JP5307478B2 - Method and apparatus for recovering copper-containing solid from copper-containing acidic waste liquid - Google Patents

Description

  The present invention treats copper by treating an acidic waste liquid containing copper ions, such as an etching waste liquid generated when etching a copper printed board with a cupric chloride etchant or a plating bath renewal waste liquid in electrolytic copper foil production. The present invention relates to a removal and recovery method and apparatus.

  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%. Further, in the etching waste liquid, chloride ions are contained at a high ratio of 2 times or more in molar ratio with respect to the contained copper ions.

  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 volume of sludge to be produced is high and the amount is large, it is not suitable for the treatment of 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 or bleaching powder is used as the oxidizing agent in the art, the concentration of chloride ions in the liquid after the addition becomes higher, 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 solids mainly composed of this double salt are bulky, when it is used for the treatment of this waste liquid containing copper at a high concentration, the waste liquid changes to paste-like sludge during the neutralization process. There was a problem that would be difficult.

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

  In order to avoid paste-like treatment liquid (waste liquid) due to precipitation of solids composed mainly of this double salt, the copper ion concentration is about 10 g / L or less, chloride ions or sulfate ions during neutralization treatment. It is effective to dilute so that the concentration is about 20 g / 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 etching waste water containing copper ions, an acid containing copper is treated. Even if hydrogen peroxide is first added to the waste liquid and coexisted, if an alkali agent is injected into the waste liquid and the neutralization reaction proceeds from the acidic side to neutral to alkaline, Since some precipitates mainly composed of double salts are produced, most of the hydrogen peroxide is catalytically decomposed and disappears, and due to the insufficient amount of hydrogen peroxide, oxidation treatment to copper oxide is partly performed. There was a problem that the reaction ended in an incomplete situation. 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 requires a lot of water for washing 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. However, it is difficult to say that the method is efficient from this point of view.

  As mentioned above, since there is no technology for efficiently recovering only copper from acidic copper waste liquids with high salt concentrations such as chloride ions that hinder the recovery and reuse of copper, these waste liquids are generally disposed of in industrial waste. It was often collected by a waste disposal company and disposed of without being reused.

  In view of these circumstances, as a result of intensive research to solve the above problems, the present inventors have found the following matters, copper from the acidic copper waste liquid, the solids mainly composed of copper oxide, the chlorine content The present invention has been completed which can be precipitated and recovered in a state where there is little amount of.

  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, this is added to an alkaline agent solution while managing it in a predetermined pH range (alkali region). It has been found that, by mixing, 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 as copper oxide and removed and recovered. 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 when a waste solution having a high chloride ion content such as an etching waste solution generated when etching a copper printed board with a cupric chloride etchant is used. That is, in the solid obtained by washing the solid obtained by this method with water and drying, the chlorine content that is difficult to reduce by simple aqueous operation is about 400 μg / g (fluorescent X-ray diffraction). Method X-ray fluorescence measurement apparatus; manufactured by Rigaku Corporation ZSX Prims II type, tube; Cu, current / voltage; analysis result by 50 kV / 50 mA) was found to be contained.

Then, when the recovered solid matter mainly composed of copper oxide is reused as a copper ion supply source in the copper plating process, the adverse effect of chloride ions on the plating process is known (Non-Patent Document 1). In order to avoid this, the chlorine content in the solid is required to be as low as possible (for example, 50 to 100 μg / g or less). For this reason, in order to reuse the solids recovered by the above method as a copper ion feedstock to the copper plating bath, it is required to reduce the amount of chlorine taken in as much as possible. It was difficult with the conventional technology.
Japanese Patent Application No. 2002-212857 “Surface Technology”, Vol. 55, No. 6, pp. 423-427 (2004)

  Therefore, the present invention is capable of treating a highly acidic waste solution containing copper and chloride ions at a high concentration, such as a copper chloride-containing etching waste solution, with an efficient and low sludge generation amount, and further, a copper plating bath solution. It is an object of the present invention to provide a technique for recovering, as a precipitate, copper oxide having a low chlorine content that can be reused as a copper ion supply source.

  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 a high concentration of copper ions and chloride ions with an oxidizing agent, such as an etching waste liquid, and adding this to the alkaline agent solution, the pH of the alkaline agent solution is temporarily adjusted. However, in addition to the condition that the pH is not lower than 7, the temperature of the alkali solution is controlled to 55 ° C. or higher, preferably 80 ° C. It has been found that the copper ions in the waste liquid can be insolubilized and recovered as copper oxide while avoiding the production, and the chlorine ion concentration in the solid can be greatly reduced.

  Further, even if the pH of the alkaline agent solution after pouring the mixed solution is controlled to be strong alkalinity of 11.5 or more, desirably 12.5 or more, the solid containing copper oxide as a main component with a small amount of chlorine uptake. It was found that the product can be generated.

This invention is completed based on the said knowledge, The 1st invention is the following management conditions (1) and (2)
(1) The pH of the alkaline agent solution after pouring the mixed solution is not temporarily set to 7 or less. (2) The copper-containing acidity is maintained while keeping the temperature of the alkaline agent solution after pouring the mixed solution at 55 ° C or higher. A method for recovering a copper-containing solid with reduced chlorine content from a copper-containing acidic waste liquid, characterized in that a mixed liquid of a waste liquid and an oxidizing agent is poured into an alkaline agent solution to obtain a generated solid. is there.

