DE689282C - Process for cleaning copper - Google Patents

Description

Process for cleaning copper It is known that cuprous sulfate with carbon dioxide a water-soluble double compound, probably of the formula CutSO4 # 2CO # H20 forms with the formation of cupric sulfate as well as with development of carbon oxide and deposition of metallic copper decays when one of theirs. Solution to one which is above its decomposition point at the prevailing pressure Temperature warmed.

It has been found that by way of this double compound made of impure copper, such as B. raw copper obtained by metallurgy extraordinarily easy way and at low cost one of the impurities. This copper extract free copper and this with the extraction of carbon oxide can combine from such .containing gases, if one .upon the, impure copper in an acidic solution of cupric sulfate a gas mixture containing carbon monoxide one above the decomposition pressure at the temperature used Partial pressure of the carbon oxide: lets act, the solution thus obtained from the undissolved remaining impurities in the copper z. B. separates by filtration, the Cuprous sulfate-carbon-D-carbon dioxide which has gone into solution, decomposed by the fact that. the solution is exposed to such pressure and temperature conditions that the decomposition point the double compound is exceeded and the precipitated metallic Separates copper from the solution by filtration.

The inventor's experiments have shown that the copper obtained in this way even when processing heavily contaminated raw copper due to its extraordinary high pure. is excellent in that the impurities in the copper, as far as they do not go into solution, by filtering the solution under the action of the carbon monoxide formed from this solution. .removed can. In this The present procedure offers considerable relationship Advantages compared to the electrolytic cleaning process that was previously used for cleaning copper Process in which only small amounts of contamination are significant technical and economic "difficulties are raised.

It was further found that instead of or in addition to solutions of Cupric sulfate also solutions of salts of other acids, the cuprous salts of which are capable of without the formation of compounds with carbon monoxide which are insoluble in the reaction liquid to join together to form a double connection, can be used such. B. Solutions of the cupric salts of aromatic sulfonic acids, such as benzene sulfonic acid, the Phenol sulfonic acids or cresol sulfonic acids, or hydrofluoric acid or phosphoric acid.

According to a further embodiment of the invention, when using solutions of the cupric salts of sulfuric acid or the other aforementioned acids to form double compounds, which can then be broken down with regression of the cupric salts of the acids present and separation of pure metallic copper, also gas mixtures or vapor or gas-steam mixtures are brought into action on these solutions, which instead of or in addition to carbon monoxide unsaturated hydrocarbons, z. B. those of the formula series C. H2 "to C, 112.-6, such as ethylene, propylene, butylene, amylene, hexene, acetylene, methyl, ethyl, dimethyl, propylacetylene, propadiene, butadiene, isoprene, and contain Gas mixtures or steam or gas-steam mixtures which contain unsaturated derivatives of hydrocarbons such as alcohols, aldehydes and ethers. Examples of such compounds are: allyl alcohol, methyl allyl ether, acrolein.

In general, such substances have proven to be components of the processed gas, steam or gas-steam mixtures proved to be particularly suitable, their boiling points below the boiling temperature of the water or the used Copper salt solution, as z. B. the case with allyl alcohol or acrolein is because this results in the separation after the decomposition of the cupro salt double compound the substances mentioned that are set free again from the double compound facilitated by the formed aqueous cupric salt solution by distilling off will.

Gas or steam or gas-steam mixtures can also be used are, instead of or in addition to carbon monoxide, two or more of the aforementioned contain unsaturated carbon-containing compounds at the same time.

Mixtures of different copper salts can also be used Acids are used in the context of the invention.

The result of the splitting of the double compound with the cupro salt in Carbon oxides set free and / or the unsaturated ones set free here Carbon compounds or mixtures of such can be used for any purpose use, if necessary again for the production of pure copper from contaminated Raw copper, by adding these substances with suitable cupric salt solutions, to the impure Brings copper to the effect and the double connection formed in the process when suitable Temperature and pressure conditions split again.

