TWI641561B - Treatment method of copper-containing acidic waste liquid - Google Patents

Abstract

The present invention relates to a method for treating an acidic waste liquid containing copper, and relates to a method for removing and recovering copper oxide from the acidic waste liquid containing copper, and a device for the purpose.

The treatment method of copper-containing acidic waste liquid of the present invention is that after mixing the copper-containing acidic waste liquid with an oxidant, the mixed liquid is added to the alkaline agent while the pH of the alkaline solution after the mixed liquid is added. Even if it is temporary, it will not be reduced to less than 7 for management. The method for treating copper-containing acidic waste liquid generated by recovering solids containing copper oxide as the main component is to dilute the alkali agent in advance to adjust the concentration. The mixed solution is added to the alkali agent, or the alkali solution is diluted beforehand to adjust the concentration and the diluted alkali agent is warmed, and then the mixed solution is added to the alkali agent.

Description

Method for treating acid waste liquid containing copper

The present invention relates to a method for treating an acidic waste liquid containing copper. More specifically, the present invention relates to, for example, an etching waste liquid generated when a copper printed substrate is etched using a copper chloride etchant, and is produced in electrolytic copper foil. Neutralization treatment of copper plating acid bath containing high concentration copper ions and other waste liquids such as refreshing waste liquid of plating bath, etching waste liquid produced by roughening the substrate surface during the lamination step when producing multilayer printed substrates, etc. Method and device for making copper into copper oxide and removing and recovering it from acid waste liquid containing copper. The present invention also relates to a method for producing copper oxide by treating copper-containing acidic waste liquid to produce copper oxide.

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 generated when a copper printed substrate is etched using a copper chloride etchant, and electrolytic copper is known. A waste liquid for renewing a plating bath during the production of a foil, a waste liquid for etching produced by roughening a substrate surface in a lamination step in the production of a multilayer printed substrate, and the like. The copper ion concentration of these waste liquids is as high as 5 to 20% by mass (hereinafter, only expressed as "%"). On the other hand, the concentration of coexisting chloride ions and sulfate ions is usually It is also as high as 5 ~ 30%.

As part of the copper recovery treatment for copper-containing acidic waste liquid, a part of it is a method that utilizes a difference in ionization tendency, for example, reacts with iron waste to precipitate and recover metallic copper. However, this method has a problem that the copper recovery rate from the waste liquid is low. In addition, since a waste liquid containing iron ions eluted by the reaction with copper ions and residual copper ions remains, the waste liquid must be treated separately, which is difficult to say as an efficient treatment method.

In addition, as a general treatment method of a copper-containing acidic waste liquid, a treatment method is known in which heavy metals are precipitated and removed by adding an alkaline substance such as sodium hydroxide, but the sludge produced by this method ( Sludge) has a large volume and a high water content and is not easy to handle, so it is not suitable for treating copper-containing acidic waste liquid with high copper ion concentration.

Furthermore, with regard to etching wastewater, for example, as disclosed in Japanese Patent Application Laid-Open No. 2004-50096 (Patent Document 1), an attempt has been made to add alkali to make copper ions become copper hydroxides without dissolving, and then add an oxidant to make copper oxides and recover them. method. However, when an oxidant containing chloride ions such as hypochlorite and bleaching powder is used as the oxidant, the chloride ion concentration in the added liquid becomes more concentrated, and there is a concern that copper chloride and There are many problems such as the complex salt of copper oxide and the mixing of salt into sludge. When high-concentration waste liquid is used as a treatment object, there must be many improvements such as increasing the impurity content of the recovered copper oxide.

A copper recovery and treatment method for a copper-containing acidic waste liquid is disclosed in, for example, Japanese Patent No. 4323668 (Patent Document 2). The recovery of alkaline carbonate from a copper-containing acidic waste liquid has been developed, and a copper-containing acid The technology that does not mix anions such as sulfate ions and chloride ions contained in the waste liquid with alkaline copper carbonate after recovery. When the recovered copper compound is reused, the high-purity alkaline copper carbonate is recovered to expand the use of the copper compound with a lower concentration of impurities.

The inventors of this case have previously disclosed in Patent Publication No. 4199821 (Patent Document 3) that a method of efficiently recovering copper oxide by adding a copper-containing acidic waste liquid with an oxidizing agent and adding it to an alkaline solution has been found. According to this method, a solid solution containing copper oxide as a main component can be obtained by dropping a mixed solution of a copper-containing acidic waste liquid and an oxidizing agent into an alkaline solution. This is because the copper-containing acidic waste liquid and the oxidizing agent are mixed with the alkali agent in small amounts one by one at the same time to obtain an appropriate dilution effect and neutralize the copper-containing acidic waste liquid at the same time, so that copper contained in the copper-containing acidic waste liquid can be neutralized. Ionic oxidation becomes copper oxide. However, according to tests by the inventors of the present case, the chlorine content in the copper oxide recovered by this method may be about 200 mg / kg, and the chlorine content may be required to be further reduced depending on the purpose of recovering the copper oxide.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2004-50096

[Patent Document 2] Japanese Patent No. 4323668

[Patent Document 3] Japanese Patent No. 4199821

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to provide a copper-containing copper which can reduce the anion content rate of the recovered copper oxide while efficiently treating the copper-containing acidic waste liquid and recovering the copper oxide efficiently. Method for treating acid waste liquid, method and device for recovering copper oxide from acid waste liquid containing copper.

