JP2012224901A - Method for treating and recovering copper-containing acidic waste liquid and apparatus for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for treatment that treats copper-containing acidic waste liquid, such as copper chloride-containing etching waste liquid and renewal waste liquid of an electrolytic copper foil plating bath, without requiring complex equipment, and simultaneously obtains treated water with good water quality.SOLUTION: The method for neutralization of copper-containing acidic waste liquid and recovery of copper is provided, in which the copper-containing acidic waste liquid is poured and mixed into an alkaline solution having an amount not less than a neutralization equivalent relative to the copper-containing acidic waste liquid, producing a suspension that contains a solid material including copper oxide as a main component, and the solid material is separated from the suspension; wherein (1) the copper-containing acidic waste liquid is poured and mixed into the alkaline solution after mixed with an oxidant until 70-90% of the total pouring amount of the copper-containing acidic waste liquid relative to the alkaline solution is poured from the start of the reaction, and (2) after the total pouring amount of the copper-containing acidic waste liquid exceeds the amount, the copper-containing acidic waste liquid is poured and mixed into the alkaline solution without using the oxidant. The apparatus used for the method is also provided.

Description

  The present invention relates to a method for treating and recovering a copper-containing acidic waste liquid, and more specifically, for example, an etching waste liquid generated when etching a copper printed board with a cupric chloride etchant, or a plating bath liquid in electrolytic copper foil production. Copper is removed from the solution by neutralizing copper-containing acidic waste liquid containing high-concentration copper ions, such as renewed waste liquid and etching waste liquid generated by the roughening treatment of the substrate surface in the lamination process of multilayer printed circuit board production. , A method for recovering the same, and an apparatus therefor.

  As an acidic waste liquid containing copper ions at a high concentration (hereinafter referred to as “copper-containing acidic waste liquid”), an etching waste liquid produced when etching a copper printed circuit board with a cupric chloride etchant, or in electrolytic copper foil production A renewal waste solution of a plating bath, a waste solution of etching generated by a roughening process of a substrate surface in a lamination process of multilayer printed circuit board production, and the like are 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 chlorine ions and sulfate ions is also usually high at 5 to 30%.

  As a copper recovery treatment method for such a copper-containing acidic waste liquid, a method of using a difference in ionization tendency, for example, reacting with iron scrap to deposit and recovering metallic copper is performed in part. However, this method has a problem that the copper recovery rate from the waste liquid is low. Further, since a waste liquid containing iron ions eluted by the reaction with copper ions and residual copper ions remains, it is necessary to separately treat the waste liquid, which is not an efficient treatment method.

  By the way, the present inventors previously found out a method for efficiently recovering copper oxide by mixing a copper-containing acidic waste liquid and an oxidizing agent and then adding it to an alkaline solution, and filed a patent application (Patent Document 1). According to this method, the solid substance which has a copper oxide as a main component is obtained by dripping the liquid mixture of a copper containing acidic waste liquid and an oxidizing agent in an alkaline solution. This is because the copper-containing acidic waste liquid is mixed with the oxidizing agent together with the oxidizing agent little by little to neutralize the copper-containing acidic waste liquid while obtaining an appropriate dilution effect, and oxidize the copper ions contained in the copper-containing acidic waste liquid. This is because copper oxide can be used.

  Here, the method of Patent Document 1 is a method that places emphasis on the reuse of recovered copper oxide, and has a feature that high-purity copper oxide can be recovered. However, in this method, there is some difficulty in sedimentation and separation of the generated solid components, and the sedimentation tank for solid-liquid separation has to be enlarged. Moreover, in the case of solid-liquid separation, a part of solid component produced | generated by the supernatant liquid side may remain, and the deterioration of treated water quality may occur. When operating as a waste liquid treatment facility when recovery of high-purity copper oxide is required, it is inevitable that the equipment corresponding to this will be used. There is a problem of becoming.

  Therefore, in the waste liquid treatment of copper-containing acidic waste liquid when there is no need for high-purity recovered copper oxide, neutralize the copper-containing acidic waste liquid, and at the same time, obtain treated water with good water quality and easy-to-handle copper-containing sludge There is a need to provide a simple treatment method for copper-containing acidic waste liquid that can be used.

JP2009-167462

  The present invention has been made in view of the above circumstances, and copper-containing acidic waste liquid such as copper chloride-containing etching waste liquid, electrolytic copper foil plating bath renewal waste liquid, etching waste liquid in the roughening treatment of the multilayer printed circuit board surface, etc. It is an object of the present invention to provide a treatment method and apparatus that can perform treatment without requiring complicated facilities and at the same time obtain treated water with good water quality.

