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Title:
PROCESS FOR MAKING COPPER WIRE INCLUDING SOLVENT EXTRACTION, ELECTRODEPOSITION AND COLD WORKING
Document Type and Number:
WIPO Patent Application WO/2000/049187
Kind Code:
A1
Abstract:
This invention relates to a process for making copper wire comprising the steps of (A) extracting copper ions from a copper-bearing material using an aqueous leaching solution to form a copper-rich aqueous leaching solution; (B) extracting copper ions from said copper-rich aqueous leaching solution using a water-insoluble extractant to form a copper-rich water-insolube extractant; (C) stripping said copper-rich water-insoluble extractant using an aqueous stripping solution to form a copper-rich stripping solution; (D) flowing said copper-rich stripping solution between an anode and a cathode, and applying voltage across said anode and said cathode to electrodeposit copper metal on said cathode; said copper-rich stripping solution having a copper ion concentration in the range of about 30 to about 70 grams per liter, a free sulfuric acid concentration in the range of about 120 to about 200 grams per liter, a chloride ion concentration in the range of about 10 to about 50 ppm, and an organic additive concentration in the range of about 2 to about 20 ppm; the current density being in the range of about 10 to about 40 amps per square foot; and (E) removing said copper metal from said cathode and forming copper wire from said removed copper metal, said step of forming copper wire being conducted without subjecting said removed copper metal to melting; said copper wire being reducible in tensile testing to greater than 98 % RIA and being characterized by a twinning or stacking fault population in its crystal structure. The copper wire can be drawn to any desired thickness, but is particularly suitable for making ultra thin copper wire.

Inventors:
HASEGAWA CRAIG J
SCHATZBERG SUSAN E
PECKHAM PETER
Application Number:
PCT/US1999/023282
Publication Date:
August 24, 2000
Filing Date:
October 06, 1999
Export Citation:
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Assignee:
ELECTROCOPPER PROD LTD (US)
International Classes:
B21C37/04; C22B3/26; C22B15/00; C25C1/12; C25D1/04; (IPC1-7): C22B15/00; C22B3/30; C25C1/12; C25D1/04; B21C37/04
Foreign References:
US5670033A1997-09-23
US5830583A1998-11-03
US5458746A1995-10-17
GB2003413A1979-03-14
US5516408A1996-05-14
Other References:
DATABASE WPI Section Ch Week 198731, Derwent World Patents Index; Class F02, AN 1987-216358, XP002129600
Attorney, Agent or Firm:
Duchez, Neil A. (Otto Boisselle & Skla, P.L.L. 19th floor 1621 Euclid Avenue Cleveland OH, US)
Download PDF:
Claims:
Claims
1. A process for making copper wire comprising the steps of: (A) extracting copper ions from a copperbearing material using an aqueous leaching solution to form a copperrich aqueous leaching solution; (B) extracting copper ions from said copperrich aqueous leaching solution using a waterinsoluble extractant to form a copperrich water insoluble extractant; (C) stripping said copperrich waterinsoluble extractant using an aqueous stripping solution to form a copperrich stripping solution; (D) flowing said copperrich stripping solution between an anode and a cathode, and applying voltage across said anode and said cathode to electrodeposit copper metal on said cathode; said copperrich stripping solution having a copper ion concentration in the range of about 30 to about 70 grams per liter, a free sulfuric acid concentration in the range of about 120 to about 200 grams per liter, a chloride ion concentration in the range of about 10 to about 50 ppm, and an organic additive concentration in the range of about 2 to about 20 ppm; the current density being in the range of about 10 to about 40 amps per square foot; and (E) removing said copper metal from said cathode and forming copper wire from said removed copper metal, said step of forming copper wire being conducted without subjecting said removed copper metal to melting; said copper wire being reducible in tensile testing to greater than 98% RIA and being characterized by a twinning or stacking fault population in its crystal structure.
2. The process of claim 1 wherein prior to step (D), additional copper ions, sulfuric acid, organic additive or chloride ions are added to said copper rich stripping solution.
3. The process of claim 1 wherein said copperbearing material is copper ore, copper concentrate, copper smelter products, smelter flue dust, copper cement, copper sulfate or coppercontaining waste.
4. The process of claim 1 wherein said aqueous leaching solution comprises sulfuric acid, halide acid or ammonia.
5. The process of claim 1 wherein said waterinsoluble extractant is dissolve in an organic solvent selected from the group consisting of kerosene, benzene, naphthalene, fuel oil and diesel fuel.
6. The process of claim 1 wherein said waterinsoluble extractant comprises at least one compound represented by the formula wherein R', R2, R3, R4, R5, R'and R'are independently hydrogen or hydrocarbyl groups.
7. The process of claim 1 wherein said waterinsoluble extractant comprises at least one compound represented by the formula wherein R'and R2 are independently hydrogen or hydrocarbyl groups.
8. The process of claim 1 wherein said waterinsoluble extractant comprises at least one compound represented by the formula wherein R'and R2 are independently alkyl groups or aryl groups.
9. The process of claim 1 wherein said waterinsoluble extractant comprises at least one ion exchange resin.
10. The process of claim 1 wherein said removed copper metal in step (E) is in the form of a circular disk, said circular disk having a thickness in the range of about 0.1 to about 1 inch, and a diameter of up to about 60 inches.
11. The process of claim 1 wherein said removed copper metal in step (E) is in the form of a square or rectangular copper plate, said square or rectangular copper plate having a thickness of about 0.1 to about 1 inch, a length of about 12 to about 60 inches, and a width of about 12 to about 60 inches, said process including the step of forming a circular disk from said square or rectangular copper plate.
12. The process of claim 10 wherein said circular disk has one side that is smooth and one side that is rough, and prior to forming said wire said rough side is smoothed.
13. The process of claim 10 wherein said circular disk has one side that is smooth and one side that is rough, and prior to forming said wire said rough side is not smoothed.
14. The process of claim 1 wherein during step (E) said step of forming copper wire includes: providing said removed copper metal in the form of a circular disk; rotating said disk about its center axis; feeding a cutting tool into the peripheral edge of said disk to peel a strip of copper metal from said disk, said cutting tool moving towards the center axis of said circular disk as said strip of copper metal is removed from said circular disk; and slitting said strip of copper metal to form a plurality of strands of copper wire.
15. The process of claim 15 with the step of shaping said strands of copper wire to provide said strands with desired cross sections.
16. The process of claim 15 wherein said circular disk rotates in a horizontal plane.
17. The process of claim 15 wherein said cutting tool has a sharpened edge of about 40° to about 60° that is defined between a clearance face and a rake face.
18. The process of claim 15 wherein said cutting tool has a composition comprising tungsten carbide.
19. The process of claim 15 wherein the speed of the peripheral edge of said rotating disk is about 5 to about 5000 feet per minute.
20. The process of claim 15 wherein said strip of copper metal has a thickness in the range of about 0.002 to about 0.5 inch, and a width in the range of about 0.1 to about 1 inch.
21. The process of claim 15 wherein each strand of copper wire formed during step (E) has a rectangular or square cross section.
22. The process of claim 21 wherein said wire with a rectangular or square cross section is shaped to have a round cross section.
23. The process of claim 1 wherein said wire has a cross sectional diameter in the range of about 0.0002 to about 0.25 inch.
24. The process of claim 1 wherein said wire has a gage of about 10 AWG to about 62 AWG.
25. The process of claim 1 wherein said wire is an ultra fine wire having a gage of about 50 AWG to about 62 AWG.
26. The process of claim 1 wherein said wire has a gage of about AWG 55 or smaller.
27. The process of claim 1 wherein said wire has a gage of about AWG 62 of smaller.
Description:
PROCESS FOR MAKING COPPER WIRE INCLUDING SOLVENT EXTRACTION, ELECTRODEPOSITION AND COLD WORKING Technical Field This invention relates to a process for making copper wire. More particularly, this invention relates to a process for making copper wire that is reducible in tensile testing to greater than 98% RIA and thereby available as ultra thin wire, said copper wire being made directly from an impure copper source such as copper ore or copper-containing waste without subjecting the copper to melting.

Background of the Invention Conventional methods for making copper wire involve the following steps.

Electrolytic copper (electrorefined, electrowon, or both) is melted, cast into bar shape, and hot rolled into a rod shape. The rod is then cold-worked as it is passed through drawing dies that systematically reduce the diameter while elongating the wire. In a typical operation, a rod manufacturer casts the molten electrolytic copper into a bar having a cross section that is substantially trapazoidal in shape with rounded edges and a cross sectional area of about 7 square inches. This bar is passed through a preparation stage to trim the corner, and then through 12 rolling stands from which it exits in the form of a 0.3125" diameter copper rod. The copper rod is then reduced to a desired wire size through standard drawing dies. Typically, these reductions occur in a series of dies with a final annealing step and in some instances intermediate annealing steps to soften the worked wire.

The conventional method of copper wire production consumes significant amounts of energy and requires extensive labor and capital costs. The melting, casting and hot rolling operations subject the product to oxidation and potential contamination from foreign materials, such as refractory and roll materials, which can subsequently cause problems to wire drawers which include wire breaks during drawing.