In order to achieve the above object, the method for treating a copper-containing acidic waste liquid of the present invention is to mix the copper-containing acidic waste liquid with an oxidant, while adding the mixed liquid to an alkali agent, and while adding the mixed liquid to the The treatment method of the alkaline solution does not lower the pH to below 7 even temporarily, and a method for treating a copper-containing acidic waste liquid that is produced by recovering a solid substance containing copper oxide as a main component, wherein: After the alkali agent is diluted to adjust the concentration, the aforementioned mixed solution is added to the alkali agent, or after the alkali agent is diluted to adjust the concentration and the diluted alkali agent is warmed, the aforementioned mixed solution is added to the alkali agent.

Here, the so-called dilution of the alkali agent means that the alkali agent (liquid or solid alkali agent) is diluted at any time, any place, and in any form before adding the mixed liquid to the alkali agent. Both. That is, it can be diluted when the alkali agent is purchased, it can also be diluted when the solid alkali agent is dissolved, or the alkali agent that has been diluted to a predetermined concentration can be purchased and used.

According to one aspect of the present invention, a sodium hydroxide solution is used as an alkaline agent.

According to one aspect of the present invention, a solution containing sodium hydroxide and sodium carbonate is used as an alkaline agent.

According to one aspect of the present invention, a sodium carbonate solution is used as an alkali agent.

According to one aspect of the present invention, the concentration of the sodium hydroxide solution is set to 6% by mass or less.

According to one aspect of the present invention, the concentration of the sodium hydroxide solution is 0.2% by mass or less and the concentration of sodium carbonate is 1.1% by mass or less.

According to one aspect of the present invention, the temperature of the alkali agent is set to 70 ° C or higher.

The device for recovering copper from a copper-containing acidic waste liquid according to the present invention includes: a mixing tank for mixing the copper-containing acidic waste liquid with an oxidizing agent; and an injection means for making an alkali solution after the mixed liquid is injected. Add the mixed solution from the mixing tank to the reaction tank even if the pH does not decrease temporarily to below 7. The reaction tank is the reaction of the mixed solution with the alkaline agent solution to form a solid with copper oxide as the main component; the alkaline agent The supply means is to supply an alkaline agent to the reaction tank; and the solid-liquid separation device is to separate and recover the solid matter generated in the reaction tank; the reaction tank and the solid-liquid separation device are capable of transferring a liquid containing solid matter The method is connected, in which a diluent supply means is provided to dilute the alkaline agent to adjust the concentration, and the reaction tank or the alkaline agent supply means is provided with an alkaline agent warming means to warm the diluted alkaline agent.

The method for producing copper oxide from a copper-containing acidic waste liquid of the present invention is to mix a copper-containing acidic waste liquid with an oxidant, while adding a mixed solution of a copper-containing acidic waste liquid and an oxidant to an alkali agent, while mixing The pH of the alkaline solution after the liquid injection does not decrease below 7 even temporarily The method for managing and recovering the produced solids with copper oxide as the main component to produce copper oxide from a copper-containing acidic waste liquid is characterized in that the alkali agent is diluted beforehand to adjust the concentration, and the aforementioned mixture is mixed The liquid is added to the alkaline agent, or the alkaline agent is diluted beforehand to adjust the concentration and warmed, and then the aforementioned mixed liquid is added to the diluted and warmed alkaline agent.

According to the present invention, a copper-containing acidic waste liquid having a high concentration of 5 to 20% of copper ions, which is difficult to handle due to the formation of double salts and copper hydroxide, can be directly processed without dilution. In addition, since the recovered material from the copper-containing acidic waste liquid contains copper oxide as a main component, it is different from double salt and copper hydroxide and has good dehydration property, so that the concentration of impurities contained in the recovered copper oxide can be increased. reduce. Moreover, since the chlorine content of the recovered material is low, copper oxide in a form that can be easily reused can be obtained.

1‧‧‧copper recovery device

11‧‧‧ mixing tank

12‧‧‧ reaction tank

13‧‧‧Solid-liquid separation device

14‧‧‧ Copper-containing acid waste liquid pipe

15‧‧‧Oxidant supply piping

16‧‧‧ mixed liquid supply piping

17‧‧‧ Alkali agent supply piping

18‧‧‧ dilution water supply piping

19‧‧‧ Mixer

20‧‧‧ Washing water supply piping

21‧‧‧ Valve

22‧‧‧ Dehydration device

23‧‧‧ thermometer

24‧‧‧ heater

25‧‧‧ Alkali agent heating tank

26‧‧‧Transferred to Pupu

FIG. 1 is a diagram showing one aspect of the copper recovery device of the present invention.

Fig. 2 is a diagram showing another aspect of the copper recovery device of the present invention.

FIG. 3 is a view showing still another aspect of the copper recovery device of the present invention.

In the treatment process of the present invention, the alkaline agent is initially diluted. Next, a mixture obtained by mixing a copper-containing acidic waste liquid with an oxidant Liquid injection is added to the diluted alkaline agent to produce a solid.

The copper-containing acidic waste liquid to be treated in the present invention need only contain ionic copper at a concentration of 10,000 mg / L or more and be acidic. Even if the copper ion concentration is lower than 10000 mg / L, it can be processed according to the present invention, but when the copper ion concentration is low, the amount of copper oxide obtained is small. Therefore, considering the amount of the recovered material, it is better to apply the economically economical waste liquid. In addition, even when a high concentration of ionic copper is contained, when the liquidity is neutral and alkaline, a clamp agent may be contained so that copper ions are not precipitated. Such a waste liquid containing a clamp agent is not suitable in the present invention because the clamp agent is considered to inhibit the oxidation of copper.