  The present inventors mixed an acidic waste liquid containing a high concentration of copper ions, which is a liquid to be treated, and an oxidizing agent, and then added and mixed little by little into an alkaline solution, thereby adding a copper-containing acidic waste liquid in the copper-containing acidic waste liquid. About the method of the above-mentioned Patent Document 1 in which the contained copper ions are oxidized to copper oxide and settled, after performing an improvement study, after repeating the pouring operation of the mixed liquid of copper-containing acidic waste liquid and oxidizing agent to some extent, By adding only the copper-containing acidic waste liquid to the alkaline solution, a sludge with good sedimentation can be obtained unexpectedly, and the residual fine suspended matter in the supernatant and the amount of copper ions were suppressed. The inventors found that good treated water can be obtained and completed the present invention.

That is, the present invention is a suspension containing a solid containing copper oxide as a main component by adding and mixing a copper-containing acidic waste liquid into an alkaline solution having a neutralization equivalent or more with respect to the copper-containing acidic waste liquid. A method for neutralizing a copper-containing acidic waste liquid and separating copper from the suspension to recover the copper,
(1) From the start of the reaction, the copper-containing acidic waste liquid and the oxidizing agent are mixed for 70 to 90% of the total amount added to the alkaline solution of the copper-containing acidic waste liquid, and then poured into the alkaline solution and mixed. And
(2) After the total amount of the copper-containing acidic waste liquid exceeds the above amount, the copper-containing acidic waste liquid is characterized by adding and mixing the copper-containing acidic waste liquid into the alkaline solution without using an oxidizing agent. Neutralization and copper recovery method.

Further, the present invention provides a mixing tank for mixing the copper-containing acidic waste liquid and the oxidizing agent from the oxidizing agent supply means, and the mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent obtained in the mixing tank is supplied with an alkaline agent. A copper-containing acidic waste liquid treatment apparatus comprising: a means for supplying to the mixed reaction tank; and a mixed reaction tank for mixing the mixed liquid and the alkaline agent to generate an alkaline suspension.
The copper-containing acidic waste liquid further comprises means for measuring the cumulative amount of the copper-containing acidic waste liquid, and means for controlling the supply of the oxidizing agent according to the cumulative amount of the copper-containing acidic waste liquid. Waste liquid neutralization and recovery treatment equipment.

Furthermore, the present invention has a supplying means for alkaline aqueous solution, a pouring means for copper-containing acidic waste liquid, a pouring means for oxidizing agent and a mixing means, and the mixed liquid of copper-containing acidic waste liquid and oxidizing agent reacts with the alkaline aqueous solution. A first mixing reactor that produces an alkaline suspension;
The copper-containing acidic waste liquid is communicated with the first mixing reaction tank, and has an addition means and a mixing means for the copper-containing acidic waste liquid, and contains the alkaline suspension from the first mixing reaction tank, A copper-containing acidic waste liquid neutralization / recovery treatment apparatus comprising a second mixing reaction tank for reacting the alkaline suspension.

  According to the present invention, it is difficult to treat with conventional treatment techniques due to the generation of double salts, etc., without diluting the copper-containing acidic waste liquid with a high concentration of copper ions of 5 to 20%. Can be processed. In addition, since the product contains copper oxide, the sedimentation and dehydrating properties are good, and the handling is easy as compared with the method of producing copper hydroxide. Furthermore, the treated water also has good water quality with less suspended matter and copper ions.

  Furthermore, since the recovered product obtained by the method of the present invention has a low water content compared to a simple hydroxide precipitation method, it is possible to reduce sludge discharge. Moreover, since the recovered material is a compound mainly composed of copper oxide, it is easy to use the recovered material as a raw material for copper refining after dehydration.

It is a neutralization curve of the copper etching waste liquid and sodium hydroxide solution in Example 1. 2 is a powder X-ray diffraction peak chart of the recovered product obtained in Example 1. FIG. It is drawing which showed typically an example of the apparatus used with the method of this invention.

  In the treatment process by the method for recovering copper from the copper-containing acidic waste liquid of the present invention (hereinafter referred to as “method of the present invention”), a mixture in which an excessive amount of alkaline solution is supplied relative to the neutralization equivalent of the treated copper-containing acidic waste liquid In the reaction vessel, the copper-containing acidic waste liquid is gradually added with the oxidant mostly from the beginning and without the oxidant in the last part.

