DE1245141B - Process for the electrolytic processing of copper alloys - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C22d

German KL: 40 c-1/16

Number: 1 245 141

File number: N 26636 VI a / 40 c

Filing date: April 24, 1965

Opened on: July 20, 1967

The invention relates to electrolytic decomposition of copper alloys with deposition of as much as possible pure, dense copper on the cathode. It is beneficial for this purpose to check the copper ion content to keep practically constant in the electrolyte. This happened in the prior art e.g. B. by supplement caused by the formation of permanent sulphates of the impurity metals or alloy metals In addition to copper, sulfuric acid and the addition of as much copper oxide as this amount of acid were consumed and the sulfuric acid formed by hydrolysis of the volatile sulfates. Another well-known one Procedure turned the direct oxidation of copper at the anode by introducing air under it Warming the bath z. B. by simultaneous introduction of steam to copper sulfate formation within the electrolysis bath in the one for maintaining the copper ion concentration in the electrolysis strip to achieve the required level.

According to a more recent proposal, the disadvantages associated with these cumbersome procedures should be addressed be avoided in such a process taking place in sulfuric acid electrolytes between Anode and cathode in a triode connection a grid-shaped, net-like or perforated auxiliary electrode as is switched in such a way that there is a higher potential gradient between the anode and the auxiliary electrode than between the auxiliary electrode and the cathode. When reworking this procedure with a nickel silver anode of composition 13.8% nickel, 1.0% zinc, 0.5% tin, 0.25% lead, 84.5% copper and one Auxiliary electrode made of perforated lead sheet on an experimental scale in various conceivable electrolytic Circuits, however, resulted in a drop in the copper concentration in the electrolyte, as shown in FIG Anode composition was normally to be expected.

It has now been found that the by the drop in copper ion concentration and its necessary Compensation for the electrolytic disadvantages occurring in the process according to the prior art Processing of copper alloys, such as B. nickel silver, to electrolytic copper in z. B. sulfuric acid Electrolytes can thereby be avoided and a dense cathode copper of such Process of usual purity can be obtained that the cathodes used for copper deposition no more current is supplied than is necessary for the deposition of the anodically dissolved copper, as a result of which the drop in the copper ion concentration in the electrolyte is prevented. The proportion of electricity the anodic process for the electrolytic processing of, in addition to copper in the anode Copper alloys

Applicant:

North German Affinerie,
Hamburg 36, Alsterterrasse 2

Named as inventor:

Dipl.-Ing. Siegfried Goedecke,

Dr.-Ing. Otto Nielsen,

Dr.-Ing. Egon Süssmuth, Hamburg;

Jens Hoffmann, Hamburg-Neugraben

Tending metals dissolves or oxidizes or anodically performs other than copper-dissolving work, is in accordance with the invention cathodically forced to do some other electrochemical work than the deposition of copper represents. For example, this can be done by separating hydrogen on a parallel happen by means of a diaphragm from the bathing electrolyte separated and surrounded by copper ions free electrolyte auxiliary cathode. The copper-free electrolyte consists z. B. from dilute sulfuric acid. During operation water is supplied to the extent that the penetration of copper ions from the main electrolyte into the interior of the diaphragm is prevented.

Embodiment 1

The process was carried out, for example, in an apparatus as shown in the schematic Fig. 1 can be seen. In this 1 is a tub for the electrolysis bath, 2 is an anode made of a copper alloy, 3 a cathode of the usual type made of thin copper sheet. An auxiliary electrode 4 is located in one Diaphragm cell 5 which, in contrast to the electrolysis tank 1, has an electrolyte free of copper ions contains. The auxiliary electrode 4 is connected to the main cathode 3 via a line 6 and a variable resistor 7 connected in parallel.

The auxiliary cathode consisted of a corrugated copper sheet. The rheostat was necessary to adapt the current distribution between the cathode and auxiliary cathode of the alloy.

In the experiment, 4.8 to 5.0 A flowed in the main circuit, of which 4 A between anode and cathode. 0.8 to 1.0 A between anode and auxiliary cathode.

