JP5158665B2 - Copper salt solution purification method, purification apparatus, and copper salt solution - Google Patents

Description

  The present invention relates to a technique for removing and purifying calcium and barium contained in a copper salt solution such as a copper chloride etching waste liquid.

  Copper salt solution such as copper chloride etching waste liquid after etching copper printed circuit boards, etc. is effectively used with cupric chloride solution, but one of its uses is copper used in electrolytic plating Plating materials are known.

The electrolytic plating method is a method in which a copper plating material is supplied to a plating working solution (sulfuric acid and copper sulfate as main components), and electricity is passed between the insoluble anode and the object to be plated forming 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 liquid, it needs to 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 in which copper chloride etching waste liquid is used as a raw material to produce basic copper carbonate, and then the basic copper carbonate is thermally decomposed to obtain copper oxide powder.
Japanese Patent No. 2753855

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

  When copper oxide powder mixed with calcium or barium is used as the plating material, these impurities accumulate in the plating working solution, and if left as they are, the electrolytic plating will be adversely affected. It is necessary to make a bath before reaching the fixed amount. However, if the copper plating material (replenishment material) contains a large amount of impurities, it is necessary to frequently perform a bathing bath, which increases the cost of the plating process 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, but it is difficult to remove the impurities sufficiently. . In addition, copper oxide with few impurities can be obtained by oxidizing electrolytic copper powder. However, in the case of using electrolytic copper powder, the cost of electrolytic copper powder is high even if copper oxide with few impurities is made, and copper oxide made from electrolytic copper powder is not easily soluble in the plating solution. I know that and I can't hire it.

  The present invention has been made in view of such circumstances, and the object of the present invention is to provide a copper plating material with less impurities, so that calcium and barium are removed from a copper salt solution such as a copper chloride etching waste liquid and purified. It is an object of the present invention 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 includes a neutralization step of neutralizing a copper salt solution with an alkali so as to be in a range of pH 3.5 to 5.0, and obtaining a solid-liquid mixture;
A solid-liquid separation step for solid-liquid separation of the solid-liquid mixture into a solid containing copper and a liquid containing calcium;
And re-dissolving the solid content in an inorganic acid to obtain a copper salt solution from which calcium has been removed. You may obtain the copper salt solution from which barium was removed by the same 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 etchant, the cupric chloride reacts with the copper and changes to cuprous chloride. Since this cuprous chloride reduces the etching rate, for example, by adding hydrogen peroxide and hydrochloric acid to the etching solution, the cuprous chloride is regenerated into cupric chloride. 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 has a pH in the range of 3.5 to 7.0, and is performed in a temperature range in which the solid-liquid mixture is 40 ° C. or higher. Is preferred. The alkali may be selected from an alkali group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, or potassium bicarbonate.

  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, it is easy to mix with alkali → solid-liquid separation → solid re-dissolution. By performing an appropriate 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, and it is possible to suppress the frequency of constructing the plating bath. The cost and the labor of building bath can be reduced. Moreover, since the copper chloride etching waste liquid or the like can be used as a raw material for the copper oxide powder that is the plating material, the raw material cost can be reduced as compared with, for example, obtaining copper oxide with less impurities using the electrolytic copper powder as a raw material. .

  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. FIG. 1 is a flowchart relating to a process for purifying a copper chloride etching waste liquid (hereinafter referred to as an etching waste liquid) which is an example of a copper chloride solution. In the figure, the part surrounded by a 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, such as a copper printed circuit board surface, with an etching liquid containing hydrochloric acid mainly composed of cupric chloride. As the composition, for example, 19 to 21% by weight of cupric chloride and 7 to 8% by weight of hydrochloric acid are contained. Furthermore, in the etching waste liquid, 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 during the etching, for example, about several tens of ppm by weight. Dissolved in concentration. “Purification” refers to a process for removing impurities such as calcium from such 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. In general, when an alkali is added to an aqueous solution containing Ca ²⁺ or Ba ²⁺ , it is known that carbonates of Ca and Ba are precipitated at pH 8 or more and hydroxides are precipitated at pH 12 or more. Since Cu ²⁺ precipitates around pH 3-4, it was considered possible to separate Cu, Ca, and Ba due to pH difference. However, as a result of conducting tests on this case, it was found that Ca and Ba were present more than expected in the generated precipitate even when the pH was 7 or less. It is considered that the Ca and Ba components co-precipitated with the precipitation of Cu. Even when 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 purification process. In view of such a 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 0.0, 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 liquid mixture is heated so as to be constant in a temperature range of 40 ° C. or higher, for example, 70 ° C. (step S1 (neutralization step)). The alkali that neutralizes the etching waste liquid is not limited to sodium hydroxide. For example, potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, or potassium hydrogen carbonate may be used. Moreover, it is not limited to using alkaline aqueous solution, For example, you may use alkali powder.

