JP5102157B2 - Method and apparatus for removing and recovering copper from copper-containing acidic waste liquid - Google Patents

Description

  The present invention contains a high concentration of copper ions and acidic ions, such as an etching waste solution generated when etching a copper printed board with a cupric chloride etchant or a renewal waste solution of a plating bath solution in the production of electrolytic copper foil. The present invention relates to a method and an apparatus for removing and recovering copper by treating an acidic waste liquid.

  As an acidic waste liquid containing copper ions at a high concentration (hereinafter referred to as “copper-containing acidic waste liquid”), etching waste liquid generated when etching a copper printed board with a cupric chloride etchant or plating in the production of electrolytic copper foil Renewed waste liquid of bath liquid is known. These waste liquids have a high copper concentration of about 5 to 20% by mass (hereinafter simply referred to as “%”), while the concentration of coexisting chloride ions and sulfate ions is usually as high as 5 to 30%.

  As a copper recovery process for such a copper-containing acidic waste liquid, a method of depositing and recovering metallic copper by reacting with, for example, iron scrap using a difference in ionization tendency is performed in part. . However, this method has a low copper recovery rate from the waste liquid, and a waste liquid containing iron ions eluted by reaction with copper ions and copper ions that have not been recovered remains. It is hard to say that there is an efficient processing method.

  In addition, as a general treatment method for copper-containing acidic waste liquid, a treatment method is known in which heavy metals are precipitated and removed as a hydroxide by adding an alkaline substance such as sodium hydroxide. Since the sludge to be produced is bulky and large in volume, it is not suitable for the treatment of a copper-containing acidic waste liquid having a high copper ion concentration.

  Furthermore, as for the etching wastewater, a treatment method (Patent Document 1, etc.) is attempted in which alkali is added to insolubilize copper ions as copper hydroxide, and further an oxidizing agent is added to obtain copper oxide. However, when an oxidizing agent containing chloride ions such as hypochlorite and bleaching powder is used as the oxidizing agent in the art, the concentration of chloride ions in the liquid after addition is further increased, so that copper chloride and There are problems such as concern about the formation of double salts with copper oxide and the inclusion of salt in sludge, and when high concentration waste liquid is targeted, the amount of impurities contained in the recovered copper oxide is large. There are many points to be improved.

  On the other hand, when hydrogen peroxide is used as the oxidizing agent, the above-described increase in the salt concentration does not occur, but due to the following problems, this method cannot perform an efficient treatment. That is, when treating a strongly acidic waste liquid in which copper ions and chloride ions or sulfate ions coexist at a high concentration, an alkaline agent is added to the acidic liquid so that the acid side becomes neutral or alkaline. In the method of proceeding with neutralization, a solid containing a double salt of copper hydroxide and copper chloride or copper sulfate as a main component is precipitated at pH≈1.5 or more. And since the solid substance mainly composed of this double salt is not only high in impurity concentration, but also bulky compared to copper oxide, if it is used for the treatment of this waste liquid containing copper at a high concentration, There was a problem that it changed to paste-like sludge on the way, making the treatment difficult.

  Furthermore, this double salt does not proceed with oxidative decomposition with hydrogen peroxide, but acts as a decomposition catalyst for hydrogen peroxide. Therefore, even if hydrogen peroxide is added as an oxidizing agent to the liquid in which this solid is precipitated, There was also a problem that the reaction was terminated in a situation where hydrogen was unilaterally decomposed and consumed, and the oxidation treatment to copper oxide was incomplete.

  In order to avoid the formation of a paste of the target liquid accompanying the precipitation of the solid substance containing the double salt as a main component, the copper ion concentration is about 10 g / L or less and the chloride ion or sulfate ion concentration is 20 g / L during the neutralization treatment. It is effective to dilute to about L or less. However, this requires a large amount of dilution water, and there is a problem that the apparatus for processing becomes large accordingly.

  Furthermore, when processing a highly acidic waste liquid in which copper ions contained in the waste liquid and chloride ions or sulfate ions coexist at a high concentration, such as an etching waste liquid containing copper ions, an acidic solution containing copper is used. Even if hydrogen peroxide is first added to the waste liquid and coexisted, if the neutralization reaction proceeds from the acidic side to neutral or alkaline by injecting an alkaline agent, the reaction on the acidic side In the middle of the process, a precipitate mainly composed of the above-mentioned double salt is generated, so that much of the hydrogen peroxide is catalytically decomposed and disappears. There was a problem that the reaction was terminated when the oxidation treatment was partially incomplete. On the other hand, it is possible to improve the oxidation treatment status by adding a sufficient amount of hydrogen peroxide in anticipation of the shortage, but the amount of chemicals added increases and the efficiency is poor. Double salts that do not undergo oxidative decomposition with hydrogen oxide remain in the sludge. And this double salt itself can be dissolved from sludge by sufficiently washing with water to reduce the content concentration, but it requires a lot of washing water and contains copper ions in the washing waste water. Therefore, the processing is separately required, and the processing efficiency is poor from this point.

  Furthermore, in these techniques, the acidic liquid is treated with the alkaline side of pH = 8 to 12, so the situation on the rear side such as dehydration of the collected solids and the discharge of the supernatant water is taken into consideration, and the neutral side is located on the rear side. In this case, it is difficult to say that the method is efficient from this point of view.

