WO2015159810A1 - Method for treating copper-containing acidic liquid waste - Google Patents

Abstract

The present invention relates to: a method for treating a copper-containing acidic liquid waste, whereby it becomes possible to remove and collect copper in the form of copper oxide from the copper-containing acidic liquid waste; and an apparatus for achieving the method. The method for treating a copper-containing acidic liquid waste comprises: mixing the copper-containing acidic liquid waste with an oxidizing agent to prepare a mixed solution; then adding the mixed solution to an alkaline agent while managing in such a manner that the pH value of an alkaline agent solution prepared by the injection of the mixed solution never decreases to 7 or lower even temporarily, thereby producing a solid matter that contains copper oxide as the main component; and then collecting the solid matter. In the method, the alkaline agent is diluted in advance so as to adjust the concentration thereof and then the mixed solution is added to the alkaline agent or, alternatively, the alkaline agent is diluted in advance so as to adjust the concentration thereof, then the diluted alkaline agent is warmed and then the mixed solution is added to the alkaline agent.

Description

Treatment method for copper-containing acidic waste liquid

The present invention relates to a method for treating a copper-containing acidic waste liquid, and more specifically, for example, an etching waste liquid produced when a copper printed board is etched with a cupric chloride etchant, a renewed waste liquid for a plating bath in electrolytic copper foil production, Neutralizes copper-containing acidic waste liquid containing high-concentration copper ions, such as etching waste liquid generated in the roughening process of the substrate surface in the lamination process when producing multilayer printed circuit boards, and oxidizes copper from the copper-containing acidic waste liquid The present invention relates to a method for removing and recovering as copper and an apparatus therefor. Moreover, this invention relates to the production method of the copper oxide which processes a copper containing acidic waste liquid and produces 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 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 ion concentration of about 5 to 20% by mass (hereinafter simply referred to as “%”), while the concentration of coexisting chloride ions and sulfate ions is usually as high as 5 to 30%.

As a copper recovery process for the 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 partly performed. 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.

Further, as a general treatment method for copper-containing acidic waste liquid, a treatment method is known in which heavy metals are precipitated and removed as a hydroxide by adding an alkaline substance such as sodium hydroxide. This method is generated. The sludge is bulky and has a high water content, which makes it difficult to handle and is not suitable for the treatment of copper-containing acidic waste liquid having a high copper ion concentration.

Further, for etching wastewater, for example, as disclosed in Japanese Patent Application Laid-Open No. 2004-50096 (Patent Document 1), an alkali is added to insolubilize copper ions as a copper hydroxide, and an oxidizing agent is further added. Thus, a processing method for recovering copper oxide has been attempted. However, when an oxidizing agent containing chloride ions such as hypochlorite or bleaching powder is used as the oxidizing agent, the concentration of chloride ions in the liquid after addition is further increased, so that copper chloride and copper oxide There are problems such as concern about the formation of double salt and the mixing of salt into sludge, and when high concentration waste liquid is treated, the content of impurities in the recovered copper oxide increases. There are many points to be improved.

In the copper recovery treatment method for the copper-containing acidic waste liquid, for example, as shown in Japanese Patent No. 4323668 (Patent Document 2), basic carbonate is recovered from the copper-containing acidic waste liquid, and a large amount is contained in the copper-containing acidic waste liquid. Technology has been developed to prevent the anions such as sulfate ions and chloride ions contained in the base from being mixed into the recovered basic copper carbonate. When the recovered copper compound is reused, the copper compound having a lower impurity concentration has a wider range of uses for reuse, and therefore, high-purity basic copper carbonate is recovered.

The present inventors previously found a method in which copper oxide can be efficiently recovered by adding a copper-containing acidic waste liquid and an oxidizing agent to an alkaline solution after mixing the copper-containing acidic waste liquid and the oxidizing agent in Japanese Patent No. 4199821 (Patent Document 3). . 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. And copper oxide. However, according to the tests by the inventors, the chlorine content in the copper oxide recovered by this method may be about 200 mg / kg, and further reduction of the chlorine content is required depending on the use of the recovered copper oxide. There was a case.

JP 2004-50096 A Japanese Patent No. 4323668 Japanese Patent No. 4199821

The present invention has been made in order to solve the above-mentioned problem, and is capable of efficiently recovering copper oxide by treating a copper-containing acidic waste liquid and reducing the anion content in the recovered copper oxide. It aims at providing the processing method of an acidic waste liquid containing, the recovery method and apparatus of copper oxide from a copper containing acidic waste liquid.

In order to achieve the above-mentioned object, the copper-containing acidic waste liquid treatment method of the present invention mixes the copper-containing acidic waste liquid and the oxidizing agent, and then mixes the mixed liquid into an alkaline agent, and the pH of the alkaline agent solution after the mixture liquid is poured. In the treatment method for copper-containing acidic waste liquid that recovers the solid matter mainly composed of copper oxide, the concentration is adjusted by diluting the alkaline agent in advance. Then, the mixed solution is added to the alkaline agent, or the concentration is adjusted in advance by diluting the alkaline agent, and the diluted alkaline agent is heated and then the mixed solution is added to the alkaline agent. .
Here, diluting the alkaline agent in advance means that any form of alkaline agent (liquid or solid alkaline agent) is diluted when, where, and before the mixed solution is added to the alkaline agent. Means good. That is, it may be diluted when the alkaline agent is purchased, or may be diluted when the solid alkaline agent is dissolved, or an alkaline agent diluted to a predetermined concentration may be obtained and used.