By neutralizing the etching waste solution with a sodium hydroxide aqueous solution, cupric chloride and sodium hydroxide in the etching waste solution react, and for example, a solid content such as CuCl ₂ .3Cu (OH) ₂ is precipitated and mixed. The latter solution becomes a solid-liquid mixture. At this time, the larger the amount of sodium hydroxide 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 included in the solid content or the liquid content depends on the pH of the solid-liquid mixture. That is, in the region where the pH is low, calcium is dissolved in the liquid in the form of calcium chloride (CaCl ₂ ) or the like.

However, as the amount of sodium hydroxide aqueous solution increases and the pH increases, the solid content in which some of the copper atoms in the CuCl ₂ .3Cu (OH) ₂ molecule are replaced with calcium atoms or the like is increased. It is generated or calcium or the like is adsorbed to the solid content, so that calcium or the like is contained in the solid content.

  The inventor recovers 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 leaves impurities such as calcium in the liquid content. I know that will be possible.

  By the way, in the precipitation generation 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 differs depending on the substance. Further, 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 diameter. Therefore, the inventor conducted a test and ascertained conditions that facilitate solid-liquid separation by filtration. As a result, the neutralization step was performed in a temperature range in which the temperature of the solid-liquid mixture was 40 ° C. or higher. It was grasped that the filterability was improved.

  Next, the solid-liquid mixture obtained in the neutralization step is subjected to solid-liquid separation into, for example, a solid component and a liquid component using a filter or the like (step S2 (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 step and redissolved (step S3 (re-dissolution step)), and water is added as necessary to adjust the concentration to remove impurities such as calcium. A purified copper chloride solution can be obtained. Here, the inorganic acid for re-dissolving the solid content is not limited to hydrochloric acid, and may be sulfuric acid or nitric acid, for example.

  The liquid component containing calcium and the like obtained in the solid-liquid separation step in step S2 is neutralized to about pH 7 with an aqueous sodium hydroxide solution or the like (step S4), and becomes a solid-liquid mixture again. This solid-liquid mixture is again solid-liquid separated (step S5), and a ferric chloride solution is added to the solid content to form a redissolved solution (step S6). The re-dissolved solution is subjected to a process for recovering 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, the refiner | purifier which refine | purifies a copper chloride solution based on the above-mentioned flow is demonstrated. FIG. 2 shows an example of a continuous copper chloride solution purifier. The apparatus is roughly separated from a neutralization reaction tank 10 for neutralizing an etching waste liquid and an aqueous sodium hydroxide solution, and a filter press 30 for solid-liquid separation of the solid-liquid mixture generated in the neutralization reaction tank 10. And a redissolving tank 40 for redissolving the solid content in hydrochloric acid.

  Specifically, the neutralization reaction tank 10 is connected to the sodium hydroxide tank 1 through a sodium hydroxide supply pipe 11 a provided with a sodium hydroxide supply valve 11. The sodium hydroxide 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. The neutralization reaction tank 10 is connected to the etching waste liquid tank 2 via an etching waste liquid supply pipe 12 a provided with an etching waste liquid supply valve 12. The etching waste liquid supply valve 12 is also a solution for the neutralization reaction tank 10. Serves as a means of supply.