Specific examples of the copper-containing acidic waste liquid include copper chloride etching waste liquid generated in the etching treatment step of the printed substrate, and copper sulfate plating bath liquid waste liquid generated in the electrolytic copper plating treatment step. These waste liquids are suitable for the present invention because they contain ionic copper of about 10 to 150 g / L and have a pH of 1 or less. In addition, since the concentration of copper ions in the waste liquid is high, the amount of copper oxide that can be recovered increases.

The oxidant used in the present invention is not particularly limited as long as it can make the divalent copper ions into copper oxide. As the oxidant that does not adversely affect the properties of the recovered copper oxide, hydrogen peroxide is used. Suitable for.

The alkali agent used in the present invention is not particularly limited as long as it can neutralize the copper-containing acidic waste liquid, and it is considered that if the anion remaining after the reaction forms an insoluble salt, it will become the recovered copper oxide. The reason for the low purity is to use an alkali metal hydroxide as a base Agent is better. Specific examples thereof include an aqueous solution of sodium hydroxide which is inexpensive and easily available.

In addition, an alkali metal hydroxide can be used in combination with an alkali metal carbonate as an alkali agent. Further, it is also possible to use an alkali metal carbonate as an alkali agent instead of the alkali metal hydroxide. In order to reduce the concentration of impurities in the recovered material, for example, an aqueous solution of sodium carbonate can be used.

In the present invention, since it is not necessary to dilute and treat a high-concentration copper-containing acidic waste liquid, it is important to make the reaction in accordance with the procedure described above. Here, the case where hydrogen peroxide water is used as an oxidant solution and sodium hydroxide is used as an alkali agent is taken as an example, and the importance of the processing procedure, mixing, and reaction order of the present invention will be described below.

First of all, the conventional common treatment method is to add an alkaline agent to a copper-containing acidic waste liquid. When treating a copper-containing acidic waste liquid containing a high concentration of copper ions, an alkaline agent is added to the acidic waste liquid containing copper. However, in the order of adding the alkaline agent to the high concentration copper-containing acidic waste liquid, the double salt CuCl ₂ is generated. 3Cu (OH) ₂ and copper hydroxide. Among them, the double salt system has a high water content, is difficult to dehydrate, and contains chlorine. Therefore, copper oxide containing the double salt cannot be reused directly after recovery. Moreover, when high-concentration copper hydroxide is also produced, it has a high water content and is difficult to handle, making it unsuitable for reuse.

In addition, after adding a copper-containing acidic waste liquid containing a high concentration of copper ions to an alkali agent, and when adding hydrogen peroxide water, first, a sludge-like double salt and copper hydroxide having a high water content in the alkali agent will be added. Precipitation and accumulation. Then, when hydrogen peroxide water was added thereto, the double salt and copper hydroxide-based sludge-like solids precipitated in the liquid were not easily dispersed. Hydrogen peroxide is oxidized, but the oxidation inside the double salt and copper hydroxide becomes slower. Since the oxidation cannot proceed uniformly to the inside of the double salt and copper hydroxide, the efficiency of the oxidation reaction by hydrogen peroxide is low.

In addition, during the etching process of the copper chloride etching waste liquid, the divalent copper ions in the etching solution may be reduced to monovalent, and may contain cuprous ions. When such an etching waste liquid is directly injected into an alkali agent, in addition to copper hydroxide, cuprous chloride (CuCl) having a low solubility is also precipitated. Even if hydrogen peroxide water is injected in this state, the cuprous chloride (CuCl) acts as a decomposition catalyst for hydrogen peroxide. Therefore, when the contribution to the production of copper oxide is insufficient, the Hydrogen oxide is consumed, resulting in a further reduction in the efficiency of the oxidation reaction by hydrogen peroxide.

In order to avoid the above problems, it is important to mix the acid waste liquid containing copper with hydrogen peroxide water before mixing and reacting with the alkali solution (diluted alkali solution) in the treatment process according to the present invention. Thereby, when the copper ion contained in the waste liquid becomes an oxidation reaction of copper oxide, when a mixed solution of a copper-containing acidic waste liquid and hydrogen peroxide water is injected into the alkaline agent, it proceeds rapidly. Further, when the waste liquid contains cuprous ions, the cuprous ions are oxidized to copper ions by the oxidation of hydrogen peroxide by being mixed with hydrogen peroxide before being brought into contact with the alkaline agent, so that precipitation solubility can be avoided. Lower cuprous salts such as cuprous chloride (CuCl).

In the present invention, although the time required for mixing the copper-containing waste liquid with hydrogen peroxide water also depends on the concentration of the two to be mixed, when the two are at a high concentration, even within a short time of about 5 seconds In time, the cuprous ion is also oxidized in a considerable proportion. At about 20 seconds, the oxidation reaction has been charged. Divide.

On the other hand, when a copper-containing acidic waste liquid is mixed with hydrogen peroxide water, copper ions serve as a catalyst for the decomposition reaction of hydrogen peroxide. This decomposition reaction begins to become noticeable after about 60 seconds have elapsed after mixing the two, and after 7 minutes to 10 minutes have elapsed, it is accompanied by intense foaming. Although it also depends on the concentration of the two, for example, when mixing 2 times the amount of hydrogen peroxide in terms of molar concentration with respect to copper ions, the foaming system caused by the decomposition of hydrogen peroxide will elapse after 20 minutes. It is reduced, and becomes slightly after 25 minutes, and when it is added to the alkaline agent at this time, a precipitate containing a larger amount of copper hydroxide than copper oxide is generated.

Because of this situation, the mixing and reaction time of the copper-containing acidic waste liquid and hydrogen peroxide water is about 5 seconds to 20 minutes, preferably 20 seconds to 7 minutes, before adding it to the alkaline agent. The time around is better.

