DE472850C - Process for refining alloys of any composition by electrolysis - Google Patents

Description

Process for refining alloys of any composition by electrolysis The application of electrolysis with cold liquid electrolytes is limited to this day, as far as the extraction of metals is intended, in the The main thing is the actual precious metal alloys and precious metal-containing copper, as it is obtained from the smelting of copper ores as raw or black copper. In the latter, the precious metal content usually not only covers the costs of electrolysis, but throws a more or less large profit.

The following essentially stand for the actual precious metal alloys Procedure available: i. = The method of D. i e t z e 1 for processing low-grade Noble metal alloys, according to which copper is the electrolyte metal, silver on the other hand, is obtained as Zernentsilver. The latter must be repeated after you have melted it after M ö b i u s are electrolyzed. The gold stays with lead, tin, silver, etc. as anode scum, usually in a very fine distribution, and must also continue be refined.

2. The Dietzel process modified by W a e s e r, which is differs from it only through the other apparatus.

3. The iVI ö b i u s - process for low-gold, high-silver alloys, according to which only alloys with at least 70 ° 10 silver and at most io ° / o have gold processed, otherwise operational disruptions will occur continuously. In the As a rule, only alloys and the incendiary silver of the Lead and silver smelters processed to save electricity and acid costs.

d .. The same procedure in execution and in conjunction with the copper removal of waste liquor from Siemens & Halsk-e is due to the large amount of acid used in the preparation and renewal of the baths as well as the interest-free investment of large amounts of silver uneconomical in the view of the inventor of the present process. It requires in addition, constant professional monitoring through analytical control of the Bath composition so that it is suitable for continuous operation, as is the rule not suitable.

5. The method according to Dr. Carl appears very much at first glance impressive, but on closer examination for practical usability it proves According to the inventor of the present new process, there are major shortcomings. So alone the fact that copper, silver and gold are extracted from the alloys four different electrolytic systems are required, one below the other have no direct connection, namely: a) the preliminary decision according to Dr. C a r 1 (sodium perchlorate electrolyte), b) the silver electrolysis after M ö b i u s, c) gold electrolysis according to W o h 1 w i 11, d) copper sulfate electrolysis.

In addition there are the many intermediate operations, which take a lot of time claim, also the great cost of the system, the considerable power requirement and the high license fees, which make it competitive with the others Completely exclude proceedings.

6. The method of W o h 1 w i 11 for gold electrolysis is only for Gold alloys from about 95 °] a gold can be used upwards, thus conditionally with poorer ones Alloys a pre-refining process.

It is also known: r. that using a suitable electrolyte, a suitable diaphragm, optionally also without a diaphragm and a smaller cathode area compared to a larger anode area, it is possible to bring a metal or an alloy into solution; 2. that in a galvanic element, the electrodes of which are made of different metals, which, separated by a diaphragm, are immersed in a salt solution of the more electronegative (in the sense of noble) metal in the cathode compartment and in a liquid suitable for dissolving the more electropositive metal in the anode compartment The more negative metal forms the cathode, the more positive the anode, be it through direct connection of the poles, be it through current consumption outside the element, in the cathode compartment the metal is precipitated from the solution of its salt, while in the anode compartment an equivalent amount the anode metal is dissolved; 3. That, according to the information from B arth (see patent 393 963 and 393 964), instead of the pole anode consisting of only one metal, an alloy of the pole cathode metal with more electropositive metals can also be used, the more electropositive metals in a suitable electrolyte can be dissolved, while the most negative metal (i.e. the metal from which the pole cathode is made) remains undissolved. However, it was found in tests that alloys with a high. Content of the most electronegative metal (the limit is around 700 / °) only weakly attacked. will. It was found that the more positive (less noble) metals dissolve on the surface, but that the more negative metal that remains undissolved does not appear to be more porous, but rather as compressed. This layer is so dense that the electrolyte can not penetrate deeper, whereby both poles of the galein vanischen 'consist in elektroc h i ch # he relationship is member of the same metal, thereby no longer have a potential difference and, consequently, no galvanic current can produce. Otherwise, this process is limited to the precipitation of metals from the aqueous solutions of their salts, but a metal salt solution is formed again in the anode compartment of the cell. The process says nothing about the production of the catholyte and the utilization of the anolyte.