709 617/435

Claims (9)

There was a potential difference of 170 mV between anode and cathode, 0.7 to 0.9 V between anode and auxiliary cathode; the difference was reduced by the resistance. In the course of 46 hours, 279 g of the anode were dissolved and 217 g of copper were deposited cathodically. Hydrogen was deposited on the hoof cathode. The acid concentration in the electrolyte fell from 186.0 g / l to 184.5 g / l. The copper concentration remained practically constant in the experiment. It could also be both increased and decreased with the arrangement described. The energy requirement for the cathodically deposited copper is calculated as £ = 680 kWh / t. Embodiment 2 For the sake of simplicity, the rheostat can be dispensed with during operation and instead several normal electrolysis baths can be combined with a "diaphragm bath". The numerical ratio ao depends on the alloy composition. The baths are to be connected in series in terms of current; they must belong to a common electrolyte circulation system. The energy requirement per ton of copper is lower than the above. For the above-mentioned copper alloy with 84.5% copper, 0.25% lead, 0.5% tin, 1% zinc and 13.8% nickel, for example, an arrangement according to A b b. 2 used. Five normal electrolysis cells 1 are electrically connected by a series circuit to a diaphragm bath 8, which can also be put out of operation by a bypass switch 16. Main busbars 14 and triangular bars 15 are arranged for supplying the current to the cells and for the electrical connection of the baths to one another. The baths are connected to one another in the multiple circuit customary for copper electrolysis according to the state of the art. The electrolyte flows in a circuit via a collecting vessel 13 common to all six baths, where the copper-depleted electrolyte flowing back from the normal electrolysis baths mixed with the copper-enriched drain from the anode compartment of the diaphragm bath. The electrolyte line system consists of pump 9, pressure line 10, bath feed line 11, drain lines 12 and collecting tank 13. In this way it is achieved that an electrolyte of the same concentration is supplied to all six baths. The level of this concentration can be regulated, in particular also kept constant, by switching the diaphragm bath on and off. Such a device would be tested on a trial scale: With a current yield of about 98.5%, the energy requirement was only 542 kWh per ton of electrolytic copper. The electrolyte, which contained 28.5 g / l copper at the beginning of the experiment, contained 28.3 g / l copper at the end. 60 claims: 1. Process for the electrolytic processing of copper alloys, especially those with With less than about 90% copper content for the purpose of obtaining electrolytic copper in sulfuric acid electrolytes using one or more auxiliary cathodes, thereby characterized in that no more current is applied to the cathodes used for copper deposition than is sufficient, to deposit the anodically dissolved copper on these cathodes. 2. The method according to claim 1, characterized in that the anodically other than copper-dissolving Work-making current on the auxiliary cathodes, in order to keep the surrounding them free electrolytes free of copper ions are surrounded by a diaphragm, cathodic is forced to do some other electrochemical work than the deposition of copper represents. 3. The method according to claims 1 and 2, characterized in that that current component which should not deposit any copper cathodically, causes the deposition of hydrogen. 4. Process according to claims 1 to 3, characterized in that the current distribution on cathodes and auxiliary cathodes according to the alloy composition of the anodes using Rheostat is carried out. 5. The method according to claims 1 to 3, characterized in that the current distribution on cathodes and auxiliary cathodes according to the alloy composition of the anodes by assigning a corresponding number of normal, current-wise in series, lye-wise baths connected in parallel to form a diaphragm bath. 6. The method according to claim 5, characterized in that the current distribution to cathodes and auxiliary cathodes is also influenced by means of a variable resistor. 7. The method according to claim 5 and 6, characterized in that the diaphragm bath for regulation the concentration of the electrolyte is temporarily switched off from the circuit. 8. Device for performing the method according to claims 1 to 7, characterized by one or more arranged in the same electrolyte circulation system as the cathodes Auxiliary cathodes, which are delimited from the electrolyte within a by a diaphragm Space are surrounded by an electrolyte free of copper ions, and optionally by a rheostat connected between the cathodes and the auxiliary cathodes. 9. Apparatus according to claim 8, characterized by the arrangement of the auxiliary cathodes in a diaphragm container (8) separated from the electrolysis baths, a collecting container (13) for the electrolyte containing copper ions and a pump (9) and pipeline system (10,11,12) for the constant circulation of the Electrolytes containing copper ions from the collecting container (13) via the electrolytic cells (1) and the diaphragm container (8) back to the collecting container (13). Considered publications:
German Patent No. 1142 240;
Journal for ore mining and metallurgy, 1963, pp. 227/238 and 558/571. 1 sheet of drawings 709 617/435 7.67 ® Bundesdruckerei Berlin