In addition, when the total amount of hydrogen peroxide water is added at a time with respect to the total amount of the copper-containing acidic waste liquid to be reacted, there may be a large amount of the two liquids, and the hydrogen peroxide is rapidly decomposed and the mixed liquid is mixed. Vigorous foaming, meanwhile, the liquid temperature rises sharply. In this case, because the accident caused by the rapid decomposition reaction of hydrogen peroxide may also occur, the acid waste liquid containing copper and hydrogen peroxide water must be mixed only once in the amount used for the injection operation, and the foaming becomes Complete the filling operation before the heat.

As the method for mixing the copper-containing waste liquid and hydrogen peroxide water, for example, a method in which two liquids are poured into a mixing tank and stirred, and a method in which the copper-containing waste liquid is mixed with hydrogen peroxide water and mixed are applied.

Among them, the method of adding two liquids to the mixing tank and stirring is easy. Check and adjust the injection volume. In addition, when an overflow pipe is installed in the tank, even if foaming occurs during mixing, the system is an open system, so that it has the advantage of being able to prevent problems on the device such as tank explosion.

Further, as a method for mixing and mixing a copper-containing waste liquid and hydrogen peroxide water, a method of connecting two solution pipes by a Y-shaped pipe or the like and joining them together, and using the other pipe in one of the pipes can be used. Method of mixing by liquid injection. Moreover, the two liquids can be stirred and mixed after passing through the static mixer. Although this method must be useful for the pressure resistance of a foaming device or a mechanism capable of exhausting the generated gas, it has the advantage of being able to maintain the time from mixing the two liquids to the supply evenly and to continuously supply it.

Secondly, it is a reaction between a mixed liquid of copper-containing waste liquid and hydrogen peroxide water (hereinafter referred to as "mixed liquid") and an alkaline agent. In order to avoid the formation of double salts, it is necessary to make the copper ion concentration thin. Its response. In order to rapidly advance the oxidation reaction of copper ions, the reaction is preferably performed under strong alkaline conditions in which the reactivity of hydrogen peroxide becomes high.

In order to achieve these conditions, in the technique of the present invention, a solution-based alkali agent having good operability is used, and the aforementioned mixed solution must be injected at an appropriate speed when the alkali agent solution is stirred. This injection acceleration must be managed in the alkaline solution after the injection in such a way that the pH does not decrease temporarily to below 7 even if temporarily, so that the sequential reaction proceeds and is completed.

It is important to dilute the alkali agent used in the present invention in advance. When using sodium hydroxide as an alkaline agent, the sodium hydroxide solution is usually 25 It is sold at high concentrations above mass percent. In the present invention, an alkali agent is not used directly, but is supplied to the reaction after dilution. By using a diluted alkali agent in the reaction, it is possible to reduce the chlorine content rate in the recovered solid matter (hereinafter, simply referred to as recovered copper oxide) containing copper oxide as a main component.

For example, when a 25% by weight sodium hydroxide solution is used, it is diluted by 5 times in volume ratio to a concentration of about 6% by mass, and the chlorine content of the recovered copper oxide is reduced by about 40%.

The alkali agent can be diluted by supplying the alkali agent to the reaction tank and diluting it by supplying water from the dilution water supply pipe to the reaction tank containing the alkali agent. The alkali agent can also be diluted in a storage tank other than the reaction tank. The concentration of a commercially available alkali agent can be adjusted in such a manner as to achieve a predetermined dilution. The water used for dilution must be water with low chlorine concentration, and tap water and ion exchange treated water can be used. In addition, it is also possible to reuse washing water having a lower chlorine concentration generated in the step of washing and recovering a solid material containing copper oxide as a main component. It can also be used as dilution water after desalination of washing and drainage by ion exchange treatment and reverse osmosis membrane treatment. In order to prevent re-contamination of impure substances mixed with solid matter containing copper oxide as a main component, the reuse of washing and drainage can use the reclaimed water after removing impurities such as organic matter, chlorine, and metals as dilution water.

In addition, when a mixed solution of a 25% by mass sodium hydroxide solution and a 15% by mass sodium carbonate solution is used as an alkali agent, compared with when a sodium hydroxide solution is used alone, the recovered copper oxide is used as a main component. The content of chlorine in the solid is further reduced. Copper oxide with a low chlorine content is an effective method when necessary. Even with hydroxide In the case of a mixed solution of sodium and sodium carbonate, the chlorine content of the recovered copper oxide is reduced by diluting the alkaline agent. Therefore, it is preferable to determine the dilution ratio in accordance with the required quality of the recovered copper oxide.

In the present invention, by warming the alkaline agent in advance, the content of chlorine in the recovered solid containing copper oxide as a main component is reduced. It is known that copper hydroxides usually change to copper oxide by auto-oxidation at 60 ° C or higher. Therefore, it is considered that even if the copper ion in the waste liquid becomes the form of copper hydroxide during the treatment reaction, when the temperature of the alkali agent is 60 ° C or higher, it is easy to oxidize to copper oxide, and it is not easy to introduce the chlorine existing in the reaction liquid.化 剂。 Compound ion. In addition, the experimental results show that the chlorine content of the recovered copper oxide can be reduced by heating the alkaline agent. The effect can be significantly observed when the temperature of the alkaline agent is 70 ° C. or higher. The agent is preferably heated to above 70 ° C.

In order to warm the alkaline agent, a heater can be provided in the reaction tank to which the alkaline agent is added; a heating tank for the alkaline agent can also be provided outside the reaction tank to prepare and heat the alkali for the next reaction in the reaction tank. A heater may be provided in the supply pipe of the alkaline agent.

