JP2012224902A - 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 a copper-containing acidic waste liquid, such as a copper chloride-containing etching waste liquid and a 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 a 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 being mixed with 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. Neutralizing copper-containing acidic waste liquid containing high-concentration copper ions, such as renewed waste liquid and etching waste liquid generated by roughening the substrate surface in the lamination process of multi-layer printed circuit board production, removes copper from the solution. And a device for the same.

  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, an etching waste solution 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 usually as high as 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 difficult to say that this waste liquid needs to be treated separately and is 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.

  When the present inventors examined about the processing method of copper-containing acidic waste liquid, when the acidic waste liquid containing the copper ion which is a process target liquid in high concentration is poured into the alkaline solution heated to a certain temperature or more, and mixed. It was found that the copper ions in the acidic waste liquid poured into the alkaline solution were auto-oxidized to copper oxide via copper hydroxide. However, since fine copper oxide is generated by this method, problems remain in handling such as poor sedimentation of the slurry containing copper oxide after the reaction is completed.

  Therefore, the inventors further researched, during the operation of pouring the copper-containing acidic waste liquid into the alkaline solution, when the temperature of the alkaline solution was lowered and copper hydroxide was generated, the precipitated particles were coarsened and the slurry As a result, the present inventors have found that the suspended solid concentration and copper ion concentration in the supernatant liquid are reduced.

That is, the present invention includes a solid containing copper oxide and copper hydroxide as a main component by adding and mixing the 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 of neutralizing a copper-containing acidic waste liquid and separating copper from the suspension,
(1) From the start of the reaction, at least 50 to 90% of the total amount of copper-containing acidic waste liquid added to the alkaline solution is poured and mixed with the copper-containing acidic waste liquid into the alkaline solution.
At a temperature of ℃ or more,
(2) After the total amount of the copper-containing acidic waste liquid exceeds the above amount, the copper-containing acidic waste liquid is added to the alkaline solution and mixed at a temperature of at least 40 ° C. This is a method for neutralizing acidic waste liquid and recovering copper.

The present invention also has means for supplying an alkaline aqueous solution, means for pouring a copper-containing acidic waste liquid, heating means, cooling means and mixing means, and reacting the alkaline aqueous solution with the copper-containing acidic waste liquid to produce an alkaline suspension. A mixed reactor;
Means for measuring the cumulative amount of the copper-containing acidic waste liquid;
And an apparatus for neutralizing and recovering a copper-containing acidic waste liquid containing a control mechanism for controlling the heating means and / or the cooling means of the mixed reaction tank, corresponding to the cumulative amount of the copper-containing acidic waste liquid.

Furthermore, the present invention has means for supplying alkaline aqueous solution, means for adding copper-containing acidic waste liquid, heating means, cooling means and mixing means, and the alkaline aqueous solution and copper-containing acidic waste liquid react to produce an alkaline suspension. A first mixing reactor;
A cooling or cooling means that communicates with the first mixing reaction vessel and lowers the temperature of the alkaline suspension fed from the first mixing reaction vessel;
It has a means for adding and mixing copper-containing acidic waste liquid, and communicates with the cooling or cooling means, contains an alkaline suspension from the cooling or cooling means, and adds the poured copper-containing acidic waste liquid and the alkaline A copper-containing acidic waste liquid neutralization and recovery treatment apparatus provided with a second mixing reaction tank for reacting a suspension.

  According to the present invention, direct treatment without diluting a high-concentration copper-containing acidic waste liquid having a copper ion content concentration of 5 to 20%, which has been difficult to process by the generation of double salts, etc. with conventional treatment techniques. A product having a large particle size and good sedimentation can be recovered. In addition, it is possible to obtain good treated water with less suspended substances and copper ions. Furthermore, since the self-oxidation action of copper hydroxide is used, the chemical necessary for the treatment is only an alkaline agent, which has a feature of high economic efficiency.

  And since the collection | recovery obtained by this invention method has a low moisture content compared with a simple hydroxide precipitation system, it becomes possible to reduce sludge discharge. Further, since the recovered material is a compound mainly composed of copper oxide, the recovered material can be used as a raw material for copper refining after dehydration.