The method of operation and the apparatus of the new process avoids the disadvantages of all of these procedures. The new process makes it possible from any alloy, with analogous application also from metal-containing ones Alkalis, which extract metals as electrolyte metals, as detailed in the following described: An alloy of the most electronegative is put into an electrolysis vessel Metal (it is advisable to use either the pure metal to initiate the process Metal or an alloy of the same as high-content as possible) suspended as an anode and connected to the positive pole of a power source. With the negative pole of Power source is connected to the correspondingly smaller cathode, which, if necessary in a current-permeable, but as liquid-impermeable as possible diaphragm is located. Also, there are so many diaphragms in the electrolyzer from the same material as the cathode junction than to extract the individual Metals are required. It is immaterial whether they are used as partitions are firmly built into the vessel or nested inside one another as cells. One fills now the anode and cathode compartment of the part of the apparatus provided with power supply If an electrolyte is suitable for dissolving the anode, turn the anode forming metals dissolved by the current. At the same time you do the first of the Diaphragm cells not under external power supply with one in the electrolyte of the outer cell immersed pole cathode made of the most negative metal, which is connected to a Pole anode made of an alloy containing the same metals (but of lesser Content of the most negative metal than the outer anode) is short-circuited. These Pole anode is in the r. inner cell in one to dissolve the .electropositive Metals suitable electrolytes. The galvanic element thus formed is from the outer, while electrolyte excreted only the most negative metal in the r. Inner cell only the. This will make the i. Vessel again immediately operational. The nitric acid remaining after the copper excretion is also reusable.

In the i. The concentration of the inner cell remains when the work is good Nitric acid is always the same because that from the alloy (as the pole anode of the i. galvanic element) dissolving copper on the (the pole cathode of the 2nd element representing) copper sheet is immediately excreted again. The anode is removed, when the copper is thrown out of it and replaced by a new one, while the previous one Anode is now dissolved as such in the outer cell under current.

That in the i. Inner cell secreted copper will from time to time removed and used as electrolytic copper.

For convenience, it is recommended that you keep all electrodes to be surrounded by a well-permeable sack. This will make the falling off of anode parts in the electrolyte avoided taking out the excreted Metals relieved. In the case of silver containing gold, the gold collects in the anode bag the outer cell and is easiest with small amounts. on chemical Ways processed on fine gold. In the case of larger quantities, processing can be carried out after be classified in the following example. z. Example The aim is gold-silver-copper alloys the most varied of composition can be processed. The preparation is that same as in example i. The equipment is also the same, but is still to come a 3rd inner cell added. The electrodes and the electrolyte receive the the following composition or arrangement a) a fine gold cathode is used in the outer cell, a high-grade gold alloy or fine gold (at the beginning) as the anode and hydrochloric acid or hydrochloric acid gold chloride solution used as the electrolyte; the temperature is up To keep about 6o to 70 ° C, the best by using the Heraeus temperature regulator with electrical. Heating is maintained without constant control; b) for the i. Inside cell one uses a pole cathode made of fine gold sheet and a smaller one Gold alloy as pole anode and dilute nitric acid as electrolyte; c) for the 2nd inner cell has a pole cathode made of fine silver, a pole anode from a Silver-copper alloy and also nitric acid are used as electrolytes. The alloy used here can have a low gold content or be made from so-called un Güld @ isch exist. Incidentally, all of them can be found in every precious metal separating facility possible legacies, so that there are no difficulties in the selection.

d) For the 3rd inner cell is the same as for the 2nd inner cell in the example i copper sheet as. Cathode and iron used as pole anode.

If the apparatus is loaded in this way, the cores must be maintained of the concentrations, the same moments as in example i must be observed accordingly.

In all cases, after starting the power source, the external Current flows through the cell, the anode is brought into solution by the current. This solution immediately becomes the most electronegative through the galvanic element of the dissolved metals, the pole cathode is completely the most electronegative metal purely excreted. All other metals remain in solution and can after enrichment can be obtained one after the other in the same way. From the pole anode, which from an alloy of the most negative with more positive metals only dissolve the latter. An almost pure metal remains, which is used for complete cleaning migrates into the outer cell as an anode. From that created in the galvanic cell Solution can also be the most negative metal by using a second analogous composite .galvanic element win. By arranging further elements further metals can be deposited one after the other. As the pole anode of the last For economic reasons, a metal will have to be selected, which is either is very cheap, so that the recovery can be dispensed with, or by Electrolysis is recovered under electricity. In this case it isn't even , required to completely knock down the metal in question, often only dared , at the expense of the quality of the precipitation, since that is only partially of the metal-free solution at the appropriate point within the process can be reused. It can also be recovered by chemical means or the utilization of the metal salt formed in this process.

