WO2007113926A1

WO2007113926A1 - Method of purifying copper salt solution, purification apparatus and copper salt solution

Info

Publication number: WO2007113926A1
Application number: PCT/JP2006/313928
Authority: WO
Inventors: Shiroshi Matsuki
Original assignee: Tsurumi Soda Co., Ltd.
Priority date: 2006-04-05
Filing date: 2006-07-06
Publication date: 2007-10-11
Also published as: JP2007277035A; JP5158665B2; TW200738562A

Abstract

A method of purifying, in which calcium and barium are removed from a copper salt solution, such as a copper chloride etchant waste occurring after etching with a cupric chloride solution, to thereby attain purification; a relevant purification apparatus; and a copper chloride solution purified by the purification method. In particular, there is provided a method comprising neutralizing a copper salt solution, such as a copper chloride etchant waste, with an alkali, such as sodium hydroxide, so that, for example, the pH value falls within the range of 3.5 to 7.0 (step S1); subjecting the obtained solid-liquid mixture to solid-liquid separation (step S2); and re-dissolving the solid contents obtained by the solid-liquid separation in an inorganic acid, such as hydrochloric acid (step S3), thereby obtaining a copper chloride solution having calcium and other impurities removed therefrom.

Description

Specification

TECHNICAL FIELD The present invention relates to a technology for removing and purifying calcium and barrier contained in a copper salt solution such as a copper chloride etching waste solution. Background art

A copper salt solution such as copper chloride etching waste liquid after etching a copper printed circuit board, etc., is etched with a cupric chloride solution, but it is used in the electrolytic plating method as one of its applications. Copper plating materials are known.

The electrolytic plating method is a method in which a copper plating material is supplied to a plating working fluid (sulfuric acid and copper sulfate as main components), and an electric current is passed between the insoluble anode and the substrate to be the cathode. As a copper plating material used in this method, copper oxide powder obtained by thermally decomposing basic copper carbonate is known. Since the copper plating material is appropriately replenished in the working fluid, it must be easily soluble in sulfuric acid. In this regard, copper oxide powder obtained by thermally decomposing basic copper carbonate is suitable as a copper plating material because it is readily soluble in sulfuric acid. Patent Document 1 describes a method of producing copper oxide powder by thermally decomposing basic copper carbonate after producing basic copper carbonate using a copper chloride etching waste solution as a raw material.

As described above, according to the method for producing copper oxide powder, which is a copper plating material, using a salt copper etching waste liquid, the waste liquid can be effectively used, and commercially available basic copper carbonate is used as a raw material. Compared to the case, it is advantageous in terms of cost. However, in the copper chloride etching waste solution, the copper printed circuit board may be dissolved during etching, and impurities contained in the copper printed circuit board, such as calcium and barium, may be dissolved. For this reason, the above calcium and barium may be mixed in the copper oxide powder obtained using the copper chloride etching waste solution as a raw material.

When copper oxide powder mixed with calcium or barium is used as a plating material, these impurities accumulate in the plating working solution, and if left untouched, the electrolytic mesh is adversely affected, so the amount of impurities accumulated Necessary to build before reaching the prescribed amount There is. However, if the copper plating material (replenishment material) contains a lot of impurities, the bathing must be carried out frequently, which increases the cost of the plating treatment and takes time. Therefore, it is important to remove as much of the impurities as possible at the basic copper carbonate stage before supplying copper oxide powder as a copper plating material to the working fluid. However, it is important to remove impurities sufficiently. difficult. In addition, copper oxide with few impurities can be obtained by oxidizing electrolytic copper powder. However, in the case of electrolytic copper powder, the cost of electrolytic copper powder is high even if low-impurity copper copper is produced, and copper oxide made from electrolytic copper powder is less than the plating solution. It is known that it is not easily soluble and cannot be adopted.

Patent Literature 1

Japanese Patent No. 2 7 5 3 8 5 5 Disclosure of Invention

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a copper plating material with less impurities. Therefore, by removing force barium from a copper salt solution such as a copper chloride etching waste liquid, The object is to provide a purification method, a purification apparatus, and a copper salt solution purified by these purification methods.

The method for purifying a copper salt solution according to the present invention comprises a neutralization step of neutralizing a copper salt solution with Al force to obtain a solid-liquid mixture,

A solid-liquid separation step of solid-liquid separation of the solid-liquid mixture into a solid content containing copper and a liquid content containing force Luc;

And a re-dissolution step of re-dissolving the solid content in an inorganic acid to obtain a copper salt solution from which calcium has been removed. A copper salt solution from which barium has been removed may be obtained by a similar method.