  On the other hand, since the wastewater generated in the copper recovery process has a high salt concentration, it may be difficult to process and discharge the wastewater. Especially in places where wastewater with high salt concentration cannot be discharged and there is no contractor for industrial waste treatment, if there is no appropriate treatment means for wastewater with high salt concentration, the copper ion recovery process itself cannot be performed. .

  As described above, the copper ion concentration is high, but at the same time, there is no technology for efficiently recovering only copper from the copper-containing acidic waste liquid with a high salt concentration such as chloride ions that hinders copper recovery and reuse. The waste liquid was generally collected by an industrial waste disposal company and disposed of without being reused.

  In view of these circumstances, as a result of intensive studies to solve the above problems, the present inventors have found the following matters, and solid matter mainly composed of copper oxide from a copper-containing acidic waste liquid has a low chlorine content. The present invention has been completed which can be deposited and recovered in a state.

  That is, after mixing an acidic waste liquid containing a high concentration of copper ions, which is a treatment target liquid, for example, an etching waste liquid, and an oxidizing agent, the alkaline solution is poured into an alkaline agent solution while maintaining the pH within a predetermined pH range (alkali region). By adding and mixing, it was found that the formation of double salts can be avoided even in waste liquids containing a high concentration of chloride ions and the like, and copper ions in the waste liquid can be insolubilized and recovered as copper oxide. In addition, by sequentially proceeding with this oxidation reaction, a liquid with a low residual copper ion concentration can be obtained. By effectively utilizing the dilution effect of this liquid, the formation of double salts is avoided even in the final neutralized state. Therefore, the production reaction of copper oxide from copper ions by an oxidizing agent such as hydrogen peroxide can be maintained and proceeded well, which makes it possible to deposit copper oxide efficiently, and the final liquidity Has been found to be able to carry out a treatment that becomes weakly alkaline or neutral.

However, the above method also has a problem in terms of economy when put to practical use. That is, in the above method, a copper-containing acidic waste liquid is injected into a high-concentration alkaline solution, and a large amount of salt is generated by this neutralization reaction. However, the processing cost of the solution containing this salt as a waste liquid is low. It is expected to become a problem. It is also expected that the cost of the alkali agent and oxidant used in the reaction will reduce the economics of the reaction itself. Therefore, it is desired to reduce these costs and make the method more practical.
Japanese Patent Application No. 2002-212857

  Therefore, the present invention suppresses the generation amount of waste water, and also contains a high concentration of copper such as copper chloride-containing etching waste liquid and electrolytic copper foil plating bath renewal waste liquid that have been disposed of as industrial waste until now. It is an object of the present invention to provide a method and an apparatus for treating the waste liquid with high economic efficiency and with an efficient and low sludge generation amount and recovering copper oxide as a precipitate.

  As a result of intensive studies to solve the above problems, the present inventors have found the following matters and have completed the present invention. That is, after mixing an acidic waste liquid containing copper ions as a treatment target liquid at a high concentration with an oxidizer, the mixture is poured into an alkaline agent solution while being controlled within a predetermined pH range, and mixed, whereby the waste liquid is mixed. The copper ions are insolubilized as copper oxide and can be recovered by a solid-liquid separator. However, an oxidizing solution and an alkaline solution can be recovered by subjecting the resulting separated liquid from the solid-liquid separator to electrodialysis. It was found that the obtained oxidizing solution and alkaline solution can be reused as the oxidizing agent and alkaline agent used in the reaction, respectively. And in connection with this, it discovered that both the amount of water used, the amount of chemical | medical agents used, and a waste_water | drain discharge | emission flow volume could be reduced, and completed this invention.

  That is, the present invention adds a mixed solution of copper-containing acidic waste liquid and an oxidizing agent to an alkaline agent solution while controlling the pH of the alkaline agent solution after pouring the mixed solution so that it does not drop below 7 or less. In the method for recovering copper from the copper-containing acidic waste liquid obtained by solid-liquid separation of the solid matter mainly composed of copper oxide to be produced, the separated liquid after solid-liquid separation and / or the solid-solid separated washing is washed. A method for recovering copper from a copper-containing acidic waste liquid, characterized in that the effluent is subjected to electrodialysis and the oxidizing solution generated in the electrodialysis is recovered and used as at least a part of the oxidizing agent.

  In addition, the present invention adds a mixed liquid of copper-containing acidic waste liquid and an oxidizing agent to an alkaline agent solution while controlling the pH of the alkaline agent solution after pouring the mixed solution so as not to drop to 7 or less even temporarily. In the method for recovering copper from the copper-containing acidic waste liquid obtained by solid-liquid separation of the solid matter mainly composed of copper oxide to be produced, the separation liquid after solid-liquid separation and / or the solid matter after solid-liquid separation A method for recovering copper from a copper-containing acidic waste liquid, comprising subjecting the washing drainage to electrodialysis and recovering and using the alkaline solution generated in the electrodialysis as at least part of the alkaline agent.