According to one embodiment of the present invention, a sodium hydroxide solution is used as the alkali agent.
According to one embodiment of the present invention, a solution containing sodium hydroxide and sodium carbonate is used as an alkaline agent.
According to one embodiment of the present invention, a sodium carbonate solution is used as the alkali agent.
According to one aspect of the present invention, the concentration of the sodium hydroxide solution is 6% by mass or less.
According to one embodiment 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 embodiment of the present invention, the temperature of the alkaline agent is 70 ° C. or higher.

The apparatus for recovering copper from the copper-containing acidic waste liquid according to the present invention includes a mixing tank for mixing the copper-containing acidic waste liquid and the oxidizing agent, and the pH of the alkaline agent solution after the mixture liquid is poured from the mixing tank to the reaction tank. In particular, a means for pouring the mixed solution so as not to decrease to 7 or less, a reaction vessel for reacting the mixed solution with an alkaline agent solution to produce a solid mainly composed of copper oxide, and an alkaline agent in the reaction vessel And a solid-liquid separation device for separating and recovering the solid matter generated in the reaction tank, and the reaction tank and the solid-liquid separation device are communicated with each other so that a liquid containing the solid matter can be transferred. In the apparatus for recovering copper from the copper-containing acidic waste liquid, a dilute supply means is provided to adjust the concentration by diluting the alkaline agent, and the alkaline agent heating means for heating the diluted alkaline agent is the reaction vessel or It is provided in the alkaline agent supply means. To.

The method for producing copper oxide from the copper-containing acidic waste liquid of the present invention comprises mixing a copper-containing acidic waste liquid and an oxidant, using the mixed liquid of the copper-containing acidic waste liquid and the oxidant as an alkaline agent, and adding the mixed solution to the alkaline agent. In a method for producing copper oxide from a copper-containing acidic waste liquid by adding a solid solution mainly containing copper oxide to be added while controlling so that the pH of the solution does not temporarily drop to 7 or less. After diluting the alkaline agent and adjusting the concentration, add the mixture to the diluted alkaline agent, or dilute and add the alkaline agent in advance to adjust the concentration and warm the mixture. It is added to the alkaline agent after warming.

According to the present invention, it is possible to directly process a copper-containing acidic waste liquid having a high concentration of 5 to 20%, which is difficult to process due to the formation of double salts and copper hydroxide, without dilution. . In addition, since the recovered material from the copper-containing acidic waste liquid contains copper oxide as a main component, unlike a double salt or copper hydroxide, it has good dewaterability, and the concentration of impurities contained in the recovered copper oxide can be reduced. Furthermore, since the chlorine content of the recovered product is low, it is possible to obtain copper oxide in a form that can be easily reused.

FIG. 1 is a drawing showing an embodiment of the copper recovery apparatus of the present invention. FIG. 2 is a drawing showing another embodiment of the copper recovery apparatus of the present invention. FIG. 3 is a drawing showing still another aspect of the copper recovery apparatus of the present invention.

The treatment process according to the present invention first dilutes the alkaline agent. Next, a copper-containing acidic waste liquid and an oxidizing agent are mixed, and the obtained mixed liquid is poured into a diluted alkaline agent to generate a solid.

The copper-containing acidic waste liquid to be treated in the present invention may be acidic as long as it contains ionic copper at a concentration of 10,000 mg / L or more. Even if the copper ion concentration is lower than 10,000 mg / L, the treatment according to the present invention is possible, but when the copper ion concentration is low, the amount of copper oxide obtained is reduced. For this reason, it is preferable to apply to waste liquids that are economically appropriate in consideration of the amount of recovered material to be obtained. Moreover, even if it contains a high concentration of ionic copper, if the liquidity is neutral or alkaline, a chelating agent may be contained so as not to precipitate copper ions. A waste liquid containing such a chelating agent is not suitable for the present invention because the chelating agent may inhibit copper oxidation.

Specific examples of the copper-containing acidic waste liquid include a copper chloride etching waste liquid generated in the etching process of the printed circuit board and a copper sulfate plating bath waste liquid generated in the electrolytic copper plating process. These waste liquids contain about 10 to 150 g / L of ionic copper and have a pH of 1 or less, which is suitable for the present invention. Moreover, since the copper ion concentration in the waste liquid is high, the amount of copper oxide that can be recovered increases.

The oxidizing agent used in the present invention is not particularly limited as long as it can convert divalent copper ions into copper oxide. However, as an oxidizing agent that does not adversely affect the properties of recovered copper oxide, it is possible to peroxidize. Hydrogen is suitable.