Examples of the copper salt solution to be purified include copper chloride etching waste liquid. In general, when a material to be etched made of copper (for example, a copper printed circuit board surface) is etched with a cupric chloride etching solution, the cupric chloride reacts with the copper and changes to cuprous chloride. Since this cuprous chloride decreases the etching rate, for example, by adding hydrogen peroxide and hydrochloric acid to the etching solution, the cuprous chloride can be converted into chloride. Recycle to the copper. The copper chloride etching waste liquid according to the present invention is a surplus liquid obtained as a result of an increase in the etching liquid by such a regeneration process.

In these methods, the neutralization step is preferably performed so that the copper salt solution is in the range of pH 3.5 to 7.0, and the temperature at which the solid-liquid mixture is 40 ° C. or higher. It is preferable to be performed within a range. The alkali is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate or potassium hydrogen carbonate.

According to the method for purifying a copper salt solution according to the present invention, for example, with copper chloride etching waste liquid after etching with a copper chloride solution, mixing with alkali → solid-liquid separation → re-dissolution of solids By performing a simple treatment, a copper chloride solution from which calcium or the like has been removed (purified) can be obtained. For this reason, even if copper oxide powder made from a copper salt solution purified by this method is used as a plating material, it is difficult for impurities to accumulate in the plating bath, making it possible to reduce the frequency of building the plating bath. It is possible to reduce the processing cost and the time required for bathing. In addition, since copper chloride etching waste liquid can be used as a raw material for copper oxide powder, which is a plating material, it is possible to keep raw material costs low compared to, for example, obtaining copper oxide with less impurities using electrolytic copper powder as a raw material. it can. Brief Description of Drawings

FIG. 1 is a flowchart illustrating a method for purifying a copper chloride solution according to the present invention. FIG. 2 is a configuration diagram showing an example of a copper chloride solution purifying apparatus according to the first embodiment.

FIG. 3 is an explanatory view showing an operation procedure of the neutralization reaction tank of the copper chloride solution purifying apparatus according to the second embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

As an example of an embodiment relating to a method for purifying a copper salt solution according to the present invention, a method for purifying a copper chloride solution will be described with reference to FIG. Figure 1 shows an example of a copper chloride solution. It is a flowchart regarding the process which refine | purifies a certain copper chloride etching waste liquid (henceforth an etching waste liquid). In the figure, the part surrounded by the dotted line shows the content of the process for purifying the etching waste liquid, and the other part shows the post-treatment. Here, the etching waste liquid is an excess waste liquid generated as a result of etching a material to be etched made of copper, for example, a copper printed circuit board surface, with an etching liquid containing hydrochloric acid mainly composed of cupric chloride. As its composition, for example, 19 to 21% by weight of cupric chloride and 7 to 8% by weight of hydrochloric acid are contained. In addition, impurities such as calcium and barium contained in the copper printed circuit board, the stage to be etched, the tank container, and the tank lorry container are dissolved in the etching waste liquid during etching, for example, several tens of weight p pm It is dissolved at a certain concentration. “Purification” refers to a treatment for removing an impurity such as calcium from such an etching waste liquid to obtain a copper chloride solution that does not contain calcium or has a low content of calcium or the like.

Here, the concept of the copper chloride solution purification method according to the present invention will be described. Generally, if went by adding an alkali to an aqueous solution containing a C a ^{2 +} and B a ^2+, Ji 3 Ya 8 & carbonate of pH 8 or higher, the hydroxide will be precipitated by p HI 2 or more It has been known. Since Cu ²⁺ precipitates around pH 3-4, it was considered possible to separate Cu, Ca, and Ba due to pH differences. However, as a result of conducting tests on this case, it was found that even when the pH was 7 or less, Ca and Ba were present more than expected in the formed precipitate. It is thought that Ca and Ba were co-precipitated with the precipitation of Cu. Even if this precipitate was washed with a large amount of water, the Ca and Ba concentrations in the precipitate did not decrease. Depending on the pH value, it may be necessary to add some additional purification process. In view of this concept, the specific contents of the process for purifying the etching waste liquid will be described below. '

