of a chemical mechanical planarization (CMP) process and using the reclaimed metal in an electroplating process. The steps of the method include using a chemical solution in a CMP process to remove material from a semiconductor device. An effluent is produced by this step that contains a dissolved first species removed from the semiconductor device. Then a second step of treating the effluent is performed to remove the dissolved first species and to produce a reclaimed metal. Then a third step of using the metal in an electroplating process is performed.

Abstract: An electrolytic copper foil is electrodeposited onto the cathodic drum surface of a rotating cathode drum by feeding an electrolytic solution between the cathode drum and an anode facing each other and applying direct current between them, while the initial formation of the crystal nuclei of the electrolytic copper foil is performed by providing an auxiliary anode, an electrolytic solution receiver and a flashboard above the anode and applying an electric current between the cathode drum and the auxiliary anode and feeding an electrolytic solution separately onto the cathodic drum surface from an electrolytic solution feeder placed near the auxiliary anode and discharging it through the gap between the cathodic drum surface and the edge of the electrolytic solution receiver, keeping an electrolytic solution holdup between the cathodic drum surface and the auxiliary anode by the electrolytic solution receiver and the flashboard.

Abstract: CMOS processing is enhanced via a method and system that use a chemical bath purification process. According to an example embodiment of the present invention, solution from a CMOS wet chemical bath is passed over a powered circuit. The powered circuit plates out copper from the solution, and the solution is then returned to the bath. By removing copper from the chemical bath in this manner, cross-contamination of wet chemical equipment is reduced, and the need for redundant tool sets can be eliminated.

Abstract: This invention relates to a low density high surface area copper powder having an apparent density in the range of about 0.20 to about 0.60 gram per cubic centimeter, and a surface area of at least about 0.5 square meter per gram. This invention also relates to an electrodeposition process for making the foregoing copper powder by electrodepositing the copper powder from an electrolyte solution using a critical combination of process parameters. These critical parameters include: a copper ion concentration for the electrolyte solution in the range of about 2 to about 7 grams per liter; a free chloride ion concentration for the electrolyte solution in the range of about 8 to about 20 ppm; an impurity level for the electrolyte solution of no more than about 1.0 gram per liter; and an electrolyte solution that is free of organic additives.

Abstract: The invention is directed to the use of copper as via and interconnect structures for an integrated circuit. The process in accordance with a preferred embodiment produces an interconnect layer of continuous copper with superior adhesion while requiring only a minimum number of steps for its production. This process addresses the current need in semiconductor manufacturing for reliable and performance-oriented vias and interconnect structures, while not being susceptible to many of the problems which plague the use of aluminum for similar structures. Fabrication of an integrated circuit in accordance with a preferred embodiment of the invention begins with the formation of semiconductor devices on a silicon wafer. Next, an intermetallic dielectric layer (IDL) is formed by materials such as silicon dioxide (SiO2), polymide, or silicon nitride over the devices. This step is followed by the laying of a diffusion barrier layer on the IDL surface.

Abstract: Waste slurry containing dissolved metal from e.g., CMP is subjected to sludge-free processing. Embodiments include separating the waste slurry with a solids filter into a solids-free dissolved metal-containing liquid filtrate portion and a concentrated solids-containing portion, removing the dissolved metal from the filtrate by means of an ion exchanger, back-washing the concentrated solids-containing portion with metal-free effluent from the ion exchanger to further reduce its dissolved metal content, discharging the washed concentrated solids-containing portion to a waste drain, removing the metal from the ion exchanger in solution form, and optionally extracting solid metal from the solution by electrowinning.

Abstract: A procedure for the generation of organosulfonic acids from solutions of corresponding metal organosulfonate compounds by electrowinning, electrolytically driven hydrolysis or chemically driven hydrolysis is described. Appropriate organosulfonate compounds include the water soluble salts of alkanesulfonic and aromatic sulfonic acids which incorporate metals from Group VIB, VIIB, VIIIB, IB, IIB or VA of the periodic table. The electrowinning and electrolytic techniques described can be applied in divided or undivided cells and can be operated in continuous fashion to provide the greatest efficiency. Hydrolysis based methods can employ either anodic oxidation or oxidation both of which function to oxidize the metal cation(s) present to hydrolytically unstable higher oxidation states.

Abstract: Copper is extracted from a heap of low-grade ore by transforming the heap into an electrolytic cell, and imposing a voltage thereon. Anodic conditions of redox and pH cause the sulphide to break down, and the copper to pass into solution. The copper can be recovered elsewhere if the electrolyte is drawn off, or in-situ if allowed to plate onto the cathode. Electrodes are formed as grids of conductors, or as layers of e.g. graphite.