It is known that even in high purity copper wire, there are microvoids and small oxide inclusions in the material that orient themselves along the drawing line (the tensile axis) during metalworking. As these voids come together or coalesce, they eventually reach a sufficient size such that failure occurs. This phenomenon

limits the size to which the wire may be reduced or drawn. This often occurs when the wire diameter is about 0.0008" or 52 AWG. Drawing to finer gages is very difficult and expensive due to breakouts and often not possible.

The term"high reduction copper wire"refers to copper wire which when subjected to tensile testing undergoes a high reduction in its cross sectional area prior to fracturing. The reduction is measured as a percentage reduction in cross sectional area (% RIA) from the original cross sectional area to the cross sectional area of the tip of the fracture surface. A copper wire that is 98% reducible undergoes a reduction in its cross sectional area of 98% prior to fracturing. A copper wire that is 100% reducible is a copper wire that exhibits a pure ductile rupture when subjected to tensile testing; this wire ultimately breaks during the tensile testing but the fracture surface resembles a pin point. Standard electrolytic tough pitch (ETP) copper wire with 100-600 ppm oxygen typically shows about 80- <BR> <BR> 90% RIA. Oxygen-free electronic (OFE) wire with less than 10 ppm oxygen typically<BR> shows from 90-97% RIA. Ultra-pure copper typically shows 95-98% RIA. Until now the general consensus in the industry has been that greater than 98% RIA, and especially 100% RIA, was impossible to achieve in commercial practice. This invention provides for a process for making a copper wire capable of achieving an RIA greater than 98%, and in one embodiment an RIA of 100%.

U. S. Patent 5,516,408 discloses a process for making copper wire 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 stripping solution from said copper- depleted extractant; (F) flowing said copper-rich stripping solution between an anode and a cathode, and applying an effective amount of voltage across said anode and said cathode to deposit copper on said cathode; (G) removing said copper from said cathode; and (H) converting said removed copper from (G) to copper wire at a temperature below the melting point of said copper.

Summary of the invention This invention relates to a process for making copper wire comprising the steps of (A) extracting copper ions from a copper-bearing material using an aqueous leaching solution to form a copper-rich aqueous leaching solution; (B) extracting copper ions from said copper-rich aqueous leaching solution using a water-insoluble extractant to form a copper-rich water-insoluble extractant; (C) stripping said copper- rich water-insoluble extractant using an aqueous stripping solution to form a copper- rich stripping solution; (D) flowing said copper-rich stripping solution between an anode and a cathode, and applying voltage across said anode and said cathode to electrodeposit copper metal on said cathode; said copper-rich stripping solution having a copper ion concentration in the range of about 30 to about 70 grams per liter, a free sulfuric acid concentration in the range of about 120 to about 200 grams per liter, a chloride ion concentration in the range of about 10 to about 50 ppm, and an organic additive concentration in the range of about 2 to about 20 ppm; the current density being in the range of about 10 to about 40 amps per square foot; and (E) removing said copper metal from said cathode and forming copperwire from said removed copper metal, said step of forming copper wire being conducted without subjecting said removed copper metal to melting; said copper wire being reducible in tensile testing to greater than 98% RIA and being characterized by a twinning or stacking fault population in its crystal structure. The copper wire can be drawn to any thickness, but is particularly suitable for making ultra thin copper wire.

Brief Description of the Drawings In the annexed drawings, like references indicate like parts or features:

Fig. 1 is a flow sheet illustrating a solvent extraction, electrodeposition process for making copper metal, the copper metal thereafter be used to make copper wire.

Fig. 2 is a schematic illustration of a copper plate formed during the electrodeposition step of the inventive process.

Fig. 3 is a schematic illustration of a circular disk of copper used with the inventive process.

Fig. 4 is a schematic illustration of the top plan view of an apparatus used for peeling a strip of copper from the peripheral edge of a circular disk of copper pursuant to the inventive process.

Fig. 5 is an enlarged top plan view of the cutting tool illustrated in Fig. 4.

Fig. 6 is an enlarged partial schematic illustration of the cutting of the peripheral edge of a circular disk using the cutting tool illustrated in Figs. 4 and 5.

Fig. 7 is an enlarged partial schematic illustration of a modified design of the cutting tool illustrated in Figs 4 and 5.

Fig. 8 is a schematic illustration of the apparatus used to slit a strip of copper to form a plurality of strands of copper wire pursuant to the inventive process.

Fig. 9 is a schematic illustration of a fragmented strip of copper which has been partially slit using the apparatus illustrated in Fig 8.

Fig. 10 is an exploded schematic illustration of the cutting blades used in the apparatus illustrated in Fig 8 to slit a strip of copper.

Fig. 11 is a flow sheet illustrating the step of converting a strand of copper wire having a square or rectangular cross section to a strand of copper wire having a round cross section pursuant to the inventive process.

Fig. 12 is a schematic illustration of a process for drawing copper wire pursuant to the inventive process.

Description of the Preferred Embodiments The inventive process involves the combination of two separate technologies to produce copper wire directly from a relatively impure copper source such as copper ore or copper-containing waste. The first of these technologies involves solvent-extraction, electrodeposition; and the second involves metal-working.

Solvent-Extraction, Electrodeposition The copper feedstock for making copper wire by the inventive process can be any copper-bearing material from which copper may be extracted. The feedstock includes copper ore, smelterflue dust, copper cement, copper concentrates, copper smelter products, copper sulfate, and copper-containing waste. The term"copper- containing waste"refers to any solid or liquid waste material (e. g., garbage, sludge, effluent streams, etc.) that contains copper. These waste materials include hazardous wastes. Specific examples of wastes that can be used are copper oxides obtained from treating spent cupric chloride etchants.

The copper ore can be ore taken from an open pit mine. The ore is hauled to a heap-leaching dump which is typically built on an area underlain with a liner, such as a thick high-density polyethylene liner, to prevent loss of leaching fluids into <BR> <BR> the surrounding water shed. A typical heap-leaching dump has a surface area of, for example, about 125,000 square feet and contains approximately 110,000 tons <BR> <BR> of ore. As leaching progresses and new dumps are built on top of the old dumps, they become increasingly higherand eventually reach heights of, forexample, about 250 feet or more. A network of pipes and wobbler sprinklers is laid on the surface of a newly completed dump and a weak solution of sulfuric acid is continuously sprayed at a rate of, for example, about 0.8 gallon per minute per 100 square feet of surface area. The leaching solution percolates down through the dump, dissolves copper in the ore, flows from the dump base as a copper-rich aqueous leach solution, drains into a collection pond, and is pumped to a feed pond for subsequent treatment using the inventive process.

With some mining operations in-situ leaching is used to extract copper values from copper ore. The copper-rich leach solution obtained by this process can be used in the inventive process as the copper-bearing material. In-situ leaching is useful when reserves of acid-soluble oxide ore lie beneath an open pit area and above the depleted portion of an underground mine or when a deposit is buried too deeply to be economically developed by open pit methods. Injection wells are drilled into this zone at a depth of, for example, about 1000 feet. The wells are cased with polyvinylchloride pipe, the bottom portion of which is slotted to allow

solution into the ore. A leach solution of weak sulfuric acid is injected into each well at a rate dependent upon the permeability of the zone into which it is drille. The solution percolates down through the ore zone, dissolves the copper mineras, and drains into a prepared collection area. The collection area can be, for example, haulage drifts of the underground mine. The copper-bearing aqueous leach solution that is produced is pumped to the surface by means of a corrosion-resistant pumping system where it is available for use as the copper-bearing material for the inventive process.

In mining operations wherein both leach dumps and in-situ leaching are employed, the copper-bearing leach solution (sometimes referred to as a pregnant leach solution) from each can be combined and used asthe copper-bearing material in the inventive process.

The copper metal used to make the copper wire is formed by the steps of: (A) extracting copper ions from the copper-bearing material using an aqueous leaching solution to form a copper-rich aqueous leaching solution; (B) extracting copper ions from the copper-rich aqueous leaching solution using a water-insoluble extractant to form a copper-rich water-insoluble extractant; (C) stripping the copper-rich extractant using an aqueous stripping solution to form a copper-rich stripping solution; (D) flowing the copper-rich stripping solution between an anode and a cathode, and applying an effective amount of voltage across the anode and the cathode to deposit copper metal on the cathode; and (E) removing the copper metal from the cathode.

The aqueous leaching solution used in step (A) of the inventive process is, in one embodiment, a sulfuric acid solution, halide acid solution (HCI, HF, HBr, etc.) or an ammonia solution. The sulfuric or halide acid solution generally has a sulfuric or halide acid concentration in the range of about 5 to about 50 grams per liter, and in one embodiment about 5 to about 40 grams per liter, and in one embodiment about 10 to about 30 grams per liter.

The ammonia solution generally has an ammonia concentration in the range of about 20 to about 140 grams per liter, and in one embodiment about 30 to about

90 grams per liter. The pH of this solution is generally in the range of about 7 to about 11, and in one embodiment about 8 to about 9.