First, as shown in FIG. 1, an etching waste liquid and an alkali, for example, a 10 wt% sodium hydroxide aqueous solution are mixed, and the hydrogen ion concentration (hereinafter referred to as PH) of the mixed liquid is, for example, 3.5 to 7 Within the range of 0, for example, the mixing ratio of the etching waste liquid and the sodium hydroxide aqueous solution is adjusted so that the pH becomes 4.0. At this time, the mixed solution is heated so as to be constant in a temperature range of 40 ° C. or higher, for example, 70 ° C. (step S 1 (neutralization step)). In addition, the alkali that neutralizes the etching waste liquid Is not limited to sodium hydroxide. For example, potassium hydroxide, ammonium hydroxide, sodium carbonate, carbonated lithium, ammonium carbonate, sodium bicarbonate or potassium bicarbonate may be used. Moreover, it is not limited to the case of using an alkaline aqueous solution, and for example, an alkaline powder may be used.

By neutralizing the etching wastewater with aqueous sodium hydroxide solution, cupric chloride and sodium hydroxide in the etching wastewater react with each other. For example, C u C l ₂ ■ 3 C u (OH) ₂ And the like, and the mixed solution becomes a solid-liquid mixture. At this time, the larger the amount of sodium hydride aqueous solution added to the etching waste solution, that is, the higher the pH value of the mixed solution, the higher the yield of recovering copper as a solid content from the etching waste solution.

On the other hand, in this neutralization step, whether calcium or the like, which is an impurity, is contained in the solid content or the liquid content depends on the pH of the solid-liquid mixture. That is, in the region where pH is low, calcium is dissolved in the liquid component in the form of calcium chloride (C a C l ₂ ).

However, the mixing amount is more a connexion of aqueous sodium hydroxide solution, the p H is large Do connexion go, said the _{C u C l 2 · 3 C} u (OH) partially Karushiu beam atoms of copper atoms in the _two molecules As a result, a solid content that is replaced with a solid content is generated, or calcium is adsorbed on the solid content, so that the solid content is contained in the solid content.

The inventor collects copper as a solid content from the etching waste liquid by adjusting the pH in the neutralization step to a range of 3.5 to 7.0, and impurities such as calcium are contained in the liquid content. I know I can keep it.

By the way, in the precipitation reaction by neutralization, when it is desired to increase the size of the precipitated particles, it is common to increase the reaction temperature. However, the tendency of particle growth varies from material to material. In order to improve the filterability, generally increasing the particle diameter can be mentioned. However, the filterability is greatly affected by the shape of the particles and the presence of fine particles. Therefore, the filterability cannot be judged only by the particle size. Therefore, the inventor conducted a test and ascertained the conditions that facilitate solid-liquid separation by filtration. As a result, the neutralization step is performed in a temperature range in which the temperature of the solid-liquid mixture is 40 ° C or higher. As a result, it was understood that the filterability was improved. Next, the solid-liquid mixture obtained in the neutralization step is subjected to solid-liquid separation into a solid component and a liquid component using, for example, a filter (step S 2 (solid-liquid separation step)). In this solid-liquid separation step, copper and impurities such as calcium mixed in the etching waste liquid are separated into a solid content and a liquid content, respectively.

Next, hydrochloric acid is added to the solid content obtained in the solid separation process and redissolved (Step S3 (about redissolution)), and water is added as necessary to adjust the concentration. A purified copper salt copper solution from which the impurities are removed can be obtained. Here, inorganic acids that re-dissolve solids are not limited to hydrochloric acid, but may be sulfuric acid or nitric acid, for example.

The liquid component containing calcium and the like obtained in the solid-liquid separation process in step S 2 is neutralized to about pH 7 with an aqueous sodium hydride solution (step S 4), and becomes a solid-liquid mixture again. This solid-liquid mixture is again solid-liquid separated (step S 5), and a ferric chloride solution is added to the solid content to form a redissolved solution (step S 6). The redissolved solution is treated to recover copper. On the other hand, the liquid obtained in step S5 is subjected to waste liquid treatment (step S7) and discharged to the environment.