Abstract: A high performance method for recovery of metal from aqueous solutions is carried out using an electrochemical cell having a cathode assembly that includes a nonporous support member, a primary cathode, and a nonconductive or conductive porous material covering the primary cathode. An anode is spaced apart from the cathode assembly. Fluid is caused to flow through the porous material to the primary cathode, through openings or fluid collection channels in the nonporous support member, and uniformly out of the cell. Uniform and efficient deposition of metal is accomplished over the entire cathode assembly because of modulation of fluid flow and increased mass transfer.

Abstract: The present invention provides a structure of an electric contact of an electrolytic cell, wherein an elongated conductive member is provided as a bus bar 10 on a wall of an electrolytic cell for feeding current to anodes 1 and cathodes 2 arranged in the electrolytic cell; the conductive member 10 forms a convex portion 12 in parallel with the longitudinal direction on the upper surface of an elongated plate member 11 forming a base; and at least the upper surface of the convex portion 12 is totally or partially gold plated 13 in the longitudinal direction.

Abstract: This invention relates to a low density high surface area copper powder having an apparent density in the range of about 0.20 to about 0.60 gram per cubic centimeter, and a surface area of at least about 0.5 square meter per gram. This invention also relates to an electrodeposition process for making the foregoing copper powder by electrodepositing the copper powder from an electrolyte solution using a critical combination of process parameters. These critical parameters include: a copper ion concentration for the electrolyte solution in the range of about 2 to about 7 grams per liter; a free chloride ion concentration for the electrolyte solution in the range of about 8 to about 20 ppm; an impurity level for the electrolyte solution of no more than about 1.0 gram per liter; and an electrolyte solution that is free of organic additives.

Abstract: Disclosed is a method for reducing metal acid or salt evolved from electrolytic baths housed in electrolytic tanks during electrolytic operations. This method involves covering all of the surface of the electrolytic bath with a layer of shredded foam (e.g., polymeric foam, metal foam, glass foam, or vitreous material foam). The shredded foam is irregular in shape, lacking in uniform particle size, is inert to the electrolytic operation, and floats at the surface of the electrolytic bath. Desirably, the layer of shredded foam is about 3 to 4 inches (76-102 mm) in thickness. Examples of specific processes benefiting from the present invention are anodizing, electroplating, electrowinning, and electrophoresis operations.

Abstract: Ores containing copper, zinc, silver in the form of sulfides are treated by a solution of sulfurated sulfite ions and ammonium ions in order to remove most of the metals from the sulfide ores. This treatment renders the resulting gold bearing ores much more amenable to cyanide extraction. Dissolved metals are reclaimed by appropriate techniques, such as electrowinning or liquid-liquid extraction, and the solution of sulfurated sulfites and ammonia is recycled for further lixiviation of fresh ores.

Abstract: An electrorefining cell permits increased electrolyte flow rates while maintaining the slime layer at the bottom of the cell and on the anode faces substantially intact. The cell includes an inlet manifold located near the bottom of the cell and having a plurality of discharge orifices for the electrolyte solution. An inlet baffle shrouds the discharge orifices to regulate and direct the flow of electrolyte solution within the cell. The inlet baffle and the cell wall form an elongated slot that resides beneath the surface of the electrolyte solution. An analogous configuration is employed for electrolyte discharge to enable relatively high electrolyte flow into and out of the cell. The specific shape, size, and location of the inlet baffle and an outlet baffle may be selected to optimize the electrolyte flow characteristics of the cell.

Abstract: A method to prevent corrosion of a stainless steel cathode in a copper electrowinning system uses compounds added to the electrowinning solution which reduce the level of free chlorine. Examples of such compounds are thiourea, alkyl sulphonate surfactants and protein glues.

Abstract: This invention relates to a process for making a shaped copper article directly from a copper-bearing material, comprising: (A) contacting said copper-bearing material with an effective amount of at least one aqueous leaching solution to dissolve copper ions into said leaching solution and form a copper-rich aqueous leaching solution; (B) contacting said copper-rich aqueous leaching solution with an effective amount of at least one water-insoluble extractant to transfer copper ions from said copper-rich aqueous leaching solution to said extractant to form a copper-rich extractant and a copper-depleted aqueous leaching solution; (C) separating said copper-rich extractant from said copper-depleted aqueous leaching solution; (D) contacting said copper-rich extractant with an effective amount of at least one aqueous stripping solution to transfer copper ions from said extractant to said stripping solution to form a copper-rich stripping solution and a copper-depleted extractant; (E) separating said copper-rich st

Abstract: A method of purifying a copper electrolytic solution circulated in a copper electrorefining system, wherein a portion of the solution is withdrawn and recycled to the system after purification treatment. The purification treatment includes the addition of a hydrosulfide to the withdrawn solution to generate only the necessary quantity of hydrogen sulfide gas required in the reaction. The hydrogen sulfide gas generated is utilized for purification treatment. One process comprises dividing the solution withdrawn into two portions. Sodium hydrosulfide is added to the first portion to precipitate and separate metals as sulfides. Excess sodium hydrosulfide is further added to the first portion for reaction with residual sulfuric acid in the solution to generate hydrogen sulfide gas, then contacting the second divided portion with the hydrogen sulfide gas thus produced to precipitate and separate metals in the form of sulfides. The filtrate is then recycled to an electrorefining system.