The copper-rich aqueous leaching solution or pregnant leaching solution formed during step (A) generally has a copper ion concentration in the range of about 0.8 to about 5 grams per liter, and in one embodiment about 1 to about 3 grams per liter. When the leaching solution used in step (A) is a sulfuric acid solution, the concentration of free sulfuric acid in the copper-rich aqueous leaching solution is generally from about 5 to about 30 grams per liter, and in one embodiment about 10 to about 20 grams per liter. When the leaching solution used in step (A) is an ammonia solution, the concentration of free ammonia in the copper- rich aqueous leaching solution is generally from about 10 to about 130 grams per liter, and in one embodiment about 30 to about 90 grams per liter.

The water-insoluble extractant used in step (B) 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 not soluble in water above a level of about 1 gram per liter at 25°C.) The solvent can be any water-immiscible solvent for the extractant with kerosene, benzene, toluene, xylene, naphthalene, fuel oil, diesel fuel and the like being useful, and with kerosene being preferred. Examples of useful kerosenes are SX-7 and SX-12 which are available from Phillips Petroleum.

In one embodiment the extractant is an organic compound containing at least two functional groups attached to different carbon atoms of a hydrocarbon linkage, one of the functional groups being-OH and the other of said functional groups being =NOH. These compounds can be referred to as oximes. In one embodiment the extractant is an oxime represented by the formula

wherein R', R2, R3, R4, R5, R6 and R'are independently hydrogen or hydrocarbyl groups. In one embodiment, R'and R4 are each butyl; R2, R3 and R6 are each hydrogen; and Rs and R7 are each ethyl. Compounds with this structure are available from Henkel Corporation under the trade designation LIX 63.

In one embodiment the extractant is an oxime represented by the formula wherein R'and R2 are independently hydrogen or hydrocarbyl groups. Useful embodiments include those wherein R'is an alkyl group of about 6 to about 20 carbon atoms, and in one embodiment about 9 to about 12 carbon atoms; and R2 is hydrogen, an alkyl group of 1 to about 4 carbon atoms, and in one embodiment 1 or 2 carbon atoms, or R2 is phenyl. The phenyl group can be substituted or unsubstituted with the latter being preferred. The following compounds, which are based upon the above-indicated formula, are available from Henkel Corporation under the trade designations indicated below and are useful with the inventive process: Trade Designation R'R2 LIX 65 Nonyl Phenyl LIX 84 Nonyl Methyl LIX 860 Dodecyl Hydrogen Other commercially available materials available from Henkel Corporation that are useful include: LIX 64N (identified as a mixture of LIX 65 and LIX 63); and LIX 864 and LIX 984 (identified as mixtures of LIX 860 and LIX 84).

In one embodiment the extractant is a betadiketone. These compounds can be represented by the formula wherein R'and R2 are independently alkyl groups or aryl groups. The alkyl groups generally contain 1 to about 10 carbon atoms. The aryl groups are generally phenyl.

An example of a commercial extractant available from Henkel Corporation corresponding to the above formula is LIX 54. These betadiketones are useful when the leaching solution used in step (A) is an ammonia solution.

The concentration of the extractant in the organic solution is generally in the range of about 2% to about 40% by weight. In one embodiment the organic solution contains from about 5% to about 10%, or about 6% to about 8%, or about 7% by weight of LIX 984, with the remainder being SX-7.

In one embodiment the extractant is an ion-exchange resin. These resins are typically small granular or bead-like materials having of two principal parts: a resinous matrix serving as a structural portion, and an ion-active group serving as the functional portion. The functional group is generally selected from those functional groups that are reactive with copper ions. Examples of such functional groups include-SO3,-COO-, Useful resin matrixes include the copolymers of styrene and divinylbenzene.

Examples of commercially available resins that can be used include IRC-718 (a

product of Rohm & Haas identified as a tertiary amine substituted copolymer of styrene and divinylbenzene), IR-200 (a product of Rohm & Haas identified as sulfonated copolymer of styrene and divinylbenzene), IR-120 (a product of Rohm & Haas identified as sulfonated copolymer of styrene and divinylbenzene), XFS 4196 (a product of Dow identified as a macroporous polystyrene/divinylbenzene copolymer to which has been attached N- (2-hydroxyethyl)-picolylamine), and XFS 43084 (a product of Dow identified as a macroporous polystyrene/divinylbenzene copolymer to which has been attached N- (2-hydroxypropyl)-picolylamine). These resins are typically used in the inventive process as fixed beds or moving beds.

During step (B) of the inventive process, the resin is contacted with the copper-rich aqueous leach solution from step (A), the contacting being sufficient to transfer copper ions from the leach solution to the resin. The copper-rich resin is then stripped during step (C) to provide a copper-stripped or copper-depleted resin which can be re-used during (B).

The copper-rich extractant that is formed during step (B) has a concentration of copper in the range of about 1 to about 6 grams per liter of extractant, and in one embodiment about 2 to about 4 grams per liter of extractant. A copper-depleted aqueous leaching solution is formed during step (B). This solution typically has a copper ion concentration in the range of about 0.01 to about 0.8 grams per liter, and in one embodiment about 0.04 to about 0.2 grams per liter. When the leaching solution used in step (A) is a sulfuric acid solution, the concentration of free sulfuric acid in the copper-depleted aqueous leaching solution formed during step (B) is generally from about 5 to about 50 grams per liter, and in one embodiment about 5 to about 40 grams per liter, and in one embodiment about 10 to about 30 grams per liter. When the leaching solution used in step (A) is an ammonia solution, the concentration of free ammonia in the copper-depleted aqueous leaching solution formed during step (B) is generally from about 10 to about 130 grams per liter, and in one embodiment about 30 to about 90 grams per liter.

The stripping solution used in step (C) of the inventive process is a sulfuric acid solution which has a free sulfuric acid concentration generally in the range of about 80 to about 300 grams per liter. In one embodiment, the free sulfuric acid

concentration of the stripping solution used in (C) is about 100 to about 200 grams per liter, and in one embodiment about 130 to about 170 grams per liter.

The electrodeposition step (D) involves advancing the copper-rich stripping solution from step (C) into an electroforming cell and electrodepositing copper on the cathodes in the cell. The copper-rich stripping solution treated in the electroforming cell can be referred to as either a copper-rich stripping solution or an electrolyte solution. In one embodiment, this electrolyte solution is subjected to a purification or filtering process prior to entering the cell. The copper metal that is electrodeposited is in the form of circular disks of copper, or square or rectangular copper plates. These circular disks or copper plates can be referred to as copper cathodes or cathodic copper.

The circular disk of copper or copper plate typically has a copper content of at least about 99% by weight, and in one embodiment at least about 99.9% by weight, and in one embodiment at least about 99.95% by weight, and in one embodiment at least about 99.98% by weight, and in one embodiment at least about 99.99% by weight, and in one embodiment at least about 99.999% by weight. The density of the circular disk copper plate is typically in the range of up to about 8.96 grams per cube centimeter (g/cc), and in one embodiment about 8.5 to about 8.96 g/cc, and in one embodiment about 8.7 to about 8.96 g/cc, and in one embodiment about 8.9 to about 8.96 g/cc, and in one embodiment about 8.92 to about 8.96 g/cc, and in one embodiment about 8.94 to about 8.96 g/cc.

The electroforming cell used to form the circular disk of copper or copper plate is typically equipped with a series of cathodes and anodes. The cathodes are usually vertically mounted and have flat surfaces. The cathodes can be circular in the form, or they can have square or rectangular shapes. The anodes are adjacent to the cathodes and are typically in the form of flat plates having the same shape as the cathodes. The gap between the cathodes and the anodes is typically from about 1 to about 10 centimeters, and in one embodiment about 2.5 to about 5 centimeters. In one embodiment, the anode is insoluble and made of lead, lead alloy, or titanium coated with a platinum family metal (i. e., Pt, Pd, Ir, Ru) or oxide thereof. The cathode has smooth surfaces on each side for receiving the electro-

deposited copper and, in one embodiment, the surface is made of stainless steel, chrome plated stainless steel or titanium.

The copper-rich stripping solution or electrolyte solution flows in the gaps between the anodes and cathodes, and an electric current is used to apply an effective amount of voltage across the anodes and the cathodes to deposit copper on the cathodes. The electric current can be a direct current or an alternating current with a direct current bias. The flow rate of the electrolyte solution through the gap between the anodes and the cathode is generally in the range of about 5 to about 60 gallons per minute (gpm), and in one embodiment about 20 to about 50 gpm, and in one embodiment about 30 to about 40 gpm.

The chemistry of the stripping solution or electrolyte solution is critical to obtaining the desired copper wire that is reducible in tensile testing to greater than 98% RIA. The electrolyte solution has a free sulfuric acid concentration in the range of about 120 to about 200 grams per liter, and in one embodiment about 140 to about 180 grams per liter, and in one embodiment about 150 to about 170 grams per liter. The temperature of the electrolyte solution in the electroforming cell is in <BR> the range of about 15°C to about 60°C, and in one embodiment about 30°C to about 50°C. The copper ion concentration is in the range of about 30 to about 70 grams per liter, and in one embodiment 35 to about 65 grams per liter, and in one embodiment about 40 to about 60 grams per liter, and in one embodiment about 50 to about 55 grams per liter. The free chloride ion concentration is in the range of about 10 to about 50 ppm, and in one embodiment about 10 ppm to about 35 ppm, and in one embodiment about 15 to about 30 ppm.