Next, a purification apparatus for purifying a copper chloride solution based on the above flow will be described. Figure 2 shows an example of a continuous copper chloride solution purifier. The apparatus generally includes a neutralization reaction tank 10 for neutralizing the etching waste liquid and the aqueous sodium hydroxide solution, and a filter press 30 for solid-liquid separation of the solid-liquid mixture produced in the neutralization reaction tank 10. In detail, the neutralization reaction tank 10 is composed of a hydroxylated sodium hydroxide supply valve 1 1, which is composed of a redissolution tank 40 for redissolving the separated solid content in hydrochloric acid. The sodium hydroxide tank 1 is connected to the sodium hydroxide tank 1 via a 1a. The sodium hydride supply valve 11 has a function as an alkali supply means, and plays a role of continuously supplying a sodium hydroxide aqueous solution to the neutralization reaction tank 10 while increasing or decreasing the supply amount. In addition, the neutralization reaction tank 10 is connected to the etching waste liquid tank 2 through the etching waste liquid supply pipe 1 2 a provided in the etching waste liquid supply valve 12, and the etching waste liquid supply valve 1 2 is also in the middle. It serves as a solution supply means for the sum reactor 10. Further, in the neutralization reaction tank 10, a mixer 13 for mixing the etching waste liquid and the sodium hydride aqueous solution, and a solid-liquid mixture (hereinafter referred to as slurry) in the neutralization reaction tank 10 are heated, for example, by electric heating. A heater 14 consisting of a vessel and a liquid level gauge 15 for measuring the level of the slurry in the neutralization reactor 10 are installed. In addition, a bottom pipe 1.6a is attached to the bottom of the neutralization reaction tank 10, and the slurry can be extracted from the neutralization reaction tank 10 by, for example, a bottom pump 16 comprising a slurry pump. It has become possible to do. The bottom pipe 1 6 a branches into a return pipe 1 7 a and an extraction pipe 1 8 a, and the return pipe 1 7 a plays a role of returning the slurry to the neutralization reaction tank 10. In addition, the extraction pipe 1 8 a is connected to the filter press 30 with the extraction valve 1 8 interposed, and the extraction valve 1 8 is connected to the extraneous slurry from the neutralization reaction tank 10. It plays a role as an extraction means to continuously extract one. Further, a sampling pot 17 having a thermometer 19 for measuring the temperature of the slurry and a pH meter 20 for measuring the pH of the slurry is interposed in the return pipe 17a.

The purification apparatus further includes a control unit 21, and a pH meter 20, a sodium hydroxide supply valve 11, and an etching waste liquid supply valve 12 are connected to each other through signal lines 2 2 to 24. Connected to the control unit 2 1. The control unit 21 sends an opening / closing instruction to the sodium hydroxide supply valve 11 and the etching waste liquid supply valve 12 based on the indicated value of the pH meter 20 so that the slurry has a pH of 3. It plays a role of controlling to increase / decrease the supply amount of the sodium hydroxide aqueous solution and the etching waste liquid so as to become a predetermined value in the range of 5 to 7.0, for example, 4.0.

Further, the liquid level gauge 15 and the extraction valve 18 are connected to the control unit 21 via signal lines 25 and 26. The control unit 21 sends an opening / closing instruction to the extraction valve 18 based on the indicated value of the liquid level gauge 15 so that the liquid level of the slurry in the neutralization reaction tank 10 becomes constant. It also has a function of controlling the slurry to be extracted. The thermometer 19 and the heater 14 are connected to a controller (not shown), and the temperature of the slurry in the neutralization reaction tank 10 becomes a predetermined temperature by this controller. So that it is controlled.

The slurry extracted from the neutralization reaction tank 10 by the extraction valve 18 to the outside of the system is separated into a solid and a liquid by a filter press 30 (hereinafter referred to as a mother liquor). The filter press 30 functions as a solid-liquid separation means for feeding the slurry at a high pressure into the chamber covered with the filter cloth and separating the solid content of the slurry and the mother liquor. The solid-liquid separation means is not limited to the case where the filter press 30 is used. For example, the precipitation tank may use a liquid cyclone.

The mother liquor that has exited the filter press 30 is sent to the post-treatment device 3 through the mother liquor pipe 30 b and subjected to post-treatment. On the other hand, the solid content is conveyed to the remelting tank 40 via the solid content conveyance path 30 a. For example, a belt conveyor or a bulldozer or the like may be used for conveyance by the solid content conveyance path 30a.

The redissolving tank 40 is connected to the hydrochloric acid tank 4 via a hydrochloric acid supply pipe 40 a so that a predetermined amount of hydrochloric acid can be received therefrom. The redissolving tank 40 has a function as a redissolving means for mixing the received solid content and hydrochloric acid to redissolve the solid content. If an etching waste solution with a low calcium or barium concentration is available, it can be used in place of hydrochloric acid to redissolve the solids.