  Furthermore, the present invention provides a reaction tank for reacting a mixed solution of an acid waste liquid containing copper and an oxidizing agent with an alkaline agent solution to precipitate as a solid containing copper oxide as a main component, and a solid / liquid for separating and recovering the solid. A reaction vessel and a solid-liquid separation device, including a separation device, a device for mixing an oxidizing agent and a copper-containing acidic waste liquid, and pouring the mixture into a reaction vessel, and an electrodialysis device for treating the separation liquid from the solid-liquid separation device Is communicated so that an alkaline suspension containing solids can be transferred, and the solid-liquid separation device and the electrodialysis device can separate the separation liquid from the solid-liquid separation device and / or the washing waste liquid of the solid matter after solid-liquid separation. It is connected to the desalination chamber of the electrodialyzer so that it can be supplied. Further, a pipe for returning the oxidizing solution generated in the anode chamber of the electrodialyzer to the oxidizer pipe and the alkaline solution generated in the alkali concentrating chamber are alkalinized. Features piping for returning to the agent piping A recovery device of copper from copper-containing acidic waste liquid to be.

  Furthermore, according to the present invention, the electrodialysis apparatus is partitioned by a cathode and a first anion exchange membrane, and is partitioned by a cathode chamber filled with an anion exchanger, a first anion exchange membrane and a first cation exchange membrane. An alkali concentration chamber, a desalting chamber defined by a first cation exchange membrane and a second anion exchange membrane, an acid concentration chamber defined by a second anion exchange membrane and a second cation exchange membrane, and a second cation It is the recovery apparatus of copper from the said copper containing acidic waste liquid comprised in order of the anode chamber divided with the exchange membrane and the anode, and being filled with the cation exchanger.

  According to the present invention, the copper-containing acidic waste liquid and the oxidizing agent are mixed, and then added to the alkaline agent solution while being controlled in a predetermined pH range (alkaline range), and mixed, so that the copper ions in the waste liquid are mixed. Can be insolubilized and recovered as copper oxide. In addition, by using the electrolyzed separation water or the like generated by the solid-liquid separation operation, the amount of the chemical used, the amount of waste, and the amount of water for use can be reduced by generating an oxidizing solution and an alkaline solution.

  In the treatment process according to the method of the present invention, a copper-containing acidic waste liquid and an oxidizing agent are first mixed, and the obtained mixed solution is poured into an alkaline agent solution to produce a solid mainly composed of copper oxide. Liquid separation is performed, copper oxide is recovered, and the separated water is further electrodialyzed and reused as an oxidizing solution and an alkaline solution.

  The copper-containing acidic waste liquid to be treated by the method of the present invention is an acidic waste liquid containing copper in an ionic state, and can be applied to the copper ion concentration and anion concentration contained therein without any particular restrictions. For example, a copper printed board It can be applied particularly advantageously to waste liquids with high copper ion concentration or salt concentration, such as etching waste liquid generated when etching copper cupric chloride etching solution or plating bath liquid renewal waste liquid in electrolytic copper foil production. .

  Moreover, as an oxidizing agent utilized by this invention method, various oxidizing agents can be utilized if a bivalent copper ion can be made into a copper oxide. Since it can be handled as a solution and no components other than water remain after the reaction, hydrogen peroxide, ozone water, etc. are used effectively, and hydrogen peroxide is particularly suitable because it does not require a special generator and is easy to handle. However, gaseous ozone may be directly blown into the waste liquid or oxidant solution as an oxidant. As will be described in detail later, an oxidizing solution produced in the anode chamber by electrodialysis can be used as an oxidizing agent.

  Further, as the alkali agent used in the present invention, various alkali agents can be used, but alkali metal hydroxides which do not have the possibility of forming a precipitating salt with an anion that may coexist. Sodium hydroxide is preferably used because it is relatively inexpensive and easily available. Moreover, when it obtains as aqueous solution, there exists an advantage which can be used easily, However, You may dissolve and use a solid alkali agent suitably. In addition, when using a solid alkali, you may make it melt | dissolve previously and you may supply to a reaction tank, and you may supply a reaction tank as a solid state, and may make a reaction tank and a dissolution tank serve as both. Moreover, although demonstrated in detail later, the alkaline solution produced | generated in the alkali concentration chamber by electrodialysis can be utilized.

  It is particularly important that the method of the present invention be carried out in the order of first mixing the copper-containing acidic waste liquid and the oxidizing agent, and pouring the resulting mixed liquid into the alkaline agent solution. Therefore, the importance of the mixing and reaction sequence will be described below, taking as an example the case of using a hydrogen peroxide solution as the oxidant solution and sodium hydroxide as the alkali agent.

  First, in the order of adding an alkaline agent to a copper-containing acidic waste liquid containing copper ions at a high concentration, as described in the prior art, double salt formation occurs, and sludge with properties that are difficult to treat is deposited. It becomes.

  In addition, when the copper-containing acidic waste liquid is added to the alkaline agent before mixing with the hydrogen peroxide solution, copper hydroxide is precipitated first. When a hydrogen peroxide solution is added thereto, the copper hydroxide solid precipitated in the solution is oxidized, so that the efficiency of the oxidation reaction of hydrogen peroxide to copper oxide is reduced.

  In addition, when waste liquid containing cuprous ions, such as etching waste liquid, is treated, if it is added to an alkaline agent before mixing with hydrogen peroxide, it will also precipitate as cuprous chloride (CuCl). To do. Since the cuprous chloride (CuCl) precipitate acts as a decomposition catalyst for hydrogen peroxide, the hydrogen peroxide is consumed, and the efficiency of the oxidation reaction with hydrogen peroxide is further reduced.

