Process for making copper metal powder, copper oxides and copper foil

Description: TECHNICAL FIELD [Detailed description of the invention]

Technical field The present invention relates to a method for producing a copper metal powder, a copper oxide, or a copper foil. More specifically, the present invention relates to a method of using an extractant to extract copper from a copper bearing material and producing copper metal powders, cuprate oxides, or copper foils. Background of the invention The method of recovering metallic copper from ore and the method of processing a liquid by solvent extraction-electrowinning (hereinafter referred to as "SX-EW") are well known. Briefly, the method uses an aqueous solution with copper obtained by dissolving copper (generally from ore) in a leaching aqueous solution, or with a solution with copper such as process drainage. It is carried out by doing. The resulting copper solution is mixed with a water-insoluble organic solvent (eg, kerosene) containing a water-insoluble ion exchange composition having a selective affinity for copper. The ion exchange composition selectively extracts copper from the aqueous solution. The aqueous and organic phases are separated. The aqueous solution deprived of copper is usually referred to as the "drawing residue". The extract can be reused as a leachate (in the leaching process) or discarded (in a process such as recovery of copper from process effluent). The organic phase, which contains the ion exchange composition and the extracted copper, is usually "loaded". It is called "organic)". The copper of interest is removed from the loaded organic phase by mixing with a back-extracted aqueous solution that contains a strong acid such as sulfuric acid, phosphoric acid, or perchloric acid and has a lower pH value than the aqueous solution with copper described above. Is done. The back extraction aqueous solution extracts the desired copper from the loaded organic phase. After separation of the organic phase and the aqueous phase, the copper of interest is present in the back-extracted aqueous solution. The resulting copper-rich back-extracted aqueous solution is usually referred to as an "electrolyte" or "enriched electrolyte". The organic phase deprived of copper is usually referred to as the "barren organic". This barren organic phase can be reused. Copper is recovered in its purified form from the electrolyte by a technique known as "electrowinning" (hereinafter referred to as "EW"). The electrowinning process is typically a copper starting sheet or a stainless steel cathode mother blank. Includes plating copper on blank). To obtain 100 lbs of cathode from each side of the mother blank, the plating cycle typically takes about 7 days. The cathode is mechanically stripped from each surface of the mother blank and then utilized for subsequent processing that may include stretching, stretching and the like. These cathodes are often transported to a rod plant where they undergo continuous casting. After recovery of the desired copper, the copper-deprived electrolyte is specifically referred to as the "dilute electrolyte", which can be reused as a back-extracted aqueous solution for a new load of copper. The production of copper powder by electrodeposition includes the use of an electrolytic cell containing an anode, a cathode, an electrolyte solution containing copper and sulfate ions, and a power source. Through the application of a voltage between the anode and the cathode, precipitation of copper powder is brought about on the cathode surface. The powder is then removed at defined time intervals or in a continuous fashion. This process begins with a copper feedstock that is dissolved in sulfuric acid to produce an electrolyte solution. A relatively pure electrolyte is required so that the copper powder has sufficient purity for standard commercial purposes such as friction materials, bearings, alloy additives, powder metallurgy and the like. Copper removed from the electrolyte by the electrolytic production of copper powder is typically replenished continuously to maintain the concentration of copper ions in the solution. The purity of the electrolyte and the replenishment of copper removed from the electrolyte are maintained by using a relatively pure copper-soluble anode. The copper used for the anode is pre-purified by electrolysis to remove unwanted contaminants. Electrolytically purified copper is typically recast into an anode shape suitable for powder production. An alternative is to use a copper rod called a copper shot, which is electrolyzed, cut to about 1/2 inch in diameter, 1 inch in length, and then placed in an insoluble wire mesh anode basket. Including. The production of copper foil by electrodeposition also includes the use of electroplating tanks containing anodes, cathodes, electrolyte solutions containing copper and sulfate ions, and power supplies. Through the application of voltage between the anode and the cathode, the precipitation of copper is brought about on the surface of the cathode. The copper feedstock is dissolved in sulfuric acid to produce an electrolyte solution, which is copper in an electrolytically purified form such as copper shots, copper wire, copper oxide or recycled copper. The resulting copper sulphate solution is then purified to ensure the production of high-purity copper sulphate required for foil production. Drugs for controlling the properties of various types of foils, such as animal glue and thiourea, can be added to the electrolyte solution. The electrolyte solution is pumped into an electroplating tank, and copper electrodeposition occurs by applying a voltage between the anode and the cathode. Typically, the method comprises the use of a cylindrical cathode that can have various diameters and widths. The anode is curved as well as the cathode so as to maintain a constant separation distance or distance between the anode and the cathode. Electrolytically purified copper feedstocks used in prior art electrodeposition processes for producing copper powder and copper foil are often produced using the types of SX-EW technology described above. They are also produced using traditional refining and refining techniques. The prior art electrodeposition process involves first melting the copper feedstock in the digester to produce copper ions, but the process is slow, difficult to control, and expensive pure to be charged into the digester. Requires a large amount of copper. If the copper powder is pure to obtain copper ions for the first step and then the electrolyte solution using the electrolytic method to recover copper from a relatively impure copper source such as copper ore or copper-containing waste. It would be beneficial if it could be produced directly without going through the additional steps of melting the copper metal. It would also be beneficial if the copper foil could be produced from a copper source that is relatively pure and easily soluble in sulfuric acid. The present invention provides such advantages. According to the method of the present invention, the copper powder is simplified and produced by a lower cost method as compared with the prior art. The method of the present invention is the production of an electrolytically purified copper source (eg, copper shot, copper wire, copper oxide, recycled copper, etc.) used in prior arts such as electrowinning and stretching in its production. Utilize a copper source that does not require the additional steps used in. The impurities carried from the extraction step used in the method of the present invention to the electrolyte solution used to produce the copper powder do not degrade the performance characteristics of the copper powder. The copper powder produced by the method of the present invention can be dissolved in sulfuric acid to produce an electrolyte solution. These electrolyte solutions can be used in the production of copper foil, and therefore the foil production methods provided herein are more easily controlled as compared to prior art methods for producing similar foils. And more efficient. Copper powder is also calcined to produce cuprous oxide, cupric oxide or mixtures thereof. These copper oxides can be easily dissolved in sulfuric acid and can be used in the production of copper foil. The paper "Production of Copper Pwder by the Method of Electrolytic Extraction Using a Reversing Current" by IDEnchev et al. Discloses the results of studies on the production of copper from electrolyte solutions produced from dilute ore solutions. Subsequent extractions were used using the electrolyte solution produced by leaching the ore waste and the ABF dissolved in kerosene. The paper shows that the disclosed method can produce high purity powders (99.98% copper) at oxygen concentrations of 0.2-0.4%. Abstract of the invention The present invention is a method for producing a copper metal powder from a material having copper, in which the following steps: (A) the material having copper is brought into contact with at least one effective amount of leachate solution to leach copper ions. The step of dissolving in a solution and producing a copper-rich leachate; (B) contacting