Further, the re-dissolution tank 40 is further provided with a mixer 41 for mixing solids and hydrochloric acid, and a liquid level gauge 42 for measuring the level of the re-dissolution liquid in the re-dissolution tank 40. Yes. A bottom pipe 43a is attached to the bottom of the remelting tank 40 so that the remelted liquid can be extracted from the remelting tank 40 by the bottom pump 43. The bottom pipe 4 3 a branches into a return pipe 4 4 a and an extraction pipe 4 5 a, and the return pipe 4 4 a plays a role of returning the redissolved liquid to the redissolving tank 40.

In addition, the extraction pipe 4 5 a is connected to the purified copper chloride solution tank 5 with the extraction valve 4 5 interposed, and the extraction valve 4 5 is connected to the purified copper chloride of the re-dissolved liquid. It performs the function of continuously dispensing as a solution. At this time, the extraction valve 4 5 and the liquid level gauge 4 2 are connected to a controller (not shown) via the signal line 46, and the liquid level of the redissolved liquid in the redissolving tank 40 is constant. The amount of the re-dissolved liquid extracted is controlled by the controller. For example, a water supply means and a pH meter may be installed in the redissolving tank 40 so that the redissolved solution is diluted with water to a certain concentration, and the adjusted copper chloride solution is dispensed. Good.

By reconciling the functions of the devices described above, the refiner can It is possible to execute the neutralization process of the waste liquid, the solid-liquid separation process of the slurry and the solid re-dissolution process in parallel. As a result, it is possible to continuously process the etching waste liquid and dispense the purified copper chloride solution.

Next, a second embodiment of the copper chloride solution purification apparatus will be described. Figure 3 shows an example of a batch-type copper chloride solution purifier. The neutralization reaction tank 10 and its peripheral equipment in the apparatus have substantially the same configuration as that shown in FIG. However, it is provided with water supply means (not shown), has no return pipe 1 Ί a for returning the extracted slurry to the neutral reaction tank 10, and the mother liquor after the slurry is settled and separated Neutralization reaction tank 1 0 The mother liquor extraction pipe 1 6 b has a thermometer 1 9 and pH meter 2 0 instead of the sampling pot 1 7 This is different from the first embodiment in that it is directly attached to the first embodiment. For convenience, the liquid level indicator 15 is not shown in FIG.

The control unit 21 is connected to each device such as a sodium hydroxide supply valve 11 and an etching waste liquid supply valve 1 2 and has a role of executing sequence control related to the operation of the neutralization reaction tank 10. is doing. The details of the control executed by the control unit 21 will be described below. First, the control unit 21 performs the neutralization reaction using the water supply means (not shown) with the on-off valves provided in the bottom pipe 16a and the mother liquor extraction pipe 16b closed. Fill the tank 10 with a predetermined amount of water, turn the mixer 1 3 “ON”, and heat to the predetermined temperature using the heater 14. Next, as shown in FIG. 3 (a), the control unit 21 opens the etching waste liquid supply valve 12 to start supplying the etching waste liquid. Here, the control unit 21 monitors the pH of the solution in the neutralization reaction tank 10 using a pH meter 20, and the value of pH is, for example, a predetermined value from 3.5 to 7.0. Supply only the etching waste liquid until the value reaches (eg 4.0). In FIG. 3, the supply valves 1 1 and 1 2 in the open state are marked with “0”, and the closed valves are blacked out and marked with “S”.

When the pH of the solution in the neutralization reactor 10 reaches a predetermined value, as shown in FIG. 3 (b), the control unit 21 opens the sodium hydroxide supply valve 11 and opens the sodium hydroxide solution. The supply of the solution is started and neutralization of the etching waste liquid is started. Then, the degree of opening of the sodium hydroxide supply valve 1 1 and the etching waste liquid supply valve 1 2 is adjusted so that the neutralization reaction tank 1 The supply amounts of the etching waste liquid and the aqueous sodium hydroxide solution are controlled so that the pH of the solution within 0 maintains a predetermined value of, for example, 3.5 to 7.0. By these operations, the slurry generated by the neutralization reaction between the etching waste liquid and the aqueous sodium hydroxide solution is stored in the neutralization reaction tank 10.

As a result of prior experiments, the inventor found that when the etching waste liquid and the sodium hydroxide aqueous solution were mixed under such conditions, the slurry was filtered and the mother liquor and solid content were compared with the case where neutralization was performed under other conditions. We understand that it becomes easy to separate. This is because, for some reason, the particle size of the solid content to be produced becomes larger than when adding an aqueous sodium hydroxide solution to the neutralization reaction tank 10 in which the etching waste liquid is previously added. It is thought that. Therefore, in the purification apparatus shown in FIG. 3, as described above, only the etching waste liquid is first supplied to the neutralization reaction tank 10 filled with water in advance, and the solution in the neutralization reaction tank 10 is predetermined. After adjusting to the pH of the solution, a method of supplying a sodium hydroxide aqueous solution is adopted so that the value does not fluctuate greatly.