The alkali agent used in the present invention is not particularly limited as long as it neutralizes the copper-containing acidic waste liquid, but when the anion remaining after the reaction forms an insoluble salt, the purity of the copper oxide to be recovered is In consideration of the cause of the decrease, it is desirable to use an alkali metal hydroxide as the alkali agent. Specifically, an aqueous solution of sodium hydroxide that is inexpensive and easily available can be mentioned.
Further, an alkali metal hydroxide and an alkali metal carbonate can be mixed and used as an alkali agent. Further, an alkali metal carbonate may be used as the alkali agent instead of the alkali metal hydroxide. For example, an aqueous solution of sodium carbonate can be used because it is effective in reducing the impurity concentration of the recovered product.

In the present invention, in order to treat a high-concentration copper-containing acidic waste liquid without diluting it, it is important to cause the reaction according to the procedure described above. Therefore, taking the case of using hydrogen peroxide as the oxidizing agent solution and sodium hydroxide as the alkaline agent as an example, the importance of the processing procedure and mixing / reaction order in the present invention will be described below.

First, in a method of adding an alkaline agent to a copper-containing acidic waste liquid that is a conventional general treatment method, when treating a copper-containing acidic waste liquid containing copper ions at a high concentration, an alkaline agent is added to the copper-containing acidic waste liquid. Add. However, in the order of adding the alkaline agent to the high concentration copper-containing acidic waste liquid, double salt CuCl ₂ .3Cu (OH) ₂ and copper hydroxide are generated. Among these, the double salt has a high water content and is difficult to dehydrate and contains chlorine. Therefore, the copper oxide containing the double salt is difficult to reuse as it is after being recovered. Further, when copper hydroxide is also produced at a high concentration, it is difficult to handle because of its high water content and is not suitable for reuse.
In addition, when hydrogen peroxide is added after pouring a copper-containing acidic waste solution containing copper ions at a high concentration into the alkaline agent, the sludge-like double salt or hydroxide having a high water content is first added to the alkaline agent. Copper precipitates and accumulates. When hydrogen peroxide solution is added to this, the double salt and copper hydroxide precipitated in the liquid are sludge-like solids and are difficult to disperse, so the surface of the double salt and copper hydroxide is oxidized by hydrogen peroxide. However, since the oxidation inside the double salt or copper hydroxide is slow, or the inside of the double salt or copper hydroxide is not uniformly oxidized, the efficiency of the oxidation reaction with hydrogen peroxide is reduced.

Also, the copper chloride etching waste liquid may contain cuprous ions in the course of the etching process, in which divalent copper ions in the etching liquid are reduced to monovalent. When such an etching waste liquid is poured as it is into the alkali agent, cuprous chloride (CuCl) having low solubility in addition to copper hydroxide is also precipitated. Even if hydrogen peroxide solution is added in this state, the cuprous chloride (CuCl) acts as a catalyst for decomposition of hydrogen peroxide. Is consumed, and the efficiency of the oxidation reaction with hydrogen peroxide is further reduced.

In order to avoid the above problems, in the treatment process according to the present invention, prior to mixing and reacting with an alkaline agent solution (diluted alkaline agent solution), the copper-containing acidic waste liquid and hydrogen peroxide solution are mixed. This is very important. As a result, the oxidation reaction of cupric ions contained in the waste liquid into copper oxide proceeds promptly when a mixed liquid of the copper-containing acidic waste liquid and hydrogen peroxide is added to the alkaline agent. In addition, when cuprous ions are contained in the waste liquid, the cuprous ions are converted to cupric ions by the oxidizing action of hydrogen peroxide by mixing with hydrogen peroxide before contacting with the alkaline agent. Since it is oxidized, precipitation of cuprous salts such as cuprous chloride (CuCl) having low solubility can be avoided.

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

On the other hand, when the copper-containing acidic waste liquid and hydrogen peroxide water are mixed, the decomposition reaction of hydrogen peroxide proceeds using copper ions as a catalyst. The decomposition reaction becomes apparent after about 60 seconds have passed after mixing the two, and after 7 to 10 minutes, the decomposition reaction proceeds violently with significant foaming. Depending on the concentration of both, for example, when hydrogen peroxide in a molar concentration of copper ions is mixed twice as much as that of copper ions, the foaming accompanying the decomposition of hydrogen peroxide decreases after 20 minutes and 25 minutes. After the lapse of time, the amount becomes slight, and when added to the alkaline agent at this point, a precipitate containing more copper hydroxide than copper oxide is formed.
Therefore, prior to pouring into the alkaline agent, mixing of the copper-containing acidic waste liquid and hydrogen peroxide solution, the reaction time is about 5 seconds to 20 minutes, preferably about 20 seconds to 7 minutes. It is preferable to take.

In addition, when all the required amount of hydrogen peroxide solution is added at once to the total amount of copper-containing acidic waste liquid used for the reaction, the amount of both liquids may be large, and hydrogen peroxide decomposes rapidly. The liquid temperature rises rapidly while foaming vigorously. In such a case, an accident caused by the rapid decomposition reaction of hydrogen peroxide may occur, so the copper-containing acidic waste liquid and the hydrogen peroxide solution are mixed in only the amount used in one injection operation, and foaming occurs. It is necessary to complete the pouring operation before it becomes violent.