The metallic impurity level is at a level of no more than about 50 grams per liter, and in one embodiment no more than about 20 grams per liter, and in one embodiment no more than about 10 grams per liter, and in one embodiment from about 10 ppm to about 5 grams per liter, and in one embodiment from about 10 ppm to about 2 grams per liter.

The current density is critical and is in the range of about 10 to about 40 amps per square foot (ASF), and in one embodiment about 15 to about 25 ASF.

During electrodeposition it is critical that the the electrolyte solution has an organic additive concentration in the range of about 2 to about 20 ppm, and in one embodiment about 2.5 to about 15 ppm, and in one embodiment about 2.5 to about 10, and in one embodiment about 2.5 to about 5 ppm. The organic additive can be an active sulfur-containing material. The term"active-sulfur containing material" refers to materials characterized generally as containing a bivalent sulfur atom, both bonds of which are directly connected to a carbon atom together with one or more nitrogen atoms also directly connected to the carbon atom. In this group of compounds, the double bond may in some cases exist or alternate between the sulfur or nitrogen atom and the carbon atom. Thiourea is a useful active sulfur-con- taining material. The thioureas having the nucleus NH- / S=C \ NH- and the iso-thiocyanates having the grouping S=C=N-are useful. Thiosinamine (allyl thiourea) and thiosemicarbazide are also useful. The active sulfur-containing material should be soluble in the electrolyte solution and be compatible with the other constituents.

The organic additive can be a gelatin. The gelatins that are useful herein are heterogeneous mixtures of water-soluble proteins derived from collage. Animal glue is a preferred gelatin because it is relatively inexpensive, commercially available and convenient to handle.

The organic additive can be any of the organic additives known in the art for controlling the properties of electrodeposited copper. Examples include saccharin, caffeine, molasses, guar gum, gum arabic, the polyalkylene glycols (e. g., polyethylene glycol, polypropylene glycol, polyisopropylene glycol, etc.), dithio- threitol, amino acids (e. g., proline, hydroxyproline, cysteine, etc.), acrylamide, sulfopropyl disulfide, tetraethylthiuram disulfide, benzyl chloride, epichlorohydrin, chlorohydroxylpropyl sulfonate, alkylene oxides (e. g., ethylene oxide, propylene

oxide, etc.), the sulfonium alkane sulfonates, thiocarbamoyldisulfide, selenic acid, or a mixture of two or more thereof.

While not wishing to be bound by theory, it is believed that the interaction of the chloride ions and the organic additives at the concentrations specified above is critical to obtaining the desired wire that is reducible in tensile testing to greater than 98% RIA.

The process will now be described with reference to Fig. 1, which is a flow sheet illustrating a solvent-extraction, electrodeposition process for making the circular disks of copper or copper plates required by the inventive process. In this process copper is extracted from copper leach dump 100 and treated in accordance with steps (A) to (D) of the inventive process to produce the copper disks or plates 102. The process involves the use of setters 104,106 and 108, collection pond 110, mixers 112,114 and 116, dissolution vessel 118, electroforming cell 120, and filters 122,124 and 126. Step (A) of the inventive process is conducted at the leach dump 100. Step (B) is conducted in two stages using mixers 112 and 114, and settlers 104 and 106. Step (C) is conducted using mixer 116 and settler 108. Step (D) is conducted using electroforming cell 120.

An aqueous leach solution from line 130 is sprayed on the surface of leach dump 100. The leach solution is a sulfuric acid solution having a free sulfuric acid concentration generally in the range of about 5 to about 50, and in one embodiment about 5 to about 40, and in one embodiment about 10 to about 30 grams per liter.

The leach solution percolates down through the dump and extracts copper ions from the ore. The leach solution flows through dump space 132 as a copper-rich aqueous leach solution (sometimes referred to as a pregnant leach solution), and through line 138 into collection pond 110. The leach solution is pumped from collection pond 110 through line 136 to mixer 114. The copper-rich leach solution that is pumped to mixer 114 has a copper ion concentration generally in the range of about 0.8 to about 5, and in one embodiment about 1 to about 3 grams per liter; and a free sulfuric acid concentration generally in the range of about 5 to about 30, and in one embodiment about 10 to about 20 grams per liter. In mixer 114, the copper-rich aqueous leach solution is mixed with a copper-bearing organic solution

which is pumped into mixer 114 through line 138 from weir 140 of settler 106. The concentration of copper in the copper-bearing organic solution that is added to mixer 114 is generally from about 0.4 to about 4 grams per liter of extractant in the organic solution, and in one embodiment about 1 to about 2.4 grams per liter of extractant in the organic solution. During the mixing in mixer 114, an organic phase and an aqueous phase form and intermix. Copper ions transfer from the aqueous phase to the organic phase. The mixture is pumped from mixer 114 through line 142 to settler 104. In settler 104, the aqueous phase and organic phase separate with the organic phase forming the top layer and the aqueous phase forming the bottom layer. The organic phase collects in weir 144 and is pumped through line 146 to mixer 116. This organic phase is a copper-rich organic solution (which can be referred to as a loaded organic). This copper-rich organic solution generally has a copper concentration in the range of about 1 to about 6 grams per liter of extractant in the organic solution, and in one embodiment about 2 to about 4 grams per liter of extractant in the organic solution.

The copper-rich organic solution is mixed in mixer 116 with a copper-depleted stripping solution. The copper-depleted stripping solution (which can be referred to as a lean electrolyte) is produced in the electroforming cell 120 and is pumped from the cell 120 through line 148 to mixer 116. This copper-depleted stripping solution generally has a free sulfuric acid concentration in the range of about 120 to about 220, and in one embodiment about 150 to about _190 grams per liter; and a copper ion concentration in the range of generally about 10 to about 100, and in one embodiment about 20 to about 60, and in one embodiment about 35 to about 45 grams per liter. Fresh stripping solution make-up can be added to line 148 through line 150. The copper-rich organic solution and copper-depleted stripping solution are mixed in mixer 116 with the result being the formation of an organic phase intermixed with an aqueous phase. Copper ions transfer from the organic phase to the aqueous phase. The mixture is pumped from mixer 116 through line 152 to settler 108. In settler 108, the organic phase separates from the aqueous phase with the organic phase collecting in weir 154. This organic phase is a copper- depleted organic solution (which is sometimes referred to as a barren organic). This

copper-depleted organic solution generally has a copper concentration in the range of about 0.5 to about 2 grams per liter of extractant in the organic solution, and in one embodiment about 0.9 to about 1.5 grams per liter of extractant in the organic solution. The copper depleted organic solution is pumped from settler 108 through line 156 to mixer 112. Fresh organic solution make-up can be added to line 156 through line 158.

Copper-containing aqueous leach solution is pumped from settler 104 through line 160 to mixer 112. This copper-containing aqueous leach solution has a copper ion concentration generally in the range of about 0.4 to about 4, and in one embodiment about 0.5 to about 2.4 grams per liter; and a free sulfuric acid concentration generally in the range of about 5 to about 50, and in one embodiment about 5 to about 30, and in one embodiment about 10 to about 20 grams per liter.

In mixer 112, an organic phase and aqueous phase form, intermix and copper ions transfer from the aqueous phase to the organic phase. The mixture is pumped through line 162 to settler 106. In setter 106, the organic phase separates from the aqueous phase with the organic phase collecting in weir 140. This organic phase, which is a copper-containing organic solution, is pumped from settler 106 through line 138 to mixer 114. This copper-containing organic solution has a copper concentration generally in the range of about 0.5 to about 4 grams per liter of extractant in the organic solution, and in one embodiment about 1 to about 2.4 grams per liter of extractant in the organic solution. The aqueous phase in settler 106 is a copper-depleted aqueous leaching solution which is pumped through line 130, to the leach dump 100. Fresh leaching solution make-up can be added to line 130 from line 164.

The aqueous phase which separates out in settler 108 is a copper-rich stripping solution. It is pumped from settler 108 through line 170 to filter 126 and from filter 126 through line 172 and then either: through line 174 to electroforming cell 120; or through line 176 to filter 124 and from filter 124 through line 178 to dissolution vessel 118. Filter 126 can be by-passed through line 180. Similarly, filter 124 can be by-passed through line 182. This copper-rich stripping solution has a copper ion concentration generally in the range of about 20 to about 120 grams

per liter, and in one embodiment about 30 to about 70 grams per liter; and a free sulfuric acid concentration generally in the range of about 110 to about 200, and in one embodiment about 140 to about 180 grams per liter. The copper-rich stripping solution entering electroforming cell 120 or dissolution vessel 118 can also be referred to as electrolyte solution 190. If the composition of the electrolyte solution requires adjustment (e. g., addition of organic additives, increase in copper ion concentration, increase in sulfuric acid concentration, increase in chloride ion concentration, etc.) the electrolyte solution is advanced to dissolution vessel 118 prior to being advanced to electroforming cell 120. If no adjustment in the composition of the electrolyte solution is required, the electrolyte solution is advanced directly to electroforming cell 120 through line 174. In electroforming cell 120, the electrolyte solution 190 flows between anodes 192 and cathodes 194.

When voltage is applied between the anodes 192 and cathodes 194, electrode- position of copper occurs at the cathode surface resulting in the formation of electrodeposited copper plates 102 on each side of each of the cathodes 194.