  As described above, in the treatment process according to the present invention, it is important to mix the copper-containing waste liquid and the hydrogen peroxide solution before mixing and reacting with the alkaline agent solution. Thereby, the oxidation reaction to the copper oxide of the cupric ion contained in a waste liquid advances rapidly, when it adds to an alkaline agent. In addition, when cuprous ions are contained in the waste liquid, the solubility of the cuprous salt is low. However, mixing with hydrogen peroxide before contacting with the alkali agent causes the oxidation of hydrogen peroxide. Since cuprous ions are oxidized to cupric ions, precipitation of cuprous salts such as cuprous chloride (CuCl) can be avoided.

  In the present invention, the time required for mixing the copper-containing waste liquid and the hydrogen peroxide solution depends on the concentration of both of the mixing, but when both are high in concentration, the cuprous ion is about 5 seconds. Oxidation is carried out at a considerable rate even in a short time, and the oxidation reaction proceeds sufficiently in about 20 seconds.

  On the other hand, when the copper-containing acidic waste liquid and the hydrogen peroxide solution are mixed, the decomposition reaction of hydrogen peroxide proceeds. The decomposition reaction becomes apparent from the time when about 60 seconds have passed after mixing the both, and proceeds violently with remarkable foaming after 7 to 10 minutes. Depending on the concentration of both, for example, when hydrogen peroxide in a molar concentration of copper ions is mixed twice as much, foaming accompanying the decomposition of hydrogen peroxide decreases after 20 minutes of mixing, After a lapse of 25 minutes, the amount becomes slight, and when added to the alkaline agent at this time, a precipitate containing more copper hydroxide than copper oxide is formed.

  For this reason, prior to pouring into the alkaline agent, mixing the copper-containing acidic waste liquid and the hydrogen peroxide solution, the reaction time is about 5 seconds to 20 minutes, preferably about 20 seconds to 7 minutes. This time setting is one of the features of the present technology.

  As described above, as a method of mixing the copper-containing waste liquid and the hydrogen peroxide solution, for example, a method of adding both liquids into one or a plurality of mixing tanks and stirring, a copper-containing waste liquid and a hydrogen peroxide solution, It is possible to apply a method of mixing and mixing them.

  Among these, in the method of injecting both liquids into the mixing tank and stirring, when the mixing tank is used in a batch system, control of the reaction time from mixing to pouring becomes a problem. It is easy to check and adjust the amount, and there is an advantage that even if foaming occurs during mixing, there is no problem on the apparatus because it is an open system.

  In addition, in the method of mixing and mixing the copper-containing waste liquid and the hydrogen peroxide solution, the pipes of both solutions are connected by connecting them with a two-letter pipe or the like, and the other liquid is injected into one of the pipes. A method of mixing can be used. Furthermore, both liquids can be stirred and mixed by passing through a static mixer after merging. This method requires pressure resistance of the device to cope with foaming or a mechanism that can discharge the generated gas, but keeps the time from mixing and supplying both solutions uniform and continuous. There is an advantage that can be supplied to. Further, the copper-containing waste liquid and the hydrogen peroxide solution can be brought into the air from the water surface of the reaction tank to join them. In this case, it is desirable to place a baffle or the like in the falling flow to ensure the reaction time and the mixed state.

  Next, a reaction between a mixed solution of a copper-containing waste liquid and a hydrogen peroxide solution (hereinafter abbreviated as “mixed solution”) and an alkaline agent is used. It is necessary to react under conditions where the copper concentration is dilute. Moreover, in order to advance the oxidation reaction of copper ions promptly, it is desirable to carry out the reaction under strongly alkaline conditions where the reactivity of hydrogen peroxide is high.

  In order to realize these conditions, in the technology of the present invention, an alkaline agent of a solution body with good operability is used, and the above mixed solution is poured at an appropriate rate while stirring the alkaline agent solution. It is necessary to go. The pouring acceleration is added and mixed in the alkaline agent solution after pouring while controlling the pH so that it does not partially drop to 7 or less, preferably 8 or less. Therefore, it is necessary to proceed and complete the sequential reaction, and this is another feature of the technology of the present invention.

  As a method of pouring the mixed liquid, for example, a method such as a method of dropping into a reaction tank containing an alkaline agent or a method of pouring into a liquid through a pipe can be applied. Among these, the method of dropping into the reaction tank has an advantage that the supply status can be visually confirmed and that it is easy to cope with the supply status being unsatisfactory. On the other hand, the method of supplying the liquid through the pipe has an advantage that it can be supplied to a position where the mixing can be satisfactorily mixed on the distribution of the stirring flow as compared with the case of supplying from the liquid surface. When the mixing tank is sufficiently smaller than the reaction tank and can be added within the reaction time limit, dispensing can be performed with simple equipment by dispensing each batch of the mixing tank. There are also a method of sequentially using a plurality of mixing tanks and a method in which the mixing tank is completely mixed so that the residence time is within the reaction limit time. In addition, in the method of inject | pouring into a liquid through piping, the method of adding continuously the liquid mixture created by making a copper containing waste liquid and a hydrogen peroxide solution merge can be used conveniently.