the copper-rich leachate with at least one effective amount of a water-insoluble extractor to bring copper ions to the copper. It is a step of moving a rich leachate solution to the extractant to produce a copper-rich extractant and a copper-deprived leachate solution, wherein the extractant is on the (I) hydrocarbon chain. At least one oxime characterized by a hydrocarbon chain having at least one -OH group and at least one = NOH group attached to different carbon atoms, (ii) at least one β-diketone, or (iii) at least Steps comprising one ion exchange resin; (C) Separation of the copper-rich extractant from the copper-deprived leachate solution; (D) At least one copper-rich extractant. A step of contacting with an effective amount of a back-extract solution to move copper ions from the extract to the back-extract to produce a copper-rich back-extract and a copper-deprived extract; (E) The step of separating the copper-rich back-extract solution from the copper-deprived extractant to produce a first electrolyte solution; (F) the first electrolyte solution being separated from at least one first anode and at least An effective amount of voltage is applied between the first anode and the first cathode to feed the copper metal powder onto the first cathode. It is a method including a step of precipitating in In one embodiment, the copper metal powder is processed into copper foil. In one embodiment, the copper metal powder is processed into cuprous oxide, cupric oxide, or a mixture thereof; these copper oxides can be easily dissolved in sulfuric acid and used in the production of copper foil. Can be done. A brief description of the drawing In the attached drawings, similar parts and mechanisms are indicated by similar reference numbers: FIG. 1 is a flow sheet showing one embodiment of the method of the invention; FIG. 2 is a flow sheet showing another embodiment of the method of the present invention. Description of preferred embodiments A material having copper can be any copper source from which copper can be extracted. These sources include copper ore, smelter exhaust stack dust, copper cement, copper sulphate, and waste containing copper. The term "copper-containing waste" refers to any solid or liquid waste material containing copper (eg, waste, sludge, effluent, etc.). These waste materials include hazardous waste. A particular example of a waste that can be used is copper oxide obtained by treating a worn-out copper chloride etchant. Copper sources used in the prior art, such as copper shots, copper wire, recycled copper, etc., may also be used, but if such prior art sources are used, the methods of the invention are used. The economic benefits of doing so are diminished. In one embodiment, copper ore from an open pit mine is used as the material with copper. The ore is typically constructed in areas where a thick, high-density polyethylene liner-like backing is laid underneath to prevent the leachate from being lost into the surrounding watershed. Transported to a leachate dump. A typical sedimentary leach dump has a surface area, eg, about 125,000 square feet, and can accommodate approximately 110,000 tonnes of ore. As the leaching progresses, and as new dumps pile up on top of the old dumps, the dumps get taller and taller, eventually reaching heights of, for example, about 250 feet or more. A network of pipes and a wobbler sprinkler are installed on the surface of the newly completed dump, and a dilute sulfuric acid solution is continuously applied at a flow rate, eg, about 0.8 gallons per minute per 100 square feet of surface area. Sprayed at a flow rate. The leachate solution penetrates the dump, dissolves the copper in the ore, flows from the dump base as a copper-rich leachate solution, is discharged into the collection pond, and is used for subsequent treatments using the methods of the invention. It is pumped into the supply pond. In-situ leachation, along with some mining operations, is used to extract copper from copper ore. The copper-rich leachate obtained by this process can be used as a copper-bearing material in the methods of the invention. In-situ leachation is useful when the acid-soluble oxide ore reserve is directly below the open pit area and above the mining portion of the underground mine. Injection wells are dug in this area at some depth, for example about 1000 feet deep. The well is covered with a PVC pipe and the bottom is grooved to allow the solution to enter the ore. The dilute sulfuric acid leachate is poured into each well at a flow rate that depends on the permeability of the area where the well is dug. The solution penetrates the ore area, dissolves the chalcopyrite, and flows out to the prepared collection area. The collection area can be, for example, a carrier of an underground mine. The leached aqueous solution with copper produced is pumped to the surface by a corrosion resistant pump system, which is useful as a copper-bearing material for the methods of the invention. In mining operations where both leach dump and in-situ leach are used, the copper-bearing leachate from each (sometimes referred to as the pregnant leachate) is combined and the copper-bearing material in the method of the invention. Can be used as. The leaching aqueous solution used in step (A) of the method of the present invention is preferably a sulfuric acid solution or an ammonia solution. The sulfuric acid solution preferably has a sulfuric acid concentration in the range of about 5 to about 50 grams per liter, more preferably about 5 to about 40 grams per liter, and even more preferably about 10 to about 30 grams per liter. Ammonia solutions preferably have an ammonia concentration in the range of about 20 to about 140 grams per liter, more preferably about 30 to about 90 grams per liter. The pH value of this solution is preferably in the range of about 7 to about 11, more preferably about 8 to about 9. The copper-rich leachate or pregnant leachate produced during step (A) preferably ranges from about 0.8 to about 5 grams per liter, more preferably from about 1 to about 3 grams per liter. Has a copper ion concentration. When the leaching solution used in step (A) is a sulfuric acid solution, the concentration of free sulfuric acid in the copper-rich leaching aqueous solution is preferably from about 5 to about 30 grams per liter, more preferably per liter. From about 10 to about 20 grams. When the leaching solution used in step (A) is an ammonia solution, the concentration of free ammonia in the copper-rich leaching aqueous solution is preferably from about 10 to about 130 grams per liter, more preferably per liter. It weighs about 30 to about 90 grams. The water-insoluble extractant used in step (B) of the method of the present invention can be any water-insoluble extractant capable of extracting copper ions from an aqueous medium. In one embodiment, the extractant is dissolved in a water-immiscible organic solvent. (The terms "water-immiscible" and "water-insoluble" refer to compositions that are insoluble in water above a level of about 1 gram per liter at 25 ° C.) The solvent is extracted. Any water-immiscible solvent for the agent, kerosene, benzene, toluene, xylene, naphthalene, fuel oil, diesel fuel, etc. are useful, and kerosene is preferred. Examples of useful kerosene are SX-7 and SX-12 available from Phillips Petroleum. In one embodiment, the extractant is an organic compound containing at least two functional groups attached to different carbon atoms on the hydrocarbon chain, one of which is a -OH group, and The other functional group is = NOH. These compounds may be called oximes. In one embodiment, the extractant is an oxime represented by the following formula.<img file="JP2968043B2_D0001.tif" /> Here R¹, R², R³, R⁴, R⁵, R⁶And R⁷Is an independent hydrogen or hydrocarbyl group. In a preferred embodiment, R¹And R⁴Are each butyl; R², R³And R⁶Are each hydrogen; and R⁵And R⁷Are ethyl respectively. A compound having the structure of this preferred embodiment is available from Henkel Corporation under the trade name of LIX 63. In one embodiment, the extractant is an oxime represented by the following formula.<img file="JP2968043B2_D0002.tif" /> Here R¹And R²Is an independent hydrogen or hydrocarbyl group. A useful embodiment is R¹Is an alkyl group having about 6 to about 20 carbon atoms, preferably about 9 to about 12 carbon atoms; and R²Is hydrogen, an alkyl group having 1 to about 4 carbon atoms, preferably 1 or 2 carbon atoms, or R²Is phenyl. The phenyl group cannot be substituted or substituted, but the latter is preferred. The following compounds are compounds based on the above formula, are available from Henkel Corporation under the trade names below, and are useful for the methods of the invention: Product name R¹ R² LIX 65 Nonyl phenyl LIX 84 Nonyl Methyl LIX 860 Dodecyl Hydrogen Other useful materials are commercially available and available from Henkel Corporation: LIX 64N (same as the mixture of LIX 65 and LIX 63); and LIX 864 and LIX 984 (with the mixture of LIX 860 and LIX 84). Same) is included. In one embodiment, the extractant is a β-diketone. These compounds are represented by the following formulas.