  In addition, the second invention of the present invention is to add a mixed liquid of copper-containing acidic waste liquid and oxidizing agent to an alkaline agent solution while keeping the above management conditions (1) and (2), and to produce a solid matter to be generated. A method for producing a copper-containing solid material having a low chlorine content.

Furthermore, the third invention of the present invention is the following management condition (3):
(3) Solid matter produced by pouring the mixed solution of the copper-containing acidic waste liquid and the oxidizing agent into the alkaline agent solution while keeping the pH of the alkaline agent solution after pouring the mixed solution at 11.5 or higher. Is a method for recovering a copper-containing solid with reduced chlorine content from a copper-containing acidic waste liquid.

  Furthermore, the fourth invention of the present invention is to add the mixed solution of the copper-containing acidic waste liquid and the oxidizing agent to the alkaline agent solution while keeping the above management condition (3), and obtain a solid matter to be generated. This is a method for producing a copper-containing solid having a low chlorine content.

  Furthermore, the fifth invention of the present invention comprises a reaction tank comprising a heating means and a pH measurement means, wherein a reaction liquid containing a copper-containing acidic waste liquid and an oxidizing agent and an alkaline agent solution are reacted to precipitate as a solid, Includes a solid-liquid separator that separates and recovers solids, and a mixed liquid pipe that joins the oxidizer pipe and copper-containing acidic waste liquid pipe on the way. The mixed liquid pipe can pour the mixed liquid into the reaction tank. The reaction vessel and the solid-liquid separator are connected to each other so as to be able to transfer a suspension containing the solid matter so as to recover the copper-containing solid matter from the copper-containing acidic waste liquid.

  Furthermore, the sixth invention of the present invention comprises a mixing tank for mixing the copper-containing acidic waste liquid and the oxidant solution, a heating means and a pH measuring means, and reacting the mixture with the alkaline agent solution as a solid matter. A reaction tank for precipitation, a solid-liquid separation device for separating and recovering the solid matter, and a means for pouring the mixed solution from the mixing tank to the reaction vessel. The reaction tank and the solid-liquid separation device are solid materials. It is the collection | recovery apparatus of the copper containing solid substance from the copper containing acidic waste liquid characterized by the above-mentioned.

  According to the present invention, it is possible to efficiently recover copper as a solid containing copper oxide as a main component from an acidic waste liquid having a high copper-containing concentration, which has been difficult to recover with the prior art.

  In particular, even waste liquids containing a high content of chloride ions in addition to copper ions, such as etching waste liquids produced when etching copper printed circuit boards with cupric chloride etchants, are treated directly while preventing the formation of double salts. In addition, copper ions can be generated and recovered as a solid mainly composed of copper oxide having a low chlorine content.

  The recovered solid matter mainly composed of copper oxide having a low chlorine content can be returned as a copper ion supply source to the copper plating process in the production of a copper printed circuit board. If incorporated in the manufacturing process of printed circuit boards, copper can be effectively recycled and reused as a resource, which is extremely efficient.

The basis of the treatment process according to the method of the present invention is to first mix the copper-containing acidic waste liquid and the oxidizing agent, and then pour the obtained mixed liquid into the alkaline agent solution to produce a solid. The feature of the present invention is that this solid matter generation is controlled by the following control conditions (1) and (2)
(1) The pH of the alkaline agent solution after pouring the mixed solution is not temporarily set to 7 or less. (2) The temperature of the alkaline agent solution after pouring the mixed solution is set to 55 ° C. or higher, or the following control conditions ( 3)
(3) By maintaining the pH of the alkaline solution after pouring the mixed solution at 11.5 or higher, a solid matter with a small amount of chlorine uptake is generated.

  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 Can be advantageously applied to an etching waste solution generated when etching with a cupric chloride etchant, particularly those having high copper ion concentration and chloride ion concentration.

  In addition, as the oxidizing agent used in the method of the present invention, various oxidizing agents can be used as long as they can convert divalent copper ions into copper oxide, but they can be handled as a solution, Since no components other than water remain after the reaction, hydrogen peroxide, ozone water or the like is effectively used, and hydrogen peroxide is particularly suitable. Moreover, it can also be set as a liquid mixture with an oxidizing agent by blowing gaseous ozone directly into copper containing acidic waste liquid.

  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. In addition, when obtained as an aqueous solution, there is an advantage that it can be easily used, but for the purpose of increasing the liquid temperature by effectively utilizing the heat of reaction accompanying dissolution, a solid alkaline agent is appropriately dissolved and used. Also good.

  In carrying out the method of the present invention, it is particularly important to first observe the order described above. 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. Then, when a hydrogen peroxide solution is poured thereafter, the copper hydroxide solid precipitated in the solution is oxidized, so that the efficiency of the oxidation reaction to copper oxide by hydrogen peroxide 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 is added to copper hydroxide and has a low solubility. Monocopper (CuCl) is also deposited. This cuprous chloride (CuCl) acts as a hydrogen peroxide decomposition catalyst, so that hydrogen peroxide is consumed in a situation where the contribution to the formation of copper oxide is insufficient, and the efficiency of the oxidation reaction by 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. Also, when cuprous ions are contained in the waste liquid, the cuprous ions are oxidized to cupric ions by the oxidizing action of hydrogen peroxide by mixing with hydrogen peroxide before contacting with the alkaline agent. Therefore, precipitation of cuprous salts such as cuprous chloride (CuCl) having low solubility 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. The foaming due to the decomposition of hydrogen peroxide depends on the concentration of both of them. For example, when hydrogen peroxide of 2 times the molar concentration is mixed with copper ions, the foaming decreases after 20 minutes. After 25 minutes, the amount is slight, and when added to the alkaline agent at this point, 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 also important.