  Further, as a method of adding and mixing in the alkaline agent solution while controlling so that the pH does not drop to 7 or less even temporarily, a small amount of the mixed solution is added to the alkaline agent solution in a stirring and mixing state, for example. Examples thereof include a method of intermittently adding at intervals and a method of adding a mixed solution little by little. At this time, the amount of the mixed solution added to the alkaline agent solution may be 7 or less, preferably 8 or more at the end of the final reaction, even if the pH of the alkaline solution is temporarily 7 or less. For example, it can be arbitrarily adjusted within a certain range described later. By this operation, the main oxidation reaction can be efficiently performed under the strong alkaline condition of pH 11.5 to 14.5 with high reactivity of hydrogen peroxide while obtaining the dilution effect by the alkaline agent solution, A liquid having a low concentration of copper as ions can be obtained by sequentially advancing and completing the oxidation reaction. In addition, as a pH control method of the alkaline agent solution in the reaction vessel, the alkaline agent can be replenished and supplied to the reaction vessel.

  In addition, at the stage where the amount of acid relative to the alkaline agent reaches the same level, the amount of liquid with a low copper ion-containing concentration obtained as a result of the previous reaction is relative to the amount of liquid mixture added. Therefore, it is possible to avoid the formation of double salt even under the conditions of pH 7 to 11.5, preferably pH 8 to 11 by the effect of diluting by this, and from the copper ions by hydrogen peroxide. The formation reaction of copper oxide can be well maintained and progressed. As a result, it is possible to efficiently deposit copper oxide and to perform a process in which the final liquidity is near neutral.

  The concentration of the alkaline agent solution to which the mixed solution is poured is not particularly limited as long as the pH in the reaction vessel can be maintained within a predetermined range, but can be treated when the alkali concentration in the reaction vessel is low. For example, it is preferable to use a sodium hydroxide solution having a concentration of 25% because there is a problem that the amount of waste liquid becomes small or the amount of drainage increases.

  On the other hand, the concentration of hydrogen peroxide used in the above treatment is not particularly limited. However, if the concentration is too low, the required amount of liquid becomes large and the reaction efficiency becomes low. For example, it is preferable to use a concentration of about 30%. .

  The solid matter generated after the treatment of the copper-containing acidic waste liquid described above has copper oxide as a main component, and is relatively easy to solid-liquid separation and has a relatively good dehydration property. However, in the case of a copper-containing acidic waste liquid containing a high concentration of copper ions, since a concentrated acid and alkali are mixed and processed, the solids at the completion of the reaction are highly concentrated salts generated by the neutralization reaction. Coexist with. Therefore, when collecting solids for reuse, it is effective to wash these salts by repeating washing with water a plurality of times to increase the purity of the collected material.

  As a solid-liquid separation method in this case, for example, filtration separation, centrifugal separation, sedimentation separation, and the like can be applied. Thereby, an alkaline separation liquid having a high salt concentration can be obtained. Moreover, the solid substance which separated into solid and liquid can also wash | clean the attached salt with washing water. As washing water used here, clear water with a low salt content, for example, tap water or industrial water, may be used. It is also effective to reuse the treated water obtained by desalting the drained water and / or the filtrate separated by solid-liquid.

  The basic feature of the present invention is that the separated liquid (alkaline solution containing a large amount of salts) and / or solid after the solid matter mainly composed of copper oxide produced as described above is separated by solid-liquid separation. The liquid separated solid waste liquid (not so much as the separated liquid but alkaline solution containing a lot of salts) is subjected to electrodialysis, and at least a part of the alkaline solution and the oxidizing solution generated in the electrodialysis is recovered. These are reused as an alkali agent and an oxidizing agent, respectively.

  Thus, in the present invention, in addition to the above alkaline agent, an alkaline aqueous solution can be obtained by subjecting a separation liquid produced by solid-liquid separation treatment or washing waste liquid to electrodialysis, and the reason why this can be used as an alkaline agent solution. It is as follows.

  That is, as shown in FIG. 2 to be described later, the electrodialysis apparatus is divided by a cathode and a first anion exchange membrane, and is filled with an anion exchanger, a first anion exchange membrane and a first cation exchange membrane. An alkali concentrating chamber partitioned by, a desalting chamber partitioned by a first cation exchange membrane and a second anion exchange membrane, an acid concentrating chamber partitioned by a second anion exchange membrane and a second cation exchange membrane, and The anode chamber is partitioned by the second cation exchange membrane and the anode, and the anode chamber filled with the cation exchanger is arranged in this order.

  Then, after injecting an alkaline solution containing a large amount of a salt such as a separation solution into the desalting chamber, electrodialysis is performed, and by applying current, the cation exchange membrane passes through the cation exchange membrane to the alkali concentration chamber on the cathode side. However, this cation cannot pass through the anion exchange membrane that partitions the alkali concentrating chamber on the opposite side, and accumulates in the alkali concentrating chamber, thereby increasing the alkalinity of the solution in the alkali concentrating chamber. For this reason, the alkaline solution can be recovered in the alkaline concentration chamber and reused as an alkaline agent. However, if the concentration of the alkaline solution is low, the alkaline agent concentration is further increased by replenishing the alkaline agent concentration. It is desirable to increase.

  Similarly, an oxidizing aqueous solution can be obtained by subjecting the separation liquid produced in the solid-liquid separation treatment or the washing waste liquid to electrodialysis, and this can be used as an oxidizing agent for the following reasons.