As a mixing method of the copper-containing waste liquid and the hydrogen peroxide solution described above, for example, a method in which both liquids are poured into the mixing tank and stirred, or the copper-containing waste liquid and the hydrogen peroxide solution are merged and mixed. Methods etc. are applicable.
Among these, in the method of injecting both liquids into the mixing tank and stirring, it is easy to check and adjust the injection amount. In addition, if an overflow pipe is provided in the tank, there is an advantage that problems on the apparatus such as an explosion of the tank can be prevented because it becomes an open system even if foaming occurs during mixing.

Also, in the method of mixing and mixing the copper-containing waste liquid and the hydrogen peroxide solution, the pipes of both solutions are connected and joined by Y-shaped pipes, etc., the other liquid is injected into one of the pipes. A method of mixing can be used. Furthermore, both liquids can also be stirred and mixed by passing through a static mixer after merging. This method requires pressure resistance of the device to cope with foaming or a mechanism that can discharge the generated gas, but keeps the time from mixing and supplying both solutions uniform and continuous. There is an advantage that can be supplied to.

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

In order to realize these conditions, in the technology of the present invention, a solution-like alkali agent with good operability is used, and the mixture solution is poured at an appropriate rate while the alkali agent solution is being stirred. It is necessary to go. This injection acceleration may be carried out and mixed in a controlled manner so that the pH does not drop below 7 in the alkaline agent solution after the addition, and the reaction proceeds and completes sequentially. is necessary.

It is important to dilute in advance the alkaline agent used in the present invention. When sodium hydroxide is used as the alkaline agent, sodium hydroxide solutions are generally sold at high concentrations of 25 weight percent or higher. In the present invention, the alkaline agent is not used as it is, but is used after diluting. By using the diluted alkaline agent in the reaction, the chlorine content in the solid (mainly abbreviated as recovered copper oxide) mainly containing recovered copper oxide can be reduced.
For example, when using a 25% by weight sodium hydroxide solution, the chlorine content of the recovered copper oxide is about 40% by diluting it by a factor of 5 to a volume ratio of about 6% by weight. descend.

The alkali agent may be diluted by supplying the alkali agent to the reaction tank and supplying the reaction tank containing the alkali agent with water from a dilution water supply pipe, or by diluting the alkali agent in a separate storage tank from the reaction tank. It may be diluted or the concentration may be adjusted so as to obtain a predetermined dilution when adjusting a commercially available alkaline agent. The water used for dilution needs to be water with a low chlorine concentration, and tap water and ion exchange treated water can be used. Moreover, you may reuse the washing | cleaning waste_water | drain with a low chlorine concentration generate | occur | produced in the process which wash | cleans the solid substance which has the recovered copper oxide as a main component. The washing waste water may be desalted by ion exchange treatment or reverse osmosis membrane treatment and used as dilution water. In the reuse of washing wastewater, in order to prevent recontamination such as contamination of solids mainly composed of copper oxide, reclaimed water from which impurities such as organic matter, chlorine, and metals are removed can be used as dilution water. it can.

In addition, when a mixed solution of a 25% by weight sodium hydroxide solution and a 15% by weight sodium carbonate solution is used as the alkali agent, the recovered copper oxide as a main component is more than when the sodium hydroxide solution is used alone. The chlorine content in the solid matter to be further reduced. This is an effective technique when low chlorine content copper oxide is required. Even when a mixed solution of sodium hydroxide and sodium carbonate is used, the chlorine content of recovered copper oxide is reduced by diluting the alkaline agent. For this reason, it is desirable to determine the dilution factor according to the quality required for the recovered copper oxide.

In this invention, the chlorine content rate in the solid substance which has the copper oxide collect | recovered by heating an alkaline agent in advance as a main component falls. In general, it is known that copper hydroxide changes to copper oxide by auto-oxidation at 60 ° C. or higher. For this reason, even if the copper ions in the waste liquid are in the form of copper hydroxide during the treatment reaction, if the temperature of the alkaline agent is 60 ° C. or higher, it is easily oxidized to copper oxide and is present in the reaction liquid. This is thought to be because it is difficult to take in chloride ions. In addition, as a result of the experiment, it is possible to reduce the chlorine content of the copper oxide recovered by heating the alkali agent, and the effect is remarkably recognized when the temperature of the alkali agent is 70 ° C. or higher. In the present invention, it is desirable to heat the alkaline agent to 70 ° C. or higher.
In order to warm the alkaline agent, a heater may be provided in the reaction tank containing the alkaline agent, or as a warming tank for the alkaline agent provided separately from the reaction tank for the next reaction during the reaction in the reaction tank. The alkaline agent may be prepared and heated, or a heater may be provided in the alkaline agent supply pipe.

Examples of the method of pouring the mixed liquid of copper-containing acidic waste liquid and oxidant into the alkaline agent include, for example, a method of dropping the mixed liquid into a reaction tank containing the alkaline agent and injecting the mixed liquid into the alkaline agent liquid through a pipe. A method such as a method of performing is applicable.

The method of dropping a mixed solution of copper-containing acidic waste liquid and oxidant into the reaction tank has the advantage that the supply status can be confirmed visually, and that the supply status can be easily accommodated. On the other hand, the method of supplying the liquid through the pipe has an advantage that the liquid can be supplied to a position where it can be mixed well compared with the case of supplying from the liquid surface. When the mixing tank for mixing the copper-containing acidic waste liquid and the oxidizing agent is sufficiently smaller than the reaction tank, it can be carried out with simple equipment by dispensing each batch of the mixing tank. In addition, in the method of inject | pouring into a liquid through piping, the method of adding continuously the liquid mixture created by making a copper containing waste liquid and a hydrogen peroxide solution merge can be used conveniently.