  Examples of the mixing method of the copper-containing waste liquid and the hydrogen peroxide solution described above include, for example, a method in which both liquids are poured into the mixing tank and stirred, or the copper-containing waste liquid and the hydrogen peroxide solution are merged and mixed. The method of doing etc. is applicable.

  Among these, the method of injecting both liquids into the mixing tank and stirring them has the merit that the injection amount can be easily confirmed and adjusted, and there is no problem on the apparatus because it is open even if foaming occurs during mixing. .

  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 Y-shaped 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.

  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 alkali agent is used. It is necessary to react under conditions of dilute concentration. That is, it is necessary to add the mixed solution intermittently or continuously little by little to the alkaline agent solution. In addition, in order to recover copper ions as a solid substance containing a small amount of chlorine and containing copper oxide as a main component, the temperature during the reaction after pouring the mixed solution into the alkaline solution is higher than usual. Is necessary.

In order to realize these conditions, in the technology of the present invention, the following management conditions (1) and (2)
(1) The pH of the alkaline agent solution after pouring the mixed liquid should not be 7 or less even temporarily (2) It is necessary to maintain the temperature of the alkaline agent solution after pouring the mixed liquid at 55 ° C or higher. Become.

  More specifically, for example, an alkaline agent of a solution body with good operability is used, and the alkaline agent solution is heated to 55 ° C. or higher, and the mixture is mixed with the alkaline solution while stirring the solution. Even if the pH is partially, it is necessary to add at an appropriate rate so as not to temporarily drop below 7.

  Since the heat of neutralization is generated by pouring the mixed solution into the alkaline agent solution, the liquid temperature rises from the initial stage as the reaction proceeds, but in order to obtain a copper-containing solid with a reduced chlorine content It is necessary and effective to heat the mixed liquid to 55 ° C. or more, which is the control limit of (2) above, at the stage of first adding the mixed liquid.

  In addition, as a method of adding and mixing while controlling so that the pH does not drop to 7 or less even temporarily, for example, a small amount of mixed solution is intermittently provided at intervals in an alkaline agent solution in a stirred and mixed state. And a method of continuously adding the mixed solution little by little. At this time, the relationship between the amount of the alkaline agent solution and the amount of the mixed solution added is such that the final pH of the mixed reaction solution at the end of the final mixing reaction is 7 or more, preferably 8 or more. It ’s fine.

  On the other hand, as another method for recovering copper ions as a solid substance having a small amount of chlorine uptake and containing copper oxide as a main component, the pH of the alkaline agent solution after pouring the mixed solution is 11.5 or more, preferably 12 And a method of proceeding and terminating the reaction with a strong alkalinity of .5 or more.

In order to realize these conditions, in the technology of the present invention, the following management condition (3)
(3) It is necessary to maintain the pH of the alkaline agent solution after pouring the mixed solution at 11.5 or higher.

  Specifically, in this method, as the mixed solution is poured into the alkaline agent solution, the pH approaches neutral, so the alkaline solution is monitored while monitoring the pH of the alkaline agent solution after the mixed solution is poured. In this method, the agent is added as necessary, and the reaction is allowed to proceed and complete while maintaining a strong alkalinity of 11.5 or higher, preferably 12.5 or higher in the reaction mixing tank. By this operation, the main oxidation reaction can be efficiently carried out under strong alkaline conditions of pH 11.5 to 14.5 with high reactivity of hydrogen peroxide while obtaining the dilution effect by the alkaline agent solution. By sequentially advancing and completing the oxidation reaction, it is possible to obtain a liquid having a low copper ion-containing concentration. In this case, there is almost no problem in setting the pH to 7.0 or higher. However, for example, if a large amount of a mixed solution is added when stirring is weak, the pH is temporarily temporarily reduced to 7 or lower. The injection acceleration in this case should also be controlled so that the alkaline agent solution after the injection does not drop below 7 in order to prevent it from dropping temporarily to 7 or less even partially. Needless to say, is necessary.

  Among the above, in the method in which the liquid temperature of the alkaline agent solution is 55 ° C. or higher, the pH of the liquid at the end of the reaction can be treated from weakly alkaline to near neutral, and is used for neutralization in the post-treatment process. On the other hand, there is a merit that the required amount of acid is small, while the method of maintaining the pH of the alkaline agent solution at 11.5 or higher does not require a special heat source or apparatus for heating the solution, and accordingly, There is an advantage that the device structure and operation management are simplified.

  As described above, in the method of the present invention, it is necessary to intermittently or continuously add the mixed solution little by little to the alkaline agent solution. It is possible to apply a method such as a method of dropping the mixed solution into a reaction tank in which is added or a method of injecting the mixed solution into the liquid through a pipe.