After reaching a certain concentration in the outer cell The solution obtained occurs on the metals that are not precipitated here the processing according to the same principles, either using of anodes, which only contain the metals still present in the solution, under external power supply or only by using appropriate galvanic Elements. Above all, must the more positive metals go into solution. If you now dive into the i. Inner cell a pole cathode made of the next negative metal, shorts it with a pole anode made of an alloy, which all in the i. Inner cell can contain metals going into solution, and leaves this pole anode in a second inner cell in one suitable for dissolving the more electropositive metals Immerse electrolytes and create a second one. galvanic element on whose Polkathode again the most negative of the dissolved metals is precipitated while the more positive metals are dissolved at the anode. The number of as galvanic From a purely theoretical point of view, internal cells that function could go so far increase until the last of the metals present in the alloys has precipitated were. In practice, on the other hand, you only use so many cells that the main components be excreted while keeping the accompanying metals so far in over time enriches the electrolyte so that its extraction as metal or salt is worthwhile is. Which metal is used in the innermost cell as the Piolanode is can only be decided on a case-by-case basis. To assess the suitability of the relevant Metal must be the price of the same, the equivalent going into solution for that to be eliminated Metal and the price of the latter are taken into account. It would of course be uneconomical be, just for the sake of the inventive concept, a more valuable metal to be eliminated to propose a less valuable one. It may therefore appear in the following Hand of two examples from the practical experience of the inventor an explanation for binary and ternary alloys: i. Example The aim is to use silver-copper alloys the most varied of composition can be processed. The alloys are as usual, cast in anodes or granules for the present process, however, each category for itself.

The electrolysis vessel contains: a) a fine silver cathode with a smaller surface than the anode, possibly in a diaphragm (for this the porous porcelain of the state porcelain manufactory has proven to be special proven suitable, also for the galvanic cells) with the negative pole .der external power source (dynamo, converter, etc.) connected; b) Fine silver or the highest grade Alloy as anode when initiating the: process, later the copper is removed Pol anodes of the i. Internal cells used; the anode is connected to the positive pole of the Power source connected; If granules are used, a U-shaped current-conducting one must be used Choose a support; c) as i. galvanic element a diaphragm (see a) with a Fine silver sheet as a pole cathode and a lower <alloy as a pole anode; d) as the 2nd galvanic element, within the i. Inner cell, the same diaphragm with a pure copper sheet as a pole cathode and to one. Copper rod or a copper sheet ajar iron waste as an anode.

The pole electrodes of the galvanic elements are short-circuited.

The main electrolytes that come into question here are: for the outer cell Nitric acid (about 1 to 2 normal) or silver nitrate solution acidified with nitric acid, for the i. Inner cell dilute nitric acid (about 0.5 normal); for the 2nd inner cell a very dilute sulfuric acid (about 0.5 normal).