Furthermore, as a method of adding and mixing the alkali solution in the alkaline agent solution while controlling the mixed solution so that the pH does not drop to 7 or less even temporarily, a small amount of the alkaline agent solution in the stirred and mixed state is used. Examples thereof include a method of intermittently adding the mixed solution at intervals and a method of continuously adding the mixed solution little by little. At this time, the amount of the mixed solution added to the alkaline agent solution can be arbitrarily adjusted within a certain range described later as long as the pH at the end of the final reaction is 7 or more. However, when the copper-containing acidic waste liquid is poured into the alkaline agent and the pH is lowered to a value close to pH 7, the chlorine content in the solid material mainly composed of the recovered copper oxide may increase, which is required. It is preferable to adjust the pH as the reaction end point in accordance with the quality of the copper oxide.

In the present invention, the concentration of the hydrogen peroxide solution used for the treatment is not particularly limited, but, for example, one having a concentration of 30% can be used directly.

According to the technology of the present invention described above, the solid material obtained after the treatment of the copper-containing acidic waste liquid is mainly composed of copper oxide, is relatively easy to separate solid and liquid, and has a relatively good dehydration property. belongs to. However, in the case of a copper-containing acidic waste liquid containing a high concentration of copper ions, a concentrated acid and alkali are mixed and processed, so that the solid matter at the completion of the reaction has a high concentration generated by the neutralization reaction. Salts also coexist. Therefore, when collecting solids for reuse, it is effective to wash these salts by repeating washing with water a plurality of times to increase the purity of the collected material. As a solid-liquid separation method in this case, for example, filtration separation, centrifugation, sedimentation separation, or the like is applicable.

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

Next, with reference to the drawings, a collection device used for carrying out the method of the present invention will be described.
FIG. 1 is a system diagram showing an embodiment of a copper recovery apparatus when the present invention is implemented. In the figure, 11 is a mixing tank, 12 is a reaction tank, 13 is a solid-liquid separator, 14 is a copper-containing acidic waste liquid pipe, 15 is an oxidant supply pipe, 16 is a mixed liquid supply pipe, 17 is an alkaline agent supply pipe, 18 Is a diluting water supply pipe, 19 is a stirrer, 20 is a washing water supply pipe, 21 is a valve, 22 is a dehydrator, 23 is a thermometer, and 24 is a heater. 2 and 3, the same components are denoted by the same reference numerals, and redundant description is omitted.

1 includes a reaction tank 12 equipped with a stirrer 19 and a solid-liquid separation device 13 communicated with the reaction tank 12. A mixing tank 11 is provided in the upper part of the reaction tank 12 and is connected to the reaction tank 12 by a mixed liquid supply pipe 16. A mixed liquid of the copper-containing acidic waste liquid and the oxidizing agent in the mixing tank 11 is supplied to the reaction tank 12. It has a structure that can be added. A copper-containing acidic waste liquid pipe 14 and an oxidant supply pipe 15 are connected to the mixing tank 11 so that the copper-containing acidic waste liquid and the oxidizing agent can be mixed in the mixing tank 11. The mixed liquid supply pipe 16 is provided with a valve 21 so that the supply of the mixed liquid can be arbitrarily controlled.

The alkaline agent is supplied to the reaction tank 12 from the alkaline agent supply pipe 17. Further, water for diluting the alkaline agent is supplied from the dilution water supply pipe 18. The reaction vessel 12 is provided with a thermometer 23 and a heater 24, and has a structure that can heat a supplied diluted solution of the alkaline agent and maintain it at a predetermined temperature. In order to heat the alkaline agent to an arbitrary temperature of 70 ° C. or higher, it is desirable that the heater 24 has a temperature adjustment function so as to keep the temperature constant. Moreover, in order to prevent the liquid temperature from decreasing, a heat insulating material can be dispersed in the reaction tank 12 as necessary to form a heat retaining structure. In the reaction tank 12, since an acid is supplied to the alkaline agent, a neutralization reaction also occurs in parallel. Since the neutralization reaction is an exothermic reaction, the temperature may increase excessively. For this reason, it is good also as a structure which can supply a cooling water, when a water jacket is used for the heating apparatus of the reaction tank 12, and temperature rises too much. In addition, when the alkaline agent diluted beforehand from the alkaline agent supply pipe 17 is supplied 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 embodiment of the copper recovery apparatus when the present invention is carried out. In FIG. 2, the part of the reaction tank 12 is different from the form shown in FIG. In order to heat the alkali agent, an alkali agent heating tank 25 is installed in the reaction tank 12, and the alkali agent is heated in advance before supplying the alkali agent to the reaction tank 12. 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 heated to a set temperature while mixing. The alkaline agent heated to the set temperature is supplied to the reaction vessel 12.
When the alkaline agent heating tank 25 is provided as shown in FIG. 2, the alkaline agent can be heated in parallel during the reaction in the reaction tank 12. For this reason, after completion | finish of reaction, after transferring the produced | generated copper oxide slurry from the reaction tank 12, the heated alkaline agent can be newly supplied to the reaction tank 12, and the operating rate of processing equipment can be raised. .