  Among the methods described above, the method of dropping into the reaction tank has an advantage that the supply status can be visually confirmed, and 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 the liquid can be supplied to a position where it can be mixed well compared with the case of supplying from the liquid surface. When the mixing tank is sufficiently smaller than the reaction tank, it can be carried out with simple equipment by dispensing one batch of the mixing tank. 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.

  The concentration of hydrogen peroxide used for the treatment is not particularly limited. For example, a concentration of 30% can be used directly. Similarly, the concentration of the alkaline agent solution is not particularly limited. For example, a sodium hydroxide solution having a concentration of 25% can be used directly.

  According to the technology of the present invention described above, a solid material mainly composed of copper oxide can be obtained by processing the copper-containing acidic waste liquid. And since this solid substance has a high bulk density and good sedimentation, solid-liquid separation is extremely easy, and the dehydrating property is also good. However, at the completion of the reaction, it contains a high concentration of salts resulting from the acid it originally had and the alkali used in the treatment. 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, known solid-liquid separation means, for example, filtration separation, centrifugation, sedimentation separation, etc. can be applied.

  In addition, as washing water for washing away salts, clear water having a low salt content, for example, tap water or industrial water, may be used, but instead, the treated liquid is separated into solid and liquid. It is also effective to reuse the obtained separation liquid, washing waste water from which solids have been washed away with water, and / or treated water obtained by desalting the separation liquid obtained by solid-liquid separation. . As a method in this case, for example, a membrane filtration method, a vacuum distillation method, an electrodialysis method, or the like is applicable.

  Next, with reference to the drawings, a collection device used for carrying out the method of the present invention will be described.

  FIG. 1 is a system diagram showing an embodiment of an apparatus for recovering copper having a low chlorine content while keeping management conditions (1) and (2). In the figure, 1 is a copper recovery device, 2 is a reaction tank, 3 is a solid-liquid separation device, 4 is an acidic copper 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. A pipe, 9 is a pH meter, 10 is a stirrer, 11 is a transfer pump, 13 is a washing water supply pipe, and 14 is a heating device for the alkaline solution.

  A copper recovery apparatus 1 shown in FIG. 1 has a reaction tank 2 equipped with a stirrer 10, a pH meter 9 and a heating apparatus 14, 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 acidic copper waste liquid pipe 4 and the oxidant supply pipe 5 are combined, and the mixed liquid of the acidic copper waste liquid and the oxidant is poured into the reaction tank 2. It is possible to add. The amount of the acid copper waste liquid and the oxidant to be added is adjusted by the flow rate regulators 7a and 7b provided in the acid copper waste liquid pipe 4 and the oxidant supply pipe 5, respectively. 6 is generated.

  The alkaline agent solution is supplied to the reaction tank 2 from the alkali supply pipe 8. Then, the alkaline solution is heated by the heating device 14 so as to maintain a temperature of 55 ° C. or higher, and the mixed solution of the acidic copper waste liquid and the oxidizing agent is injected from the mixing pipe 6 into the alkaline agent solution stirred by the stirrer 10. The The pH change at that time is measured by a pH meter 9, and the measured value is managed by a control device (not shown). By opening and closing the flow rate regulators 7a to 7c, the pH can be temporarily changed. It is controlled not to be 7 or less.

  In this reaction tank 2, a solid mainly composed of copper oxide is generated, and the alkaline agent solution becomes an alkaline suspension. This suspension is transferred to the solid-liquid separator 3 via the transfer pump 11. Here, it is divided into solid and separated water. Further, the cleaning water supplied from the cleaning water supply pipe 13 is cleaned and reused.

  The system diagram shown in FIG. 2 is a drawing showing a copper recovery apparatus in a mode different from that shown in FIG. 1 that enables continuous processing. In the figure, 1 to 13 are the same as in FIG. 1, 12 is an overflow, 15 is a mixing tank, and 16 is a mixing tank stirrer.

  In the method of the present invention, basically, the mixed solution is poured continuously or intermittently into the alkaline agent solution in the reaction tank 2 and stirred to produce a solid containing copper oxide as a main component. At this time, since the higher alkalinity is advantageous for obtaining a solid having a low chlorine content, the alkali agent is supplied from the alkali supply pipe 8. However, if the mixture is continuously poured and the alkali agent is supplied, the volume of the alkaline suspension in which the solid produced by the reaction is suspended increases. Therefore, in order to continuously treat the acidic copper waste liquid by the method of the present invention, a part of the increased alkaline suspension is taken out from the reaction tank 2 continuously or intermittently, and the solid-liquid separation device 3 performs the solid-liquid separation treatment. Need to do.

  The overflow 12 in FIG. 2 is a means for continuously taking out a part of the alkaline suspension, and sends out to the solid-liquid separation device 3 a capacity that is commensurate with the increase due to the addition of the mixed liquid and the supply of the alkaline agent. It works.

  Further, in the apparatus of FIG. 1, the acidic copper waste liquid pipe 4 and the oxidant supply pipe 5 are directly combined to form a mixing pipe 6, but in the apparatus of FIG. 2, the acidic copper waste liquid pipe 4 and the oxidant supply are provided. Each of the pipes 5 is provided in the upper part of the mixing tank. In the mixing tank 15, the pipes 5 are sufficiently mixed by the mixing tank stirrer 16 and then poured into the reaction tank 2 through the mixed liquid pipe 6.