<img file="JP2968043B2_D0003.tif" /> Here R¹And R²Is an independently alkyl or aryl group. Alkyl groups preferably contain from 1 to about 10 carbon atoms. The aryl group is preferably phenyl. One example of a commercially available extract that corresponds to the above formula and is available from Henkel Corporation is LIX 54. These β-diketones are particularly useful when the leachate solution used in step (A) of the method of the present invention is an ammonia solution. The concentration of the extractant in the organic solution is preferably in the range of about 2% by weight to about 40% by weight. In one embodiment, the organic solution comprises from about 5% to about 10% by weight, preferably from about 6 to about 8% by weight, more preferably from about 7% by weight of LIX 984, the rest being SX-7. In one embodiment, the extractant is an ion exchange resin. These resins are typically small granular or bead-like materials consisting of two basic parts: a resin substrate served as a structural part and an ionic active group served as a functional part. The functional group is preferably selected from the group of functional groups that are reactive to copper ions. An example of such a functional group is -SO₃^-, -COO^-、 <img file="JP2968043B2_D0004.tif" /><img file="JP2968043B2_D0005.tif" />Including. Preferred resin matrices include copolymers of styrene and divinylbenzene. Examples of commercially available resins that can be used are IRC-718 (a product of Rohm &amp; Haas, a copolymer of tertiary amine-substituted styrene and divinylbenzene), IR-200 (sulfonated styrene). Rohm &amp; Haas product, a copolymer with divinylbenzene), IR-120 (Rohm &amp; Haas product, a copolymer of sulfonated styrene and divinylbenzene), XFS 4196 (N- (2- (2-) Dow's product, a macroporous polystyrene / divinylbenzene copolymer to which N (-2-hydroxyethyl) -picolylamine) has been added), and XFS. Includes 43084 (Dow's product, a foramen magnum polystyrene / divinylbenzene copolymer to which N- (2-hydroxypropyl) -picolylamine) has been added. These resins are preferably used as fixed beds or moving beds in the methods of the invention. During step (B) of the method of the invention, the resin is contacted with the copper-rich leachate from step (A), which is the transfer of copper ions from the leachate to the resin. It's enough. The copper-rich resin is then back-extracted during step (D) to supply a copper-deprived resin that can be used during step (B). The copper-rich extractant separated during step (C) of the method of the invention preferably comprises from about 1 to about 6 grams per liter of extractant, more preferably from about 2 to about 2 to about per liter of extractant. It has a copper concentration in the range of 4 grams. The copper-deprived leachate separated during step (C) preferably has a copper ion concentration in the range of about 0.01 to about 0.8 grams per liter, more preferably about 0.04 to about 0.2 grams per liter. Have. When the leachate used in step (A) is a sulfuric acid solution, the concentration of free sulfuric acid in the deprived leach solution separated during step (C) is preferably from about 5 per liter. About 50 grams, more preferably about 5 to about 40 grams per liter, even more preferably about 10 to about 30 grams per liter. When the leachate used in step (A) is an ammonia solution, the concentration of free ammonia in the deprived leach solution separated during step (C) is preferably from about 10 per liter. About 130 grams, more preferably about 30 to about 90 grams per liter. In one embodiment, the contact and separation steps (B) and (C) of the methods of the invention are performed in two steps. In this embodiment, steps (B-1) and (B-2) are contact steps and (C-1) and (C-2) are separation steps. Thus, in this embodiment, the method of the present invention comprises the following series of steps (A), (B-1), (C-1), (B-2), (C-2), ( It is a method that includes D), (E), (F) and (G), and the process flow from some of these steps is recirculated to other steps of this method. In step (B-1), the copper-rich leachate produced during step (A) is contacted with an effective amount of a water-insoluble extractant having at least one type of copper from step (C-2). The copper ions are transferred from the copper-rich leachate solution to the copper-rich extractant to produce a copper-rich extractant and a first copper-deprived leachate solution. .. Step (C-1) deprives the copper-rich extractant produced during step (B-1) of the first copper produced during step (B-1). Includes separation from aqueous solution. The copper-rich extract that is separated during step (C-1) is preferably from about 1 to about 6 grams per liter of extractant, more preferably from about 2 to about 4 grams per liter of extract. Has a range of copper concentrations. The first copper-deprived leachate solution separated during step (C-1) is preferably from about 0.4 to about 4 grams per liter, more preferably from about 0.5 to about 2. It has a copper ion concentration in the range of 4 grams. When the leachate used in step (A) is a sulfuric acid solution, the concentration of free sulfuric acid in the deprived leaching aqueous solution of the first copper separated during step (C-1) is preferably 1. About 5 to about 50 grams per liter, more preferably about 5 to about 30 grams per liter, even more preferably about 10 to about 30 grams per liter. When the leachate used in step (A) is an ammonia solution, the concentration of free ammonia in the deprived leaching aqueous solution of the first copper separated during step (C-1) is preferably 1. About 10 to about 130 grams per liter, more preferably about 30 to about 90 grams per liter. Step (B-2) extracts the first copper-deprived leaching aqueous solution separated during step (C-1) from step (E) with at least one effective amount of copper deprived. Upon contact with the agent, copper ions are transferred from the first copper-deprived leachate solution to the copper-deprived extractant, resulting in a copper-deprived extractant and a second copper-deprived leachate solution. Includes producing. Step (C-2) removes the copper-bearing extractant produced during step (B-2) from the second copper-deprived leachate solution produced during step (B-2). Includes separation. The extractant with copper separated during step (C-2) preferably ranges from about 0.4 to about 4 grams per liter of extractant, more preferably from about 1 to about 2.4 grams per liter of extractant. Has a copper concentration. The second copper-deprived leachate solution separated during step (C-2) preferably ranges from about 0.01 to about 0.8 grams per liter, more preferably from about 0.04 to about 0.2 grams per liter. Has a copper ion concentration of. When the leaching solution used in step (A) is a sulfuric acid solution, the concentration of free sulfuric acid in the second copper-deprived leaching aqueous solution separated during step (C-2) is preferably 1. About 5 to about 50 grams per liter, more preferably about 5 to about 40 grams per liter, even more preferably about 10 to about 30 grams per liter. When the leachate used in step (A) is an ammonia solution, the concentration of free ammonia in the second copper-deprived leachate solution separated during step (C-2) is preferably 1. About 10 to about 130 grams per liter, more preferably about 30 to about 90 grams per liter. The back-extract solution used in step (D) of the method of the invention preferably has a free sulfuric acid concentration in the range of about 80 to about 300 grams per liter, more preferably about 150 to about 250 grams per liter. It is a sulfuric acid solution. The copper-rich back-extract solution produced during step (D) preferably has a copper ion concentration in the range of about 2 to about 60, more preferably about 5 to about 15 grams per liter; and preferably. It has a free sulfuric acid concentration in the range of about 70 to about 290, more preferably about 140 to about 240 grams per liter. The electrodeposition steps (F) and (G) of the method of the present invention send a copper-rich back-extraction solution from step (E) to an electrolytic cell and electrolyze copper metal powder onto the cathode of the electrolytic cell. Includes dressing. The copper-rich back-extraction solution processed in the electrolytic cell is referred to as either a copper-rich back-extraction solution or an electrolyte solution. In one embodiment, the electrolyte solution is subjected to a purification or filtration process before being placed in an electrolytic cell. The current used in the electrolytic cell is preferably direct current or alternating current with a direct current bias. The electrodeposited copper metal powder is removed from the cathode using conventional techniques. The flow of the electrical solution through the electrolytic cell is sufficient to maintain a constant copper ion concentration difference between the electrolyte solution entering the electrolytic cell and the electrolyte solution leaving the electrolytic cell. This difference in copper ion concentration is preferably about 1 to about 10 grams per liter, more preferably about 1 to about 3 grams