Next, when the slurry in the neutralization reactor 10 reaches a certain amount, the control unit 21 closes the sodium hydroxide supply valve 11 and the etching waste liquid supply valve 1 2 as shown in FIG. 3 (c). Then, the supply of the etching waste liquid and the sodium hydroxide aqueous solution is stopped, and the mixer 13 is further stopped. Then, the slurry is allowed to stand for a predetermined time, and the solid content in the slurry is precipitated and roughly separated from the mother liquor. Thereafter, the control unit 21 opens the on-off valve of the mother liquor extraction pipe 16 b, discharges the supernatant in the neutralization reaction tank 10 as a mother liquor to an unshown post-treatment device, and then the neutralization reaction tank 10 The slurry that has settled at the bottom of the filter is extracted toward a filter press (not shown). Since then, the equipment for solid-liquid separation of the slurry and the equipment for re-dissolving the solid content with hydrochloric acid are almost the same as those described in FIG. In these devices, the slurry and solids may be processed in batches, or may be processed continuously after a certain amount is accumulated.

In addition, in FIG. 3, a series of operations for neutralizing the etching waste liquid has been described as an example of sequence control by the control unit 21, but a part or all of the above operations are manually performed by a human. Also good. In this case, the equipment cost can be reduced because the instrumentation installed in the equipment can be reduced.

In the embodiment, as an example of a copper salt solution, a copper chloride etching waste solution ( However, the copper salt solution that can be purified according to the present invention is not limited to the exemplified one. For example, the present invention can also be applied to a copper salt solution such as a copper sulfate solution that is a waste liquid for printed circuit boards.

(Example)

(Experiment 1)

We evaluated the effect of pH during the neutralization reaction on copper yield and impurity removal rate.

(Example 1 1 1)

Put 500 g of the etching waste solution in a laboratory-level apparatus (2 L beaker) that performs the neutralization process in batch mode and stir at 70 ° C. Thereto, the aqueous solution of sodium hydroxide was supplied at a constant supply rate using a tube pump while monitoring the pH of the solution. When the pH of the solution reached a predetermined value (target value), the supply of the sodium hydroxide aqueous solution was stopped. Thereafter, stirring was continued for 30 minutes, and the obtained slurry was subjected to solid-liquid separation by suction filtration, and the solid content obtained was washed with water. Table 1 shows the experimental conditions.

(table 1 )

Experimental conditions of (Example 1-11)

In Example 1-11, the copper concentration remaining in the mother liquor obtained by solid-liquid separation of the slurry was analyzed, and the copper yield from the etching waste liquid to the solid content was calculated. In addition, by analyzing the concentration of calcium and barium in the solids, the removal rate of these components (mother The ratio remaining in the liquid) was calculated. The results are shown in (Table 2). Note that (Table 2) also shows the results of Example 1-1-2 to 1-3.

(Table 2)

Effect of pH target values on copper yield and calcium and barium removal rates

(Examples 1-2, 1-3)

The etching waste solution was neutralized in the same manner as in Example 1-11, except that the pH target values were set to 5.0 and 7.0, respectively.

(Consideration of Experiment 1)

From Table 2, it can be seen that the higher the pH target value, that is, the higher the amount of sodium hydroxide aqueous solution supplied to the etching waste liquid, the higher the yield of copper recovered as a solid. On the other hand, the removal rate of calcium and barium decreases as the pH target value increases, and there is a tendency for these impurities to be mixed into the solid content. However, with regard to calcium, the removal rate of about 90% or more is maintained when the pH target value is in the range of 4.0 to 7.0. Barium has a removal rate of about 80% or more when the pH target value is in the range of 4.0 to 5.0, and removes about half of the barium even when the pH target value is 7.0. Is able to. From the above, it can be said that by neutralizing the etching waste liquid, the copper yield can be increased to 90% or more, and impurities such as calcium can be maintained at a practically sufficient removal rate.

(Experiment 2)

During the neutralization, the effect of the method of mixing the etching waste solution and aqueous sodium hydroxide solution on the filterability of the slurry (solid-liquid separation) was evaluated.