  The mixing tank 15 does not need to have a capacity capable of containing the acidic copper waste liquid to be treated and the oxidizing agent added thereto at a time because the oxidizing power of the oxidizing agent cannot be maintained for a long time. What is necessary is just a capacity | capacitance which can accommodate an acidic copper waste liquid and the oxidizing agent added to this.

  In using the apparatus of FIG. 2, the acidic copper waste liquid to be divided and the oxidant added thereto are divided into flow controllers 7 a and 7 b provided in the acidic copper waste liquid pipe 4 and the oxidant supply pipe 5, respectively. The mixture is added to the mixing tank 15 while being adjusted, and mixed with the pH meter 9 provided in the reaction tank 2 while the pH in the alkaline agent solution is desirably controlled so as not to fall below 11.5. A small amount is added from the pipe.

  Also in this apparatus, the alkaline agent solution is heated to 55 ° C. or higher by the heating device 14, and the pH change in the alkaline agent solution is measured by the pH meter 9, so that the pH does not temporarily become 7 or less. What is controlled is the same as the apparatus of FIG.

  FIG. 3 is a view showing an embodiment of the copper recovery apparatus of the present invention to which a desalting apparatus is attached. This apparatus is basically similar to the apparatus shown in FIG. 1, but is different in that it includes a concentration / dehydration unit 17, a desalting apparatus 18 and a desalting water pipe 19 after the solid-liquid separation apparatus.

  In this apparatus, the separated water separated in the solid-liquid separation device 3 is desalted in the desalting device 18 and then used again as washing water for the solid-liquid separation device 3 through the desalting water pipe 19. . On the other hand, the solids washed and separated by the solid-liquid separator 3 are transferred to the concentration / dehydration unit 17 and further concentrated / dehydrated. The solid material concentrated and dehydrated here is recovered and reused as a copper resource. On the other hand, the separated water obtained here is desalted in the desalinator 18 in the same manner as the separated water, and then the desalted water pipe. 19 is used again as washing water for the solid-liquid separator 3.

  In the apparatus of the present invention, clean water having a low salt content, such as industrial water, is generally used as the washing water, but the apparatus shown in FIG. 3 can be obtained by reaction instead of or as part of this. Since it is possible to use the desalted water obtained by treating the separated water and the dewatered filtrate from the washing waste water and the concentrated dewatering unit with a desalinator, it is effective when considering the wastewater treatment in the latter stage. .

  EXAMPLES Next, although an Example and a reference example are given and this invention is demonstrated in more detail, this invention is not restrict | limited at all by these Examples.

Reference example 1
(1) Etching waste solution (pH = -1.2, copper ion concentration = 120 g / L, chloride ion concentration = 220 g / L; hereinafter referred to as “etching” generated when a copper printed circuit board is etched with a cupric chloride etchant. Waste solution)), a 30% hydrogen peroxide solution and a 25% sodium hydroxide solution, and thereby producing and precipitating a solid mainly composed of copper oxide, the reaction solution (alkaline suspension) The state of pH change and the amount of chlorine contained in the finally obtained solid were examined.

  First, the acidity of the etching waste liquid was measured, and the volume of a 25% sodium hydroxide solution (hereinafter abbreviated as “sodium hydroxide solution”) that would have a pH of 7.2 when it was completely mixed with this was calculated. As a result, it was found that the volume of the sodium hydroxide solution necessary to neutralize 1000 mL of the etching waste liquid (pH 7.2) was 870 mL.

  On the other hand, the copper ion concentration of the etching waste liquid was measured, and the amount of hydrogen peroxide that was twice the number of moles of copper ions contained was calculated as the amount of hydrogen peroxide used. When a 30% hydrogen peroxide solution (hereinafter abbreviated as “hydrogen peroxide solution”) was used, the amount of hydrogen peroxide used with respect to 1000 ml of the etching waste liquid was 380 ml.

  The experiment was performed by taking 870 ml of a sodium hydroxide solution in a beaker equipped with a stirrer and a pH meter, and pouring a mixed solution of etching waste liquid and hydrogen peroxide into the beaker by the following pouring method. At this time, sodium hydroxide was not heated.

  (2) To add the mixed solution, first, 100 mL of the etching waste solution and 38 mL of the hydrogen peroxide solution (both are one-tenth of the amount required for neutralization) were collected, mixed, and allowed to stand for 60 seconds. This was then poured in small portions into the beaker's sodium hydroxide solution over 2 minutes. At this time, it was monitored with a pH meter so that the pH of the liquid after pouring did not temporarily become 7 or less.

  After the addition, the mixture was left for 3 minutes with continued stirring, and the same amount of etching waste solution and hydrogen peroxide solution were mixed and allowed to stand for 60 seconds. Then, the mixture was poured into the sodium hydroxide solution over 2 minutes, and further waited for 3 minutes while stirring was continued.

  This operation was repeated seven times until the addition amount of the mixed solution of the etching waste liquid and the hydrogen peroxide solution became 9/10 of the necessary amount during neutralization.