  In more detail, when adding the copper-containing acidic waste liquid, most of the mixture from the beginning is poured into and mixed in the mixing reaction tank as a mixed liquid with an oxidizing agent, and fine particles mainly composed of copper oxide are suspended. A cloudy alkaline suspension (hereinafter abbreviated as “alkaline suspension”) is produced. The remaining part after the addition of the predetermined amount of copper-containing acidic waste liquid is stopped, the supply of the oxidizing agent is stopped, the copper-containing acidic waste liquid is poured into the mixing reaction tank, and the copper oxide is mixed. And a solid mainly composed of copper hydroxide is precipitated.

  In the method of the present invention, it is important to neutralize the copper-containing acidic waste liquid and the alkaline solution basically on the alkali side from the neutralization point. Therefore, in order to carry out the method of the present invention, it is necessary to carry out neutralization with an alkaline solution in an excess state, for example, an excess of about 1.2 times the neutralization amount. It is necessary to add the copper-containing acidic waste liquid (and the oxidizing agent) gradually and with sufficient stirring. In addition, it is necessary that the alkaline solution is always in excess of the neutralization equivalent during the reaction.

  Moreover, what is important in the present invention is to switch the supply of the copper-containing acidic waste liquid from the supply as a mixture of the copper-containing acidic waste liquid and the oxidizing agent to the supply of the copper-containing acidic waste liquid alone.

  That is, until the cumulative injection amount of the copper-containing acidic waste liquid to be treated reaches 70 to 90% of the total injection amount (hereinafter, this time point may be referred to as “switching time point”), it is placed in the alkaline aqueous solution together with the oxidizing agent. It is preferable to add only the copper-containing acidic waste liquid without using the oxidizing agent from the time when the amount exceeds this amount.

  If the start of the injection of only the copper-containing acidic waste liquid is too early than the switching point, the ratio of copper oxide in the solid matter is low, the ratio of copper hydroxide increases, the sludge sedimentation deteriorates and the sludge moisture content increases. To increase. On the other hand, when the injection of only the copper-containing acidic waste liquid is later than the switching point, the sludge settles well, but there may be a problem that the suspension in the treated water from which solids have been removed and the copper ions increase. is there.

  Therefore, in carrying out the method of the present invention, an appropriate timing (switching time point) for switching to the supply of the copper-containing acidic waste liquid alone is performed in advance according to the copper-containing acidic waste liquid to be treated, the alkaline solution to be used, and the oxidizing agent. ) Is preferred.

  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 the copper ion concentration and the anion concentration in the copper-containing acidic waste liquid are not particularly limited. As a specific example of the copper-containing acidic waste liquid that can be particularly suitably treated by the method of the present invention, an etching waste liquid generated when etching a copper printed board with a cupric chloride etchant, or a renewed waste liquid of a plating bath liquid in electrolytic copper foil production, Examples include a waste liquid having a high anion concentration such as a copper ion concentration, a chlorine ion concentration, and a sulfate ion concentration, such as an etching waste solution generated in a roughening process of a substrate surface in a lamination process of multilayer printed circuit board production.

  The oxidizing agent used in the method of the present invention is not particularly limited as long as it can oxidize divalent copper ions, and various oxidizing agents can be used. However, since it can be handled as a solution and no components other than water remain after the reaction, hydrogen peroxide, ozone water, or the like is suitable as the oxidizing agent in the present invention. Among these oxidizing agents, hydrogen peroxide is particularly suitable for this application because it does not require a special generator and is easy to handle. The concentration in the case of using hydrogen peroxide as the oxidizing agent is not particularly limited, and for example, a commercially available hydrogen peroxide solution of about 30% is easily available. When ozone water is used as the oxidant, gaseous ozone may be directly blown into the copper-containing acidic waste liquid instead of ozone water.

  Furthermore, various alkaline agents can be used as the alkaline agent used for preparing the alkaline solution in the method of the present invention, and the form thereof may be solid or liquid. However, for the selection of a specific alkaline agent, an alkali metal hydroxide that does not form a sedimentary salt with an anion that may coexist in the copper-containing acidic waste liquid is appropriate. On the other hand, the amount of the alkaline agent to be used is determined by the copper ion concentration, the anion concentration and the liquid amount of the copper-containing acidic waste liquid to be treated. Therefore, in a small-scale experiment, the amount of alkali agent necessary to neutralize the copper-containing acidic waste liquid to be treated is obtained in advance, and in actual treatment, the amount of alkali agent required may be determined based on this result. .