Neutralization curve of copper etching waste solution and sodium hydroxide solution in Example 1 Schematic diagram showing one embodiment of the neutralization and recovery treatment device for copper-containing acidic waste liquid having one mixed reaction tank used in the present invention. Schematic diagram showing one embodiment of a neutralization and recovery treatment device for copper-containing acidic waste liquid having two mixed reaction tanks used in the present 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 The copper-containing acidic waste liquid is gradually poured into the reaction vessel, mostly from the beginning at a high temperature and the last part at a low temperature.

  More specifically, a suspension containing a solid containing copper oxide as a main component is generated by pouring and mixing a copper-containing acidic waste liquid into a heated alkaline solution mostly from the beginning. After the addition of the predetermined amount of copper-containing acidic waste liquid is completed, the temperature of the alkaline suspension that is the reaction liquid is allowed to cool or cool, and then the remaining copper-containing acidic waste liquid is poured and mixed. And solid matter mainly composed of copper oxide and copper hydroxide is deposited.

  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 the addition of the copper-containing acidic waste liquid,
(1) mixed with an alkaline solution at 50 ° C or higher,
(2) Mixing with an alkaline solution at 40 ° C. or lower is performed in this order.

  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”), the alkaline solution It is preferable to add and mix with an alkaline solution at 40 ° C. or less from the point of addition and mixing and exceeding this amount.

  When mixing with an alkaline solution at 40 ° C. or less earlier than the switching point, the proportion of copper oxide in the solid matter is low, the proportion of copper hydroxide is increased, sludge sedimentation is deteriorated, and the sludge is hydrated. The rate increases. Conversely, if the injection of only the copper-containing acidic waste liquid is slower than the switching point, the sludge sedimentation is good, but the suspension in the treated water from which the solids have been removed and the concentration of the copper-containing component in the suspended matter increase. Problems may occur.

  Therefore, in carrying out the method of the present invention, it is preferable to conduct an experiment in advance on the copper-containing acidic waste liquid to be treated and the alkaline solution to be used, and to investigate an appropriate timing (switching time) for switching the temperature of the reaction system.

  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.

  Moreover, as an alkaline agent utilized for preparation of the alkaline solution by the method of the present invention, various alkaline agents can be used, 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 amount. .

  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 an acidic copper etching waste liquid discharged from the printed circuit board manufacturing process and a sodium hydroxide solution as an alkaline solution will be described as an example, and the treatment of the 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 liquid to be treated is prepared and placed in a mixed reaction tank, and the temperature is at least 50 ° C. or higher, preferably Heat and maintain at 60-80 ° C. Next, the copper-containing acidic waste liquid is poured into the mixed reaction tank little by little. This addition may be continuous or intermittent, but is preferably performed intermittently.

  Next, when the total amount of the copper etching waste liquid reached 70 to 90% of the total amount of the etching liquid (switching point), the copper etching waste liquid injection was stopped and the alkaline suspension in the mixing reaction tank was stopped. Reduce the temperature of the suspension to at least 40 ° C. or less. As a means for lowering the temperature, it may be simply allowed to cool, or a cooling device may be installed in the mixing reaction tank and operated. Alternatively, a temperature may be lowered by preparing a mixing reaction tank different from the mixing reaction tank used first, installing a cooling device between them, and transferring the alkaline suspension.

  Then, the remaining amount of the acid etching waste liquid is gradually poured again into the alkaline suspension whose temperature is lowered to 40 ° C. or less, preferably 30 ° C., and the reaction is completed. In addition, the lower limit of the temperature of the alkaline suspension after the switching point is not particularly limited, but it is preferable to set the temperature to the ambient temperature (environmental temperature) in consideration of the economic aspect such as the cooling cost.

  In the method of the present invention, in the mixing of the aqueous sodium hydroxide solution and the acid etching solution at the first high temperature condition, the copper ions in the copper etching waste solution are first changed to copper hydroxide, but then rapidly by auto-oxidation. Change to copper oxide. That is, without using an oxidizing agent, an alkaline suspension in which fine particles containing copper oxide as a main component are suspended by heating (hereinafter, abbreviated as “alkaline suspension”) is generated.