FIG. 3 is a system diagram showing still another aspect of the copper recovery apparatus when the present invention is implemented. In FIG. 3, the part of the reaction tank 12 is different from the form shown in FIGS. In order to heat the alkaline agent, the alkaline agent supply pipe 17 and the diluting water supply pipe 18 are connected, and the heater 24 is installed in a single pipe so that the alkaline agent can be heated. In the recovery device 1 shown in FIG. 3, the alkaline agent can be heated without installing the alkaline agent heating tank 25 (see FIG. 2), but the ability of the heater 24 according to the flow rate of the alkaline agent and dilution water is high. Necessary.

The solid matter mainly composed of copper oxide generated in the reaction tank 12 is transferred to the solid-liquid separation device 13 via the transfer pump 26, and is separated into solid matter and supernatant water in the solid-liquid separation device 13. Further, the cleaning water supplied from the cleaning water supply pipe 20 is cleaned and reused.

In the apparatus shown in FIGS. 1 to 3, the copper-containing acidic waste liquid pipe 14 and the oxidant supply pipe 15 are respectively provided on the upper part of the mixing tank 11, and after being sufficiently mixed in the mixing tank 11, It is poured into the reaction vessel 12 through the mixed solution pipe 16. It is also possible to connect the copper-containing acidic waste liquid pipe 14 and the oxidant supply pipe 15 without providing the mixing tank 11 and supply the mixed liquid directly to the reaction tank 12 from the connected pipe.

The mixing tank 11 does not need to have a capacity capable of accommodating the copper-containing acidic waste liquid to be treated and the oxidizing agent added thereto at a time because the oxidizing power of the oxidizing agent cannot be maintained for a long time. Any copper-containing acidic waste liquid and a volume capable of accommodating an amount of oxidizing agent added to the waste liquid may be used.

In using the apparatus shown in FIG. 1 to FIG. 3, it is necessary to use an appropriate amount of oxidizing agent and alkali agent for the amount of copper-containing acidic waste liquid used in one reaction. The amount of the oxidizing agent is preferably set to an amount that is equal to or greater than the equivalent in terms of molar ratio with respect to the amount of copper in the copper-containing acidic waste liquid. In addition, since the amount of alkaline agent needs to have a pH of 7 or more at the end of the reaction, the amount of alkaline agent necessary to neutralize a certain amount of copper-containing acidic waste liquid is determined beforehand in a small scale test. It is desirable to determine the amount of the alkaline agent based on this amount ratio.

Further, according to the present invention, the alkali agent is subjected to the reaction after diluting the alkali agent and adjusting the concentration in advance. By adopting such a procedure, the chlorine content of the recovered copper oxide can be reduced, but the chlorine content of the recovered copper oxide varies depending on the degree of dilution as shown in the examples described later. For this reason, it is desirable to determine the dilution ratio or alkali agent concentration of the alkali agent that satisfies the chlorine content required in a small-scale test in advance.

As described above, in the present invention, copper is oxidized while obtaining a dilution effect by adding a mixed solution of a copper-containing acidic waste liquid and an oxidizing agent little by little to a diluted alkaline agent. For this reason, it is preferable to supply a liquid mixture to an alkaline agent intermittently. In this case, for example, 1/8 of the amount of the copper-containing acidic waste liquid used for one reaction and an oxidizer commensurate therewith are supplied to the mixing tank 11, and after mixing, the valve 21 is opened and supplied to the reaction tank 12. In this case, the alkaline agent is supplied to the reaction tank 12 before the reaction, diluted to a predetermined dilution ratio, and then heated to 70 ° C. or higher, so that the mixed solution is diluted and heated to the alkaline agent. Can be supplied.

Repeat the pouring operation of the mixed liquid of copper-containing acidic waste liquid and oxidizing agent, and the reaction is completed when all of the predetermined amount of copper-containing acidic waste liquid is treated. The copper oxide generated in the reaction tank 12 is supplied to the solid-liquid separator 13 and separated into a liquid containing copper oxide and a high concentration salt. The purity of copper oxide can be increased by leaving the copper oxide as it is in the solid-liquid separator 13 and performing a washing operation through pure water. The washed copper oxide is supplied to the dehydrator 22 and dehydrated and recovered as copper oxide.

In the copper recovery apparatus of the present invention, clean water generally having a low salt content, such as tap water or industrial water, is used as the washing water, but instead of this, it is obtained by reaction as a part thereof. It is effective when considering the subsequent wastewater treatment, because the desalinized water obtained by treating the supernatant water obtained and the dewatered filtrate from the washing waste water and the dewatering device with the desalting device can be used. .

Example 1
In Example 1, the copper chloride etching waste liquid discharged from the printed circuit board manufacturing process was processed. This waste liquid was acidic with hydrochloric acid having a copper ion concentration of about 140 g / L. Further, a 25 mass percent sodium hydroxide solution was used as the alkali agent, and a 30 mass percent hydrogen peroxide solution was used as the oxidizing agent. The amount of waste liquid added should be 0.9 equivalent, 0.8 equivalent, and 0.5 equivalent when the amount of waste liquid required to neutralize 1000 mL of the alkaline agent used is 1 equivalent. It was.