  In addition, when using a solid alkali as an alkali agent, there exists an advantage which can suppress the increase in the amount of waste liquids. When a solid alkaline agent is used, the solid alkaline agent may be dissolved in water or the like before being supplied to the mixing reaction tank, or supplied as a solid in the mixing reaction tank and dissolved in the mixing reaction tank. You may let them. Furthermore, as the water for dissolving the solid alkaline agent, a separation liquid separated from the solid by solid-liquid separation described later, a washing waste water generated by the washing treatment of the separated solid, and the like can also be used. On the other hand, when an alkaline solution is used as the alkaline agent, there are advantages in terms of handling such as easy control of the amount of alkaline agent used, easy replenishment of chemicals, and no dissolution operation.

  In the method of the present invention, sodium hydroxide is preferred because it is relatively inexpensive and easily available as an alkaline agent. When sodium hydroxide is used, a solid or solution such as flakes or granules can be used. In the case of using a sodium hydroxide solution, the concentration is not particularly limited. For example, a sodium hydroxide solution having a concentration of about 25% can be used.

  Based on the form summarized above, the case of using a hydrogen peroxide solution as the oxidant and a sodium hydroxide solution as the alkaline solution will be described as an example, and the treatment of the copper etching waste liquid which is a copper-containing acidic waste liquid will be described below.

  In the treatment process according to the method of the present invention, first, an aqueous sodium hydroxide solution in an amount exceeding the neutralization equivalent of the copper etching waste solution to be treated is prepared. And this sodium hydroxide solution is put into a mixing reaction tank, and the copper etching waste liquid which added hydrogen peroxide in this is poured little by little. Then, when the cumulative amount of the copper etching waste liquid reaches 70 to 90% of the total copper etching waste liquid amount (switching point), only the copper etching waste liquid is poured into the sodium hydroxide solution.

  The amount of the hydrogen peroxide solution with respect to the copper etching waste liquid before the switching point is not particularly limited as long as the copper ions in the copper etching waste liquid are oxidized, but generally, the copper in the copper etching waste liquid after mixing is not limited. It is preferable that the molar ratio of the oxidizer and the molar ratio of the oxidizing agent be an amount that is about 1.2 to 2 times. In addition, the mixed liquid mixture may be continuously or intermittently added to the sodium hydroxide solution in the mixing reaction tank. However, in order to sufficiently mix the mixed liquid and the sodium hydroxide liquid, the mixed liquid is intermittent. Preferably. By carrying out like this, reaction from the copper ion in a liquid mixture to copper oxide advances rapidly, when pouring a liquid mixture into a sodium hydroxide solution and neutralizing. As a method of pouring the mixed liquid, for example, a method of dropping into a mixed reaction tank or a method of supplying the mixed liquid into the liquid through piping is applicable.

  On the other hand, the method of pouring the sodium hydroxide solution is not particularly limited except that it is supplied so as not to be mixed with the mixed solution before reaching the mixed reaction tank. The method of injecting continuously is mentioned.

  Next, after the cumulative amount of the copper etching waste liquid reaches the switching point, hydrogen peroxide is not added, and only the copper etching waste liquid is poured into the sodium hydroxide solution. In this reaction, the copper etching waste solution is poured into the sodium hydroxide solution in the absence of an oxidant, so that the copper ions in the copper etching waste solution are not completely oxidized to copper oxide and partly hydroxylated. It remains as copper. If this copper hydroxide is present in a large amount, it swells with water and becomes sludge that is difficult to handle. However, when present in a small amount as in the method of the present invention, this facilitates solid-liquid separation by incorporating fine suspended solids. As a result, the properties of the treated water obtained are improved.

During the reaction, if the amount of the copper etching waste solution exceeds the neutralization equivalent of the sodium hydroxide solution in the mixing reaction tank, the pH of the suspension in the mixing reaction tank becomes less than 7, and the copper is Cu. ^It dissolves again in the form of ²⁺ and the copper concentration in the treated water increases. In the present invention, which is intended to remove and recover copper from the copper etching waste liquid (copper-containing acidic waste liquid), such a phenomenon is not preferable. Therefore, in the addition and mixing of the copper-containing acidic waste liquid, It is also important to control the pH so that it does not become acidic from the neutralization point, either temporarily or partially. Specifically, during the reaction, the pH of the mixed reaction tank is measured, and the pH of the liquid during the reaction is controlled to maintain 7 or more, preferably 8 or more, so that copper is redissolved in the form of Cu ^2+. It is desirable to suppress this.