  Moreover, in the mixing of the acid etching into the alkaline suspension under the low temperature condition after the switching time, the copper ions in the copper etching waste liquid are changed to copper hydroxide by the action of the alkali. However, due to the low temperature, it is not completely oxidized to copper oxide. That is, in this reaction, copper oxide and a small amount of copper hydroxide are present in the alkaline suspension.

  And if it is present in a large amount, it is copper hydroxide that swells with water and becomes sludge that is difficult to handle, but as in the present invention, if it is present in a small amount in a suspension in which other fine particles are present, this takes in fine suspended matter It acts as a flocculant and increases the particle size in the suspension, improving the sedimentation properties of the product and the properties of the treated water after solid-liquid separation.

In any reaction, if the amount of the copper etching waste liquid 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 during the reaction. Copper re-dissolves in the form of Cu ²⁺ and the copper concentration in the treated water increases. And, for the purpose of the present invention, which is removal / recovery of copper from the copper etching waste liquid (copper-containing acidic waste liquid), such a phenomenon is not preferable, and 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.

The neutralization and recovery treatment apparatus (hereinafter referred to as “apparatus”) for carrying out the method of the present invention includes alkaline aqueous solution supply means, copper-containing acidic waste liquid pouring means, heating means, cooling means, and mixing means. A mixed reaction tank for reacting an alkaline aqueous solution with a copper-containing acidic waste liquid to produce an alkaline suspension;
Means for measuring the cumulative amount of the copper-containing acidic waste liquid;
And an apparatus containing a control mechanism for controlling the heating means and / or the cooling means of the mixed reaction tank corresponding to the cumulative amount of the copper-containing acidic waste liquid.

  One embodiment of this apparatus is schematically shown in FIG. In FIG. 2, 1 is a copper-containing acidic waste liquid, 2 is an alkaline solution, 3 is an alkaline suspension, 4 is a copper oxide cake, 12 is a mixing reaction tank, 13 is a dehydrator, 14 is a controller, and 15 is a heating means. Each is shown.

  In the apparatus shown in FIG. 2, the copper-containing acidic waste liquid 1 is poured little by little into a mixed reaction tank 12 supplied with an alkaline solution 2 that has been heated to 50 ° C. or higher in advance. At the time of the addition, the amount of the copper-containing acidic waste liquid 1 added is integrated by the control device 14. In the control device 14, the alkaline solution 2 in the mixed reaction tank 12 is added from the start of the reaction to 90% of the total amount of the copper-containing acidic waste solution added to the alkaline solution 2 until 90%. The temperature is controlled to be at least 50 ° C. or higher. Moreover, in the control apparatus 14, after the total injection amount of the copper-containing acidic waste liquid 1 exceeds the said amount, injection | pouring operation is once interrupted and the alkaline suspension 3 in the mixing reaction tank 12 is 40 degrees C or less. After cooling, the remaining copper-containing acidic waste liquid 1 is controlled to be poured. After completion of the reaction, the alkaline suspension 3 is transferred to the dehydrator 13 and the copper oxide cake 4 is recovered after solid-liquid separation.

  Since the above apparatus uses only one mixing reaction tank and changes the temperature in the tank, the mechanism is simple and the equipment cost is low. Because of cooling, it is disadvantageous in terms of energy.

As another apparatus, there is a supply means for an alkaline aqueous solution, a pouring means for a copper-containing acidic waste liquid, a heating means, a cooling means, and a mixing means. A first mixing reactor to produce;
A cooling or cooling means that communicates with the first mixing reaction vessel and lowers the temperature of the alkaline suspension fed from the first mixing reaction vessel;
It has a means for pouring and mixing copper-containing acidic waste liquid, communicates with the cooling or cooling means, contains an alkaline suspension from the cooling or cooling means, and adds the poured copper-containing acidic waste liquid and the alkaline An apparatus provided with a second mixing reaction tank for reacting the suspension may be mentioned.

  Another embodiment of this apparatus is schematically shown in FIG. In FIG. 3, 18 is a liquid transfer pump, 19 is a cooling / cooling means, 20 is a second mixing reaction tank, and the rest is substantially the same as FIG.