The concentration of the electrolyte in the outer cell is: by Dripping in nitric acid in an amount equivalent to the dissolved copper maintain. The copper concentration can be without the goodness of the silver precipitate to affect, a very high one. In general, however, you don't get any higher than, about i 50 g copper per liter go. If: this concentration is reached, interrupt one the external power supply and leaves after lifting the .Anode the silver through the Completely suppress the effect of the galvanic current. It usually winds up Hardein only by small amounts, since the main amount already differs during the time precipitates, in which the anode is dissolved by the external effect of current. then the electrolyte silver is removed and, by inserting a diaphragm with a pole cathode made of copper sheet, a pole anode made of iron waste, to one Leaning copper rod, which is short-circuited with the pole cathode, and thinned Sulfuric acid as an electrolyte excreted the copper. The concentration of sulfuric acid wind maintained by the dropwise addition of concentrated sulfuric acid; she can consistently kept very low. be to a purely chemical dissolution of the iron after Possibility to avoid. The same applies to the 2nd inner cell. As a by-product one obtains iron sulphate, which is used in sufficiently large quantities, otherwise can be neglected. Instead of excreting the copper in the outer cell, you can also drain the desilvered solution into another vessel and in this one excrete the copper Alloys, however, only on wet or dry Paths need to be prepared for electrolysis. The respective process requires the most careful monitoring, in particular with regard to the composition of the electrolyte, the current strength, the bath voltage and the quality of the generated N precipitate. the Processing the used electrolyte is usually difficult and expensive. As a result of the impossibility, one of the dissolved electrolytes always occurs directly in the electrolyte Metals without participation, completely withdrawing from another, intermediate operations to clean the electrolyte on; related to this, there are intermediate products, the processing of which is often difficult and not easy to use inserts; in smaller companies this always leads to operational breaks, especially Because of the dimensions of the electrolyzer vessels, which are mostly only suitable for large-scale operations. In the processes aimed at the recovery of several metals by electrolysis comes in addition to the time and costs for cleaning the electrolyte .der greater electricity demand added; often also a large consumption of acids or chemicals as a result of the impossibility of making this part of the electrolyte usable again make while for the preparation of the new electrolyte the same or multiple Amount is required. The direct electrolysis of alkaline solutions containing metal offers great difficulties. If several metals are present, a cumbersome, expensive, extensive cleaning of the alkalis precede. As a result of application In the case of insoluble anodes, polarization currents usually occur, which reduces the current yield very significant.

In contrast, the advantages of the new process are that alloys two or more metals of any composition can be processed directly. The monitoring is limited to: timely replacement of the anodes and pole anodes, which the latter are finally dissolved in the outer cell under current and on the change of the electrolyte required only in very large gaps effective concentration maintained by a set drip device will. The precipitates generated are always pure. The current and voltage has no influence on the purity of the precipitate, so it can be used within wide limits vary. The processing of the electrolyte is inevitably part of the overall process one, does not cause any special costs and delivers pure metals one after the other, no intermediates; Operational disruptions are therefore excluded. The apparatus can be put together in all dimensions, so that the procedure for the smallest. how the largest operation is suitable. The power consumption is very low, because you get pure metals, high-grade alloys or the pre-refined pole anodes as current-carrying anodes, so that in the main only one metal passes through the stream is brought into solution and the precipitation of the metals as well as the pre-refining by means of the galvanic elements at no cost. The electrolyte is almost Can be used indefinitely as it contains only small amounts of non-directly precipitable metals records, most of which in certain periods of time by switching or continuously are precipitated in the circuit, so that the electrolyte is largely regenerated wind. Metallic alkalis, which also include used electrolytes from other processes belong without external power supply; otherwise processed according to the same principle, thereby achieving substantial savings and the dissolving constituents of the alkalis be regenerated.

The main advantages can be summarized briefly: i. processing of alloys and metal-containing alkalis of any composition.

2. Profit young pure metals.

3. Regeneration of the electrolyte or the leaching agent.

d. Low power and chemical consumption.

5. Widest range of applicability.

6. Light surveillance. -

Claims (3)