  In the method of the present invention, in the operation of pouring the copper-containing acidic waste liquid, by selectively using the presence or absence of the addition of the oxidizing agent, in addition to the recovered material mainly composed of copper oxide and copper oxide, some copper hydroxide is included. It is important to obtain a collection. For example, if the addition of the oxidizing agent is stopped when the cumulative amount of the copper-containing acidic waste liquid is small, the amount of copper hydroxide that easily swells increases, and as a result, it becomes difficult to handle the recovered material. Therefore, the addition of the oxidant should be stopped in the second half of the pouring operation, specifically at the time of switching, so that an amount of copper hydroxide sufficient to take in fine suspended matters is generated. Is desirable.

  After completion of the reaction in the mixing reaction tank as described above, an alkaline suspension containing a solid material mainly composed of copper oxide is drawn out, and this is separated into a solid material (mainly copper oxide) and a separated liquid (supernatant). Liquid). For the solid-liquid separation, known means such as filtration separation, centrifugation, sedimentation separation, etc. can be applied. By carrying out like this, the solid which has copper oxide as a main component which can be reused as a resource, and the separated liquid with little content of a suspension and a copper ion can be obtained.

In general, the method of the present invention is carried out using an apparatus having one reaction mixing tank, and after the alkaline solution is put therein, the mixture of the acid waste liquid containing copper and the oxidizing agent is added gradually. And then thoroughly agitate to produce a recovered product mainly composed of copper oxide. After the switching point, only a copper-containing acidic waste liquid is added to produce a precipitate containing copper oxide and copper hydroxide. However, using a device having two mixing tanks as shown in FIG. 3 below, a mixture of copper-containing acidic waste liquid and an oxidizing agent is added to the first mixing tank, and in the second mixing tank, Only the copper-containing acidic waste liquid may be added.

  FIG. 3 is a drawing schematically showing an example of an apparatus having two mixing vessels that can be used in the method of the present invention. In FIG. 3, 1 is a copper-containing acidic waste liquid, 2 is an oxidizing agent, 3 is an alkaline aqueous solution, 4 is an alkaline suspension, 5 is a copper oxide cake, 6 is a supernatant, 11 is a mixing tank, 12 is the first One mixing reaction tank, 13 is a dehydrating device, 14 is a control device, 15 is a copper-containing acidic waste liquid supply pump, 16 is an oxidizing agent supply pump, 17 is a second mixing reaction tank, and 18 is a liquid transfer pump.

  In the apparatus of FIG. 3, the copper-containing acidic waste liquid 1 and the oxidant 2 are mixed in the mixing tank 11 and then poured little by little into the first mixing reaction tank 12 supplied with the alkaline aqueous solution 3. At the time of the addition, the amounts of addition of the copper-containing acidic waste liquid 1 and the oxidizing agent 2 are integrated by the control device 14. The controller 14 controls the copper-containing acidic waste liquid 1 and the oxidizing agent until the amount of the copper-containing acidic waste liquid 1 added from the start of the reaction to 90% of the total amount of the copper-containing acidic waste liquid 1 added to the alkaline solution 3 is 70%. It controls so that 2 liquid mixture may be poured into the 1st mixing reaction tank 12. FIG. In addition, after the total amount of the copper-containing acidic waste liquid exceeds the above amount, the control device 14 temporarily stops the pouring operation, operates the liquid transfer pump 18, and causes the alkaline suspension in the mixing reaction tank 12. Control to transfer the liquid 4 to the second mixing reaction tank 17 is performed. Thereafter, the remaining copper-containing acidic waste liquid 1 is poured into the alkaline suspension 4 supplied to the second mixing reaction tank 17 to complete the reaction. After completion of the reaction, the alkaline suspension 4 is transferred to the dehydrator 13 and the copper oxide cake 5 is recovered after solid-liquid separation.

  In general, it is known that when copper hydroxide is present at a high concentration, the moisture content is high and it becomes a hardly dewatering sludge. However, in a suspension already containing a large amount of solids (copper oxide particles) as in the present invention, if present in a small amount, the agglomeration action causes the solids to agglomerate and coarsen the copper oxide particles, Improve solid-liquid separation.

  Based on such a principle, the present invention consciously controls the supply of an oxidant during the neutralization reaction between the copper-containing acidic waste liquid and the alkaline solution, thereby generating a small amount of copper hydroxide, thereby improving the efficiency of copper. It was possible to obtain a supernatant liquid with high recoverability and high processability.