  That is, in the anode chamber of the electrodialysis apparatus, the anion in the acid concentrating chamber is blocked by the cation exchange membrane that partitions the chamber, and the cation from the desalting chamber is blocked by the anion exchange membrane in front of it. Therefore, only water will exist. In this anode chamber, there is no chlorine as an anion, so there is no generation of free chlorine, and the reaction in this anode chamber is an electrolysis of water represented by the following formulas (I) and / or (II) A reaction occurs, and an oxidizing solution containing hydrogen peroxide and the like is generated.

2H ₂ O → H ₂ O ₂ + 2H ⁺ + 2e ⁻ (I)
2H ₂ O → 4H ⁺ + O ₂ + 4e ⁻ (II)

  In the method of the present invention, the oxidizing solution produced in the anode chamber by electrodialysis can be used as an oxidizing agent. However, when the oxidizing power is low, hydrogen peroxide solution is added or gaseous ozone is added. It is desirable to increase the oxidizing power by a method such as blowing.

  In this way, separation liquid and washing waste liquid that are originally treated as waste liquid can be recovered and used as an alkaline solution or an oxidizing solution by using electrodialysis, thereby reducing costs and labor of waste liquid treatment. In particular, copper can be recovered from the copper-containing acidic waste liquid as a solid containing copper oxide as a main component.

  Next, some aspects of the recovery apparatus used for carrying out the method of the present invention will be described with reference to the drawings.

  FIG. 1 is a system diagram showing an embodiment of a copper recovery apparatus when the present invention is implemented. In the figure, 1 is a copper recovery device, 2 is a reaction tank, 3 is a solid-liquid separation device, 4 is a copper-containing acidic waste liquid piping, 5 is an oxidizing agent supply piping, 6 is a mixing piping, 7 is a flow controller, and 8 is an alkali. Supply pipe, 9 is a pH meter, 10 is a stirrer, 11 is a transfer pump, 12 is a liquid level meter, 13 is a wash water supply pipe, 14 is an electrodialyzer, 15 is a desalted water return pipe, and 16 is an oxidant solution return. Pipes 17 are alkaline agent return pipes.

  A copper recovery apparatus 1 shown in FIG. 1 has a reaction tank 2 provided with a stirrer 10, a pH meter 9 and a liquid level meter 12, and a solid-liquid separation apparatus 3 communicated with the reaction tank 2 via a transfer pump 11. The upper part of the reaction tank 2 is provided with a mixed pipe 6 in which the copper-containing acidic waste liquid pipe 4 and the oxidant supply pipe 5 are combined, and the mixed liquid of the copper-containing acidic waste liquid and the oxidant is in the reaction tank 2. Can be added. The amounts of the copper-containing acidic waste liquid and the oxidant to be added are adjusted by the flow rate controllers 7a and 7b provided in the copper-containing acidic waste liquid pipe 4 and the oxidant supply pipe 5, respectively. It is generated by the mixing pipe 6.

  The alkaline agent solution is supplied to the reaction tank 2 from the alkali supply pipe 8. Then, a mixed solution of copper-containing acidic waste liquid and oxidizing agent is injected from the mixing pipe 6 into the alkaline agent solution stirred by the stirrer 10, and the pH change at that time is measured by the pH meter 9, and the flow rate controller The pH is controlled by 7a and 7b so as not to become 7 or less even temporarily.

  The solid matter mainly composed of copper oxide generated in the reaction tank 2 is transferred to the solid-liquid separation device 3 via the transfer pump 11, and is separated into the solid matter and the separation liquid here. Further, the solid matter is washed by the washing water supplied from the washing water supply pipe 13 in the solid matter purification device 18, taken out of the system, and reused as copper oxide.

  On the other hand, a part of the separation liquid is directly returned to the reaction tank 2 through the separation liquid return pipe 19, and the other is sent to the electrodialysis apparatus 14 and subjected to electrodialysis.

  FIG. 2 shows an example of the configuration of the electrodialysis equipment used in the present invention. In the figure, 20 is a cathode, 21 is a first anion exchange membrane, 22 is a first cation exchange membrane, 23 is a second anion exchange membrane, 24 is a second cation exchange membrane, 25 is an anode, 26 is a cathode chamber, Reference numeral 27 denotes an alkali concentration chamber, 28 denotes a desalting chamber, 29 denotes an acid concentration chamber, and 30 denotes an anode chamber. An anion exchanger (including fibers and spacers) 31 is filled in a cathode chamber 26 that is partitioned and configured between the cathode 20 and the first anion exchange membrane 21, and between the anode 25 and the second cation exchanger 24. These anode chambers 30 are filled with a cation exchanger (including fibers and spacers) 32.

  In the desalting chamber 28 between the first cation exchange membrane 22 and the second anion exchange membrane 23, the separation liquid and / or the washing waste liquid (hereinafter referred to as “salt solution”) may be used. ) Is supplied. Further, the alkali concentration chamber 27 partitioned by these between the first anion exchange membrane 21 and the first cation exchange membrane 22, and the partition between these by the second anion exchange membrane 23 and the second cation exchange membrane 24 are partitioned. The acid concentration chamber 29 and the cathode chamber 26 are respectively supplied with effluent water or pure water from the desalting chamber 28, and the anode chamber 30 is supplied with cathode chamber effluent water or gas separated by a gas-liquid separator 33. Pure water is supplied.