  In the apparatus shown in FIG. 3, the copper-containing acidic waste liquid 1 is poured little by little into the first mixed reaction tank 12 to which the alkaline aqueous solution 2 previously heated to 50 ° C. or higher is supplied. At the time of the addition, the amount of the copper-containing acidic waste liquid 1 added is integrated by the control device 14. The controller 14 is in a state where the amount of the copper-containing acidic waste liquid 1 added is maintained at least at 50 ° C. or more from the start of the reaction to 90% of the total amount of the copper-containing acidic waste liquid added to the alkaline solution, which is not 70%. Control is performed so that the copper-containing acidic waste liquid 1 is poured into the first mixing reaction tank 12.

  Then, 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 alkaline suspension in the mixing reaction tank 12. Control to transfer the liquid 3 to the second mixing reaction tank 20 is performed. At this time, the alkaline suspension 3 is cooled to 40 ° C. or lower by the cooling / cooling means 19 during the transfer. If a heat exchanger is used as the cooling and cooling means, the heating of the alkaline aqueous solution 2 that supplies the heat recovered by cooling the alkaline suspension 3 to the mixed reaction tank 12 during the next reaction as described above. This is preferable because it can reduce the energy consumption. The cooled alkaline suspension 3 is supplied to the second mixed reaction tank 20, and the remaining copper-containing acidic waste liquid 1 is poured to complete the reaction. After completion of the reaction, the alkaline suspension 3 is transferred to the dehydrator 13 and the copper oxide cake 4 is recovered after solid-liquid separation.

  The above apparatus uses two mixed reaction tanks and always heats in one of the reaction tanks, and is low in energy waste corresponding to continuous processing. In addition, a heat exchanger is used as the intermediate cooling and cooling means 15, and water to be poured into the first mixing reaction tank 12, for example, the alkaline aqueous solution 2, is passed through the alkaline suspension from the first mixing reaction tank 12 in this means. Heat exchange with the turbid liquid 3 is advantageous because it further increases the thermal efficiency.

  Moreover, the capacity | capacitance of the 1st mixing tank 12 and the 2nd mixing tank 20 shall be 70-90: 10-30 in those ratio, and the alkaline suspension produced | generated by the 1st mixing tank is continuously made into 2nd. It is possible to continuously treat the copper-containing acidic waste liquid 1 by feeding it into the mixing tank.

  In the method of the present invention described above, it is important to obtain a product containing copper oxide as a main component and a product containing copper hydroxide by changing the reaction temperature in the pouring operation of the copper-containing acidic waste liquid. It is. For this purpose, it is necessary to set the reaction temperature to at least 50 ° C. or more, preferably about 60 to 80 ° C. at the start of the reaction. In the latter half of the reaction, the temperature of the alkaline suspension is at least 40 ° C. or less. It is necessary to lower the temperature, preferably below 30 ° C. For example, if the temperature of the alkaline suspension is reduced when the cumulative amount of copper-containing acidic waste liquid is low, the amount of copper hydroxide that tends to swell increases, resulting in difficult handling of the recovered material. become. Therefore, the cooling or cooling of the alkaline suspension is performed in the latter half of the pouring operation, specifically after the switching point, to produce a sufficient amount of copper hydroxide to take in fine suspended matters. It is desirable to manage to

  After completion of the reaction as described above, an alkaline suspension containing a solid containing copper oxide as a main component is drawn, and this is solid-liquid separated into a solid (mainly copper oxide) and a separated liquid (supernatant). To do. For the solid-liquid separation, known means such as filtration separation, centrifugation, sedimentation separation, etc. can be applied. By doing so, it is possible to obtain a solid having a copper oxide as a main component, which can be reused as a resource, and a separated liquid having a low content of a suspension or a suspendable copper-containing component.

  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.

  The present invention utilizes this principle and the fact that the reaction of copper ions differs depending on the reaction temperature, and by controlling the reaction temperature consciously during the neutralization reaction of the copper-containing acidic waste liquid and the alkaline solution, a small amount of By producing copper hydroxide, it was possible to efficiently collect copper and obtain a supernatant with 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 0.9 equivalent of the amount of copper etching waste liquid necessary for neutralizing the sodium hydroxide solution, the temperature of the alkaline suspension in the mixing reaction tank is maintained at 80 ° C. or higher. The copper etching waste liquid was poured into portions. Furthermore, a 0.95 equivalent pouring operation (10 th pouring) was performed after the temperature of the alkaline suspension was cooled to 26 ° C., and the reaction was completed.