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

Example 1
In Example 1, in order to set the mixed reaction tank pH at the end of the treatment (reaction) to 7 or more, the amount of copper etching waste liquid required to neutralize the 25% sodium hydroxide used to pH 7 was reduced by copper etching. An amount of 0.95 equivalent of the total amount of waste liquid added was supplied to the mixing reaction tank. In addition, in the pouring operation up to 0.8 equivalent of the amount of copper etching waste liquid necessary for neutralizing the sodium hydroxide solution, the mixed liquid of the copper etching waste liquid and the hydrogen peroxide solution is divided into 8 times to obtain sodium hydroxide. Pour into the solution intermittently. The rest time after the injection was set to 3 minutes.

  Furthermore, in the pouring operation up to 0.9 equivalent (9th time of dispensing) and the pouring operation up to 0.95 equivalent (10th time of pouring), hydrogen peroxide solution is not added and only the copper etching waste solution is water. The reaction was terminated by pouring into the sodium oxide solution.

<Preliminary test>
Prior to the treatment, neutralization treatment was performed on a small scale in order to obtain the minimum amount of 25% sodium hydroxide solution relative to the amount of copper etching waste liquid to be treated. When the copper etching waste solution was added to the 25% sodium hydroxide solution little by little and the pH with respect to the added amount of the copper etching waste solution was measured, a neutralization curve as shown in FIG. 1 was obtained. From FIG. 1, the amount of copper etching waste solution for neutralizing 1 mL of 25% sodium hydroxide solution to pH 7 (thick line in FIG. 1) was about 1.15 mL. From this result, the mixing ratio for mixing the copper etching waste solution used in this example with the amount of 25% sodium hydroxide solution to pH 7 was assumed to be 1.15: 1 in volume ratio.

<Processing operations>
478 mL of 25% sodium hydroxide solution was added to a 2 liter beaker and stirred with a magnetic stirrer. Next, 55 mL of copper etching waste solution and 12.6 mL of 30% hydrogen peroxide solution were mixed in another beaker and stirred for 3 minutes to obtain a mixed solution.

  The total amount of the mixture of the copper etching waste liquid and the hydrogen peroxide solution was added to the beaker containing the sodium hydroxide solution over 3 minutes. During this addition, the 2 L beaker was stirred so that the pH in the system was uniform. The stirring of the beaker was continued even after the pouring of the mixed liquid of the copper etching waste liquid and the hydrogen peroxide solution was completed. After 3 minutes from the previous addition, 55 mL of copper etching waste solution prepared in another beaker and 12.6 mL of hydrogen peroxide solution were added to a 2 liter beaker and left for 3 minutes. This operation was repeated a total of 8 times. During this operation, the 2 liter beaker was constantly stirred.

  After the pouring operation was completed 8 times, in the ninth pouring operation, only 55 mL of the copper etching waste liquid was poured into the beaker over 3 minutes, and the mixture was left stirring for 3 minutes after the pouring operation was completed. Next, in the tenth pouring operation, 27.5 mL of the copper etching waste liquid was poured into the beaker over 3 minutes, and then the stirring was continued for 30 minutes, after which the reaction was terminated.

  Through the above operation, a suspension containing a black solid was produced. Solids were separated from this suspension using a centrifuge. When the obtained solid was dried and evaluated by powder X-ray diffraction, it was confirmed that copper oxide was the main component (FIG. 2).

  The action mechanism of the present invention allows the formation of copper hydroxide by adding the hydrogen peroxide solution to the copper etching waste solution in the sodium hydroxide solution without adding it to the copper etching waste solution at the final stage of mixing. The copper oxide previously formed by copper acts as a precipitant for the main product. Therefore, if only the copper etching waste liquid is mixed with the alkaline solution after the seventh injection operation (after 70% of the total injection amount), a product containing copper hydroxide is generated apart from the amount generated. It is clear that the same effect can be obtained.

Comparative Example 1
<Processing operations>
478 mL of 25% sodium hydroxide solution was added to a 2 liter beaker and stirred with a magnetic stirrer. Next, 55 mL of the same copper etching waste solution as in Example 1 and 12.6 mL of 30% hydrogen peroxide solution were mixed in another beaker and stirred for 3 minutes to obtain a mixed solution.

  The total amount of the mixture of the copper etching waste liquid and the hydrogen peroxide solution was added to the beaker containing the sodium hydroxide solution over 3 minutes. During this addition, the 2 L beaker was stirred so that the pH in the system was uniform. The stirring of the beaker was continued even after the pouring of the mixed liquid of the copper etching waste liquid and the hydrogen peroxide solution was completed. After 3 minutes from the previous addition, 55 mL of the copper etching waste solution prepared in another beaker and 12.6 mL of the hydrogen peroxide solution were added to the 2 liter beaker, and then left for 3 minutes with stirring. went. This operation was repeated a total of 9 times.