The electrolyte solution 194 is converted to a copper-depleted electrolyte solution in electroforming cell 120 and is withdrawn from cell 120 through either lines 196 or 148. The copper-depleted electrolyte solution in either line 196 or line 148 has a copper ion concentration generally in the range of about 10 to about 100 grams per liter, and in one embodiment about 20 to about 60 grams per liter, and in one embodiment about 35 to about 45 grams per liter; and a free sulfuric acid concentration generally in the range of about 120 to about 220 grams per liter, and in one embodiment about 150 to about 190 grams per liter. This copper-depleted electrolyte solution is either: (1) pumped through lines 196 and 176 to filter 124 (which optionally can be by-passed through line 182) and from filter 124 (or line 182) to line 178, through line 178 to dissolution vessel 118, and from vessel 118 through line 198 to filter 122, through filter 122 (which can be by-passed through line 202) to line 200 and back to cell 120; or (2) pumped through line 148 to mixer 116 as the copper-depleted stripping solution. Optionally, additional copper feedstock as indicated by directional arrow 204, sulfuric acid, as indicated by directional arrow 206, are added to the electrolyte solution in vessel 118 to adjust the composition of

the electrolyte solution where necessary. Organic additives of the type discussed above can be added to the electrolyte solution in vessel 118, electroforming cell 120 or in line 200 as indicated by directional arrow 209. Chloride ions can be added to the electrolyte solution as indicated by directional arrow 207, if such chloride ions are needed to maintain the desired critical concentration of such chloride ions in the electrolyte solution. Chloride ions can also be removed using either or both of filters 122 and 124 in order to maintain the desired concentration of such chloride ions in the electrolyte solution. Also, impurities may be removed from the electrolyte solution 190 using either or both of filters 122 and 124 when necessary.

The additional copper feedstock entering vessel 118, as indicated by directional arrow 204, can be in any conventional form which includes copper shot, scrap copper metal, scrap copper wire, recycled copper, cupric oxide, cuprous oxide, and the like. Additional sulfuric acid enters vessel 118 as indicated by directional arrow 206. Chloride ions can be added in any convenient form (e. g., HCI, NaCI, KCI, NH4CI, etc.). Electrolyte solution 190 recycle from electroforming cell 120 also enters vessel 118 through line 178. The temperature of the electrolyte solution 190 in vessel 118 is typically in the range of about 25 °C to about 55 °C, and in one embodiment about 30°C to about 50°C, and in one embodiment about 32°C to about 43°C. The electrolyte solution 190 is advanced from vessel 118 to electroforming cell 120 through lines 198 and 200. The electrolyte solution 190 may be filtered in filter 122 prior to entering electroforming cell 120 or, alternatively, it may pass through line 202 enroute to electroforming cell 120 and thereby by-pass filter 122.

The electrolyte solution 190 advanced from vessel 118 to electroforming cell 120 has a free sulfuric acid concentration in the range of about 120 to about 200 grams per liter, and in one embodiment about 140 to about 180 grams per liter, and in one embodiment about 150 to about 170 grams per liter. The copper ion concentration is in the range of about 30 to about 70 grams per liter, and in one embodiment about 35 to about 65 grams per liter, and in one embodiment about 40 to about 60 grams per liter, and in one embodiment about 50 to about 55 grams per liter. The free chloride ion concentration is in the range of about 10 ppm to about

50 ppm, and in one embodiment about 10 ppm to about 35 ppm, and in one embodiment about 15 ppm to about 30 ppm. The organic additive concentration is in the range of about 2 ppm to about 20 ppm, and in one embodiment about 2.5 to about 15 ppm, and in one embodiment about 2.5 to about 10 ppm, and in one embodiment about 2.5 to about 5 ppm. The impurity level is at a level of no more than about 50 grams per liter, and in one embodiment no more than about 20 grams per liter, and in one embodiment no more than about 10 grams per liter, and in one embodiment from about 10 ppm to about 5 grams per liter, and in one embodiment from about 10 ppm to about 2 grams per liter. The temperature of the electrolyte solution in the electroforming cell 120 is in the range of about 15°C to about 60°C, and in one embodiment about 30°C to about 50°C.

The electrolyte solution 190 flows between the anodes 192 and cathodes 194 at a rate in the range of about 5 to about 60 gpm, and in one embodiment about 20 to about 50 gpm, and in one embodiment about 30 to about 40 gpm. A voltage is applied between anodes 192 and cathodes 194 to effect electrodeposition of the copper metal on the cathodes. In one embodiment, the current that is used is a direct current, and in one embodiment it is an alternating currentwith a direct current bias. The current density is in the range of about 10 to about 40 ASF, and in one embodiment about 15 to about 25 ASF. Copper ions in electrolyte 190 gain electrons at the surface of cathodes 194 whereby copper metal plates out in the form of copper plates 102 on each side of each of the cathodes 194. Electro- deposition of copper metal on cathodes 194 is continued until the thickness of the copper plates 102 is at a desired level which may be, for example, about 0.1 to about 1 inch, and in one embodiment about 0.1 to about 0.5 inch, and in one embodiment about 0.2 to about 0.3 inch. Electrodeposition is then discontinued.

The cathodes 194 are removed from the electroforming cell 120. The copper plates 102 are stripped from the cathodes 194, and then washed and dried. The copper plates 102 are typically in the form of squares or rectangles. However, the copper plates 102 can be in the form of circular disks.

The electrodeposition process depletes the electrolyte solution 190 of copper ions, chloride ions and organic additives. These ingredients can be replenished by

recirculating the electrolyte solution and adding these ingredients to the recirculated electrolyte solution as discussed above. Electrolyte solution 190 is recirculated by withdrawing it from electroforming cell 120 through line 196 and advancing it through line 176 to and through filter 124, line 178, dissolution vessel 190, line 198 and filter 122, and then reintroducing it into electroforming cell 120 through line 200. Filter 124 may be by-passed through line 182. Similarly, filter 122 may be by-passed through line 202.

Example 1 Copper plates 102 having the dimensions of 24 x 24 x 1/4 inches are prepared using the process illustrated in Fig. 1. The aqueous leaching solution sprayed on leach dump 100 from line 130 is a sulfuric acid solution having a sulfuric acid concentration of 20 grams per liter. The copper-rich aqueous leach solution that is pumped to mixer 114 through line 136 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 7% by weight solution of LIX 984 in SX-7. The concentration of copper in the copper-bearing organic solution that is added to mixer 114 from settler 106 has a copper concentration of 1.95 grams per liter. The copper-rich organic solution that is pumped to mixer 116 from settler 104 has a copper concentration of 3 grams per liter of LIX 984. The copper-depleted stripping solution added to mixer 116 from line 148 has a free sulfuric acid concentration of 168 grams per liter and a copper ion concentration of 40 grams per liter. The copper-depleted organic solution that is pumped from settler 108 to mixer 112 has a copper concentration of 1.25 grams per liter of LIX 984. The copper-containing aqueous leach solution pumped from settler 104 to mixer 112 has a copper ion concentration of 0.8 grams per liter and a free sulfuric acid concentration of 12 grams per liter.

The copper-depleted aqueous solution pumped from settler 106 through line 130 has a copper concentration of 0.15 grams per liter and a free sulfuric acid concentration of 12 grams per liter. The copper-rich stripping solution taken from settler 108 has a copper ion concentration of 52 grams per liter and a free sulfuric acid concentration of 158 grams per liter. 140 gallons of this copper-rich stripping solution are recirculated through a mixer/settler at a rate of 2 gallons per minute

(gpm). A fresh stream of copper-rich organic solution having a copper concentration of 3 grams per liter of LIX 984 in the solution is added to the mixer, also at a rate of 2 gpm. Sulfuric acid is added as needed to ensure acceptable stripping kinetics.

The temperature of the copper-rich stripping solution is maintained at or above 37.8°C to prevent crystallization of copper sulfate. The final electrolyte solution produced from this procedure has a copper ion concentration of 50-52 grams per liter and a free sulfuric acid concentration of 161 grams per liter. This electrolyte solution has guar gum concentration of 3 ppm, a free chloride ion concentration of 16-28 ppm, an iron concentration of 1.2-1.8 grams per liter, a cobalt concentration of 27 ppm, and a temperature of 40°C. This electrolyte solution is advanced to electroforming cell 120. Electrodeposition is conducted in cell 120 using a current density of 21 ASF until the copper plates 102 are formed.

Metal Working The copper plates 102 are either electrodeposited directly in the form of a circular disk, or they are electrodeposited in the form of square or rectangular plates of copper which are subsequently cut using known techniques (e. g., stamping, punching, machining, etc.) to form a circular disk. The circular disk is then subjected to the steps of rotating the disk about its center axis, feeding a cutting tool into the peripheral edge of the circular disk to peel a continuous strip of copper from the disk as the cutting tool moves towards the center of the disk, slitting the strip of copper to form a plurality of strands of copper wire, and shaping the strands of copper wire to provide such strands with desired cross sectional shapes and sizes.