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

It was confirmed that the chlorine content of the recovered copper oxide tends to decrease by reducing the amount of waste liquid added to the alkali agent amount. On the other hand, the soluble copper ion concentration in the produced slurry is about 24 mg / L remaining when the amount of waste liquid added is 0.5 equivalent, and the concentration of the remaining copper dissolved in the produced slurry is reduced. From this point of view, it is preferable to keep the amount of waste liquid added at 0.8 equivalent.

(Example 2)
In Example 2, the copper chloride etching waste liquid discharged from the printed circuit board manufacturing factory was processed. This waste liquid was an acidic waste liquid having a copper ion concentration of about 140 g / L. Further, a 25 mass percent sodium hydroxide solution was used as the alkali agent, and a 30 mass percent hydrogen peroxide solution was used as the oxidizing agent. The amount of waste liquid added is such that when the amount of waste liquid required to neutralize 1000 mL of the alkaline agent used is 1 equivalent, the amount is 0.8 equivalent, and the reaction start temperature is 25 ° C. and 60 ° C. , 70 ° C and 80 ° C.

　回収した酸化銅の塩素含有率は６０℃では１５７ｍｇ／ｋｇであるが、７０℃、８０℃では１００ｍｇ／ｋｇ以下に低下している。このように反応開始温度を上げることにより塩素含有率が低下することが確認され、反応開始温度は７０℃以上が適している。
　表２の結果から明らかなように、反応開始温度が上昇するにつれて塩素含有率は減少するが、反応開始温度の上限としては、装置の制限や安全性を考慮し９０℃が妥当である。 Table 2 shows the chlorine content in the solid material mainly composed of the recovered copper oxide.

The chlorine content of the recovered copper oxide is 157 mg / kg at 60 ° C., but is reduced to 100 mg / kg or less at 70 ° C. and 80 ° C. Thus, it is confirmed that the chlorine content is lowered by raising the reaction start temperature, and the reaction start temperature is suitably 70 ° C. or higher.
As is clear from the results in Table 2, the chlorine content decreases as the reaction start temperature increases, but 90 ° C. is appropriate as the upper limit of the reaction start temperature in consideration of the limitations and safety of the apparatus.

Example 3
In Example 3, the copper chloride etching waste liquid discharged from the printed circuit board manufacturing process different from Example 1 and Example 2 was processed. This waste liquid was an acidic waste liquid having a copper ion concentration of about 126 g / L. Further, a 25 mass percent sodium hydroxide solution was used as the alkali agent, and a 30 mass percent hydrogen peroxide solution was used as the oxidizing agent. Table 3 shows the processing conditions.

In Example 3, the treatment was performed with a control system used without diluting 480 mL of the alkaline agent and with a dilution system diluted so that the volume ratio was 2 times, 5 times, and 10 times, respectively.
The sodium hydroxide concentration in the dilution system corresponds to about 14, 6, and 3 weight percent concentrations, respectively. In addition, the supply amount of copper chloride etching waste liquid is equivalent to 0.8 equivalent amount of copper chloride etching waste liquid when the amount of copper chloride etching waste liquid necessary to neutralize the 480 mL of alkaline agent used is 1 equivalent. It was used for. The supply amount of the copper chloride etching waste liquid per one addition operation was set to 62.5 mL, and the oxidant amount was set to about 15 mL. The alkali agent was preheated to 80 ° C. and then the reaction was started. The copper chloride etching waste liquid and the oxidizing agent were added to the alkaline agent over about 3 minutes after mixing, and stirred for 3 minutes after the addition. This pouring operation was repeated a total of 8 times.

　本発明においては、アルカリ剤の希釈倍率が高い程すなわちアルカリ剤濃度が低くなる程、回収酸化銅の塩素含有率が低くなると考えられ、希釈倍率が１０倍を超えても回収酸化銅の塩素含有率が低くなることが期待できる。しかし希釈倍率を高くすると装置の大きさの制約や排水量の増加を招くという観点から希釈倍率の上限は決められる。 Table 4 shows the results of analyzing the obtained black copper oxide slurry. The produced slurry SS indicates the solid concentration in the slurry. The chlorine content of the recovered copper oxide decreased to 98 mg / kg in the 5-fold dilution system and to 82 mg / kg in the 10-fold dilution system, while the control system was 145 mg / kg. It was confirmed that the chlorine content of the recovered copper oxide can be reduced by adjusting the alkali agent concentration low.

In the present invention, it is considered that the higher the dilution ratio of the alkali agent, that is, the lower the alkali agent concentration, the lower the chlorine content of the recovered copper oxide. Even if the dilution ratio exceeds 10 times, the chlorine content of the recovered copper oxide The rate can be expected to be low. However, the upper limit of the dilution factor is determined from the viewpoint that increasing the dilution factor leads to restrictions on the size of the apparatus and an increase in the amount of drainage.