  In the tenth pouring operation, 27.5 mL of copper etching waste solution and 6.3 mL of hydrogen peroxide solution were mixed and stirred for 3 minutes. Next, this mixed solution was poured into a beaker over 3 minutes, and then the stirring was continued for 30 minutes, and then the reaction was completed. Through the above operation, a suspension containing a black solid was produced. Solids were separated from this suspension using a centrifuge.

Comparative Example 2
<Processing operation>
In Comparative Example 2, neutralization of the copper chloride etching waste liquid was attempted without using hydrogen peroxide. 478 mL of 25% sodium hydroxide solution was added to a 2 liter beaker and stirred with a magnetic stirrer. Next, 55 mL of copper etching waste liquid was added to the beaker containing the sodium hydroxide solution over 3 minutes. During this addition, a deep blue swollen sludge-like solid precipitated. This pouring operation was repeated 9 times, and in the 10th time, 27.5 mL of copper chloride etching waste liquid was added. During the pouring operation, the dark blue sludge material produced gradually changed to a light blue swollen sludge solid. This sludge-like substance filled the beaker and became difficult to stir. In addition, even when the reaction was allowed to stand after completion of the reaction, the supernatant liquid was not separated, and sludge having a high water content mainly composed of copper hydroxide and double salt (CuCl ₂ .3Cu (OH) ₂ ) was generated.

Test Example For each of the slurries obtained in Examples and Comparative Examples, sludge sedimentation, turbidity and SS of the supernatant water, and copper concentration of the supernatant water were measured. The results are shown in Table 1.

  As is apparent from this result, the slurry of Example 1 was slightly inferior in sludge sedimentation compared to that of Comparative Example 1, but the turbidity and SS of the supernatant water, and the residual copper concentration were low. Good supernatant water was obtained. In Comparative Example 2, since a swollen sludge-like substance was generated, the solid-liquid separation operation could not be performed, and the turbidity and SS of the supernatant water and the copper concentration in the supernatant water could not be measured.

  From the above results, by stopping the addition of the oxidizing agent in the latter half of the dispensing operation and adding only the copper-containing acidic waste liquid to the alkaline agent, while collecting solids with good sedimentation, good supernatant water is also obtained. It was shown to be obtained.

  According to the method of the present invention, it is difficult to treat with conventional treatment techniques due to the formation of double salts, etc., without diluting a high concentration copper-containing acidic waste liquid with a copper ion content concentration of 5 to 20%, Can be processed directly. In addition, since the recovered product obtained by the method of the present invention has a high content of copper oxide, it has a low water content compared to a simple hydroxide precipitation method, has good sedimentation and separability, and is easily composed mainly of copper oxide. It is also possible to recover the solid matter.

  Therefore, the method of the present invention is useful as a method for treating acidic waste liquid such as etching waste liquid and plating renewal waste liquid containing copper at a high concentration.

1: Copper-containing acidic waste liquid 2: Oxidizing agent 3: Alkaline aqueous solution 4: Alkaline suspension 5: Copper oxide cake 6: Supernatant liquid 11: Mixing tank 12: (First) mixing reaction tank 13: Dehydration device 14: Control Apparatus 15: Copper-containing acidic waste liquid supply pump 16: Oxidant supply pump 17: Second mixed reaction tank

The present inventors have, after mixing with the acidic waste liquid containing copper ions is processed liquid at a high concentration and an oxidizing agent, in small portions in an alkaline solution, pouring, by mixing, in the copper-containing acidic waste liquid About the method of the above-mentioned Patent Document 1 in which the contained copper ions are oxidized to copper oxide and settled, after performing an improvement study, after repeating the pouring operation of the mixed liquid of copper-containing acidic waste liquid and oxidizing agent to some extent, By adding only the copper-containing acidic waste liquid to the alkaline solution, a sludge with good sedimentation can be obtained unexpectedly, and the residual fine suspended matter in the supernatant and the amount of copper ions were suppressed. The inventors found that good treated water can be obtained and completed the present invention.