(Example 2-1)

In an experimental-level device (3 L beaker) corresponding to the device shown in Fig. 3, apply ion-exchanged water 1, OOO g in advance, and heat to 70 ° C and stir. The etching waste solution was supplied there, and when the pH reached the target value, the aqueous solution of sodium hydroxide (10 wt./.) Was supplied at a constant flow rate (8 mL / min) while continuing to supply the etching waste solution. I started paying. Then, the supply amount of the etching waste liquid was adjusted so that the pH was maintained at the target value. In this way, pH control was continued for 1 hour while supplying both solutions, and then the supply of the etching waste solution and the aqueous sodium hydroxide solution was stopped. Thereafter, stirring was continued for 1 hour while maintaining the temperature condition, and then heating was stopped, and the resulting slurry was allowed to stand. 40 OmL of the slurry thus obtained was taken out and suction filtered. Table 3 shows the experimental conditions.

(Table 3)

Experimental conditions of (Example 2-1)

In (Experiment 2-1), the time from when the slurry was filtered by suction until a predetermined amount of mother liquor was obtained was measured and used as an index to evaluate filterability. The results are shown in Table 4. In Table 4, the results of Comparative Example 2-1 are also shown.

(Table 4)

Effects of Etching Waste Solution and Sodium Hydroxide Aqueous Solution on Slurry Filterability

(Comparative Example 2-1)

Put 400 g of etching waste solution in a 1 L beaker in advance and heat to 70 ° C and stir. Thereto, a sodium hydroxide aqueous solution was supplied at a constant flow rate until a pH target value of 4.0 was reached. The flow rate and concentration of the aqueous sodium hydroxide solution are (Example 2-1) and It is the same. Thereafter, stirring was continued for 30 minutes while maintaining the temperature condition, heating was stopped, and the resulting slurry was allowed to stand. The same suction filtration experiment as in (Example 2-1) was performed on 400 mL of the slurry thus obtained.

(Consideration of Experiment 2)

From (Table 4), the slurry obtained by mixing the etching waste solution and the aqueous solution of sodium hydroxide solution little by little while adjusting the pH value to be constant as in (Example 2-1) is ( Compared to the slurry obtained by adding sodium hydroxide aqueous solution to the etching waste liquid filled in the container as shown in Comparative Example 2-1) until the predetermined pH is reached, the time required for filtration is about 30 times shorter. (Solid-liquid separation) It is clear that it is advantageous in actual processes that handle a large amount of slurry.

(Experiment 3)

The influence of the temperature during mixing on the filterability of the slurry was evaluated.

(Example 3-1)

A suction filtration experiment similar to (Example 2-1) was carried out using a slurry obtained in substantially the same manner as (Example 2-1) except that the temperature during mixing was 40 ° C. It was. The results are shown in (Table 5). In Table 5, Examples 3-2 to 3-3 and Comparative Example 3—! The results of ~ 3-2 are also shown.

(Table 5)

(Examples 3-2, 3-3)

A suction filtration experiment was performed using the slurry obtained under the same conditions as in Example 1-11, except that the temperature during mixing was 50 ° C and 70 ° C, respectively.

(Comparative Examples 3-1 and 3-2) A suction filtration experiment was performed using the slurry obtained under the same conditions as in Example 1-11, except that the temperature at the time of mixing was 20 ° C. and 30 ° C., respectively.

(Consideration of Experiment 3)

From Table 5, it can be seen that the higher the temperature during mixing of the etching waste liquid and the aqueous sodium hydroxide solution, the shorter the time required for filtration and the better the filterability. From these results, it is possible to filter half of a 40 OmL slurry in about 3 minutes. When mixing in a temperature range of 40 ° C or higher, the present inventors set the target value. Achieved. As described above, according to the embodiment of the present invention, when etching waste liquid and Al force solution such as sodium hydroxide aqueous solution are mixed so that pH is in the range of 3.5 to 7.0, for example, A solid-liquid mixture (slurry) in which the solid content containing copper in the cupric salt and the liquid content containing impurities such as calcium are mixed can be obtained. Therefore, a solid content obtained by solid-liquid separation of this solid-liquid mixture is redissolved in an inorganic acid such as hydrochloric acid to obtain a copper chloride solution from which impurities such as calcium are removed. At this time, if the temperature when mixing and neutralizing the etching waste liquid and Al force is set to 40 ° C. or more, it becomes possible to produce a solid-liquid mixture that is easily separated into solid and liquid by a filter or the like. . As a result, even when solid-liquid separation is performed industrially using a filter press, etc., the filter is less likely to be clogged, so the pressure loss is reduced and the power consumed by the pump is reduced. can do.