Example 4
In Example 4, the same copper chloride etching waste liquid (copper ion concentration of about 140 g / L) as used in Example 1 or Example 2 was used as the waste liquid to be treated. As the alkaline agent, a mixed alkaline agent in which a 25 mass percent sodium hydroxide solution and a 15 mass percent sodium carbonate solution were mixed at a volume ratio of 25:75 was used. Table 5 shows the processing conditions. The processing procedure was the same as in Example 1.

Table 6 shows the results obtained under the processing conditions shown in Table 5. In Example 4, compared with Example 3, since the chlorine content of the recovered copper oxide was generally low, it was confirmed that the mixed alkali agent of sodium hydroxide and sodium carbonate was effective in reducing the chlorine content. . Further, as the dilution ratio of the alkaline agent increased, the chlorine content of the recovered copper oxide decreased, and it was confirmed that there was an alkaline agent dilution effect even when the mixed alkaline agent was used.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, It cannot be overemphasized that it may be implemented with a different form within the range of the technical idea. Of course, various changes can be made without departing from the scope of the present invention.

The present invention relates to a method for treating a copper-containing acidic waste liquid, and more specifically, for example, an etching waste liquid produced when a copper printed board is etched with a cupric chloride etchant, a renewed waste liquid for a plating bath in electrolytic copper foil production, Neutralizes copper-containing acidic waste liquid containing high-concentration copper ions, such as etching waste liquid generated in the roughening process of the substrate surface in the lamination process when producing multilayer printed circuit boards, and oxidizes copper from the copper-containing acidic waste liquid The present invention can be used in a method for removing and recovering as copper and an apparatus therefor.

DESCRIPTION OF SYMBOLS 1 Copper collection | recovery apparatus 11 Mixing tank 12 Reaction tank 13 Solid-liquid separator 14 Copper containing acidic waste liquid piping 15 Oxidant supply piping 16 Mixed liquid supply piping 17 Alkaline agent supply piping 18 Dilution water supply piping 19 Stirrer 20 Washing water supply piping 21 Valve 22 Dehydrator 23 Thermometer 24 Heater 25 Alkaline agent heating tank 26 Transfer pump

Claims (9)

After mixing the copper-containing acidic waste liquid and the oxidizing agent, this mixed liquid is added to the alkaline agent while controlling so that the pH of the alkaline agent solution after pouring the mixed solution is not temporarily lowered to 7 or less. In the treatment method of copper-containing acidic waste liquid that recovers solids mainly composed of copper oxide, the alkaline solution is diluted in advance and the concentration is adjusted, and then the mixed solution is added to the alkaline agent or the alkaline agent is diluted in advance. A method for treating a copper-containing acidic waste liquid, wherein the concentration is adjusted, the diluted alkaline agent is heated, and the mixed solution is added to the alkaline agent. The method for treating a copper-containing acidic waste liquid according to claim 1, wherein a sodium hydroxide solution is used as the alkali agent. The method for treating a copper-containing acidic waste liquid according to claim 1, wherein a solution containing sodium hydroxide and sodium carbonate is used as an alkali agent. The method for treating a copper-containing acidic waste liquid according to claim 1, wherein a sodium carbonate solution is used as the alkali agent. The method for treating a copper-containing acidic waste liquid according to claim 2, wherein the concentration of the sodium hydroxide solution is 6% by mass or less. 4. The method for treating a copper-containing acidic waste liquid according to claim 3, wherein 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. The method for treating a copper-containing acidic waste liquid according to any one of claims 1 to 6, wherein the temperature of the alkali agent is 70 ° C or higher. A mixing tank for mixing the copper-containing acidic waste liquid and the oxidizing agent,
Means for pouring the mixed solution from the mixing tank to the reaction tank so that the pH of the alkaline agent solution after pouring the mixed liquid does not drop to 7 or less even temporarily,
A reaction vessel for reacting the mixed solution with the alkaline agent solution to produce a solid mainly composed of copper oxide;
Alkaline agent supply means for supplying the alkaline agent to the reaction vessel;
A solid-liquid separation device that separates and collects solid matter generated in the reaction tank,
In the apparatus for recovering copper from a copper-containing acidic waste liquid in which the reaction tank and the solid-liquid separator are communicated with each other so that a liquid containing solids can be transferred,
A copper characterized in that a diluting solution supply means is provided to adjust the concentration by diluting the alkaline agent, and an alkaline agent heating means for heating the diluted alkaline agent is provided in the reaction vessel or the alkaline agent supply means. Equipment for recovering copper from contained acidic waste liquid. Mixing copper-containing acidic waste liquid and oxidizer, and managing the mixture of copper-containing acidic waste liquid and oxidizer as an alkaline agent so that the pH of the alkaline agent solution after pouring the mixture does not drop below 7 even temporarily. In the method of producing a copper oxide from the copper-containing acidic waste liquid by recovering the solid matter mainly composed of the copper oxide to be added while diluting, the alkaline solution is diluted in advance to adjust the concentration, and then the mixture is diluted. The copper-containing acid is characterized in that it is added to a later alkaline agent, or the concentration is adjusted by diluting the alkaline agent in advance and heated, and then the mixed solution is added to the diluted and heated alkaline agent. Production method of copper oxide from waste liquid.

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