FI64654C - FOERFARANDE FOER RAFFINERING AV KOPPAR OCH DESS FRAMSTAELLNINGI FORM AV LAONGSTRAECKTA PRODUKTER - Google Patents

Abstract

Granules of copper are produced by electrodeposition on a patterned electrode having cathode surfaces 7 separated by insulating material 9, 10. Deposition may be continued until the copper coheres into a continuous sheet, in which case the sheet is broken up along its lines of weakness. The granules are fabricated by continuous friction-effected extrusion to obtain rod, wire or other elongate products. <IMAGE>

Description

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Patent and Registration Office (44) NthttvUuipano and other issue date. - Λ R

Patent · och regrsterstyrelsen Ans * kan utl * jd och uti. * KrHt * n pubii «r» d, 11.00.03 (32) (33) (31) Pyydetty «uolk eus —Begird prtorltet Ol.O6.77

England-England (GB) 23106/77 (71) BICC Limited, 21 Bloomsbury Street, London WC1B 3QN, England-England (GB) (72) Christopher John White, Billericay, Essex, Rees Jenkin Llewellyn,

Twickenham, Middlesex, England-England (GB) (71 *) Leitzinger Oy (5I *) Method for refining and producing copper as elongated products - Förfarande för refinering av koppar och dess framstalini ng i form av längsträckta produkter

The present invention relates to a process for the purification and production of copper as elongate products, by continuous extrusion of particles by friction. In this case, copper particles or particles with a size of about 1 mm -0.1 dm are mainly considered. Particles of this order of magnitude are hereinafter referred to as "granules", whatever their shape. The granules prepared by the present invention usually have a main dimension (thickness) of up to 10 mm.

The invention relates in particular, but not exclusively, to the manufacture of longitudinal copper bodies which are electrically conductive and which, in order to avoid uncertainty, must contain copper with a conductivity of at least 101% I.A.C.S. When copper contains conventional impurities, this corresponds to a total impurity (in which case oxygen is counted as an impurity) in the range of 0.05% or less.

A guitar of this type is usually made by electrolytic cleaning in the form of flat, usually rectangular cathodes 2 64654, and the conventional manufacturing method involves melting, casting (either continuously or in batches) into bars and heat treating (forging, rolling, pressing or a combination thereof) into an elongate form. In most cases, this is followed by cold rolling and / or cold rolling.

It has long been found that this process requires the use of very expensive equipment and a large amount of energy and solely to raise the temperature of the copper in order to melt it and maintain a suitable subsequent processing temperature. Attempts have been made to provide a low heat manufacturing process for the production of elongated products from unmelted cathode copper.

Most such attempts have been based on modifying the electrolytic purification process to directly obtain an elongated product. Although it is technically possible for the products made. This has hitherto proved impossible and / or uneconomical in the manufacture of electrical conductors (except for thin films) because the electrode area is not used efficiently if its component parts (eg spiral threads) are far enough away to avoid adhesion, irregular cross-section and possible post-fractures, the additions required in the electrolysis bath to shape the product can impair its electrical conductivity and / or recovery rate.

Another such company that gained commercial use in the United States to a small extent during the 1930s was known as "fused copper." The process for making fused copper was, in the broadest sense of the word, a "powder metallurgical" method because it involved the deliberate fabrication of brittle cathodes, which were then broken into pieces that could be several cm in size and 5 mm thick in their main direction. These pieces were compressed into ingots, fused together by heating for some time under reducing conditions at a temperature of about 900 ° C to effect surface deoxination, some second purification, and granulation. Thereafter, hot pressing was performed to obtain a solid electrically conductive product.

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It has now been found that the heat treatment and fusion step according to this known method are advantageous and necessary and that the provision of products with additional properties can take place without surface deoxidation, provided that the metal is never heated to such an extent that significant amounts of incidental existing impurities dissolve in copper and completely. The specification of application 31763/76 therefore describes a process for the production of a longitudinal electrically conductive copper article, comprising: electrolytically precipitating copper in the form of brittle cathodes, crushing the cathodes into pieces and feeding them as such and without any high heat treatment, cleaning or granulation , and with this machine the pieces are machined under sufficient pressure to unify them and tie them into a continuous longitudinal piece.

Fragile cathodes tend to be more porous than conventional cathodes and thus may contain higher amounts of electrolyte and possibly anode slurry, which in some cases results in higher impurities (especially in the presence of antimony, arsenic and sulfur) than conventional copper. Such a higher impurity content cannot be compensated for in all conditions by controlling the impurity solution and actually results in a product with a lower conductivity than would be the case with conventional copper particles.