PATENT CLAIMS: i. Method of refining alloys of any Composition by electrolysis, characterized in that the anode is one of an external power source .maintained cell .one of base metals in largely freed electrode is used, which was previously used as a pole anode with considerably a higher content of less noble metals in a galvanic element was used - its pole cathode in the electrolyte of the maintained by the external power source Cell is immersed and is separated from your pole anode compartment by a diaphragm: 2. Procedure according to claim i, characterized in that in the electrolyte in which the pole anode of the galvanic element of the first claim, also the pole cathode of a second galvanic element, its also through a second diaphragm Completed pole anode from an even less noble one beforehand each the metal that is precipitated first must be completely precipitated and removed. For the implementation of the process, it is of no importance in what way the arrangement of the apparatus is used he follows. You can arrange the individual cells one inside the other; you can connect them one after the other, for example by placing a larger vessel through partitions made of diaphragm material . divides into a corresponding number of cells; nian can only find a solution in each cell of the desired concentration and this solution in a special container weiterbehandehz; Finally, a circular process can also be constructed if one in the i. Cell brings the anode into solution under current, at the same time the electrolyte can flow continuously, by connecting a corresponding number of cells, which are equipped with the corresponding galvanic elements, one after the other the dissolved metals are eliminated and the electrolytes of the i. cell feeds again. A wide variety of combinations can also be formed from this. For a more detailed explanation, two schematic representations of the apparatus are attached, referring to the given example i, page 3 and q. the description and are designed around cross-section in plan view. Fig. I represents: the scheme for an electrolytic cell with inserted galvanic elements that Fig. A an electrolytic cell with permanently installed diaphragm walls. The enclosed. Numbers have the same meaning for all representations. In the electrolytic Cell i contains the anodes 2, made of fine silver or a high-grade silver alloy. The cathode 3 made of fine silver is attached between the anodes, if necessary in a diaphragm. The first galvanic element consists of a porous cell q., a pole cathode made of fine silver S and a pole anode made of a silver-copper alloy 6. The second galvanic element housed in this porous cell consists from the porous cell 7, a pole cathode made of copper 8 and iron waste as a pole anode 9, the latter leaning against a copper rod io. What here for silver-copper alloys is specified, applies accordingly to alloys with more than two components, d. H. that for each further metal a further correspondingly composed galvanic Element must be used or installed. It should also be clear that the The shape of the cells or elements is irrelevant, as is the possibility the generation of the electrolytes or the arrangement of the galvanic elements in separate or communicating vessels definitely falls within the scope of what has been described here. Furthermore, several can be used to accelerate the deposition of the dissolved metals Arrange galvanic elements in the cell or cells, thereby giving the possibility is, by means of a greater amperage or or and a larger anode surface Bring a larger amount of metal in the unit of time in solution, so that a substantial Time saving is achieved. Because at the same time through the application: more appropriate Alloys used as pole anodes are reduced by pre-refining the final refining costs are the same, both in terms of electricity as well as the electrolyte required for the solution. It is clear that the above The procedure described is not only applicable to the alloys of the precious metals, but for all alloys taking into account what has been said above. It is also clear that the electrolytes that have been used up can also be removed by this method from the electrolysis of only high-content alloys conveniently and with considerable cost savings can handle. The regeneration of the electrolyte can expediently by interposition one or more electrified cells (their cathodes in a diaphragm are housed) - between the last galvanic cell and the first electrolysis vessel take place. Furthermore, metal-containing alkalis, - as they are, for. B. at sulfuric acid leaching of copper ores, cyanide leaching of gold and silver ores, chlorinating, roasted gold ore or concentrates or copper- and zinc-containing pebble burns are obtained by this method advantageously to process. Optionally, after deposition of one or the other metal re-used alkaline solutions directly for leaching or by others usable components are freed; z. B. the liquors roasted chlorinated Gravel burns first from copper, then from electrolysis from zinc and from freezing out from the main amount of Glauber's salt, whereupon the lye is returned to the lye, or by precipitation of the copper according to this process, freezing out of the Glauber's salt, Lye new roasted goods, etc., until the zinc content has accumulated so far that its extraction by electrolysis or soda precipitation is worthwhile. The disadvantages the previously known electrolytic processes exist in the opinion of the inventor in that either only very rich or only very poor alloys are processed directly can all be in between- Metal exists as that is anodically dissolved metal or an alloy in the first galvanic element this with less noble metals. 3. The method according to claim a, characterized in that that there are further elements in addition to the two aforementioned galvanic elements connect whose pole anodes are made of ever less noble metals or alloys of the noblest metal, the anodic in the preceding galvanic element is solved, exist with less noble metals and their pole cathodes, from the associated Pole anodes separated by diaphragms, in the electrolyte of the preceding pole anode diving.- .. Device for carrying out the @ "process according to claims i to 3, characterized in that in a Behinter, the positive and negative power leads from an external power source has so many partitions made of porous, non-conductive, ; material suitable as a diaphragm are used, formed as galvanic elements should be. The walls are from. short-circuiting the electrodes of the galvanic elements Ladders attacked. Apparatus for carrying out the method according to the claims i to 3, characterized in that one is equipped with external power supplies Containers so many nested, open-topped boxes or frames made of diaphragm material are used to be formed as galvanic elements. The walls of the Boxes are made of conductors short-circuiting the electrodes of the galvanic elements encroached upon.