  FIG. 2 also illustrates the movement of ions when an alkaline solution containing a large amount of sodium chloride is placed in the desalting chamber 28, but when an electric current is applied to the electrodialysis equipment, this causes the anode from the desalting chamber 28. Anions such as chloride ions move toward the side. However, this is blocked by the second cation exchange membrane 24 and cannot move to the anode chamber 30, but is accumulated in the acid concentration chamber 29. Similarly, cations such as sodium ions move toward the cathode side, but they are also blocked by the first anion exchange membrane and cannot reach the cathode chamber 26 and are accumulated in the alkali concentration chamber 27. The

  Moreover, in the cathode chamber 26 due to the electrolysis of water at the cathode 20 generated by electrodialysis, hydroxide ions and hydrogen are generated by the following reaction, and these hydroxide ions migrate to the alkali concentration chamber 27. However, the first cation exchange membrane 22 cannot move to the desalting chamber 28.

2H ₂ O + 2e ⁻ → 2OH ⁻ + H ₂ (III)

  On the other hand, according to the formula (I) or (II), the hydrogen ions generated in the anode chamber 30 by the electrolysis of water at the anode 25 migrate to the acid concentration chamber 29 but interfere with the second anion exchange membrane 23. Thus, the desalting chamber 28 is not reached.

  With such a mechanism, alkali is concentrated in the alkali concentrating chamber 27 adjacent to the cathode side of the desalting chamber 28, and acid is concentrated in the acid concentrating chamber 29 adjacent to the anode side. The alkaline solution concentrated in the chamber 27 is recovered and used as an alkaline agent solution. The acid solution concentrated in the acid concentration chamber 29 cannot be directly recovered and used in the apparatus of the present invention, but if the acid copper-containing waste liquid mainly contains hydrochloric acid, the concentrated acid solution mainly contains hydrochloric acid. For example, it can be used as an etching solution.

  Further, as described above, since no chloride ions exist in the anode chamber 30, there is no generation reaction of free chlorine by electrolysis at the anode, and an oxidizing agent such as hydrogen peroxide is generated. . And since the free chlorine by electrolysis is not produced | generated, damage to an electrode is also prevented.

  In addition, since the demineralized water produced | generated with the electrodialyzer 14 is a thing which hardly contains salt, for example, it can return to the washing water supply piping 13, and can also be reused as washing water. Alternatively, it can be used as a replenisher in the cathode chamber 26, the alkali concentration chamber 27, the acid concentration chamber 28, and the like. In addition, the ionic water containing hydroxide ions and hydrogen generated in the cathode chamber is, for example, removed to the anode chamber 30 after removing the hydrogen gas by the gas-liquid separator 33 and used as supplementary water. You can also.

  The system diagram shown in FIG. 3 is a drawing showing a copper recovery apparatus according to another aspect of the present invention. The copper recovery device of this embodiment is basically the same as the recovery device of FIG. 1, but differs in that a membrane filtration device 44 is provided in the previous stage of the electrodialysis device 14.

  In the apparatus of this aspect, the concentrated water by membrane filtration is discharged out of the system from the concentrate pipe 46, and the permeate is supplied to the electrodialyzer 14 through the membrane filtration permeate pipe 45 as in the embodiment of FIG. In this embodiment, since alkali is also discharged as concentrated water, the alkali recovery rate is low and the replenishment amount of the alkaline agent is increased, but impurities in the acidic waste liquid are discharged out of the system as concentrated water for membrane treatment. Therefore, there is an advantage that demineralized water can be obtained with a high stability as a device and a small current requirement.

  According to the copper recovery method and apparatus of the present invention described above, it is necessary to install an electrodialysis apparatus and its operating power, but it is possible to recover a high-purity solid of copper oxide and to recover the alkalinity recovered by electrodialysis. Since the solution and the oxidizing solution can be reused, the purchase amount of the alkaline agent and the oxidizing agent can be reduced, and furthermore, the amount of waste and drainage can be greatly reduced, so that the economy is excellent It can be said.

  Therefore, the copper recovery method and apparatus of the present invention is particularly advantageously used when it is necessary to treat a waste solution having a high copper ion concentration or salt concentration, such as an etching waste solution or a renewal waste solution of a plating bath in electrolytic copper foil production. be able to.

It is a systematic diagram which shows the one aspect | mode of the copper collection | recovery apparatus of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is drawing which showed typically the electrodialysis apparatus used by this invention. It is a systematic diagram which shows the other aspect of the copper collection | recovery apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ...... Copper recovery apparatus 2 ...... Reaction tank 3 ...... Solid-liquid separator 4 ...... Copper-containing acidic waste liquid piping 5 ...... Oxidant supply piping 6 ...... Mixing piping 7 ...... Flow controller 8 ...... Alkali supply piping 9…… pH meter 10…… Stirrer 11…… Transfer pump 12…… Liquid level meter 13…… Washing water supply piping 14…… Electrodialyzer 15…… Desalinated water return piping 16…… Oxidant solution return piping 17 ……… Alkaline agent return pipe 18…… Solids purification device 19…… Separation liquid return pipe 20…… Cathode 21…… First anion exchange membrane 22…… First cation exchange membrane 23…… Second anion exchange membrane 24… ... Second cation exchange membrane 25 ... ... Anode 26 ... ... Cathode chamber 27 ... ... Alkaline concentration chamber 28 ... ... Desalination chamber 29 ... ... Acid concentration chamber 30 ... ... Anode chamber 31 ... ... Fibrous anion exchanger 32 ... ... Fibrous cation exchanger 33 ... ... Gas-liquid separator 40 ... ... Solid-containing liquid pipe 41 ... ... Separation liquid pipe 42 ... ... Washing drain pipe 43 ... ... Acid (waste liquid) pipe 44 …… Membrane filtration device 45…… Membrane filtration permeate piping 46…… Concentrate piping (waste liquid)