  After that, let the mixed solution of etching waste liquid and hydrogen peroxide solution of 1/10 of the amount necessary for the last neutralization stand still for 60 seconds, so that the pH of the liquid after pouring does not become 7 or less even temporarily. The mixture was gradually poured into the sodium hydroxide solution over 5 minutes, and stirring was continued for another 30 minutes.

  FIG. 4 shows the relationship between the ratio of the mixed solution of the etching waste liquid and the hydrogen peroxide solution in the above operation (ratio to the amount required for neutralization) and the pH of the mixed solution (alkaline suspension) after the addition. Show. In addition, the temperature of the solution during the pouring and mixing operation was in the range of 20 to 55 ° C.

  (3) An alkaline suspension containing black sludge was obtained by the processing operation of (2) above. The sludge solids concentration was 72 g / L, of which about 95% was copper oxide. Moreover, the sludge capacity | capacitance (SV30) after leaving still for 30 minutes with respect to the amount of raw | natural water of alkaline suspension was 58 volume%, and the sludge capacity | capacitance after leaving still for 60 minutes (SV60) was 40 volume%. Further, the supernatant obtained by standing was colorless and transparent, and the concentration of copper ions was less than 1 mg / L.

  (4) The solid matter in the sludge obtained by the above treatment was centrifuged to remove the supernatant water. Next, the water washing operation in which the solid concentration after reslurry was 4% was added to the collected solids and stirred for 30 minutes, and then centrifuged again 5 times. The amount of chlorine contained in the recovered product obtained by drying the solid after washing with water was determined by the fluorescent X-ray diffraction method (fluorescent X-ray measurement device; ZSX Prims II type, tube manufactured by Rigaku Corporation; Cu; current / Voltage; 50 kV / 50 mA), and it was 420 μg / g. The amount of chlorine was not substantially changed even after repeated washing with water 9 times, and it was found that the chlorine content in the solid matter could not be reduced by the washing operation.

Example 1
(1) The same etching waste solution as used in Reference Example 1 (pH = -1.2, copper ion concentration = 120 g / L, chloride ion concentration = 220 g / L), 30% hydrogen peroxide solution and 25% water A sodium oxide solution was used, and the relationship between the reaction temperature and the chlorine concentration in the solid was examined when a solid containing copper oxide as a main component was produced and precipitated.

  From the results of the analysis and calculation performed in Reference Example 1, the volume of sodium hydroxide solution required to neutralize 1000 mL of etching waste liquid (pH 7.2) is 870 mL, and the amount of hydrogen peroxide used for 1000 ml of etching waste liquid is Since it was known that it was 380 ml, the experiment was conducted based on this.

  In the experiment, 870 ml of sodium hydroxide solution was placed in a beaker equipped with a stirrer and a pH meter, and this was set to a predetermined starting temperature. Then, a mixed solution of etching waste liquid and hydrogen peroxide was poured into the beaker by the following pouring method. It was done by adding. The starting temperatures were room temperature (about 20 ° C.), 55 ° C. and 80 ° C.

  (2) First, 100 mL of the etching waste solution and 38 mL of hydrogen peroxide solution (both are 1/10 of the amount required for neutralization) are collected, mixed and allowed to stand for 60 seconds. This was poured into the beaker's sodium hydroxide solution in small portions over 2 minutes. At this time, it was monitored with a pH meter so that the pH of the liquid after pouring did not temporarily become 7 or less.

  After the addition, the mixture was allowed to stand for 3 minutes with continued stirring, and then the same amount of the etching waste solution and the hydrogen peroxide solution were mixed and allowed to stand for 60 seconds. Then, the mixture was poured into the sodium hydroxide solution over 2 minutes, and further waited for 3 minutes while stirring was continued.

  This operation was repeated three more times (the amount of etching waste liquid added was 500 ml and the amount of hydrogen peroxide added was 190 ml), and stirring was continued for another 30 minutes.

  (3) The solid matter in the alkaline suspension after the above treatment was centrifuged to remove the supernatant water. Next, a water washing operation in which the solid content after reslurry was added in an amount of 4% to the collected solid and stirred for 30 minutes, and then centrifuged again was repeated five times. The amount of chlorine contained in the recovered product obtained by drying the solid material after washing with water was measured using a fluorescent X-ray diffractometry X-ray fluorescence measuring apparatus; manufactured by Rigaku Corporation, ZSX Prims II type, tube; Cu, current / The voltage was analyzed by 50 kV / 50 mA. The results are shown in Table 1.

  This result showed that the higher the temperature during the reaction, the lower the chlorine concentration in the solid. In addition, even when not heated (Test 1), the chlorine content in the solid is small, but this is considered to be because the pH during the reaction was high alkali (finally 10 minutes of the neutralization required amount). Since only 5 amounts are added, the pH is judged to be 12 or more).

Example 2
(1) By using the same etching waste solution, hydrogen peroxide solution and sodium hydroxide solution as used in Reference Example 1, and changing the amount of the mixed solution of the etching waste solution and hydrogen peroxide to the sodium hydroxide solution. The influence of pH during the reaction on the amount of chlorine contained in the solid was examined.

  From the results of the analysis and calculation performed in Reference Example 1, the volume of sodium hydroxide solution required to neutralize 1000 mL of etching waste liquid (pH 7.2) is 870 mL, and the amount of hydrogen peroxide used for 1000 ml of etching waste liquid is Since it was known that it was 380 ml, the experiment was conducted based on this.