The peeling step of this process, which includes rotating the circular disk about its center axis and feeding a cutting tool into the peripheral edge of the disk to cause a strip of copper to peel from the disk, is sometimes referred to in the art by the term"skiving." The circular disk typically has a thickness of about 0.1 to about 1 inch, and in one embodiment about 0.1 to about 0.5 inch, and in one embodiment about 0.2 to about 0.3 inch; and a diameter of up to about 60 inches, and in one

embodiment about 4 to about 60 inches, and in one embodiment about 10 to about 40 inches, and in one embodiment about 24 to about 40 inches.

When a square or rectangular plate is initially electrodeposited and then subsequently cut or shaped using known techniques (e. g., stamping, punching, machining, etc.) to form the circular disk, the plate typically has a thickness in the range of about 0.1 to about 1 inch, and in one embodiment about 0.1 to about 0.5 inch, and in one embodiment about 0.2 to about 0.3 inch; a length in the range of about 12 to about 60 inches, and in one embodiment about 24 to about 40 inches; and a width in the range of about 12 to about 60 inches, and in one embodiment about 24 to about 40 inches.

Referring to Figs. 2 and 3, the square or rectangular copper plate 102 is, in one embodiment, cut using standard techniques to form circular disk 300. The circular disk 300 has a peripheral edge 302 and a center hole 304. The circular disk 300 has one side that is smooth or shiny and an opposite side which has a rough or matte surface. The smooth or shiny side is the side that was in contact with the surface of the cathode during electrodeposition. In one embodiment, the rough or matte surface of the circular disk 300 (or the square or rectangular plate 102) is machined to form a smooth or shiny surface prior to the peeling step. However, in one embodiment, this machining step is eliminated. In fact, an advantage of this invention is that it is not necessary to smooth out the rough or matte surface of the circular disk 300 prior to peeling. The peeling or skiving step of the inventive process may be best understood with reference to Figs. 4-6. Referring to Fig. 4, the apparatus used for the peeling step includes a disk support apparatus (not shown) for supporting circular disk 300. The disk support apparatus can be of any conventional design that permits the rotation of disk 300 and the penetration of cutting tool 306 into the peripheral edge 302 of disk 300. For example, the disk support apparatus may include a horizontal aligned ball transfer unit. The disk support apparatus includes a spindle 308 that projects upwardly from the support apparatus through center hole 304. Disk 300 is secured to spindle 308. During the peeling step, circular disk 300 rotates counterclockwise in a horizontal plane on the disk support apparatus. Cutting tool 306 is mounted on sliding block 309. Sliding

block 309 is mounted on slide 310 and is adapted for horizontal movement along slide 310 in the radial direction relative to disk 300 (up and down as depicted in Fig.

4). Slide 310 has a horizontal surface positioned below and parallel to circular disk 300. During the peeling step, sliding block 309 is driven horizontally along slide 310 from the outer edge of disk 300 toward the center of disk 300 by a cutting tool feed motor (not shown). The movement of sliding block 309 causes tool 306 to penetrate the peripheral edge 302 of circular disk 300 and peel copper strip 312 from edge 302 as the disk 300 rotates. During this peeling step the cutting tool 306 moves toward the center of disk 300 as successive layers of copper strip are removed from disk 300, the removal of the successive layers resulting in the formation of continuous strip 312. Disk 300 is rotated by spindle motor 314. Spindle motor 314 drives drive chain 316 which is connected to spindle drive 318. Spindle drive 318 is part of spindle 308 and the rotation of spindle drive 318 results in the rotation of spindle 308 and disk 300. Copper strip 312 is peeled from the peripheral edge 302 of disk 300 and advanced along rolls 320,322 and 324 to take-up reel 326. Roll 320 is mounted on sliding block 309. Roll 322 is mounted on slide 310. Take up reel 326 is rotated by take up motor 328. Take-up motor 328 is connected to take- up reel 326 through drive chain 330 and take up drive 332. The rotation of take-up reel 326 results in the winding of copper strip 312 around take-up reel 326, and provides a desired tension (e. g., about 1 to about 20 pounds of force, and in one embodiment about 1 to about 8 pounds of force, and in one embodiment about 1 to about 2 pounds of force) in copper strip 312 as it is peeled from circular disk 300.

Cutting tool 306 is illustrated in greater detail in Fig. 5. Cutting tool 306 is mounted on tool holder 340 and secured in fixed position between clamps 342 and 344. Clamp 342 forms a part of tool holder 340 and projects vertically upwardly from holder 340. Clamp 344 is secured to clamp 342 by bolt 346. Tool holder 340 is mounted on sliding block 309 and secured thereto by bolt 348. Cutting tool 306 has a sharpened edge 350, rake face 352 and a clearance face 354. The sharpened edge 350 has an included angle A of about 40° to about 60° and in one embodiment about 40° to about 47°, and in one embodiment about 45° to about 47°, formed at the intersection of the rake face 352 and clearance face 354. In one

embodiment, the finish on both the rake face 352 and the clearance face 354 is an 8-12 RMS finish. The sharpened edge preferably has no imperfections greater than about 16 microns. Cutting tool 306 is a carbide tool which can have a grade of K68, K91, K910 or VR Wesson 660. In one embodiment, the composition of cutting tool 306 comprises tungsten carbide. In one embodiment, the cutting tool 306 has a composition comprising about 60% by weight tungsten carbide, about 12% by weight cobalt, and about 28% by weight tantalum carbide.

The penetration of cutting tool 306 into circular disk 300 is illustrated in Fig. 6. Tool 306 is positioned so that the clearance face 354 is at an angle C of about 2° to about 4°, and in one embodiment about 2° to about 3°, from the tangent of the disk surface 360. During a peeling run, the disk 300 rotates in the direction indicated by arrow 364 and the copper strip 312 is peeled from the disk.

During the threading stage of a peeling run, the speed of the disk surface (i. e., peripheral edge 302) is about 1 to about 50 feet per minute, and in one embodiment about 10 to about 30 feet per minute. The run speed is about 5 to about 5000 feet per minute, and in one embodiment about 100 to about 2000 feet per minute, and in one embodiment about 200 to about 1000 feet per minute, and in one embodiment about 400 to about 600 feet per minute, and in one embodiment about 500 feet per minute. The angle D between the rake face 352 and the copper strip 312 is typically up to about 5°, and in one embodiment about 0.5° to about 5°, as the copper strip is peeled off.

During the peeling step, a coolant or lubricant can optionally be used to cool and/or lubricate the cutting tool 306. Any coolant or lubricant known for use in the peeling of copper can be used.

The copper strip 312 typically has a thickness of about 0.002 to about 0.5 inch, and in one embodiment about 0.002 to about 0.25 inch, and in one embodiment about 0.002 to about 0.1 inch, and in one embodiment about 0.002 to about 0.05 inch, and in one embodiment about 0.006 to about 0.02 inch. The copper strip 312 typically has a width of 0.1 to about 1 inch, and in one embodiment about 0.1 to about 0.5 inch, and in one embodiment about 0.2 to about 0.3 inch. In one embodiment, the copper strip 312 has a width of about 0.25 inch, and a

thickness of about 0. 008 to about 0.012 inch. The length of the copper strip 312 is typically in the range of about 100 to about 40,000 feet, and in one embodiment about 100 to about 20,000 feet, and in one embodiment about 100 to about 10,000 feet, and in one embodiment about 500 to about 5000 feet, and in one embodiment about 900 to about 3000 feet.

A modified design of the cutting tool 306 is illustrated in Fig. 7. The modified cutting tool 306A illustrated in Fig. 7 is identical to the cutting tool 306 illustrated in Figs. 4-6 with the exception that the tool 306A has a relief face 355 extending from rake face 352 away from sharpened edge 350 at an angle B to rake face 352. Angle B is up to about 5°, and in one embodiment is in the range of about 1° to about 5°. The length of the rake face 352, which extends from sharpened edge 352 to edge 353, is about 0.002 to about 0.01 inch, and in one embodiment about 0.005 inch.

The slitting step of the inventive process is best illustrated with reference to Figs. 8-10. In this step of the process, the copper strip 312 that is peeled from the circular disk 300 is slit to form a plurality of strands of wire having square or rectangular cross sections. In the illustrated embodiment depicted in Figs.

8-10, the copper strip 312 is slit using slitter 380 to form product wire strands 402, 404,406,408 and 410. Scrap wire strands 400 and 412 are also formed. The sequence of this process step involves unwinding the copper strip 312 from reel 326, advancing it through accumulator 370 to tension sheave 372, and around tension sheave 372 to slitter 380. Accumulator 370 includes fixed sheave 374 and dancer sheave 376 which are provided for maintaining tension in copper strip 312 as it is advanced to slitter 380. In slitter 380, the copper strip 312 is slit to form wire strands 402,404,406,408 and 410, and these wire strands are advanced from slitter 380 to product spools 382,384,386,388 and 390, respectively. Scrap wire strands 400 and 412 are also formed in slitter 380, and these strands are advanced to spools 392 and 394, respectively. The scrap wire strands 400 and 412 may be recycled to dissolution vessel 100. The product wire strands 402,404,406,408 and 410 have square or rectangular cross sections, each of the strands having, in one embodiment, widths of about 0.008 to about 0.02 inch, and in one embodiment

about 0.008 to about 0.012 inch; and thicknesses (or heights) of about 0.002 to about 0.2 inch, and in one embodiment about 0.002 to about 0.1 inch, and in one embodiment about 0.006 to about 0.01 inch. In one embodiment, each of the product wire strands has a rectangular cross section, the width being about 0.012 inch and the thickness (or height) being about 0.008 inch. In one embodiment, each of the product wire strands has square or substantially square cross-sections that is from about 0.005 x 0.005 inch to about 0.050 x 0.050 inch, or about 0.010 x 0.010 inch to about 0.030 x 0.030 inch, or about 0.020 x 0.020 inch.