The method of the invention is characterized in that the copper particles are prepared as follows: (i) in electrolytic cleaning, copper is electrolytically doped on an electrode having a plurality of cathode surfaces substantially separated by an electrically insulating material until the copper surfaces deposited on the individual cathode surfaces coalesce; (ii) removing the precipitated copper well from the electrode; and (iii) then breaking the film from thin areas corresponding to at least a part of said boundaries to form copper granules or particles, and that the copper granules or particles thus prepared are extruded.

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The extent to which the copper regions converge or not depends primarily on the ratio of the thickness of the precipitated copper to the distances between the individual cathode surfaces, although factors affecting the structure of the precipitated copper may to some extent affect this.

The invention therefore relates to a method of manufacturing a brittle copper sheet which comprises electrolytically doping copper with an electrode having a plurality of cathode surfaces substantially separated by an insulating material until a uniform sheet is formed by the combination of copper regions initially deposited on individual cathode surfaces. , in addition to which the sheet is removed from the electrode.

If the precipitation ceases before the copper surfaces have sufficiently coalesced, granular copper is obtained directly by drawing the precipitated copper from the electrode.

The electrode can be made of any suitable material. For a traditional acidic copper sulfate bath, titanium, stainless steel, or copper is usually preferred. If copper is used, an emitter is usually used. Normally, all cathode regions form parts of the main surface initially in a continuous plate.

Normally, electrolytic precipitation forms part of the electrolytic purification process, and the requirements are preferably such that conventional copper is precipitated. Standard cleaning conditions are available and are preferably used.

Separation of the plate into separate cathode regions. between which there is a secretory substance can occur in different ways. In particular, the insulating material may be durable so that it survives to remove copper and can be re-used, or, if the material is sufficiently inexpensive, it can be thrown away and replaced after each use. The preferred durable material is an organic oxide surface. formed on a titanium (or other suitable metal) electrode. Alternative forms also include a variety of organic insulating materials that are protected from mechanical damage.

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5 64654 by immersing the electrode surface in the grooves. Organic materials suitable for this use include epoxy resins (thermosetting or heat setting), rubber (preferably vulcanized to Daikal) and ethylene-vinyl acetate acetate polymers (thermoplastic). If a removable insulating material is preferred, this will usually consist of an organic material added as a surface layer to a smooth metal surface. The surface layer may be a coating added from its fluid state or may be a preformed, perforated sheet, preferably securely bonded to the electrode metal by self-adhesive or a separate adhesive, but may alternatively be tightly tightened to the metal to provide substantially liquid tight contact. A desirable material is a silicone rubber compound. which cures at room temperature and can be added as a paste, and polyvinyl chloride which is added as a sheet.

In order to ensure the production of a uniform product, the cathode surfaces are preferably of the same shape and size or have only a few different shapes and / or sizes. It is preferable to use a regular rectangular, hexagonal or rectangular shape or other polygons separated by insulated strips of the same width, unless pre-shaped insulated sheets are used, in which case the use of round openings, possibly two different aperture sizes, may be preferred. The rectangular bands can be as long as the electrode itself, if desired. It is preferred that the long strips be no wider than 10 mm or no more than 25 mm and that the shapes of the compact travel do not exceed 100 mm. Special friction extrusion devices, such as those prototypes currently in use, may require smaller sizes than this.

The cathode regions must usually be separated every few millimeters to ensure clear streaking. Of course, a greater separation is required for a given precipitation thickness if the particles are to be formed directly than if a uniform brittle sheet is desired. In Tvy-Dill conditions, it has been found that in order to form the granules directly, the distance and thickness of the precipitate can be suitably made similar, and in forming the sheet, the thickness of the precipitate is usually several times the distance.

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After it is removed from the electrolysis chamber, the electrode is washed with precipitated copper, usually to remove the electrolyte, which is suitable considering the following steps.

The copper can then be withdrawn to a large extent as well as the copper starting sheet is removed from the material, i.e. the knife blade is forced along the electrode some distance from the electrode surface and possibly (as appropriate) then pulled off one corner or end. Depending on the conditions, the copper is released either as granules or as a uniform sheet. If a continuous sheet is formed, this can then be broken with a suitable mill, usually a mill operating on the principle of impact or folding. Jaw crushers, needle mills, ball mills, hammer mills or drums can be used.