Abstract: An electrolytic cell comprising bipolar electrodes is employed for electrochemical deposition of copper, zinc, lead, nickel or cobalt. An interior space is provided between the cathode side and the anode side of a bipolar electrode. The electrolyte can flow substantially without an obstruction through the interelectrode space between adjacent electrodes. The current densities in the interelectrode space amount to 800 to 8000 A/m.sup.2. Gas is evolved on the anode side of the bipolar electrodes and causes liquid to flow along the anode side. In the middle of the height of the anode side that liquid flow has a vertical component having a velocity of 5 to 100 cm/second. Electrolyte solution flows from the upper edge portion of the anode side to a return flow space, in which the solution flows downwardly. From the return flow space the solution is returned to the lower portion of the interelectrode space.

Abstract: A process for the extraction of a metal from an ore or concentrate comprises subjecting the ore or concentrate to pressure oxidation in the presence of oxygen and an acidic solution containing halogen ions and a source of bisulphate or sulphate ions, such as H.sub.2 SO.sub.4. The metals which can be extracted by the process comprises copper as well as non-cuprous metals such as zinc, nickel and cobalt. During pressure oxidation the metal may be precipitated as an insoluble basic salt, such as basic copper sulphate, or substantially completely solubilized and precipitated later as the basic metal salt.

Abstract: A method of treating a solid material containing a substance of economic importance so as to recover or extract the substance from the material involving the following: forming a conducting mixture of the solid with a liquid so that at least some of the substance of economic importance is dissolved in the liquid, applying an electrical potential difference between at least two electrodes in contact with the mixture at spaced apart locations so as to impart opposite charges to the respective electrodes thereby attracting the liquid containing the dissolved substance to one of the electrodes, removing the liquid from an area surrounding or from a vicinity of the one electrode, and treating the liquid containing the substance of economic importance so as to recover or extract the substance. The liquid used is at least partially conducting. The present method is particularly useful for extracting or recovering gold from gold-containing or gold bearing ores.

Abstract: The object of the invention is a method for the electrochemical preparation of metal colloids with particle sizes of less than 30 nm, characterized in that one or more salts of one or more metals of groups Ib, IIb, III, IV, V, VI, VIIb, VIII, lanthanoides, and/or actinoides of the periodic table are cathodically reduced in the presence of a stabilizer, optionally with a supporting electrolyte being added, in organic solvents or in solvent mixtures of organic solvents and/or water within a temperature range of between -78.degree. C. and +120.degree. C. to form metal colloidal solutions or redispersible metal colloid powders, optionally in the presence of inert substrates and/or soluble metal salts of the respective metals. The invention further relates to soluble or redispersible colloids as well as application on substrates and immobilization thereof, in particular for the preparation of catalysts.

Abstract: The conditions for electrowinning Zn, Ni, Co and Cd metals from baths based on chlorinated ammino complexes of Me(NH.sub.3).sub.n Cl.sub.m type are substantially improved by the addition of small levels of dissolved Br, which considerably reduce the cell voltage without exerting any negative effects on cathodic current yields.

Abstract: This invention is directed to a process for making copper metal powder from copper-bearing material, comprising: (A) contacting said copper-beating material with an effective amount of at least one aqueous leaching solution to dissolve copper ions in said leaching solution and form a copper-rich aqueous leaching solution; (B) contacting said copper-rich aqueous leaching solution with an effective amount of at least one water-insoluble extractant to transfer copper ions from said copper-rich aqueous leaching solution to said extractant to form a copper-rich extractant and a copper-depleted aqueous leaching solution, said extractant comprising (i) at least one oxime characterized by a hydrocarbon linkage with at least one --OH group and at least one .dbd.

Abstract: A process for the extraction of a metal from an ore or concentrate comprises subjecting the ore or concentrate to pressure oxidation in the presence of oxygen and an acidic solution containing halogen ions and a source of bisulphate or sulphate ions, such as H2SO4. The metals which can be extracted by the process comprises copper as well as non-cuprous metals such as zinc, nickel and cobalt. During pressure oxidation the metal may be precipitated as an insoluble basic salt, such as basic copper sulphate, or substantially completely solubilized and precipitated later as the basic metal salt.