per liter, and the solution entering the electrolytic cell is higher than the solution leaving the electrolytic cell. Has a copper ion concentration. Fortunately, the flow between the anode and the cathode is provided by natural convection. The electrolyte solution preferably has a free sulfuric acid concentration in the range of about 70 to about 300 grams, more preferably about 140 to 250 grams per liter. The temperature of the electrolyte solution in the electrolytic cell is preferably in the range of about 20 ° C to about 65 ° C, more preferably about 30 ° C to about 45 ° C. Copper ion concentration (CuSO₄Included in) is preferably in the range of about 1 to about 60 grams per liter, more preferably about 4 to about 15 grams per liter. The free chlorine ion concentration is preferably up to about 100 ppm, more preferably up to about 50 ppm. In one embodiment, the free chlorine ion concentration is up to about 20 ppm, preferably up to about 15 ppm. Impurity levels are preferably levels not exceeding about 20 grams per liter, and preferably in the range of about 0.5 to about 10 grams per liter. Current densities are preferably in the range of about 20 to about 300 amps per square foot, more preferably from about 30 to about 200 amps per square foot. During electrodeposition, one or more additives may be added to the electrolyte solution to alter the properties of the copper metal powder. These include collagen, an example of which is gelatin derived from animal glue. Other additives can be added to the electrolyte to control the particle size of the powder. Examples of such other additives include benzotriazoles and thioureas. Chlorine ions can be added to increase the dendritic properties of the powder particles and to increase the yield of fine powder. Sodium sulphate can be added to reduce the current density of the cathode. As the amount of sodium sulfate increases, the particle size of the powder tends to decrease. The sulfonate can be added to the electrolyte to provide a coarser particle size. Examples of such sulfonates include Orzan-A, a product of Tembind, which is ammonium lignosulfonate. These additives are typically added to the electrolyte solution at concentration levels up to about 20 grams per liter, more preferably up to about 10 grams per liter. Diffusion limiting current density (I) during electrodeposition step (F)_L) To the ratio of the applied current density (I) to a level of about 0.8 or higher, more preferably about 0.9 or higher. That is, I / I_LIs preferably about 0.8 or greater, more preferably about 0.9 or greater. The applied current density (I) is the amperage applied per unit area of the electrode surface. Diffusion limit current density (I_L) Is the maximum rate at which copper can be deposited. The maximum precipitation rate is limited by how quickly copper ions can diffuse to the cathode surface to replace the copper ions deprived by the previous precipitation. It's a formula<img file="JP2968043B2_D0006.tif" />Can be calculated by The terms and their units used in the above equations are defined below:<img file="JP2968043B2_D0007.tif" />Boundary layer thickness δ is a function of viscosity, diffusion coefficient, and flow velocity between the anode and cathode. The flow rate is provided by the overall flow rate of the electrolyte solution to and from the electrolytic cell and any agitation that has an effect within the electrolytic layer. In one embodiment, the following parameter values are useful in electrodeposition of copper powder: Parameter value I (A / cm²) 0.060 n (eq / mol) 2 D (cm)²/ s) 1.6x10^-5 C^*(Mol / cm³, Cu⁺²(CuSO₄As)) 1.57x10^-4 Temperature (° C) 38 Free sulfuric acid concentration (g / l) 175 Dynamic viscosity (cm²/ s) 0.0126 Flow velocity (cm / s) Natural convection The copper metal powder can be removed from the cathode by sweeping, scraping, vibration or other mechanical and / or electrical techniques known in the art. The powder can be removed by reversing the current on the cathode. The particle size can be controlled by controlling the length of the interval between removing the powder, and the powder becomes coarser as the interval increases. Also, as the length of the interval increases, the apparent density increases. In one embodiment, a series of disc-shaped rotary cathodes in which a portion is submerged in an electrolyte solution is used. This type of cathode is disclosed, for example, in US Pat. No. 3,616,277, which is incorporated herein by reference. The copper powder precipitates on the disc-shaped cathode as the cathode rotates through the electrolyte solution. Cathodes, such as those made of titanium, and insoluble anodes, such as platinum-plated titanium. titanium))) is placed in an electroformed tank in an arrangement sandwiched between cathodes. The powder is continuously deposited on the cathode and is continuously removed by the doctor blade. The doctor blade can be made of plastic or stainless steel and is installed close to the cathode above the liquid level of the electrolyte solution in the tank. In one embodiment, the copper metal powder removed during step (G) of the method of the invention is thoroughly washed to remove electrolytes that can cause oxidation of the powder. Various methods can be used to wash the powder. One method involves centrifuging the powder to remove electrolytes, washing the powder, and then dehydrating the powder. In another method, the copper metal powder is transferred to a large tank and water is added to form a slurry (suspension), which is pumped into a filter. In the filter, the powder is dehydrated, washed several times, and dehydrated again. During this process, stabilizers can be added to reduce oxidation. Examples of such stabilizers include aqueous gelatin solutions. Antioxidants added during washing or subsequent powder treatment also prevent the powder from oxidizing. Examples of these antioxidants include benzotriazoles. After cleaning and dehydration, the wet powder can be subjected to heat treatments that lead to changes in certain properties of the copper metal powder, especially particle size and shape, apparent density, and unsintered strength. In one embodiment, the powder is heat treated on a mesh belt electric furnace. To prevent the powder from falling through the belt, a continuous sheet of high wet strength paper is fed to the belt, and then the powder is transferred to the paper. Rollers compress the powder to improve heat transfer. When the powder enters the furnace, the water is expelled and the paper burns, but not before the powder is sufficiently sintered to prevent it from falling through the belt. The atmosphere in the furnace is generated in the exothermic gas device. There, natural gas and air are blended, for example about 17% hydrogen, about 12% CO, about 4% CO.₂A nitrogen-balanced atmosphere is created. The gas is sent to the furnace through a cooler. In the cooler, the gas is preferably cooled below the dew point in the range of about -22 ° C to about -40 ° C. The gas enters the furnace from the discharge end, and since the gas is cooled, it promotes the cooling of the powdered cake. In-fire operations dry the powder, change the particle shape, reduce oxidation, and sinter the fine particles. The discharge temperature is low enough to prevent reoxidation of the powdered cake. By varying the furnace temperature, preferably between about 250 ° C and about 900 ° C, more preferably between about 370 ° C and about 650 ° C, and by varying the exposure time, the fine particles Content, apparent density, and dimensional properties can be varied. Upon completion of the heat treatment operation, the resulting powdered cake is crushed and ready for grinding. Milling can be performed, for example, in a high speed water-cooled hammer mill, where the feed rate, milling rate, and sieve opening under the mill can be varied to obtain a powder of the desired properties. The powder coming out of the mill is sent to a sieve where it is separated into particle-sized fractions. Powders less than 100 mesh are classified in an air classifier, and fine particles can be blended into the final powder product. Materials that are too large are returned to the mill for further grinding. Alternatively, either the oversized particles and / or the oversized particles may be combined with a first electrolyte solution that is separated during step (E). The copper metal powder produced during the grinding and classification operations can be stored in a drum, to which a desiccant such as silica gel or camphor can be added to prevent or reduce oxidation. The properties of the copper metal powder produced by the method according to the present invention depend on various properties of the work and can therefore be controlled by changing certain process variables. The powder prepared by the method of the present invention can be of high purity and the copper content can exceed, for example, about 99.5% by weight. Oxygen content measurements can be obtained by exposing a powder sample to hydrogen at elevated temperatures, as specified in ASTM E 159, Standard of the American Institute for Materials and Testing, or MP1F 02, Standard of the Metal Powder Industry Federation. In general, hydrogen loss ranges, for example, from about 0.1 to about 0.5% and depends on the apparent density and particle size distribution of the powder. Nitric acid insoluble matter is also determined by the procedure of ASTM or MP1F standard, which can be less than about 0.05% by weight, for example. The particle size distribution of the copper powder can be selected to meet the requirements of the application and can be varied over a wide range. For example, fractions less than 325 mesh can be varied from about 5% by weight to about 90% by weight. The apparent density of the powder is, for example, about 1 to about 4 g / cm.