  The experiment was performed by taking 870 ml of a sodium hydroxide solution in a beaker equipped with a stirrer and a pH meter, and pouring a mixed solution of etching waste liquid and hydrogen peroxide into the beaker by the following pouring method. At this time, sodium hydroxide was not heated.

  (2) To add the mixed solution, first, 100 mL of the etching waste solution and 38 mL of the hydrogen peroxide solution (both are one-tenth of the amount required for neutralization) were collected, mixed, and allowed to stand for 60 seconds. This was then poured in small portions into the beaker's sodium hydroxide solution over 2 minutes. At this time, it was monitored with a pH meter so that the pH of the liquid after pouring did not temporarily become 7 or less.

  After the addition, the mixture was allowed to stand for 3 minutes with continued stirring, and then the same amount of the etching waste solution and the hydrogen peroxide solution were mixed and allowed to stand for 60 seconds. Then, the mixture was poured into the sodium hydroxide solution over 2 minutes, and further waited for 3 minutes while stirring was continued.

  This operation was repeated until the total amount of the mixed solution of the etching waste liquid and the hydrogen peroxide solution became 5/10 of the necessary amount during neutralization, and stirring was further continued for 30 minutes.

  (3) The solid matter in the alkaline suspension after the above treatment was centrifuged to remove the supernatant water. Next, a water washing operation in which the solid content after reslurry was added in an amount of 4% to the collected solid and stirred for 30 minutes, and then centrifuged again was repeated five times.

  (4) The above operations (1) to (3) are carried out by changing the total amount of the mixture of the etching waste liquid and the hydrogen peroxide solution of (2) to 7/10, 10 minutes of the necessary amount during neutralization. Solids were obtained by repeating the same conditions except that the amount was 8, 10, 8.5, 10, 9, and 10 minutes.

  (5) The amount of chlorine contained in the recovered product obtained by drying the solid was determined by measuring the X-ray fluorescence X-ray fluorescence measurement apparatus; ZSX Prims II type, tube manufactured by Rigaku Corporation; Cu, current / Table 2 shows the results of analysis by voltage; 50 kV / 50 mA.

As a result, it was confirmed that the chlorine content remaining in the obtained solid was less when the addition ratio of the mixed solution to the sodium hydroxide solution was lower, that is, when the pH at the end of the reaction was higher.

    According to the present invention, an acid waste liquid containing copper at a high concentration, in particular, copper in a waste liquid having a high chloride ion content such as an etching waste liquid generated when etching a copper printed board with a cupric chloride etchant. In addition, it can be economically and efficiently removed and recovered as a solid mainly composed of copper oxide having a low chlorine content.

It is drawing which shows the one aspect | mode of the copper collection | recovery apparatus of this invention. It is drawing which shows another aspect of the copper collection | recovery apparatus of this invention. It is drawing which shows the one aspect | mode of the copper collection | recovery apparatus of this invention which attached the desalination apparatus. It is drawing which shows the relationship between the pouring ratio of the liquid mixture of an etching waste liquid and hydrogen peroxide to a sodium hydroxide solution, and the pH of the alkaline suspension after pouring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ...... Copper recovery apparatus 2 ...... Reaction tank 3 ... Solid-liquid separator 4 ...... Acidic copper 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…… Overflow 13…… Washing water supply pipe 14…… Heating device 15…… Mixing tank 16…… Mixing tank stirrer 17…… Concentration dehydration unit 18 ... ... Desalination equipment 19 ... ... Desalination water piping

Claims (26)