Further, the present invention provides a mixing tank for mixing the copper-containing acidic waste liquid and the oxidizing agent from the oxidizing agent supply means, and the mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent obtained in the mixing tank is supplied with an alkaline agent. means for supplying to the mixing reaction tank was, by mixing the mixture and an alkaline agent, a processing apparatus of the copper-containing acidic waste liquid containing a mixed reaction vessel to produce an alkaline suspension solution,
The copper-containing acidic waste liquid further comprises means for measuring the cumulative amount of the copper-containing acidic waste liquid, and means for controlling the supply of the oxidizing agent according to the cumulative amount of the copper-containing acidic waste liquid. Waste liquid neutralization and recovery treatment equipment.

Furthermore, the present invention has a supplying means for alkaline aqueous solution, a pouring means for copper-containing acidic waste liquid, a pouring means for oxidizing agent and a mixing means, and the mixed liquid of copper-containing acidic waste liquid and oxidizing agent reacts with the alkaline aqueous solution. A first mixing reactor that produces an alkaline suspension;
The copper-containing acidic waste liquid is communicated with the first mixing reaction tank, and has an addition means and a mixing means for the copper-containing acidic waste liquid, and contains an alkaline suspension from the first mixing reaction tank. A copper-containing acidic waste liquid neutralization / recovery treatment apparatus comprising a second mixing reaction tank for reacting the alkaline suspension.

1: Copper-containing acidic waste liquid 2: Oxidizing agent 3: Alkaline aqueous solution 4: Alkaline suspension 5: Copper oxide cake 6: Supernatant liquid 11: Mixing tank 12: (First) mixing reaction tank 13: Dehydration device 14: Control Apparatus 15: Copper-containing acidic waste liquid supply pump 16: Oxidant supply pump 17: Second mixed reaction tank
18: Liquid transfer pump

Claims (5)

The copper-containing acidic waste liquid is poured into an alkaline solution having a neutralization equivalent or more with respect to the copper-containing acidic waste liquid, and mixed to produce a suspension containing a solid containing copper oxide as a main component. A method for neutralizing copper-containing acidic waste liquid for separating the solid matter from a suspension and recovering copper,
(1) From the start of the reaction, the copper-containing acidic waste liquid and the oxidizing agent are mixed for 70 to 90% of the total amount added to the alkaline solution of the copper-containing acidic waste liquid, and then poured into the alkaline solution and mixed. And
(2) After the total amount of the copper-containing acidic waste liquid exceeds the above amount, the copper-containing acidic waste liquid is characterized by adding and mixing the copper-containing acidic waste liquid into the alkaline solution without using an oxidizing agent. Neutralization and copper recovery method.   The neutralization of the copper-containing acidic waste liquid according to claim 1, which is controlled so that the pH does not become acidic from the neutralization point, either temporarily or partially, in the reaction system when the copper-containing acidic waste liquid is added and mixed. And copper recovery method.   A relatively large volume mixing reaction tank and a relatively small volume mixing reaction tank are used. The relatively large volume mixing reaction tank contains an alkaline aqueous solution, and the copper-containing acidic waste liquid is contained in the alkaline solution. A mixture of oxidant and oxidant is added and mixed, and the resulting alkaline suspension is fed to a relatively small volume of the reaction vessel, and only the copper-containing acidic waste solution is contained in the reaction vessel. The method for neutralizing a copper-containing acidic waste liquid and recovering copper according to any one of claims 1 to 2, wherein: A mixing tank for mixing the copper-containing acidic waste liquid and the oxidizing agent from the oxidizing agent supply means, and the mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent obtained in the mixing tank into the mixing reaction tank supplied with the alkaline agent A copper-containing acidic waste liquid treatment apparatus comprising: means for supplying; and a mixed reaction tank for mixing the mixed solution and an alkaline agent to generate an alkaline suspension,
The copper-containing acidic waste liquid further comprises means for measuring the cumulative amount of the copper-containing acidic waste liquid, and means for controlling the supply of the oxidizing agent according to the cumulative amount of the copper-containing acidic waste liquid. Waste liquid neutralization and recovery processing equipment. There are means for supplying alkaline aqueous solution, means for adding copper-containing acidic waste liquid, means for adding oxidizing agent and means for mixing, and the mixture of copper-containing acidic waste liquid and oxidizing agent reacts with the aqueous alkaline solution to form an alkaline suspension. A first mixing reactor to produce;
The copper-containing acidic waste liquid is communicated with the first mixing reaction tank, and has an addition means and a mixing means for the copper-containing acidic waste liquid, and contains the alkaline suspension from the first mixing reaction tank, An apparatus for neutralizing and recovering a copper-containing acidic waste liquid comprising a second mixing reaction tank for reacting the alkaline suspension.

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