³Can be in the range of. Somewhat lower and higher densities can be produced depending on the conditions of the process. Generally about 1.3g / cm³Powders with an apparent density of less than do not flow and have an apparent density of about 1.3 to about 2.3 g / cm³The powder has poor fluidity, and the powder with high apparent density flows freely. Approximately 2.2 g / cm, which is the transitional region³And the flow depends on the content of the fine particles of the powder. This is because relatively fine powders have poor fluidity, and relatively coarse powders flow freely. Typical flow volumes range from about 10 to about 50 seconds for a 50 gram sample. Unsintered density is a function of molding pressure. For example, when the molding pressure increases from about 20 to about 40 tons (tsi) per square inch, the unsintered density is 7 to about 8 g / cm.³Can rise to. Unsintered strength increases with molding pressure. For example, unsintered strength can increase from less than about 2200 psi to about 3500 psi as the molding pressure increases from about 20 to about 40 tsi. The particle shape of the copper metal powder is generally dendritic when precipitated on the cathode. However, the dendritic processes tend to be rounded during subsequent work. High conductivity can be achieved when high purity copper metal powders produced by the methods of the invention are used. High conductivity can be achieved by high density molding. The conductivity can be increased by imprinting and recrystallization. In one embodiment, the copper metal powder removed during step (G) of the method of the invention is calcinated to produce cuprous oxide, cupric oxide, or a mixture thereof. Copper oxide is stoichiometrically at least about 15%, preferably about 15%, at temperatures ranging from about 400 ° C to about 850 ° C, preferably from about 450 ° C to about 500 ° C. It is made by baking copper metal powder with about 25% excess oxygen for at least 1 minute, preferably at least 3 minutes. Copper oxide is stoichiometrically less than about 15% excess oxygen at temperatures ranging from about 200 ° C to about 300 ° C, or about 1025 ° C to about 1065 ° C. It is made by baking copper metal powder for at least 1 minute, preferably at least 3 minutes. In one embodiment, the copper metal powder or calcined copper metal powder removed during step (G) of the method of the present invention (ie, cuprous oxide, cupric oxide, or a mixture thereof) , Dissolved in sulfuric acid to produce a second electrolyte solution, and this second electrolyte solution is subjected to electrodeposition to make a copper foil. This second electrolyte solution preferably has a free sulfuric acid concentration in the range of about 70 to about 170 grams per liter, more preferably about 80 to about 120 grams per liter. Copper ion concentration (CuSO₄Included in) is preferably in the range of about 40 to about 150 grams per liter, more preferably about 90 to about 110 grams. The free chlorine ion concentration is preferably up to about 300 ppm, more preferably up to about 150 ppm, even more preferably up to about 100 ppm. In one embodiment, the free chlorine ion concentration is from about 40 to about 100 ppm, or from about 50 to about 100 ppm. Impurity levels are preferably levels not exceeding about 20 grams per liter, and typically range from about 0.5 to about 10 grams per liter. In one embodiment, the copper metal powder is dissolved in sulfuric acid by adding the powder to the digester in either batch or continuous fashion to produce a second electrolyte solution. The powder is mixed with sulfuric acid in the digester. To improve the efficiency of the digester and control of the copper ion concentration, the copper powder is kept suspended as a slurry in the digester. This can be achieved by mechanical agitation or the use of airlift columns. The use of an air lift column pumps air to the bottom of the digester. The air rises upward through a cylindrical draft tube whose diameter is smaller than the digester and whose axis is identical to the axis of the digester. The bubbles rising through the draft tube cause a mixing action in the digester, which keeps the copper powder suspended in the well-mixed slurry and promotes the rapid dissolution of the copper powder. .. The dissolution of the copper powder is accomplished by the addition of oxygen or the addition of oxygen in the form of air that is forced into the bottom of the digester. Oxygen dissolved in the electrolyte solution or oxygen contained in the bubbles rising through the electrolyte comes into contact with the surface of the copper and reacts with the acid in the electrolyte to dissolve the copper. The electrolyte circulates in the loop through the digester conduit to the liquid / solid separator. The separator removes undissolved or burnt copper powder, which can then be returned to the digester. In one embodiment, the calcined copper metal powder (ie, cuprous oxide, cupric oxide, or a mixture thereof) is added to the digester either in a batch or continuous manner. Dissolves in copper to produce a second electrolyte solution. Calcinated copper powder dissolves easily in sulfuric acid. The electrolyte circulates in the loop through the digester conduit to the liquid / solid separator. The separator removes the undissolved or burned powder, which can then be returned to the digester. The second electrolyte solution is sent to an electroplating tank equipped with an anode and a rotary cathode. This electrolyte solution may be subjected to a purification or filtration process prior to entering the electroforming tank to ensure that the electrodeposited foil is free of fractures and / or discontinuities. When a voltage is applied between the anode and the cathode, electrodeposition of copper foil occurs at the cathode. The current is preferably direct current or alternating current with a direct current bias. The electrodeposited foil is removed from the cathode as a continuous web as the cathode rotates. It can be rolled up. The rotary cathode is preferably in the form of a cylindrical mandrel. However, or, the cathode can be in the shape of a mobile belt. Both of these designs are known in the art. The anode has a curved shape similar to that of the cathode in order to provide a constant isolation between the anode and the cathode. This isolation preferably has a width of about 0.3 to about 2 centimeters. In the electroplating tank, the flow rate of the electrolyte solution flowing through the isolation between the anode and the cathode is preferably in the range of about 0.2 to about 5 meters per second, more preferably 1 to about 3 meters per second. The temperature of the electrolyte solution in the electroforming tank is preferably in the range of about 25 ° C to about 100 ° C, more preferably about 40 ° C to about 70 ° C. Current densities are preferably in the range of about 100 to about 3000 amperes per square foot, more preferably from about 400 to about 1800 amperes per square foot. During foil electrodeposition, the second electrolyte solution may optionally contain one or more active sulfur-containing materials. The term "active sulfur-containing material" refers to sulfur in which both bonds of a divalent sulfur atom are directly attached to one carbon atom, and at the same time one or more nitrogen atoms are also attached to that carbon atom. A substance generally characterized by containing an atom. In this group of compounds, double bonds between sulfur or nitrogen atoms and carbon atoms may be present or alternate in some cases. Thiourea is a useful active sulfur-containing substance. Thiourea with the following nuclei<img file="JP2968043B2_D0008.tif" />And iso-thiocyanate with an atomic configuration of S = C = N- is useful. Thiosinamine (allyl thiourea) and thiosemcarbazide are also useful. The active sulfur-containing material should be soluble in the second electrolyte solution and compatible with other components. The concentration of the active sulfur-containing material in the electrolyte solution during electrodeposition is preferably up to about 20 ppm, more preferably in the range of about 0.1 to about 15 ppm. The second electrolyte solution used in the production of the foil may also optionally contain one or more gelatins. Gelatin useful here is a heterogeneous mixture of water-soluble proteins derived from collagen. Animal glue is a preferred gelatin because it is relatively inexpensive, commercially available, and easy to handle. The gelatin concentration