The conversion of the copper and the cupric salt solution with the carbon monoxide or an unsaturated compound of the aforementioned type containing gas, vapor or gas-steam mixtures or both can be done in any way, e.g. B. in such a way, that the gas, steam or gas-steam mixture from bottom to top through a with the copper to be cleaned z. B. in the form of plates, chips or granules in a sent reaction tower lets flow through, through which in countercurrent to this from top to bottom the cupric salt solution is passed through in fine distribution. In all cases it is necessary that the partial pressure of the carbon oxide contained in the gas, steam or gas-steam mixture or the unsaturated carbon compound during the absorption process the decomposition pressure of the double compound to be formed at the prevailing temperature exceeds. To the gas, steam or gas-steam mixture that is in it in a certain amount contained carbon oxide or the carbon-containing compound as much as possible to withdraw, you can z. B. proceed so that in the course of the absorption process the applied total pressure of the gas, steam or gas-steam mixture with decreasing Content of the active substance contained therein continued or intermittently accordingly the decreasing partial pressure of the active substance so increased that the partial pressure of the constituent to be absorbed constantly the decomposition pressure of the: formed Double compound exceeds, or you can reverse the procedure in such a way that the temperature during the absorption process at constant gas pressure continued according to the reduced partial pressure of the active ingredient in the gas, steam or gas-steam mixture is lowered in order to respond to this way the reaction mixture below the decomposition point of the double compound formed to keep. Because the former method of working ultimately results in too high pressures and with the second working method, the temperatures are too low apart from the slowdown caused by the drop in temperature of the solution process, one will generally be content with extracting from the gas, Steam or gas-steam mixture only: a part of the carbon monoxide present in it or other active substance to get out, and one becomes expedient here work continuously at approximately the same total gas pressure and stop the action, as well as: the desired amount of the active ingredient from the gas, steam or Gas-vapor mixture is removed.

Since the dissolution is caused by an increase in temperature; of copper accelerates will; one is advantageous` at elevated temperature, z. B. in such a of -about roo °,, work. However, depending on the other working conditions , also higher or lower temperatures can be used, whereby it should be noted that that these must never exceed the temperature at the prevailing temperature Pressure, the desired double connection can be formed at all or is stable is.

The content of the cupric salt solution, as well as the acidity thereof fluctuate within wide limits. The pH value of the solution is to be measured as low as that a hydrolytic cleavage of the cupro salt formed with deposition of Cuprooxide, which contaminates the metallic copper to be deposited later would not be possible. When measuring the amount of existing Acid such as B. sulfuric acid or an organic sulfonic acid, is to be observed, that the decomposition pressure of the double compound generally increases with increasing concentration the acidity decreases, so that more concentrated acid, such as e.g. B. strong sulfuric acid, is suitable to take up the double compound faster than at low gas pressure the same acid in greater dilution. On the other hand, the application is available Acid concentration counteracts that with the increase in acid concentration in general the solubility of the copper salt in the reaction liquid decreases, so that one as a result in undesirable white with regard to the absorption capacity of the solution for the double connection is limited. It is true that one could do this with the solution process Eliminate the disadvantage that the reaction liquid is added to the formation the desired larger amounts of the double compound required, but in the Adds liquid insoluble cupris salt in solid form, taking this solid cupric salt gradually forming the cuprous salt double compound in solution would go. However, this mode of operation has the disadvantage that later in the following Decomposition of the cupro salt double compound formed during the dissolving process added cupris salt is excreted again in solid form, which leads to constipation the pipelines and other transport organs. On the other hand can also through in excess of the acid that is present in excess from the acid formed in the meantime Double compound precipitated metallic copper is attacked in an undesirable whiteness will.

The access of atmospheric oxygen should be during the absorption process should be avoided if possible, because the cupro salt present is undermined by oxygen Consumption of acid converted into cupric salt and the excretion of oxide-free Copper is made impossible.

The way in which the reaction components, are brought into action during the dissolution process, referenced. There one will practically in general be obliged to stop the absorption process at a higher level as. to carry out the atmospheric pressure, especially when using higher temperatures the respective partial pressure of the active component of the processed gas, steam or gas-vapor mixture at the existing temperature is to be exceeded it of course, if desired, to work at the lowest possible excess pressure to be able to, through suitable selection of other working conditions .the speed to increase the dissolution of the copper as much as possible. It has now been shown; that such an increase is particularly effective by using the. Copper in the largest possible surface and through as strong a movement as possible the liquid; opposite the copper surface can be achieved. Advantageous , one works here: so that the action of the z. B. finely distributed in the liquid introduced gas, vapor or gas-vapor mixture on the copper takes place in such a way that this is always only, expediently, continuously through as thin as possible renewed layer of liquid from that flowing past its surface Gas is disconnected.