As a method for adding a mixed solution of a copper-containing acidic waste liquid and an oxidizing agent to an alkali agent, for example, a method of dropping the mixed solution into a reaction tank containing the alkali agent, and injecting the mixed solution into the alkali agent solution through a pipe can be applied. Method and other methods.

The method of dropping a mixed solution of a copper-containing acidic waste liquid and an oxidant into a reaction tank has an advantage that the supply condition can be confirmed visually, and it is easy to respond when the supply condition is not smooth. On the other hand, through piping The method of supplying to a liquid has the advantage that it can be supplied to a position where it can be well mixed compared to when it is supplied from a liquid surface. The mixing tank in which the copper-containing acidic waste liquid and the oxidant are mixed is much smaller than the reaction tank, and the mixing tank can be dispensed and injected with each component, which can be performed with simple equipment. In addition, the method of injecting the liquid by piping is a method suitable for continuously adding a mixed liquid prepared by converging a copper-containing waste liquid and a hydrogen peroxide solution.

In addition, as a method of injecting the mixed solution into the alkaline solution and mixing it, and managing the pH so that the pH does not decrease to below 7 even temporarily, for example, a small amount of the mixed solution may be intermittently set at intervals. The method of pouring into the alkaline agent solution in the state of stirring and mixing, and the method of continuously pouring the mixed solution in small portions. At this time, the amount of the mixed solution to be added to the alkaline solution is only required to be 7 or higher at the end of the final reaction, and can be arbitrarily adjusted within a certain range described later. However, when the copper-containing acidic waste liquid is added to the alkaline agent and the pH is lowered to near pH 7, the chlorine content of the recovered solid containing copper oxide as a main component may become high, so as to meet the requirements. The quality of copper oxide is adjusted so that the pH at the end of the reaction is better.

In the present invention, the concentration of the hydrogen peroxide water used in the treatment is not particularly limited, and for example, a concentration of 30% can be used as it is.

According to the technology of the present invention described above, the solid obtained after the treatment of the copper-containing acidic waste liquid contains copper oxide as the main component, and has the characteristics of easier solid-liquid separation and better dehydration. However, in the case of a copper-containing acidic waste liquid containing a high concentration of copper ions, since a thick acid is mixed with a base for treatment, it is also in a solid state at the completion of the reaction. Coexist with high concentration of salts produced by the neutralization reaction. Therefore, when recovering a solid object for reuse, it is effective to improve the purity of the recovered material by repeatedly washing the salts with water repeatedly. As a solid-liquid separation method at this time, for example, filtration separation, centrifugation separation, sedimentation separation, and the like can be applied.

In addition, as the washing water for rinsing salts, clarified water with less salt content can be used. For example, tap water and industrial water can be used, and a separation liquid obtained by solid-liquid separation of the treated liquid can be reused. It is also effective to replace the treated water obtained by desalting treatment such as washing and drainage after washing the solid matter with water and / or separation liquid obtained by solid-liquid separation. Moreover, as a desalination processing method at this time, a membrane filtration method, a vacuum distillation method, an electrodialysis method, etc. can be applied, for example.

Next, a recovery device for implementing the method of the present invention will be described with reference to the drawings.

FIG. 1 is a system diagram showing one aspect of a copper recovery device when the present invention is implemented. The figures show: 11 is a mixing tank, 12 is a reaction tank, 13 is a solid-liquid separation device, 14 is a copper-containing acid waste liquid pipe, 15 is an oxidant supply pipe, 16 is a mixed solution supply pipe, and 17 is an alkaline agent supply Piping, 18 is a dilution water supply piping, 19 is a mixer, 20 is a washing water supply piping, 21 is a valve, 22 is a dehydration device, 23 is a thermometer, and 24 is a heater. In FIG. 2 and FIG. 3, the same components are assigned the same reference numerals, and redundant descriptions are omitted.

The copper recovery device 1 shown in FIG. 1 includes a reaction tank 12 having a stirrer 19 and a solid-liquid separation device communicating with the reaction tank 12. 13. A mixing tank 11 is provided on the upper part of the reaction tank 12. The mixing tank 11 is connected to the reaction tank 12 through a mixed liquid supply pipe 16, and a mixed solution of a copper-containing acid waste liquid and an oxidant in the mixing tank 11 can be injected into the reaction tank. 12 的 结构。 Structure of 12. The mixing tank 11 is connected to the copper-containing acid waste liquid pipe 14 and the oxidant supply pipe 15, and has a structure capable of mixing the copper-containing acid waste liquid and the oxidant in the mixing tank 11. The mixed liquid supply pipe 16 is provided with a valve 21, and has a structure capable of arbitrarily controlling the supply of the mixed liquid.

In the reaction tank 12, an alkali agent is supplied from an alkali agent supply pipe 17. Water for diluting the alkaline agent is supplied from the dilution water supply pipe 18. The reaction tank 12 is provided with a thermometer 23 and a heater 24, and has a structure capable of warming the diluted solution of the supplied alkaline agent and maintaining a predetermined temperature. In order to warm the alkaline agent to an arbitrary temperature of 70 ° C. or higher, it is preferable that the heater 24 has a temperature adjustment function to keep the temperature constant. In addition, in order to prevent the liquid temperature from being lowered, a heat-insulating material can be wound around the reaction tank 12 as necessary to form a heat-insulating structure. In the reaction tank 12, since an acid is supplied to the alkaline agent, the neutralization reaction also occurs in parallel. Since the neutralization reaction is an exothermic reaction, it is also considered that the temperature rises excessively. Therefore, the heating device of the reaction tank 12 preferably has a structure capable of supplying cooling water when the temperature rises excessively by using a water interlayer. In addition, when the previously diluted alkali agent is supplied from the alkali agent supply pipe 17 to the reaction tank 12, the installation of the dilution water supply pipe 18 can be omitted.