in the electrolyte solution is preferably up to about 20 ppm, more preferably up to about 10 ppm, and preferably in the range of about 0.2 to about 10 ppm. The second electrolyte solution used in the manufacture of the foil may optionally contain other additives known in the art to control the properties of the electrodeposited foil. Examples include molasses, guar gum, polyalkylene glycols (eg, polyethylene glycol, polypropylene glycol, polyisopropylene glycol, etc.), dithiothreitol, amino acids (eg, proline, hydroxyproline, cysteine, etc.). , Acrylamide, sulfopropyl disulfide, tetraethylthiuram disulfide, benzyl chloride, epichlorohydrin, chlorohydroxylpropyl sulfonate, alkylene oxides (eg, ethylene oxide, propylene oxide, etc.), sulfonium alkane Sulfonics), thiocarbamoyl disulfide, selenic acid), or a mixture of two or more of them. These additives are preferably used at concentrations up to about 20 ppm, more preferably from about 1 to about 10 ppm. Diffusion limiting current density (I) during electrodeposition of copper foil_L) To the applied current density (I) to a level of about 0.4 or less, more preferably about 0.3 or less. That is, I / I_LIs preferably about 0.4 or less, more preferably about 0.3 or less. In one embodiment, the following parameter values are useful in electrodepositing the foil: Parameter value I (A / cm²) 1.0 n (eq / mol) 2 D (cm)²/ s) 3.5x10^-5 C^*(Mol / cm³, Cu⁺²(CuSO₄As)) 1.49x10^-3 Temperature (° C) 60 Free sulfuric acid concentration (g / l) 90 Dynamic viscosity (cm²/ s) 0.0159 Flow velocity (cm / s) 200 The term "raw" is used herein to refer to raw or basic foil that has not undergone subsequent treatment for the purpose of refining or enhancing the properties of the foil. The term "processed" is used here to refer to raw or basic foil that has undergone such processing. This treatment is completely normal and typically involves the use of various treatment and wash solutions. For example, in one embodiment, at least one side of the foil is treated with at least one layer of copper or a crude layer of copper oxide. In another embodiment, at least one side of the foil is treated with at least one layer of metal, the metal of which metal layer is indium, zinc, tin, nickel, cobalt, copper-zinc alloy and copper-tin. Selected from the group consisting of alloys. In another embodiment, at least one side of the foil is treated with at least one layer of metal, the metal of which metal layer is selected from the group consisting of tin, chromium, and chromium-zinc alloys. In another embodiment, at least one surface of the foil is treated with at least one layer of copper or a cuprate superconductor, and then at least one layer of metal is adhered onto the coarse layer. The metal of this metal layer is selected from the group consisting of indium, zinc, tin, nickel, cobalt, copper-zinc alloys and copper-tin alloys. In another embodiment, at least one surface of the foil is treated with at least one layer of copper or a cuprate superconductor, and then at least one layer of metal is adhered onto the coarse layer. The metal of this metal layer is selected from the group consisting of tin, chromium, and chromium-zinc alloys. In another embodiment, at least one surface of the foil is treated with at least one layer of copper or a coarse layer of copper oxide, and then at least one layer of the first metal layer is adhered onto the coarse layer. The metal of this first metal layer is selected from the group consisting of indium, zinc, tin, nickel, cobalt, copper-zinc alloys and copper-tin alloys. At least one second metal layer is on top of the first metal layer. Attached, the metal of this second metal layer is selected from the group consisting of tin, chromium, and chromium-zinc alloys. Such processing methods are well known in the art. The copper foil produced by the method of the present invention has a smooth or glossy (drum) surface and a rough or matte (copper precipitation growth edge) surface. These foils can be adhered to a dielectric substrate to provide dimensional and structural stability, and in this regard, the matte electrodeposited foil so that the glossy side of the foil faces outward from the laminate. It is preferable to adhere the base material to the surface. A useful dielectric substrate can be prepared by infiltrating a partially cured resin, usually an epoxy resin, into a woven glass reinforced material. These inducible substrates are sometimes referred to as prepregs. In the preparation of the laminate, it is useful that both the prepreg material and the electrodeposited copper foil are supplied in the form of a long web material wound on a roll. The rolled material is pulled out of the roll and cut into square sheets. The square sheet is then laminated or assembled into a stack of combinatorial materials. Each combination material may include a prepreg sheet having a sheet of foil on either side, and in each example, such that the glossy side of the foil sheet faces outward on each side of the combination material. The matte surfaces of the copper foil sheet are located adjacent to the prepreg on each surface. The combination material may be exposed to normal laminating temperatures and pressures between the plates of a laminating press to prepare a laminate containing a prepreg sheet sandwiched between copper foil sheets. The prepreg can consist of a woven glass tempered fabric moistened with a partially cured two-stage resin. By heating and pressurizing, the matte surface of the copper foil is firmly pressure-bonded to the prepreg, and the temperature at which the combination material is exposed activates and cures the resin. That is, the resin is crosslinked, which causes the foil to adhere tightly to the prepreg dielectric substrate. Generally speaking, laminating operations include pressures in the range of about 250 to about 750 psi, temperatures in the range of about 175 ° C to 235 ° C and laminating cycles of about 40 minutes to about 2 hours. The finished laminate can then be used in the preparation of printed circuit boards (PCBs). Many manufacturing methods are useful for preparing PCBs from laminates. In addition, PCBs have a myriad of possible end-use applications, including radios, televisions, computers, and more. These methods and end applications are known in the art. Referring here to FIG. 1, which is a flow sheet showing one embodiment of the method of the present invention, the copper leaching dump 10 is processed according to the method of the present invention for producing copper metal powder, and the copper powder is stored hoppers 40, 42. And 44 are collected. The methods include settling tanks 14, 15 and 16, pools 17, mixers 18, 20 and 22, electrolytic cells 24 including sandwiched cathodes 26 and anodes 28, endless belts 30 and 46, filters 32, cleaning and Dehydrator 34, storage hopper 36, 38, 40, 42 and 44, powder sprayer 45, furnace 48, cooling chamber 50, calcination cake destroyer 52, mill 54, sieving 58, and chute 60, 62, 64, 66 Includes the use of 68 and 70. In this embodiment, step (A) of the method of the invention is performed on the leaching dump 10. Steps (B) and (C) are carried out in two steps using mixers 18 and 20 and settling tanks 14 and 15. Steps (D) and (E) are carried out using the mixer 22 and the settling tank 16. Steps (F) and (G) are carried out using the electrolytic cell 24. The leaching aqueous solution from the line 70 is sprayed on the surface of the leaching dump 10. The leachate is a sulfuric acid solution having a sulfuric acid concentration in the range of about 5 to about 50, more preferably about 5 to about 40 grams per liter, even more preferably about 10 to about 30 grams per liter. The leachate penetrates the dump, dissolves copper in the ore, flows through the dump space 72 as a copper-rich leachate (sometimes called a pregnant leachate), and through line 74 through the pool 17 And from there it is pumped through line 76 to mixer 20. The copper-rich leachate pumped into the mixer 20 preferably has a copper ion concentration in the range of about 0.8 to about 5, more preferably about 1 to about 3 grams per liter; and preferably about 5 to about 30, More preferably, it has a free sulfuric acid concentration in the range of about 10 to about 20 grams per liter. In the mixer 20, the copper-rich leachate is mixed with the copper-containing organic solution pumped from the weir 78 of the settling tank 15 through lines 80, 82 and 84 into the mixer 20. The copper concentration in the organic solution with copper added to the mixer 20 is preferably from about 0.5 to about 4 grams per liter of extractant in the organic solution, more preferably from about 1 to about 1 to about 1 liter of extractant in the organic solution. 