In addition, in a purification device that continuously neutralizes the etching waste liquid, the pH value in the neutralization reaction tank can be controlled within the target range. Can be purified.

In addition, in a purification system that performs batch-type neutralization, neutralization is performed so that the pH value is within the target range while mixing the etching waste liquid and alkali little by little in a neutralized reaction tank filled with water. I do. It has been experimentally found that the slurry obtained by this method is more easily separated from the slurry obtained by, for example, adding slurry to a reaction tank filled with etching waste liquid. For this reason, it is possible to reduce the power consumed in the subsequent solid-liquid separation process. Etching waste liquid is continuously removed In the case of the purification unit to neutralize also, since Gyotsu neutralized so that the value of _P H is in the range of the target, the same effect can be obtained.

Claims

The scope of the claims

1. a neutralization step of neutralizing a copper salt solution with an alkali to obtain a solid-liquid mixture; and a solid-liquid separation of the solid-liquid mixture into a solid content containing copper and a liquid content containing calcium A separation process;

A re-dissolution step of re-dissolving the solid content in an inorganic acid to obtain a calcium salt solution from which calcium has been removed, and a method for purifying a copper salt solution.

2. A neutralization step of neutralizing a copper salt solution with an alkali to obtain a solid-liquid mixture, and solid-liquid separation of the solid-liquid mixture into a solid content containing copper and a liquid content containing barium Process,

A re-dissolution step of re-dissolving the solid content in an inorganic acid to obtain a copper salt solution from which the barium has been removed, and a method for purifying a copper salt solution.

3. In the neutralization step, the copper salt solution is neutralized with Al force so as to be in the range of pH 3.5 to 7.◦ to obtain a solid-liquid mixture. Item 3. A method for purifying a copper salt solution according to Item 1 or 2.

4. The method for purifying a copper salt solution according to claim 1 or 2, wherein the neutralization step is performed in a temperature range in which the solid-liquid mixture is 40 ° C or higher.

5. The method for purifying a copper salt solution according to claim 1 or 2, wherein the copper salt solution is a copper chloride etching waste solution.

6. The alkali is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, or hydrogen carbonate power. The method for purifying a copper salt solution according to claim 1 or 2.

7. A copper salt solution purified by the purification method according to any one of claims 1 to 5.

8. Neutralization reactor,

A solution supply means capable of continuously supplying to the neutralization reaction tank while increasing or decreasing the supply amount of the copper salt solution;

An alkali supply means capable of continuously supplying to the neutralization reaction tank while increasing or decreasing the supply amount of Al power; PH measurement means for measuring the pH of the solid-liquid mixture that is a reaction product in the neutralization reaction tank;

The measurement result of the pH measurement means is 3.5 to 5 through at least one of the extraction means for continuously extracting the solid-liquid mixture from the neutralization reaction tank, the solution supply means, and the alkali supply means. The control means for controlling to increase or decrease the supply amount of at least one of the copper salt solution and the alkali power so as to be within the range of 7.0, and extracted from the neutralization reaction tank by the extraction means Solid-liquid separation means for separating the solid-liquid mixture into a solid content containing copper and a liquid content containing calcium; and

A re-dissolution means for re-dissolving the solid content in an inorganic acid to obtain a calcium salt solution from which calcium has been removed, and a copper salt solution purification device.

9. The liquid component that is solid-liquid separated by the solid-liquid separation means contains barium, and the copper salt solution obtained by the re-dissolution means has a volume removed. Copper salt solution purification equipment.

1 0. Neutralization reactor;

Alkaline supply means capable of continuously supplying to the neutralization reaction tank while increasing or decreasing the supply amount of Al power;

PH measurement means for measuring the pH of the solution in the neutralization reaction tank;

Water supply means for supplying water into the neutralization reaction tank;

Water is added to the neutralization reaction tank in advance, and then the copper salt solution is supplied until the pH of the solution in the neutralization reaction tank is in the range of 3.5 to 7.0. control means for controlling a supply amount of at least one of the copper salt solution and the aluminum force so that pH is maintained within the range;

A solid-liquid separation means for solid-liquid separation of a solid-liquid mixture which is a reaction product in the neutralization reaction tank into a solid content containing copper and a liquid content containing calcium;

1 1. The apparatus for purifying a copper salt solution according to claim 8 or 10, further comprising temperature adjusting means for adjusting the solution in the neutralization reaction tank to a temperature of 40 ° C or higher.