FIG. 2 is a system diagram showing another aspect of the copper recovery device when the present invention is implemented. In FIG. 2, a part of the reaction tank 12 is different from the form shown in FIG. 1. An alkaline agent heating tank 25 is provided in the reaction tank 12 to warm the alkaline agent. First warm the alkaline agent. In the alkaline agent heating tank 25, the alkaline agent supplied from the alkaline agent supply pipe 17 and the dilution water supplied from the dilution water supply pipe 18 are mixed and warmed to a set temperature. The alkaline agent that has been warmed to the set temperature is supplied to the reaction tank 12.

As shown in FIG. 2, when the alkali agent heating tank 25 is provided, the base agent can be heated in parallel with the reaction in the reaction tank 12. Therefore, after the completion of the reaction, after the generated copper oxide slurry is transferred from the reaction tank 12, the warmed alkaline agent can be re-supplied to the reaction tank 12 immediately, and the operation rate of the processing equipment can be improved.

FIG. 3 is a system diagram showing yet another aspect of the copper recovery device when the present invention is implemented. In FIG. 3, a part of the reaction tank 12 is different from the forms shown in FIGS. 1 and 2. In order to warm the alkaline agent, a heater 24 is installed in one pipe formed by connecting the alkaline agent supply pipe 17 and the dilution water supply pipe 18, so that the alkaline agent can be heated. The recovery device 1 shown in FIG. 3 is not provided with an alkaline agent heating tank 25 (refer to FIG. 2). Although the alkaline agent can be heated, the heater 24 must be capable of responding to the flow rate of the alkaline agent and dilution water.

In the reaction tank 12, the solid matter containing the produced copper oxide as a main body is transferred to the solid-liquid separation device 13 through the transfer pump 26, and the solid matter is separated from the upper clear water in the solid-liquid separation device 13. The washing water supplied from the washing water supply pipe 20 is washed to provide reuse.

In the apparatus shown in Figs. 1 to 3, the copper-containing acid waste liquid pipe 14 and the oxidant supply pipe 15 are separately installed in the mixing device. After the upper part of the tank 11 is sufficiently mixed in the mixing tank 11, it is injected into the reaction tank 12 through the mixed liquid pipe 16. However, the copper-containing acidic waste liquid pipe 14 and the oxidant supply pipe 15 may be connected without providing the mixing tank 11, and the mixed liquid may be directly supplied to the reaction tank 12 from the connected pipe.

From the reason that the oxidizing power of the oxidant cannot be maintained for a long time, the mixing tank 11 does not need to be capable of containing all the copper-containing acidic waste liquid to be processed and the oxidant added here at one time, as long as it can contain the content of the divided treatment. The capacity of the acidic copper waste liquid and the amount of oxidant added to the waste liquid may be sufficient.

When using the devices shown in Figs. 1 to 3, an appropriate amount of oxidant and alkali must be used relative to the amount of copper-containing acidic waste liquid that provides a single reaction. The amount of the oxidizing agent is preferably set to an amount equal to or more than the equivalent of the copper in the copper-containing acidic waste liquid. In addition, since the alkali dose must be pH 7 or higher at the end of the reaction, it is preferable to determine the alkali dose necessary for neutralizing a certain amount of copper-containing acidic waste liquid through a small-scale test in advance. The alkali dose is determined based on the amount ratio.

In addition, according to the present invention, the alkali agent is diluted beforehand to adjust the concentration, and then the alkali agent is provided for reaction. By adopting such a procedure, the chlorine content rate of the recovered copper oxide can be reduced. However, as shown in the examples described later, the chlorine content rate of the recovered copper oxide changes according to the degree of dilution. Therefore, it is preferable to determine the dilution ratio or concentration of the alkali agent by a small-scale test in advance to satisfy the required chlorine content.

As described above, in the present invention, the copper-containing acidic waste liquid is combined with The mixed solution of the oxidant is added to the diluted alkaline agent in small amounts each time to obtain a dilution effect and oxidize copper at the same time. Therefore, it is preferable to intermittently supply the mixed solution to the alkaline agent. At this time, for example, one-eighth of the amount of copper-containing acidic waste liquid that provides a single reaction and an oxidizing agent corresponding thereto are supplied to the mixing tank 11. After mixing, the valve 21 is opened and supplied to the reaction tank 12. At this time, by supplying the alkaline agent to the reaction tank 12 before the reaction and diluting it to a predetermined dilution ratio, and then warming it to 70 ° C. or more in advance, the mixed solution can be supplied to the diluted and warmed alkaline agent.

The adding operation of the mixed solution of the copper-containing acidic waste liquid and the oxidant is repeatedly performed, and the reaction is ended when all the predetermined amount of the copper-containing acidic waste liquid is processed. The copper oxide generated in the reaction tank 12 is supplied to a solid-liquid separation device 13, and the copper oxide is separated from a liquid containing a high concentration of salt. The copper oxide is left in the solid-liquid separation device 13 directly, and the purity of the copper oxide can be improved by passing pure water through a washing operation. The washed copper oxide is supplied to the dehydration device 22, and after dehydration, it is recovered as copper oxide.

In the copper recovery device of the present invention, as the washing water, clarified water with a low salt content can be generally used, for example, tap water and industrial water. However, since the clarified water obtained by the reaction can be used, or The desalination device replaces these or a part of the desalted water obtained by processing the dehydrated filtrate from the washing and drainage and dehydration device, which is effective when considering the subsequent wastewater treatment.