<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>
500 mL of 25% sodium hydroxide solution was added to a 2 liter beaker and heated while stirring with a magnetic stirrer. After the temperature of the sodium hydroxide solution reached 80 ° C., 58 mL of the copper etching waste solution was added to the sodium hydroxide solution over 3 minutes while stirring in the 2 liter beaker. After pouring of the copper etching waste liquid, the 2-liter beaker was left for 3 minutes with stirring. Thereafter, again, 58 mL of the copper etching waste solution was poured into a 2 liter beaker and allowed to stand for 3 minutes, which was repeated a total of 9 times. During the nine injection operations, the 2 liter beaker was constantly stirred, and the temperature of the reaction solution in the beaker was maintained at 80 to 90 ° C.

  After the ninth addition operation was completed, the alkaline suspension was cooled to 26 ° C. while continuing stirring. Thereafter, in the tenth pouring operation, 29 mL of copper etching waste liquid was poured into a 2 liter beaker while continuing stirring, and the pouring operation was terminated. Thereafter, stirring was continued for 30 minutes after the end of pouring, and the reaction was completed. Through the above operation, a suspension containing a slightly grayish black solid was produced.

Example 2
<Processing operation>
500 mL of 25% sodium hydroxide solution was added to a 2 liter beaker and heated while stirring with a magnetic stirrer. After the temperature of the sodium hydroxide solution reached 50 ° C., 58 mL of copper etching waste solution was added to the sodium hydroxide solution over 3 minutes. After the addition of the copper etching waste liquid, stirring of the 2 liter beaker was continued for 3 minutes. After the stirring, the operation of pouring 58 mL of the copper etching waste solution into the 2 liter beaker was repeated 9 times.

  After the ninth pouring operation was completed, the alkaline suspension was cooled until the temperature reached 26 ° C. Thereafter, in the tenth pouring operation, 29 mL of copper etching waste liquid was poured into a 2 liter beaker, and the pouring operation was terminated. Thereafter, stirring was continued for 30 minutes after the end of pouring, and the reaction was completed. Through the above operation, a suspension containing a slightly grayish black solid was produced.

  The action mechanism of the present invention is that, in the final stage of mixing, the copper etching waste liquid is poured into a sodium hydroxide solution in a low temperature state to produce copper hydroxide in addition to copper oxide. The copper oxide previously formed by copper oxide acts as a precipitant for the main product. Accordingly, if the copper etching waste liquid and the alkaline suspension are mixed in the seventh and subsequent pouring operations (after 70% of the total amount of pouring), a product containing copper hydroxide is produced apart from the amount produced. It is clear that the same effect can be obtained.

Comparative Example 1
<Processing operation>
500 mL of 25% sodium hydroxide solution was added to a 2 liter beaker and heated while stirring with a magnetic stirrer. After the liquid temperature of the sodium hydroxide solution reached 80 ° C., 58 mL of copper etching waste liquid was added over 3 minutes. Thereafter, stirring was continued for 3 minutes, and 58 mL of copper etching waste liquid was again poured. After repeating this pouring operation 9 times, in the 10th time, 29 mL of copper etching waste liquid was poured, and the reaction was terminated after stirring for 30 minutes. Through the above operation, a suspension containing a slightly grayish black solid was produced.

Comparative Example 2
<Processing operation>
500 mL of 25% sodium hydroxide solution was added to a 2 liter beaker and stirred with a magnetic stirrer. The water temperature of sodium hydroxide at this time was 26 ° C. Next, 58 mL of a copper etching waste solution was poured into the sodium hydroxide solution over 3 minutes. After completion of the addition, stirring was continued for 3 minutes, and 58 mL of copper etching waste liquid was added again.