2. Up to 4 grams. During mixing in mixer 20, an organic phase and an aqueous phase form and mix. Copper ions move from the aqueous phase to the organic phase. The mixture is pumped from the mixer 20 through line 86 into the settling tank 14. In the settling tank 14, the aqueous phase and the organic phase are separated, the organic phase is formed in the upper layer, and the aqueous phase is formed in the lower layer. The organic layer is collected in the weir 88 and pumped into mixer 22 through lines 90, 92 and 94. This organic phase is a copper-rich organic solution (which can be called a loaded organic solution). This copper-rich organic solution preferably ranges from about 1 to about 6 grams per liter of extractant in the organic solution, more preferably from about 2 to about 4 grams per liter of extractant in the organic solution. Has a concentration. The copper-rich organic solution is mixed with the copper-deprived back-extraction solution in mixer 22. The copper-deprived back-extract solution (which may be called a dilute electrolyte) is produced in the electroforming tank 24 and pumped through lines 96, 98, 100, 102, 104 and 106 to the mixer 22. This copper-deprived back-extract solution preferably has a free sulfuric acid concentration in the range of about 80 to about 300, more preferably about 150 to about 250 grams per liter; and preferably about 1 to about 50, even more preferably. It has a copper ion concentration in the range of about 4 to about 12 grams per liter. Replenishment of fresh back-extract solution can be added to line 106 through line 108. The copper-rich organic solution and the copper-deprived back-extraction solution are mixed in the mixer 22 to produce an organic phase mixed with the aqueous phase. Copper ions move from the aqueous phase to the organic phase. The mixed solution is pumped from the mixer 22 through the line 110 to the settling tank 16. In the settling tank 16, the organic phase is separated from the aqueous phase and the organic phase is collected in the weir 112. This organic phase is a copper-deprived organic solution (sometimes called a barren organic solution). This copper-deprived organic solution preferably ranges from about 0.5 to about 2 grams per liter of extractant in the organic solution, more preferably from about 0.9 to about 1.5 grams per liter of extractant in the organic solution. Has a concentration. The copper-deprived organic solution is pumped from the settling tank 16 through lines 114, 116, 118 and 120 to the mixer 18. Replenishment of fresh organic solution can be added to line 118 through line 122. The leaching aqueous solution containing copper is pumped from the settling tank 14 through lines 124, 126, 128 and 130 to the mixer 18. This copper-containing aqueous leachate preferably has a copper ion concentration in the range of about 0.4 to about 4, more preferably about 0.5 to about 2.4 grams per liter; and about 5 to about 50, more preferably about 5 per liter. It has a free sulfuric acid concentration in the range of about 30 grams, more preferably about 10 to about 20 grams per liter. In the mixer 18, an organic phase and an aqueous phase are formed and mixed, and copper ions move from the aqueous phase to the organic phase. The mixed solution is pumped to the settling tank 15 through the line 132. In the settling tank 15, the organic tank is separated from the aqueous phase and the organic phase is collected in the weir 78. This organic phase is an organic solution containing copper and is pumped from the settling tank 15 through lines 80, 82 and 84 to the mixer 20. This copper-containing organic solution preferably has a copper concentration in the range of about 0.5 to about 4 grams per liter of extractant in the organic solution, more preferably about 1 to about 2.4 grams per liter of extractant in the organic solution. Have. The aqueous phase in the settling tank 15 is a copper-deprived leachate solution that is pumped through lines 134, 136 and 138 to line 70, where it is sprayed onto the leach dump 10. Replenishment of fresh leachate can be added to line 138 through line 140. The aqueous phase separated in the settling tank 16 is a copper-rich back-extraction solution. It is pumped from the settling tank 16 through lines 142 and 144 to the filter 32 and from the filter 32 through lines 146 and 148 to the electrolytic cell 24. This copper-rich back-extract solution preferably has a copper ion concentration in the range of about 2 to about 60, more preferably about 5 to about 15 grams per liter; and about 70 to about 290, even more preferably 1 liter. It has a free sulfuric acid concentration in the range of about 140 to about 240 grams per. A copper-rich back-extraction solution entering the electrolytic cell 24 may also be referred to as an electrolyte solution. The electrolyte solution 150 in the electrolytic cell 24 preferably has a copper ion concentration in the range of about 1 to about 60 grams per liter, more preferably about 4 to about 15 grams per liter; and about 70 to about 300, more preferably. It has a free sulfuric acid concentration in the range of about 140 to about 250 grams per liter. The electrolyte solution 150 flows between the cathode 26 and the anode 28 in a state of being sandwiched by natural convection. When a voltage is applied between the anode 28 and the cathode 26, electrodeposition of copper metal powder occurs on the cathode. The electrodeposited copper powder 152 is removed from the cathode 26 using a mechanical scraper (not shown in the figure) and carried along the endless belt 30 to the cleaning and dehydrating device 34. The electrolyte solution 150 is converted into an electrolyte solution deprived of copper in the electrolytic cell 24 and is withdrawn from the electrolytic cell 24 through line 96. The copper-deprived electrolyte solution in line 96 preferably has a copper ion concentration in the range of about 1 to about 50 grams per liter, more preferably about 4 to about 12 grams per liter; and preferably about 80 to about. It has a free sulfuric acid concentration of 300, more preferably in the range of about 150 to about 250 grams per liter. This copper-deprived electrolyte solution is either (1) recirculated through lines 96, 154, 156 and 148 and returned to tank 24; or (2) line 96, as a copper-deprived back-extract solution. It is either pumped through 98, 100, 102, 104 and 106 to mixer 22. The copper metal powder 152 is carried from the electrolytic cell 24 to the cleaning and dehydrating device 34 along the endless belt 30. The powder 152 is washed and dehydrated in device 34. The cleaning and dehydrating device 34 can be, for example, a vacuum belt filter with a spray nozzle overhead for spraying water onto the powder. The powder 152 is transported from the device 34 along the endless belt 30 to the chute 60 and to the storage hopper 36. The powder 152 is carried from the storage hopper 36 through the powder spray 45 to the endless belt 46. The powder is spread on an endless belt 46 and passes through a furnace 48 and a cooling chamber 50 where it is dried and sintered and sent first to form a sintered cake. During this drying and sintering process, the oxides picked up in the washing and dehydrating apparatus 34 are reduced or eliminated. The sintered cake is transported from the cooling chamber 50 along the endless belt 46 to the sintered cake destroyer 52, and then placed in the storage hopper 38. The destroyed sintered cake is sent from the storage hopper 38 through the chute 62 to the mill 54. In the mill 54, the broken sintered cake is further broken by a crushing means such as a serrated crusher. The broken particles can be further ground, for example, on a hammer mill or plate mill (not shown). The crushed particles are sent from the mill 54 through the chute 64 to the sieve 58, where they are separated into three sizes. Particles that are too large are sent through chute 66 to the storage hopper 40. Particles that are too small in size are sent through chute 68 to the storage hopper 42. Medium-sized particles are sent through chute 70 to storage hopper 44. Particles that are too large can be returned to the mill 54 and further milled or dissolved in electrolyte 150. Particles that are too small in size within the storage hopper 42 can either be dissolved in electrolyte 150 or blended with medium sized particles collected in the storage hopper 44. Sieve 58 is copper gold The embodiment depicted in FIG. 2 is shown in FIG. 1 except that the copper metal powder 152 carried along the endless belt 30 from the washer / dehydrator 34 is sent to the digester 200 rather than the storage hopper 36. It is the same as the embodiment depicted. Powder sprayer 45, endless belt 46, furnace 48, cooling chamber 50, sintered cake destroyer 52, storage hopper 36, 38, 40, 42 and 44, mill 54, sieve 58, and chute 62 depicted in Figure 1. , 64, 66, 68 and 70 are replaced in FIG. 2 with an electroplating tank 202 containing a rotary cylindrical cathode 204 and an anode 206, and a filter 208. Instead of producing the copper powder collected in the storage hoppers 40, 42 and 44 of FIG. 1, the embodiment depicted in FIG. 2 comprises producing copper foil 210 collected as a foil roll 210a. With respect to FIG. 2, the above description with respect to FIG. 1 is also applicable to FIG. 2 in that the copper powder 152 is carried from the cleaning and dehydrating apparatus 34 to the chute 60 along the endless belt 30. In FIG. 2, the powder 152 proceeds to the digester 200 through the chute 60. In the digester 200, the copper metal powder 152 is dissolved in sulfuric acid added