After the copper has been removed and before and / or after crushing, if appropriate, the copper is preferably washed again to minimize electrolyte impurities and then the copper is preferably dried. In particular, when a brittle sheet is used as an intermediate, the copper is preferably inspected to eliminate excessive particles of batteries (which can lead to breakage).

Continuous-friction extrusion equipment. known as "Conform", "Linex" and "Extrolling" operate without a closed material chamber and instead of being pressed into the extruder by a piston or fluid pressure, one or more members of the device grip the metal and take it to a nozzle where the metal is compressed extruded through a nozzle (a more complete description of the "Conform" and "Linex" methods can be found in the Wire Journal, April 1976, pp. 64-69. The "Conform" method is patented by British Patents 1,370,894 and 1,434,201 and "Linex" - method by British Patent 1,488,445).

The copper granules or particles are preferably fed as such without any pre-compression to the friction extruder and are compressed in an actual extrusion. Furthermore, the temperature of the copper does not in any case exceed 700 ° C, thus significantly reducing the electrical conductivity by soaking impurities that could be present in insoluble form.

Optionally, the particles may be preheated prior to extrusion to reduce the required extrusion pressure. The preheating temperature does not exceed 450 ° C, otherwise there may be a risk.

7 64654 that the temperature of 700 ° C can be exceeded in the extrusion process as a result of adiabatic heating. A reducing or neutral atmosphere or the use of a vacuum may be desirable if preheating is used. Cracked ammonia or steam (which in both cases are preferably airless) are suitable.

If desired, the front of the extruder can be aspirated, at least initially. The warm-up time is so short that no protective atmosphere is considered necessary under normal circumstances. As long as the porous material is not acceptable, the extrusion ratio is preferably at least 8: 1, and a reduction of about 9: 1 to 20: 1 is considered good. In certain cases, it may be desirable to extrude two or more products simultaneously using a double nozzle or a multi-orifice nozzle. The extrusion may be coaxial, i.e. in the same direction as where the material to be extruded approaches the nozzle, or it may be rectangular or have some other angle against the axial direction.

The extruded product can be heat treated, if desired, to homogenize its structure and / or to shape its mechanical properties. The heat treatment is preferably performed at a temperature below 700 ° C to avoid significant granulation and to remove impurities.

The longitudinal product is often a "wire rod", i.e. a round bar suitable for a drawn wire. Alternatively, it may form a finished product having a rectangular or other shape in cross-section, including a perforated cross-section, which may be obtained by using bridge mouthpieces or heat pressing matrices. Furthermore, the product may form an intermediate product (e.g. a square or rectangular bar) which is used as a feed material to another continuous, friction extruder and in certain cases the wire may be extruded directly.

In the accompanying drawings, each of Figures 1 to 6 shows a schematic planar surface (not shell-like) of different electrodes for use in the first step of the method according to the invention.

The electrode of Fig. 1 comprises a strong metal plate with an upper surface 1 which is exposed and acts to obtain an electrical connection, an intermediate region 2 coated with an insulating material and in use extending partly into the electrolyte and partly into the air thereon, and a main region 3 operating 8 6 4 6 5 4 as a receiver for electrolytically precipitated copper. The edges 4, 4, 4 of the main area are coated with an insulating material and both main surfaces are divided by oblique bands 5, 6 of insulating material into a multiple rhombic cathode surface 7. Slit or other shaped areas 8 with smaller edges may be coated if unit integrity is required.

The electrode of Figure 2 differs only in that the insulating edges 9, 10 in the main region 3 run vertically and horizontally. This swells to a uniform particle size without loss of volumetric power, but it can cause a somewhat more impure precipitate because the horizontal top edges of the original copper alloy may tend to collect a whole set of partial impurities ("sludge").

The electrode of Fig. 3 has only vertically insulating strips 9 and thus has long narrow strips 11 for precipitating copper. The horizontal band t10 may be used alone, as shown in Figure 4, but this arrangement may result in a more impure product.

The electrodes of Figures 5 and 6 are completely coated in their main region 3, except for the circular regions 12, 13, which in Figure 5 are the same size and two sizes in Figure 6. The space power of this arrangement is lower, but the circular shapes of the particles can help provide a more suitable extruder feed.

Example

Electrodes measuring 235 mm x 280 mm and intended for use in a pilot electrolytic cleaning chamber are fabricated as follows.