As indicated above, one advantage of the inventive process is that the circular disk 300 does not have to be smoothed or machined prior to the peeling and slitting steps of the inventive process. This is due to the fact that the slitting step takes into account for any irregularities on the edges of the copper strip 312 by providing for the production of the scrap wire strands 400 and 412.

In slitter 380, the copper strip 312 is slit using a cutting blade assembly which is schematically illustrated in Fig. 10 and identified generally by the reference numeral 420. The cutting blade assembly 420 includes edge spacers 422,424,426 and 428, cutting blades 430,432,434,436 and 438, and spacers 440,442,444, 446 and 448. The cutting blades and spacers can be constructed of any tool steel suitable for cutting copper foil. An example of such a tool steel is M2. The thicknesses (or widths) of the cutting blades 430,432,434,436 and 438 are typically in the range of about 0.002 to about 0.2 inch, and in one embodiment about 0.008 to about 0.014 inch, and in one embodiment about 0.0105 inch. The thicknesses (or widths) of the spacers 440,442,444,446 and 448 are typically in the range of about 0.002 to about 0.2 inch, and in one embodiment about 0.008 to about 0.014 inch, and in one embodiment about 0.011 inch. The thickness (or width) of the edge spacers 422,424,426 and 428 can range from about 0.1 to about 0.5 inch, and in one embodiment about 0.2 to about 0.4 inch, and in one embodiment each of their thicknesses are about 0.3745 inch. The diameters of the edge spacers and the cutting blades can range from about 2 to about 6 inches, and in one embodiment about 3 to about 5 inches. The diameters of the spacers 440, 442,444,446 and 448 can range from about 2 to about 6 inches, and in one

embodiment about 3 to about 5 inches. The cutting blade assembly 420 may include additional cutting blades and spacers which are not shown in the drawings but would be readily apparent to those skilled in the art.

In one embodiment, a metal working lubricant is applied to the surface of copper strip 312 as it is advanced through the slitter 380. The lubricant may be any known metal working lubricant that is used for cutting or slitting copper. An example is Die Magic, which is a product of Diversified Technology Incorporated.

As indicated above, the copper strip 312 is slit in slitter 380 to form product wire strands 402,404,406,408 and 410 as well as scrap wire strands 400 and 412. All of these wire strands are advanced from slitter 380 over wire guides (or rollers) 480 and 482 to guide 484, and then under guide 484 to guide 486. Wire strand 402 is advanced over guide 486, around guide 488 to product spool 382.

Guide 484 is equipped with a load sensor which senses the tension in the wire strands in contact with it and this information is used to control the rotation of spool 382 and thereby control the tension in wire strand 402. The remaining wire strands are advanced to guide 490, and then under guide 490 to guide 492. Wire strand 404 is advanced from guide 492 to spool 384. Guide 490 is equipped with a load sensor which senses the tension in the wire strands in contact with it and provides a signal for controlling the rotation of spool 384 and the tension in wire strand 404.

The remaining wire strands are advanced from guide 492 to guide 494, and then under guide 494 to guide 496. Wire strand 406 is advanced from guide 496 around guide 498 to spool 386. Guide 494 is equipped with a load sensor which senses the tension in the wire strands in contact with it and provides a signal to control the rotation of spool 386 and thereby control the tension in wire strand 406. The remaining wire strands are advanced from guide 496 to guide 500, and then under guide 500 to guide 502. Wire strand 408 is advanced from guide 502 to spool 388.

Guide 500 is equipped with a load sensor which provides a signal to control the rotation of spool 388 and thereby control the tension in wire strand 408. The remaining wire strands are advanced from guide 502 to guide 504, and then under guide 504 to guide 506. Wire strand 410 is advanced from guide 506 around guide 508 to spool 390. Guide 504 is equipped with a load sensor which senses the

tension in the wire strands in contact with it and provides a signal to control the rotation of spool 390 and thereby control the tension in wire strand 410. The remaining wire strands are advanced from guide 506 to guide 510, and then under guide 510 to guide 512. Wire strand 400 is advanced from guide 512 to guide 514, and then around guide 514 to spool 392. Guide 510 is equipped with a load sensor that provides a signal to control the rotation of spool 392 and thereby control the tension in wire strand 400. Wire strand 412 is advanced from guide 512 to guide 516, under guide 516 to guide 518, over guide 518 to guide 520, and under guide 520 to spool 394. Guide 516 is equipped with a load sensor that senses the tension in wire strand 412 and provides a signal to control the rotation of spool 394 and thereby control the tension in wire strand 412.

It will be apparent to those skilled in the art that although the slitter assembly disclosed in Figs. 8 and 10 provides for the production of five product wire strands and two scrap wire strands, additional productwire strands can be produced by providing additional cutting blades in the cutting blade assembly 420. Similarly, the width of the product wire strands that are produced can be varied by varying the size of the spacers used in the cutting blade assembly 420. Also, the lengths of the product wire strands produced by this assembly can be varied by varying the length of the copper strip 312 that is used with this slitting step. The product wire strands that are produced can be welded to other similarly produced wire strands using known techniques (e. g., buttwelding) to produce wire strands having longer lengths.

Generally, the copper wire made in accordance with the invention can have any cross-sectional shape that is conventionally available. These include round cross sections, squares, rectangles, trapazoids, polygons, ovals, etc. The edges on these shapes can be sharp or rounded. These wires can be made using one or a series or combination of Turks heads mills, and/or drawing dies to provide the desired shape and size. They can have cross sectional diameters or major dimensions in the range of about 0.0002 to about 0.25 inch, and in one embodiment about 0.002 to about 0.1 inch, and in one embodiment about 0.004 to about 0.05 inch, and in one embodiment about 0.006 to about 0.012 inch, and in one embodiment about 0.008 to about 0.012 inch.

In one embodiment, the strands of copper wire are rolled using one or a series of Turks heads shaping mills wherein in each shaping mill the strands are pulled through two pairs of opposed rigidly-mounted forming rolls. In one embodiment, these rolls are grooved to produce shapes (e. g., rectangles, squares, etc.) with rounded edges. Powered Turks head mills wherein the rolls are driven can be used. The Turks head mill speed can be about 100 to about 5000 feet per minute, and in one embodiment about 300 to about 1500 feet per minute, and in one embodiment about 600 feet per minute.

In one embodiment, the wire strands are subjected to sequential passes through three Turks head mills to convert a copper wire with a rectangular cross section to a wire with a square cross section. In the first, the strands are rolled from a cross-section of 0.005 x 0.010 inch to a cross-section of 0.0052 x 0.0088 inch. In the second, the strands are rolled from a cross-section of 0.0052 x 0.0088 inch to a cross-section of 0.0054 x 0.0070 inch. In the third, the strands are rolled from a cross-section of 0.0054 x 0.0070 inch to a cross-section of 0.0056 x 0.0056 inch.

In one embodiment, the strands of wire are subjected to sequential passes through two Turks head mills. In the first, the strands are rolled from a cross-section of 0.008 x 0.010 inch to a cross-section of 0.0087 x 0.0093 inch. In the second, the strands are rolled from a cross-section of 0.0087 x 0.0093 inch to a cross-section of 0.0090 x 0.0090 inch.

In one embodiment, the strands of wire that are made in accordance with the invention are drawn through a die or a series of dies to provide the strands with round cross-sections. The die can be a shaped (e. g., square, oval, rectangle, etc.)-to-round pass die wherein the incoming strand of wire contacts the die in the drawing cone along a planar locus, and exits the die along a planar locus. The die or dies can be round-to-round pass dies. The included die angle, in one embodiment, is about 8°, 12°, 16°, 24° or others known in the art. In one embodiment, prior to being drawn, the strands of wire are cleaned and welded (as discussed above).

Wires having gauges of about 29 AWG to about 36 AWG, and in one embodiment about 33 AWG to about 35 AWG, can be formed. In one embodiment, a strand of wire having a square cross-section of 0.0056 x 0.0056 inch is drawn through a die in a single pass to provide a wire with a round cross-section and a cross-sectional diameter of 0.0056 inch (AWG 35).

In one embodiment, the square or rectangular cross-sectioned wire strands produced by the slitting step of the inventive process are initially subjected to treatment in a shaping line where the cross sections are converted from such squares or rectangles to wire strands with round or oval cross sections. The wire strands with oval or round cross sections are then drawn through round dies to provide wire strands with round cross sections of desired size. Referring to Fig. 11, wire strand 402 is unwound from spool 382 and advanced to accumulator 540.

(Alternatively, any of wire strands 404,406,408 or 410 may be unwound from spools 384,386,388 or 390, respectively, and advanced to accumulator 540.) Wire strand 402 is then advanced from accumulator 540 to shaping unit 550.