to the digester 200 through line 212. Optionally, the depleted electrolyte from the electrolytic cell 24 or the electroforming tank 202 is added to or in place of the sulfuric acid entering the line 212 into the digester 200. In the digester 200, an electrolyte solution 214 is produced, and the electrolyte solution is pumped from the digester 200 through lines 216, 218, 220 and 222 into the electroforming tank 202. The electrolyte solution 214 preferably has a free sulfuric acid concentration in the range of about 70 to about 170 grams per liter, more preferably about 80 to about 170 grams per liter; and preferably in the range of about 40 to about 150 grams per liter. , More preferably having a copper ion concentration in the range of about 90 to about 110 grams per liter. The electrolyte solution 214 flows through the gap 224 between the rotary cathode 204 and the anode 206. When a voltage is applied between the anode 206 and the cathode 204, copper electrodeposition occurs on the cathode surface 204a. As the cathode rotates, the electrodeposited copper is removed from the cathode 204 as a continuous web 210 of foil. The copper foil is imprinted in the shape of the foil roll 210a. The electrolyte solution 214 is converted into a copper-deprived electrolyte solution in the electroforming tank 202 and withdrawn from the tank 202 through line 226. The copper-deprived electrolyte solution in line 226 preferably ranges from about 40 to about 120, more preferably about 80 to about 100 grams per liter, and even more preferably about 90 to about 95 grams per liter. Concentrations; and preferably have free sulfuric acid concentrations in the range of about 80 to about 170 grams, more preferably about 90 to about 120 grams per liter. This copper-deprived electrolyte is recirculated through lines 226, 228 and 230 to filter 208 and then through filter 208 to lines 234, 238 and 222 and returned to tank 202. Optionally, gelatin and / or other desired additives of the type discussed above are added to the recirculated solution at line 230 through line 242. The active sulfur-containing material can be added to the recirculated solution at line 222 through line 244. In the electrolytic cell 202, electrical means well known in the art are provided to apply an electric current between the anode 206 and the cathode 204. The current is preferably direct current or alternating current with a direct current bias. Copper ions in the electrolyte solution 214 get electrons on the peripheral surface 204a of the cathode 204, whereby metallic copper is plated in the form of a foil layer. The cathode 204 rotates continuously around its axis 204b, and the foil layer is continuously drawn from the cathode surface 204a as a continuous web 210 and collected as rolls 210a. The electrodeposition process in the electroforming tank 202 deprives the electrolyte solution 214 of copper ions and, if used, gelatin and active sulfur-containing materials. These ingredients are replenished. Copper ions are replenished through line 222, gelatin is replenished through line 242, and active sulfur-containing material is replenished through line 93. The embodiments depicted in FIGS. 1 and 2 use a two-step solvent extraction step using mixers 18 and 20 and settling tanks 14 and 15, but the additional extraction steps do not deviate from the essence of the invention. It should be understood that it can be added to the method. Thus, for example, FIGS. 1 and 2 specifically disclose a two-step extraction step, and while the aforementioned discussion refers to one-step and two-step extraction, the methods of the invention are three-step, four-step, This can be done using extraction steps such as 5 or 6 steps. Similarly, the embodiments depicted in FIGS. 1 and 2 use a one-step back-extraction step using a mixer 22 and a settling tank 16, but additional back-extraction steps deviate from the essence of the invention. It should be understood that it can be added to the method without. Thus, for example, the method of the present invention can be carried out using back-extraction steps such as 2-step, 3-step, 4-step, 5-step, 6-step. The following examples are provided for purposes of explaining the present invention. Unless otherwise indicated, in the examples below and in the specification and claims, all proportions and percentages are by weight, all temperatures are in degrees Celsius, and all pressures are atmospheric pressure. Examples 1-12 Copper metal powder is available in electrolyte tank 24, endless belt 30, cleaning and dehydrating device 34, storage hopper 36, 38, 40, 42 and 44, chute 60, 62, 64, 66, 68 and 70, powder spray 45, furnace. It is produced using the method shown in FIG. 1, except that 48, cooling chamber 50, sintered cake breaking machine 52, mill 54 and sieve 58 are not used. The electrolytic cell used is a 54.25 x 48 x 14 inch polypropylene tank containing three anodes and two cathodes. The anode is a lead-calcium-tin alloy anode. The cathode is stainless steel. The upper tank is used to store the electrolyte solution. The electrolyte solution is gravity-supplied to the electrolytic cell. The leaching aqueous solution sprayed from the line 70 toward the leaching dump 10 is a sulfuric acid aqueous solution having a free sulfuric acid concentration of 20 grams per liter. The copper-rich leachate pumped through line 76 into the mixer 20 has a copper ion concentration of 1.8 grams per liter and a free sulfuric acid concentration of 12 grams per liter. The organic solution is a solution having 7 wt% LIX984 in SX-7. The copper concentration in the organic solution with copper added from the settling tank 15 to the mixer 20 has a copper concentration of 1.95 grams per liter of LIX 984 in the organic solution. The copper-rich organic solution pumped from the settling tank 14 into the mixer 22 has a copper concentration of 3 grams per liter of LIX 984 in the organic solution. The copper-deprived back-extract solution added to mixer 22 from line 106 has a free sulfuric acid concentration of 170 grams per liter and a copper ion concentration of 40 grams per liter. (This copper-deprived back-extraction solution is pumped through line 106 to mixer 22 from an EW facility that is not part of the method of the invention.) Copper-deprived organic pumped from settling tank 16 to mixer 18. The solution has a copper concentration of 1.25 grams per liter of LIX 984 in an organic solution. The copper-containing leachate pumped from the settling tank 14 to the mixer 18 has a copper ion concentration of 0.8 grams per liter and a free sulfuric acid concentration of 12 grams per liter. The deprived copper leachate pumped from the settling tank 15 through line 134 has a copper concentration of 0.15 grams per liter and a free sulfuric acid concentration of 12 grams per liter. The copper-rich back-extract solution removed from the settling tank 16 for use in the electrolytic cell has a copper ion concentration of 5-15 grams per liter and 1 liter as shown in Table (I) below. Dilute with water and sulfuric acid to provide a free sulfuric acid concentration of 150-200 grams per. The copper-rich back-extraction solution for Example 9 was not diluted. Operating the electrolytic cell under test conditions and balancing the tank with a current density of 90 and 145 amps (ASF) per square foot for 20 minutes, a current density of 60 ASF for 40 minutes, and a current density of 30 ASF for 60 minutes. By allowing the electrolytic cell to be in a balanced state. For each example, a 45-minute cycle is performed three times. At the end of each cycle, the cathode is scraped off with a carbon steel scraper. Copper metal powder is collected in a stainless steel pan. The powder is washed with tap water in a plastic bucket, and the water is gently removed. This cleaning procedure is repeated four more times. The powder is treated with a 1% benzotriazole solution by weight for 1 hour and then dried. The powder was analyzed and the results are shown in Table I below. Weigh 1 gram of powder, and HNO the sample₃Determine the copper ratio of the sample by dissolving in and analyze it for copper content. Efficacy is calculated from dry weight. Overall efficiency is calculated as the product of purity, copper ratio and dry weight efficiency. Examples 13 ~ 15 The procedure used in Examples 13-15 is similar to that shown in Examples 1-12, with the following points slowly: (1) Deionized water replaces tap water to wash the sample. (2) All three cycles are not operated using lead anodes, but rather two of the three cycles of each embodiment are operated using dimensionally stable anodes, and 1 The cycle is operated using a lead anode; and (3) a stainless steel or plastic scraper is used in place of the carbon steel scraper. The results are also shown in Table I.<img file="JP2968043B2_D0009.tif" /> Although the present invention has been described with respect to preferred embodiments, it should be understood that reading the specification will reveal various variations of the invention to those skilled in the art. Therefore, it should be understood that the inventions disclosed herein are intended to include modifications within the appended claims.