Claims (10)

  Oxidation produced by adding a mixed liquid of copper-containing acidic waste liquid and oxidizing agent to the alkaline agent solution while controlling so that the pH of the alkaline agent solution after pouring the mixed solution does not temporarily drop below 7 In a method for recovering copper from a copper-containing acidic waste liquid obtained by solid-liquid separation of solids containing copper as a main component, electrodialysis of the separated liquid after solid-liquid separation and / or the washing waste liquid of the solid-liquid separated solid is separated And a method for recovering copper from a copper-containing acidic waste liquid, wherein the oxidizing solution produced in the electrodialysis is recovered and used as at least part of an oxidizing agent.   Oxidation produced by adding a mixed liquid of copper-containing acidic waste liquid and oxidizing agent to the alkaline agent solution while controlling so that the pH of the alkaline agent solution after pouring the mixed solution does not temporarily drop below 7 In a method for recovering copper from a copper-containing acidic waste liquid that obtains solids mainly composed of copper by solid-liquid separation, the separation liquid after solid-liquid separation and / or the washing waste liquid after solid-liquid separation is electrically A method for recovering copper from a copper-containing acidic waste liquid, characterized in that the alkaline solution produced by electrodialysis is recovered and used as at least part of an alkaline agent.   The electrodialysis is divided into a cathode and a first anion exchange membrane, a cathode chamber filled with an anion exchanger, an alkali concentration chamber partitioned by a first anion exchange membrane and a first cation exchange membrane, Desalination chamber partitioned by cation exchange membrane and second anion exchange membrane, acid concentration chamber partitioned by second anion exchange membrane and second cation exchange membrane, and partitioned by second cation exchange membrane and anode Using an electrodialyzer configured in the order of an anode chamber filled with a cation exchanger, washing of the separated liquid after solid-liquid separation and / or solid matter after solid-liquid separation is performed in the desalting chamber of the electrodialyzer. The method for recovering copper from a copper-containing acidic waste liquid according to claim 1 or 2, which is carried out by supplying a drainage liquid.   The method for recovering copper from a copper-containing acidic waste liquid according to claim 1 or 3, wherein the oxidizing solution is produced in an anode chamber of an electrodialyzer.   The method for recovering copper from a copper-containing acidic waste liquid according to claim 2 or 3, wherein the alkaline solution is produced in an alkali concentration chamber of an electrodialyzer.   The method for recovering copper from a copper-containing acidic waste liquid according to any one of claims 1 to 5, wherein membrane treatment is performed prior to the electrodialysis.   In the electrodialysis, the alkali concentration chamber, the acid concentration chamber, and the cathode chamber are supplied with effluent water or pure water from a desalting chamber, and the anode chamber is subjected to gas chamber separation after effluent or pure water. A method for recovering copper from a copper-containing acidic waste liquid according to any one of claims 3 to 6.   A reaction tank for reacting a mixed solution of copper-containing acidic waste liquid and an oxidizing agent with an alkaline agent solution to precipitate the solid as a main component of copper oxide, a solid-liquid separator for separating and recovering the solid, and an oxidation Including a device for mixing the agent and the copper-containing acidic waste liquid and pouring it into the reaction tank, and an electrodialyzer for processing the separated liquid from the solid-liquid separator, and the reaction tank and the solid-liquid separator are solid substances. The alkaline suspension containing the mixture is communicated so that it can be transported. The solid-liquid separation device and the electrodialysis device remove the separation liquid from the solid-liquid separation device and / or the washing waste liquid of the solid matter after solid-liquid separation from the electrodialysis device. It is connected to the salt chamber so that it can be supplied, and further, the piping for returning the oxidizing solution generated in the anode chamber of the electrodialyzer to the oxidizing agent piping and the alkaline solution generated in the alkali concentrating chamber are returned to the alkaline agent piping. Copper-containing acid characterized by providing piping for Recovery system of copper from the waste.   The electrodialysis apparatus is partitioned by a cathode and a first anion exchange membrane and filled with an anion exchanger, an alkaline concentration chamber partitioned by a first anion exchange membrane and a first cation exchange membrane, a first Desalination chamber partitioned by the cation exchange membrane and the second anion exchange membrane, an acid concentration chamber partitioned by the second anion exchange membrane and the second cation exchange membrane, and a partition by the second cation exchange membrane and the anode 9. The copper recovery apparatus according to claim 8, wherein the copper recovery apparatus is configured in the order of an anode chamber filled with a cation exchanger. The copper recovery apparatus according to claim 8 or 9, further comprising a membrane treatment device for treating separated water between the solid-liquid separation device and the electrodialysis device.

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