Example 1

The titanium plate was coated on both sides with a photosensitive etching-protective layer and exposed on both sides in alternating order with actinic light under a negative with black strips about 4 mm wide at a distance of 15 mm. This unexposed grid ./ 64654 figure was removed by conventional development / which left squares with sides of about 1 mm. The plate was then anodized by standard techniques to put in place a permanent oxide surface and exposed metal. The remaining photosensitive etching layer was then removed from the non-anodized square area (outline of Figure 2).

Example 2

The copper plate was divided into squares of different sizes, ranging in size from 10 to 25 mm on the side, using a silicone rubber compound vulcanized at room temperature and sold under the trademark Silcoset, Silcoset RTV No. 100, No. 101 or No. 105 by Imperial Chemical Industries Limited (double fill). ) or No. 151, No. 152 and No. 153 (disposable), in which case the mixture was applied to a clean, dry surface of the board in a strip about 5 mm wide on top of the primer strip of the recommended base color OPI (sketch according to Figure 2). . A traditional procedure was then performed.

Example 3

PVC film about 1 mm thick. with glue on the back and sold as protective films for books were punched into round holes 25 mm in diameter each with center distances of 18 mm from smaller holes, about 5 mm in diameter, arranged diagonally between the former holes. The film was attached to a titanium surface (outline of Figure 6).

Example 4

A compliant, softened PVC sheet about 5 mm thick was punched into hexagonal figures with a hole of 20 mm and a center spacing of 25 mm, after which the sheet was tightened on a titanium sheet and held under pressure, which pressure was applied to the surface in several places (Figure 5). outline).

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Example 5

The thick titanium plate had an oblique 3 mm grooved oblique oblique fuzzy outline with grooves at 15 mm center distances cut into the plate on each side with a circular saw (outline according to Figure 1). The grooves were filled with a cold-curing synthetic resin compound which, by weight, included:

Low viscosity epoxy resin type Bisfenol A sold under the trademark "Araldite MY 750" 50 TAlkkia 40

Polyoxypropylenediamine with a molecular weight of about 2000 and sold under the name "Jeffamine 2000" (binder) 10

Hardener sold under the name "Jeffamine D 230", described as the bis-2-aminopropylether of the diol, with a molecular weight of 320 14

A hardener accelerator sold under the designation "Accelerator 398" 5 (Jeffamine D2000, Jeffamine D230 and Accelerator 398 are all available from Jefferson Chemical Comoanville, Houston, Texas, USA).

Once the resin has cured, the electrode surfaces are smoothed by grinding.

Example 6

The procedure was as in Example 5 except that the mean distance of the grooves was 28 mm, which left a precipitation area of 5 mm.

Example 7

The procedure was as in Example 2 except that the plate was titanium and the insulating material was an asphalt-based material sold under the trademark "Mexphalte", which was added by brushing or pressing with a molded rubber roller.

Each of the electrodes of Examples 1-7 was made as an electrolyte chamber cathode for use with a conventional anode copper having dimensions of 235 mm x 254 mm, as well as a peristaltic electrolyte and a rotation procedure. The flow tightness is kept at approximately the normal level (the effective area is initially less than for a smooth cathode of the same total size 11 64654, but increases as precipitation progresses and may in some cases exceed the smooth cathode area as copper spreads to the edges of individual units already precipitated).

All of these electrodes formed granular copper if precipitation was stopped at a thickness of about 5 mm. In Example 4, a completely perforated sheet could be drawn in DOis before copper and reused a few times before it was too worn. The electrodes of Examples 1, 5, and 6 could be reused without reinstallation.

Example 8

The procedure was as in Example 1 except that the neoative was made only by placing parallel dark strips and then forming rectangular copper bands extending the entire length of the electrode (outline of Figure 3). Also in this case, a uniform brittle sheet could be obtained, if desired.

All electrodes could be used to obtain brittle sheets by continuing to precipitate to different thickness ranges within 10 mm.

Granular copper prepared by doping on the electrode according to Example 6 to a thickness of 5 mm, washing and removing, washed again, dried and heated to 275 ° C. The largely cubic granules were sieved into a low friction extruder marked "Conform" (laboratory oroto-2 with a 9 mm input) and extruded in a ratio of 8: 1 to form a 3.6 mm diameter round bar. After being drawn into a 0.5 mm diameter wire and annealed, 2 the product had an elongation of 26%, a tensile fracture limit of 235 MN / m and an electrical conductivity of 101.8% IACS.

Similar results can be expected when extruding granules obtained with electrodes according to other examples or made by breaking a sheet which is then processed, but a larger friction-acting extrusion machine is required to receive larger granules.