To achieve this, you can, for. B. that advantageous in the form of granules. used copper while the solution is flowing through it by means of one Keep agitator in constant motion or in a rotating drum work with constant circulation of the copper and the liquid. Cheap Conditions are also present in the aforementioned action of the gas, steam or gas-vapor mixture on the copper in a reaction tower that is connected to the copper in the form of chips or ingots, the surface of which is charged by the from above added acidic cupric salt solution is sprinkled in a thin layer.

It has been shown that by .a suitable design of the Interaction of the reaction components can achieve a carbon-containing Gas the desired proportion of the carbon dioxide present in it already at a significant level to withdraw lower total gas pressures than is the case with a less effective arrangement would be the case.

It is thus possible, for example, with, a gas of 330 / a CO at a Kohlenoxydteildruck, pressure of 2 atmospheres, in i oo cc solution in 1 5 minutes 49 Cu dissolve when penetrated with the solution, granules agile at 2o ° during this time ; be stirred, while with the contents of the reaction chamber at rest and at 5 at CD pressure, only 0.5 g of Cu dissolve in 2 hours.

The remainder of the still contained in the exhaust gas of this absorption treatment Carbon oxide or the effective unsaturated organic carbon compound the gas, if the recovery of this residue is important, by known ones Measures are withdrawn. Optionally, in the starting gas or steam or Gas-vapor mixture before the treatment .according to the invention also an enrichment of the constituent or such constituents to be bound to the cupro compound in in any suitable manner.

If the exhaust gas or steam leaving the absorption process or gas-vapor mixture is under higher than atmospheric pressure, can Energy content before it is released into the atmosphere in a manner known per se Drive an expansion machine can be used.

The liquid obtained during the absorption process, which contains the impurities of the raw copper brought into solution partly in dissolved, partly in undissolved Forni contains, before the decomposition of the double compound of the undissolved constituents z. B. by filtration or by decantation, centrifugation or other Way freed.

The absorbed copper is precipitated again from the filtrate then in metallic, pure form with decomposition of the double compound formed according to the invention in such a way that, while the pressure is unchanged, the temperature is above the decomposition temperature of the double compound at this pressure increases or at unchanged temperature the pressure below the decomposition pressure of the double compound reduced at this temperature or by simultaneous use of these both measures, d. H. by increasing the temperature with a simultaneous decrease of the pressure .. It should be taken into account that, as was found, with one given temperature generally the decomposition pressure with the amount of in the Solution existing double lock increases.

After separation of the precipitated copper, the remaining Cupris salt solution used again to dissolve raw copper within the meaning of the invention will.

Small amounts of in that in the splitting of the double compound recovered gas or gas, steam or gas-steam mixture possibly present, through Oxidation of carbon monoxide or other carbon-containing compounds formed Carbon dioxide can be added to the gas or gas or steam or gas-steam mixture, if at the use of which the carbonic acid would be undesirable, in a known manner, e.g. B. by washing out with alkaline substances, such as. B. a suspension of calcium hydroxide.

A major advantage of the cleaning method according to the present Invention over conventional electrolytic cleaning processes is apart of the already mentioned greater insensitivity of the process to existing ones Impurities, in the far lower, possibly only on the supply of the sensible heat from exhaust gases limited power requirements as well as in the much better Utilization of space. Because it is possible when working according to the invention in proportion small systems far greater performance than with the electrolytic process to be achieved by, for example, using a device of a capacity from i into solution and a decomposer with a usable space of also i m3, in i hour boo to iooo kg of raw copper can be cleaned while by electrolysis under normal working conditions for 1 cm3 reaction space only about 2 kg per hour Copper can be cleaned.

Existing impurities are in contrast to the electrolytic one Cleaning process when working according to the invention is generally even advantageous, by local formation of elements under the action of such impurities Solution process is accelerated. An acceleration of the Solving process can also be provided by the presence of catalysts, e.g. B. halogen ions achieved be e.g. By adding hydrochloric acid to the reaction solution.