Accumulator 540 includes fixed sheave 542 and dancer sheave 544 which are provided for maintaining the tension in wire strand 402 as it is advanced to shaping unit 550. Wire strand 402 entering shaping unit 550 typically has a square or rectangular cross section with a width of about 0.006 to about 0.02 inch, and in one embodiment about 0.010 to about 0.014 inch; and a height (or thickness) of about 0.002 to about 0.02 inch, and in one embodiment about 0.006 to about 0.01 inch.

In one embodiment, the wire strand 402 entering shaping unit 550 has a rectangular cross section with the dimensions of about 0.008 x 0.012 inch. The shaping mill 550 is comprised of a power driven Turks head mill, a pull-through Turks head mill in combination with a capstan unit, or a die box in combination with a capstan unit. In shaping unit 550, the cross section of the wire strand 402 is transformed from a rectangular or square shape to an oval shape. In one embodiment, the major diameter of the oval is about 0.008 to about 0.014 inch, and in one embodiment about 0.008 to about 0.010 inch; and the minor diameter is about 0.004 to about 0.01 inch, and in one embodiment about 0.006 to about 0.009 inch. In one embodiment, the wire strand that is shaped in shaping unit 550 has an oval cross

section with a major diameter of about 0.010 inch and a minor diameter of about 0.008 inch. Wire strand 402 is advanced from shaping unit 550 over dead weight dancer sheave 560 to shaping unit 570. Shaping unit 570 is comprised of a die box in combination with a capstan unit. In shaping unit 570 the oval shape of the cross section of the wire is rounded to form a round cross section or a nearly rounded cross section. In one embodiment, the wire strand that is shaped in shaping unit 570 is round or nearly round and has a major diameter of about 0.008 to about 0.012 inch, and in one embodiment about 0.009 to about 0.010 inch. In one embodiment, the wire strand that is formed in shaping unit 570 is substantially round with a major diameter of 0.009 inch and a minor diameter of 0.008 inch. The wire strand is advanced from shaping unit 570 through accumulator 580 to spool 590 where it is wound. Accumulator 580 includes fixed sheave 582 and dancer sheave 584 which are provided for maintaining tension in the copper wire strand as it is advanced from shaping unit 570 to spool 590.

Referring now to Fig. 12, the round or substantially round wire strand 402 produced in shaping unit 570 (Fig. 11) is drawn through a series of dies in die box 610 to produce a wire strand with a round cross section and desired diameter which is collecte on spool 630. Die box 610 contains an array of round dies 612 selected to reduce the wire strand to the desired diameter or wire gauge. In Fig. 12, there are 14 dies depicted, but those skilled in the art will recognize that any desired number of dies can be used. Wire 402 is advanced from spool 590, over sheave 600, through the first die in die box 610, around sheave 620, under die box 610, around sheave 600 and to and through the second die in die box 610. This sequence is continued until the wire strand goes through the last die in die box 610 and is then advanced to sheave 620, and from sheave 620 to spool 630 where it is collecte. The reduction required for each die can be determined by those skilled in the art. In one embodiment, a full reduction is achieved in each die (e. g., 34 AWG to 35 AWG). In one embodiment, a 1/3 reduction is achieved with each die (e. g., 34 AWG to 34 1/3 AWG). During the reduction in die box 610, conventional metal working lubricants are employed for the purpose of lubricating the dies. Any metal working lubricant suitable for drawing copper wire can be used. Examples include

HSDL No. 2 and HSDL No. 20, both of which are products of G. Whitfield Richards Co. During this wire drawing step, the wire strands can be reduced from about AWG 32 to about AWG 48, and in one embodiment from about AWG 32 to about AWG 54. In one embodiment, copper wire strands having gages of about AWG 32 to about AWG 62 or smaller can be made. In a particularly advantageous embodiment, wire strands having gages of about AWG 20 to about AWG 62 or smaller, and in one embodiment about AWG 30 to about AWG 62 or smaller, and in one embodiment about AWG 40 to about AWG 62 or smaller, and in one embodiment about AWG 45 to about AWG 62 or smaller, and in one embodiment about AWG 50 to about AWG 62 or smaller, and in one embodiment about AWG 55 to about AWG 60 can be made.

The wire made by the inventive process can be cleaned using known chemical, mechanical or electropolishing techniques. Chemical cleaning can be effected by passing the wire through an etching or pickling bath of nitric acid or hot (e. g., about 25°C to 70°C) sulfuric acid. Electropolishing can be effected using an electric current and sulfuric acid. Mechanical cleaning can be effected using brushes and the like for removing burrs and similar roughened portions from the surface of the wire. In one embodiment, the wire is degreased using a caustic soda solution, washed, rinsed, pickeled using hot (e. g., about 35°C) sulfuric acid, electropolished using sulfuric acid, rinsed and dried.

In one embodiment, the strands of wire made by the inventive process have lengths of up to about 100,000 feet, and in one embodiment from about 5000 to about 50,000 feet, and in one embodiment about 10,000 to about 50,000 feet.

In one embodiment, strands of wire made by the inventive process have relatively short lengths (e. g., about 500 to about 5000 ft, and in one embodiment about 1000 to about 3000 ft, and in one embodiment about 2000 ft), and these strands of wire can be welded to other similarly produced strands of wire using known techniques (e. g., butt welding) to produce strands of wire having relatively long lengths (e. g., lengths in excess of about 100,000 ft, or in excess of about 200,000 ft, up to about 1,000,000 ft or more).

The copper wire made by the inventive process typically has an occluded oxygen content of less than about 200 ppm, and in one embodiment less than about 150 ppm, and in one embodiment tess than about 120 ppm, and in one embodiment less than about 100 ppm, and in one embodiment less than about 80 ppm, and in one embodiment less than about 60 ppm, and in one embodiment less than about 50 ppm.

The combined metallic impurity level of the copper wire made by the inventive process is typically no more than about 65 ppm, and in one embodiment no more than about 35 ppm.

It is critical that the copper wire made by the inventive process is reducible in tensile testing to greater than 98% RIA, and in one embodiment about 98.5% RIA or greater, and in one embodiment about 99% RIA or greater, and in one embodiment about 99.5% RIA or greater, and in one embodiment, the copper wire is reducible to 100% RIA.

In one embodiment, the wire made by the inventive process has a copper content of about 99% to about 99.999% by weight, and in one embodiment about 99.9% to about 99.99% by weight.

In one embodiment, the wire made by the inventive process has an ultimate tensile strength (UTS) at 23°C in the range of about 35,000 psi to about 95,000 psi, and in one embodiment about 50,000 psi to about 95,000 psi, and in one embodiment about 60,000 psi to about 95,000 psi, and in one embodiment about 65,000 psi to about 75,000 psi. In one embodiment, the elongation for this wire at 23°C is about 0% to about 24%, and in one embodiment about 8% to about 18%, and in one embodiment about 9% to about 16%.

In one embodiment, the wire made by the inventive process is cold worked to a reduction of about 60% and as such has a UTS at 23°C in the range of about 65,000 psi to about 90,000 psi, and in one embodiment about 70,000 psi to about 75,000 psi ; and an elongation at 23°C of about 0% to about 4%, and in one embodiment about 0% to about 2%.

In one embodiment, the wire made by the inventive process is cold worked to a reduction of about 60% and then annealed at a temperature of 200°C

for two hours and as such has a UTS at 23°C in the range of about 25,000 psi to about 40,000 psi, and in one embodiment about 27,000 psi to about 30,000 psi; and an elongation at 23°C in the range of about 30% to about _50%, and in one embodiment about 35% to about 45%.

In one embodiment, the copper wire made by the inventive process has a conductivity of at least about 100% IACS (International Annealed Copper Standard), and in one embodiment about 100% to about 102.7% IACS.

An advantage of the present invention is that ultra fine wire having gages of about AWG 50 to about AWG 62 or smaller, and in one embodiment about AWG 55 to about AWG 62 or smaller can be made. While not wishing to be bound by theory, it is believed this is possible because the crystal structure of this copper wire has a twinning or stacking fault population.

Example 2 A copper strip 312 having a width of 0.25 inch, a thickness of 0.008" inch and a length of 100 feet is peeled from a circular disk 300 of copper having a diameter of 6 inches using the apparatus illustrated in Figs. 4-6. The circular disk 300 is cut from the copper plate 102 made in accordance with Example 1. The copper strip 312 is sheared using the apparatus illustrated in Figs. 8 and 10 to form five strands of wire, each having a cross section of 0.008 x 0.012". These wire strands are degreased, washed, rinsed, pickled, electropolished, rinsed and dried.

The strands of wire are shaped to a round cross section using a combination of rolls and drawing dies. The first pass uses a miniaturized powered Turks head shaping mill to reduce the 0.012" dimension sides to approximately 0.010-0.011". The next pass is through a second Turks head mill wherein this dimension is further compressed to approximately 0.008-0.010", with the overall cross section being squared. Both passes are compressive, relative to the dimensions cited above, with an increase in the transverse dimension (the dimension in the cross section direction perpendicular to the direction of compression) and an increase in wire length. The edges are rounded with each pass. The strands of wire are then passed through a drawing die wherein they are rounded and elongated, the diameter being reduced

to 0.00795", AWG 32. The strands of wire are then drawn to a gage of AWG 55.

The wire is tensile tested and observed to have a 100% RIA.

While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification.

Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.