The following management conditions (1) and (2)
(1) The pH of the alkaline agent solution after pouring the mixed solution is not temporarily set to 7 or less. (2) The copper-containing acidity is maintained while keeping the temperature of the alkaline agent solution after pouring the mixed solution at 55 ° C or higher. A method for recovering a copper-containing solid with reduced chlorine content from a copper-containing acidic waste liquid, wherein a mixed liquid of a waste liquid and an oxidizing agent is poured into an alkaline agent solution to obtain a generated solid.   The chlorine-containing acid waste liquid containing copper from the copper-containing acidic waste liquid according to claim 1, wherein the mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent is produced by joining the supply line of the copper-containing acidic waste liquid and the oxidizing agent supply line. A method for recovering a copper-containing solid having a reduced amount.   The chlorine content from the copper-containing acidic waste liquid according to claim 1, wherein the mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent is produced by mixing the copper-containing acidic waste liquid and the oxidizing agent in a mixing tank. For recovering the resulting copper-containing solid.   The method for recovering a copper-containing solid material having a reduced chlorine content from a copper-containing acidic waste liquid according to any one of claims 1 to 3, wherein hydrogen peroxide is used as an oxidizing agent. The chlorine content from the copper-containing acidic waste liquid according to any one of claims 1 to 4 , wherein the copper-containing acidic waste liquid is an etching waste liquid produced when etching a copper printed board with a cupric chloride etchant. A method for recovering a copper-containing solid. The method for recovering a copper-containing solid with a reduced chlorine content from a copper-containing acidic waste liquid according to any one of claims 1 to 5 , wherein the solid that is produced is a solid mainly composed of copper oxide. The following management conditions (1) and (2)
(1) The pH of the alkaline agent solution after pouring the mixed solution is not temporarily set to 7 or less. (2) The copper-containing acidity is maintained while keeping the temperature of the alkaline agent solution after pouring the mixed solution at 55 ° C or higher. A method for producing a copper-containing solid having a low chlorine content, wherein a mixed liquid of a waste liquid and an oxidizing agent is poured into an alkaline agent solution to obtain a solid that is generated. The copper-containing solid with a low chlorine content according to claim 7 , wherein the mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent is produced by joining the supply line of the copper-containing acidic waste liquid and the oxidizing agent supply line. Manufacturing method. The mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent is produced by mixing the copper-containing acidic waste liquid and the oxidizing agent in a mixing tank, and manufacturing a copper-containing solid having a low chlorine content according to claim 7. Method. The method for producing a copper-containing solid having a low chlorine content according to any one of claims 7 to 9 , wherein hydrogen peroxide is used as the oxidizing agent. The method for producing a copper-containing solid having a low chlorine content according to any one of claims 7 to 10 , wherein the copper-containing acidic waste liquid is an etching waste liquid produced when etching a copper printed board with a cupric chloride etchant. The method for producing a copper-containing solid having a low chlorine content according to any one of claims 7 to 11 , wherein the produced solid is a solid containing copper oxide as a main component. Next management condition (3)
(3) While keeping the pH of the alkaline solution after pouring the mixed solution at a strong alkali of 11.5 or higher, the mixed solution of the copper-containing acidic waste liquid and the oxidizing agent is poured into the alkaline solution to produce A method for recovering a copper-containing solid having a reduced chlorine content from a copper-containing acidic waste liquid, wherein the solid is obtained. A mixed solution of copper-containing acidic waste liquid and the oxidizing agent, chlorine-containing copper-containing acidic waste liquid of claim 13 in which was generated by merging and the supply line and an oxidant supply line of the copper-containing acidic waste liquid A method for recovering a copper-containing solid having a reduced amount. 14. The chlorine content from the copper-containing acidic waste liquid according to claim 13 , wherein the mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent is produced by mixing the copper-containing acidic waste liquid and the oxidizing agent in a mixing tank. For recovering the resulting copper-containing solid. The method for recovering a copper-containing solid with reduced chlorine content from a copper-containing acidic waste liquid according to any one of claims 13 to 15 , wherein hydrogen peroxide is used as an oxidizing agent. Copper-containing acidic waste liquid, the chlorine content of the copper-containing acidic waste liquid according to any one of 13 claims a waste etching solution generated in etching the copper printed circuit board with cupric chloride etching solution 16 is reduced A method for recovering a copper-containing solid. The method for recovering a copper-containing solid with a reduced chlorine content from a copper-containing acidic waste liquid according to any one of claims 13 to 17 , wherein the generated solid is a solid mainly composed of copper oxide. Next management condition (3)
(3) While keeping the pH of the alkaline solution after pouring the mixed solution at a strong alkali of 11.5 or higher, the mixed solution of the copper-containing acidic waste liquid and the oxidizing agent is poured into the alkaline solution to produce A method for producing a copper-containing solid having a low chlorine content, wherein the solid is obtained. The copper-containing solid with a low chlorine content according to claim 19 , wherein the mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent is formed by joining the supply line of the copper-containing acidic waste liquid and the oxidizing agent supply line. Manufacturing method. The mixed liquid of a copper-containing acidic waste liquid and an oxidizing agent is produced by mixing a copper-containing acidic waste liquid and an oxidizing agent in a mixing tank, and manufacturing a copper-containing solid having a low chlorine content according to claim 19. Method. The method for producing a copper-containing solid having a low chlorine content according to any one of claims 19 to 21 , wherein hydrogen peroxide is used as an oxidizing agent. The method for producing a copper-containing solid having a low chlorine content according to any one of claims 19 to 22 , wherein the copper-containing acidic waste liquid is an etching waste liquid produced when etching a copper printed board with a cupric chloride etchant. The method for producing a copper-containing solid having a low chlorine content according to any one of claims 19 to 23 , wherein the produced solid is a solid mainly composed of copper oxide.   A reaction tank for reacting a mixed liquid of copper-containing acidic waste liquid and an oxidizing agent with an alkaline agent solution to precipitate as a solid substance, and a solid-liquid separation apparatus for separating and recovering the solid substance, comprising heating means and pH measuring means And an oxidant pipe and a copper-containing acidic waste liquid pipe joined together in the middle, and the mixed liquid pipe is provided so that the mixed liquid can be poured into the reaction tank, and the reaction tank and the solid-liquid separation are provided. An apparatus for recovering a copper-containing solid from a copper-containing acidic waste liquid is characterized in that a suspension containing the solid is communicated so as to be transportable.   A mixing tank for mixing the copper-containing acidic waste liquid and the oxidant solution, a reaction tank having a heating means and a pH measuring means for reacting the mixture with the alkaline agent solution to precipitate as a solid, and separating and recovering the solid And a means for pouring the mixed liquid from the mixing tank to the reaction tank, and the reaction tank and the solid-liquid separation apparatus communicate with each other so that a suspension containing solid matter can be transferred. An apparatus for recovering a copper-containing solid from a copper-containing acidic waste liquid.

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