Since the shape or crystal size of the decomposition of the cupro salt double compound precipitated metallic copper depends on the temperature in such a way that the crystal size grows with increasing temperature, one is working after of the invention is also able, by choosing suitable temperature conditions, the Precipitation form of the copper obtained in a desired manner more or less largely to regulate. . Examples i. In an autoclave equipped with a stirrer is a gas mixture with vigorous stirring, which in addition to nitrogen, hydrogen and Carbonic acid still contains 33% CO, at 15 atm and 80 ° with 1 liter of an aqueous solution of, 400 g CU S 04 # 5 H20 and 8o, g H2 S O4 and copper granules for action brought, which are present in such an amount that they are only partially absorbed by the liquid are covered, the gas in the reaction chamber is constantly and rapidly renewed. After 5 Minutes, the solution is removed from the autoclave, cooled, filtered and filtered through Heat to 8o to. 9o ° decomposed. In the process, 60 copper is deposited, which is filtered off and washed out. At the same time, 441 carbon oxides escape and are captured and used for other purposes.

2. In an autoclave equipped with a stirrer, a gas mixture containing 40% ethylene hydrocarbons in addition to hydrogen and methane is mixed with 1 l of an aqueous solution of 400 g Cu S 04.5 H2 O and i oo g H2 S O4 and copper granules brought into action, which are present in such an amount that they are only partially covered by the liquid, with the gas in the reaction chamber being constantly and rapidly renewed. After 10 minutes the solution is removed from the autoclave, cooled, filtered and decomposed by heating to 100 °. 759 Cu are deposited, which are filtered off, washed out and dried. At the same time, 50 1 ethylene hydrocarbons escape, which are captured and used for other purposes.

Claims (1)

PATRNT CLAIM: i. Process for cleaning copper, characterized in, that. one on impure copper in an acidic solution of a cupric salt of an acid, their cupro salt, such as. B. the cuprous salt of sulfuric acid, aromatic sulfonic acids or phosphoric acid, is capable of without forming in dep * reaction liquid insoluble compounds with carbon monoxide to form a double compound, a gas containing carbon dioxide under a j, the decomposition pressure of the formed Carbon oxide double compound at the prevailing temperature and below the the partial pressure of the carbon oxide exceeding the respective concentration conditions of the solution brings to action the solution obtained by filtration from the dissolved Copper-derived impurities are freed in the filtrate by increasing the temperature or by reducing the pressure or by both until it falls below the Decomposition pressure of the carbon oxide double compound - this with the escape of carbon oxide and separation of the copper decomposed and the copper thus obtained from the solution separates. `2. The method according to claim i, characterized in that gas, steam or gas-vapor mixtures can be used in place of or in addition to carbon monoxide unsaturated hydrocarbons, e.g. B. those of the formula series C "H2n to Cn Hzn_ß, such as ethylene, acetylene, butadiene and the like or their derivatives, and preferably those substances which boil at a lower temperature than water or the copper salt solution used or mixtures of the aforementioned substances. 3. Method according to claim i, characterized in that gas, steam or gas-steam mixtures may be used which in place of or in addition to carbon monoxide one of an unsaturated Hydrocarbon, e.g. B. one of the formula series C, H ", to C" H2 ,, _ s, derived Alcohol or aldehyde or ether or two. or several such descendants of the aforementioned Contain hydrocarbons. 4. The method according to claims i to 3, characterized in that that with the action of the cupric salt solution and the carbon monoxide or the unsaturated one Ghs-, steam or gas = steam mixture containing carbon compounds expediently existing copper in the largest possible surface area for permanent Supplying fresh liquid to the copper surface by agitating the copper and / or the liquid z. B. by means of an agitator or by continuous Circulation in its rotary drum is taken care of. 5. Procedure according to claims i to g., characterized in that the gas, steam or gas-steam mixture from bottom to top through: one with the copper z. B. sent in the form of madmen, from above with the prisalz solution sprinkled tower is passed through. 6. Procedure according to claims i to 5, characterized in that the solution process - in the presence of catalysts suitable for accelerating it, such as halogen ions, in particular Chlorine ions ,. z. B. is carried out with the addition of hydrochloric acid. 7th Process according to Claims i to 6, characterized in that the splitting off of the Carbon oxide or the unsaturated carbon compound in the re-excretion of copper by increasing the temperature or decreasing the pressure simultaneous application of these two measures takes place.-B. Method according to claims i to 7, characterized in that the decomposition of the solution of the double compound Cupric salt solution, which has been re-formed with the excretion of copper, is again to be dissolved used by copper. 9. The method according to claims i to 8, characterized in that that, that. In the dissolving process under excess pressure escaping gas, steam or Gas-steam mixture is used to operate an expansion engine.