  Immediately after the first addition, the alkaline solution without the beaker turned dark blue. Thereafter, when the pouring operation was continued, a light blue sludge-like substance was produced. This sludge-like substance gradually filled the beaker as the number of injections increased, and it became difficult to stir. Moreover, even if the beaker was left after the pouring operation, the supernatant liquid was not separated, and sludge having a high water content 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 clear from this result, the slurry of Examples 1 and 2 has a slightly higher particle size of the product, although the SV30, which is a sedimentation index, is slightly higher than that of Comparative Example 1, and the supernatant water The turbidity and the copper concentration of the supernatant water were low, and good supernatant water was obtained. In Comparative Example 2, since a swollen sludge-like substance was generated, 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, it was confirmed that the method of the present invention is effective as a method for treating a copper-containing acidic waste liquid.

  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: Alkaline solution 3: Copper oxide-containing alkaline suspension 4: Copper oxide cake 5: Supernatant liquid 12: (First) mixing reaction tank 13: Dehydrator 14: Controller 15: Heating means 16: Copper-containing acidic waste liquid supply pump 18: Liquid transfer pump 19: Cooling / cooling means 20: Second mixing reaction tank 21: Valve

Claims (6)

A copper-containing acidic waste liquid is poured into an alkaline solution having a neutralization equivalent or higher with respect to the copper-containing acidic waste liquid and mixed to obtain a suspension containing a solid containing copper oxide and copper hydroxide as main components. A method of neutralizing a copper-containing acidic waste liquid and recovering copper, which is generated and separates the solid matter from the suspension,
(1) From the start of the reaction, at least 50 to 90% of the total amount of copper-containing acidic waste liquid added to the alkaline solution is poured and mixed with the copper-containing acidic waste liquid into the alkaline solution.
At a temperature of ℃ or more,
(2) After the total amount of the copper-containing acidic waste liquid exceeds the above amount, the copper-containing acidic waste liquid is added to the alkaline solution and mixed at a temperature of at least 40 ° C. Neutralizing acidic waste liquid and recovering copper.   The method for neutralizing a copper-containing acidic waste liquid and recovering copper according to claim 1, wherein the amount of the alkaline solution relative to the copper-containing acidic waste liquid is 1 to 1.2 times the neutralization equivalent.   The copper-containing acidic waste liquid according to claim 1 or 2, wherein the pH is controlled so that the pH does not become more acidic than the neutralization point, either temporarily or partially, in the reaction system when adding or mixing the copper-containing acidic waste liquid. Neutralization and copper recovery methods.   Using a relatively large volume mixing reaction tank, a small volume mixing reaction tank, and a cooling or cooling device provided between the reaction tanks so that liquid can pass between them, the relatively large volume mixing reaction tank contains an alkaline aqueous solution. Then, the copper-containing acidic waste liquid is poured and mixed in a state where the bath temperature is maintained at 50 ° C. or more, and the resulting alkaline suspension is cooled to at least 40 ° C. via a cooling or cooling apparatus. 4. In the state described below, the solution is fed to a relatively small volume mixing reaction tank, and the copper-containing acidic waste liquid is poured again in the mixing reaction tank. A method for neutralizing a copper-containing waste liquid and recovering copper. A mixing reaction tank that has an alkaline aqueous solution supply means, a copper-containing acidic waste liquid pouring means, a heating means, a cooling means, and a mixing means, and reacts the alkaline aqueous solution with the copper-containing acidic waste liquid to produce an alkaline suspension;
Means for measuring the cumulative amount of the copper-containing acidic waste liquid;
And a copper-containing acidic waste liquid neutralization and recovery treatment apparatus that includes a control mechanism that controls the heating means and / or the cooling means of the mixed reaction tank in response to the cumulative amount of the copper-containing acidic waste liquid. A first mixing reaction in which an alkaline aqueous solution supply means, a copper-containing acidic waste liquid pouring means, a heating means, a cooling means, and a mixing means are included, and an alkaline aqueous solution and a copper-containing acidic waste liquid react to form an alkaline suspension. A tank;
A cooling or cooling means that communicates with the first mixing reaction vessel and lowers the temperature of the alkaline suspension fed from the first mixing reaction vessel;
It has a means for adding and mixing copper-containing acidic waste liquid, and communicates with the cooling or cooling means, contains an alkaline suspension from the cooling or cooling means, and adds the poured copper-containing acidic waste liquid and the alkaline The copper-containing acidic waste liquid neutralization and recovery processing apparatus provided with the 2nd mixing reaction tank which makes suspension react.

Images