(Example 1)

In Example 1, the chlorination discharged from the printed board manufacturing step The copper etching waste liquid is processed. This waste liquid has a hydrochloric acid acidity with a copper ion concentration of about 140 g / L. In addition, a sodium hydroxide solution having a concentration of 25% by mass was used as an alkali agent, and a hydrogen peroxide solution having a concentration of 30% by mass was used as an oxidant. When the amount of waste liquid necessary to neutralize 1000 mL of the alkaline agent used was set to 1 equivalent, the amount of the waste liquid added was 0.9 equivalents, 0.8 equivalents, and 0.5 equivalents.

Table 1 shows the chlorine content of the recovered solid matter containing copper oxide as the main component and the soluble copper ion concentration in the produced slurry.

By reducing the injection amount of the waste liquid with respect to the alkali amount, it can be confirmed that the chlorine content rate of the recovered copper oxide tends to decrease. On the other hand, when the injection amount of the waste liquid is 0.5 equivalent, the dissolved copper ion concentration in the produced slurry is about 24 mg / L, and from the viewpoint of reducing the concentration of copper remaining in the produced slurry after dissolution. The injection amount of waste liquid is preferably limited to 0.8 equivalents.

(Example 2)

In Example 2, the chloride was discharged from the printed circuit board manufacturing plant. The copper etching waste liquid is processed. This waste liquid is an acid waste liquid having a copper ion concentration of about 140 g / L. In addition, a 25 mass% concentration sodium hydroxide solution was used as an alkali agent, and a 30 mass% concentration hydrogen peroxide water was used as an oxidant. When the amount of waste liquid necessary to neutralize 1000 mL of the used alkaline agent is set to 1 equivalent, the amount of waste liquid added is 0.8 equivalents, and the reaction starting temperature is set to 25 ° C, 60 ° C, 70 ° C, 80 ° C.

Table 2 shows the chlorine content in the solids recovered with copper oxide as the main component.

The chlorine content of the recovered copper oxide was 157 mg / kg at 60 ° C, and decreased to less than 100 mg / kg at 70 ° C and 80 ° C. It was confirmed that by raising the reaction initiation temperature in this way, the content of chlorine was decreased, and the reaction initiation temperature was preferably 70 ° C or higher.

From the results in Table 2, it is clear that the chlorine content rate decreases as the reaction initiation temperature rises. However, considering the limitations and safety of the equipment, the upper limit of the reaction initiation temperature is preferably 90 ° C.

(Example 3)

In Example 3, the copper chloride etching waste liquid discharged from the printed substrate manufacturing steps different from those in Examples 1 and 2 was processed. This waste liquid is an acid waste liquid having a copper ion concentration of about 126 g / L. Also, use 25 quality An amount of sodium hydroxide solution in a concentration of 100% is used as an alkali agent, and an aqueous solution of hydrogen peroxide in a concentration of 30% by mass is used as an oxidant. The processing conditions are shown in Table 3.

In Example 3, a control system in which 480 mL of an alkali agent was directly used without dilution, and a dilution system in which the volume ratio was diluted to 2 times, 5 times, and 10 times, respectively, were processed.

The concentration of sodium hydroxide in the dilution system is equivalent to a concentration of approximately 14, 6, and 3 mass percent, respectively. In addition, the supply amount of copper chloride etching waste liquid is 0.8 equivalent of copper chloride etching waste when the amount of copper chloride etching waste liquid necessary to neutralize 480 mL of the alkali agent used is 1 equivalent. The liquid provides the reaction. The supply amount of copper chloride etching waste liquid per injection operation was 62.5 mL, and the amount of oxidant was set to about 15 mL. After the alkali agent is warmed to 80 ° C in advance, the reaction starts. The copper chloride etching waste liquid and the oxidant are mixed into the alkaline agent in about 3 minutes after being mixed, and stirred for 3 minutes after the injection. Combine this bet operation Repeat 8 times.

Table 4 shows the results of analyzing the obtained black copper oxide paste. The generated slurry SS shows the solid content concentration in the slurry. The chlorine content of the recovered copper oxide was reduced to 98 mg / kg in a 5-fold dilution system compared to 145 mg / kg in the control system, and to 82 mg / kg in a 10-fold dilution system. It was confirmed that the alkali The effect of diluting the agent and adjusting the concentration of the alkali agent to be low can reduce the effect of the chlorine content of the recovered copper oxide.

In the present invention, it can be considered that the higher the dilution ratio of the alkaline agent, that is, the lower the concentration of the alkaline agent, the lower the chlorine content of the recovered copper oxide, and even if the dilution ratio is more than 10 times, the recovery of the chlorine of the copper oxide can be expected. The content rate becomes low. However, the upper limit of the dilution ratio is limited from the viewpoint of limiting the size of the device and increasing the displacement when increasing the dilution ratio.

(Example 4)

In Example 4, the same copper chloride etching waste liquid (copper ion concentration of about 140 g / L) as that used in Examples 1 and 2 was used as the waste liquid for processing. In addition, as the alkali agent, sodium hydroxide having a concentration of 25% by mass was used. A mixed alkali agent obtained by mixing a solution with a sodium carbonate solution having a concentration of 15% by mass to a volume ratio of 25:75. The processing conditions are shown in Table 5. The processing procedure is performed in the same manner as in the first embodiment.

The results obtained under the processing conditions shown in Table 5 are shown in Table 6. In Example 4, compared with Example 3, the chlorine content rate of the recovered copper oxide was generally low. Therefore, it was confirmed that the mixed alkali agent of sodium hydroxide and sodium carbonate was effective in reducing the chlorine content rate. In addition, as the dilution rate of the alkaline agent was increased, the chlorine content of the recovered copper oxide was reduced, and it was confirmed that even when a mixed alkaline agent was used, the alkaline agent had a dilution effect.

The embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned embodiments. It is self-evident that various different forms can be implemented within the scope of the technical idea, without departing from the scope of the present invention Of course, various changes can be made.

(Industrial availability)

The present invention relates to a method for treating an acidic waste liquid containing copper. More specifically, the present invention relates to an etching waste liquid generated when a copper printed substrate is etched using a copper chloride etchant, and plating on an electrolytic copper foil. Neutralization treatment of copper-containing acidic waste liquid containing high-concentration copper ions, such as bath waste renewal liquid, etching waste liquid produced by roughening the substrate surface during the lamination step in the production of multi-layer printed substrates, can be used in Method for removing copper from copper-containing acidic waste liquid by making copper into copper oxide and a device for this purpose.

Claims (7)

A method for treating a copper-containing acidic waste liquid. After mixing a copper-containing acidic waste liquid with an oxidizing agent, the mixed liquid is added to the alkaline agent while the pH of the alkaline solution after the mixed liquid is injected is even. A method for temporarily managing the copper-containing acidic waste liquid that is managed without reducing the temperature to less than 7 for the time being, and recovering the generated solids with copper oxide as the main component. The treatment method is any of the following methods: One method is to add the aforementioned mixture to the alkali agent after diluting the alkali agent in advance to adjust the concentration, or add the aforementioned mixture to the alkali agent after diluting the alkali agent in advance to adjust the concentration and warming the diluted alkali agent In the method, the alkali agent is a solution containing sodium hydroxide and sodium carbonate, and the concentration is set to 0% by mass <the concentration of the sodium hydroxide solution ≦ 0.2% by mass, and 0% by mass <the concentration of the sodium carbonate ≦ 1.1%. %. A method for treating a copper-containing acidic waste liquid. After mixing a copper-containing acidic waste liquid with an oxidizing agent, the mixed liquid is added to the alkaline agent while the pH of the alkaline solution after the mixed liquid is injected is even. A method for temporarily managing the copper-containing acidic waste liquid that is managed without reducing the temperature to less than 7 for the time being, and recovering the generated solids with copper oxide as the main component. The treatment method is any of the following methods: One method is to add the aforementioned mixture to the alkali agent after diluting the alkali agent in advance to adjust the concentration, or add the aforementioned mixture to the alkali agent after diluting the alkali agent in advance to adjust the concentration and warming the diluted alkali agent In the method, the alkaline agent is a solution containing sodium hydroxide, and the concentration is set to 0% by mass <the concentration of the sodium hydroxide solution ≦ 6% by mass. According to the method for treating an acidic waste liquid containing copper as described in item 1 or 2 of the scope of the patent application, wherein the solid matter recovery system is dehydrated and recovered as copper oxide. The method for treating an acidic waste liquid containing copper according to item 1 or item 2 of the scope of patent application, wherein the temperature of the alkali agent is set to 70 ° C or more and 90 ° C or less. A device for recovering copper from a copper-containing acidic waste liquid, comprising: a mixing tank for mixing a copper-containing acidic waste liquid with an oxidizing agent; and an injection means for making the pH of the alkaline solution after the mixed liquid is injected even The mixture is injected into the reaction tank from the mixing tank temporarily without lowering it to below 7. The reaction tank reacts the mixed liquid with the alkaline solution to produce a solid with copper oxide as the main component; the alkaline supply Means for supplying alkali agent to the reaction tank; and solid-liquid separation device for separating and recovering solid matter generated in the reaction tank; the reaction tank and the solid-liquid separation device are capable of transferring liquid containing solid matter The device has the following means to reduce the chlorine content of the recovered copper oxide: the diluent supply means is to dilute the alkali agent belonging to the solution containing sodium hydroxide and sodium carbonate to 0% by mass <Concentration of the aforementioned sodium hydroxide solution ≦ 0.2% by mass and 0% by mass <Concentration of the aforementioned sodium carbonate ≦ 1.1% by mass to adjust the concentration; and means for heating the alkali agent is provided in the reaction tank or the alkali agent supply Paragraph, an alkali agent after the dilution was warmed to 70 deg.] C to 90 ℃. A device for recovering copper from a copper-containing acidic waste liquid, comprising: a mixing tank for mixing a copper-containing acidic waste liquid with an oxidant; and an injection means for making the pH of the alkaline solution after the mixed liquid is injected The mixture is injected into the reaction tank from the mixing tank temporarily without lowering it to below 7. The reaction tank reacts the mixed liquid with the alkaline solution to produce a solid with copper oxide as the main component; the alkaline supply Means for supplying alkali agent to the reaction tank; and solid-liquid separation device for separating and recovering solid matter generated in the reaction tank; the reaction tank and the solid-liquid separation device are capable of transferring liquid containing solid matter The device has the following means to reduce the chlorine content of the recovered copper oxide: the diluent supply means is to dilute the alkali agent belonging to the solution containing sodium hydroxide to 0% by mass <the hydrogen The concentration of the sodium oxide solution is ≦ 6% by mass to adjust the concentration; and the alkali agent warming means is installed in the reaction tank or the alkali agent supplying means to heat the diluted alkali agent to 70 ° C. to 90 ° C. As described in item 5 or item 6 of the scope of the patent application, the device for recovering copper from a copper-containing acidic waste liquid further includes a dewatering device for dewatering the copper oxide separated and recovered.