  Furthermore, the neutralization reaction tank 10 includes a mixer 13 for mixing the etching waste liquid and the sodium hydroxide aqueous solution, and a heater comprising, for example, an electric heater for heating the solid-liquid mixture (hereinafter referred to as slurry) in the neutralization reaction tank 10. 14 and a liquid level gauge 15 for measuring the liquid level of the slurry in the neutralization reaction tank 10 are installed. In addition, a bottom pipe 16a is attached to the bottom of the neutralization reaction tank 10, and the slurry can be extracted from the neutralization reaction tank 10 by a bottom pump 16 including, for example, a slurry pump. The bottom pipe 16a branches into a return pipe 17a and an extraction pipe 18a, and the return pipe 17a plays a role of returning the slurry to the neutralization reaction tank 10. The extraction pipe 18a is connected to the filter press 30 with the extraction valve 18 interposed, and the extraction valve 18 extracts the slurry continuously from the neutralization reaction tank 10 to the outside of the system. Serves as a means of exit. The return pipe 17a is provided with a sampling pot 17 provided with a thermometer 19 for measuring the temperature of the slurry and a pH meter 20 for measuring the pH of the slurry.

  The purification apparatus further includes a control unit 21, and the pH meter 20, the sodium hydroxide supply valve 11, and the etching waste liquid supply valve 12 are connected to the control unit 21 through signal lines 22 to 24. Yes. The control unit 21 transmits an opening / closing instruction to the sodium hydroxide supply valve 11 and the etching waste liquid supply valve 12 based on the instruction value of the pH meter 20, and the pH of the slurry is in the range of, for example, 3.5 to 7.0. It plays a role of performing control to increase / decrease the supply amount of the sodium hydroxide aqueous solution and the etching waste liquid so as to be a predetermined value of, 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 and extracts the slurry so that the liquid level of the slurry in the neutralization reaction tank 10 becomes constant. It also has a function to perform control. The thermometer 19 and the heater 14 are connected to a controller (not shown), and the controller controls the temperature of the slurry in the neutralization reaction tank 10 to be a predetermined temperature. .

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

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

  The re-dissolution tank 40 is connected to the hydrochloric acid tank 4 via a hydrochloric acid supply pipe 40a, and can receive a predetermined amount of hydrochloric acid 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 liquid having a low concentration of calcium or barium is available, the solid content may be redissolved by using this instead of hydrochloric acid.

  Further, the re-dissolution tank 40 is further provided with a mixer 41 for mixing the solid content and hydrochloric acid, and a liquid level gauge 42 for measuring the level of the re-dissolution liquid in the re-dissolution tank 40. A bottom pipe 43 a 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 43a branches into a return pipe 44a and an extraction pipe 45a, and the return pipe 44a plays a role of returning the redissolved liquid to the redissolving tank 40.

  The extraction pipe 45a is connected to the purified copper chloride solution tank 5 with the extraction valve 45 interposed, and the extraction valve 45 continuously converts the re-dissolved liquid as a purified copper chloride solution. It fulfills the payout function. At this time, the extraction valve 45 and the liquid level gauge 42 are connected to a controller (not shown) via a signal line 46, so that 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, and the redissolved solution may be diluted to a certain concentration with water, and the adjusted copper chloride solution may be dispensed.

  By coordinating the functions of the devices described above, the purification apparatus can execute the etching waste solution neutralization step, the slurry solid-liquid separation step, and the solid re-dissolution step in parallel. Become. Thereby, it becomes possible to process the etching waste liquid continuously and to discharge the purified copper chloride solution.

  Next, a second embodiment of the copper chloride solution purifying apparatus will be described. FIG. 3 shows an example of a batch type copper chloride solution purifier. The neutralization reaction tank 10 and its peripheral devices in the apparatus have substantially the same configuration as that shown in FIG. However, a point provided with water supply means (not shown), a point not having a return pipe 17a for returning the extracted slurry to the neutralization reaction tank 10, and a mother liquor after the slurry is settled and separated are neutralized. The first is that a mother liquor extraction pipe 16b is drawn out from the side surface of the tank 10, and a thermometer 19 and a pH meter 20 are directly attached to the neutralization reaction tank 10 instead of the sampling pot 17. This is different from the embodiment. For convenience, the liquid level gauge 15 is not shown in FIG.

  The control unit 21 is connected to each device such as the sodium hydroxide supply valve 11 and the etching waste liquid supply valve 12 and has a role of executing sequence control related to the operation of the neutralization reaction tank 10. Hereinafter, the contents of the control executed by the control unit 21 will be described. First, the control unit 21 closes the on-off valves provided in the bottom pipe 16a and the mother liquor extraction pipe 16b, and uses a water supply means (not shown) to put a predetermined amount in the neutralization reaction tank 10. The mixer 13 is turned on, and the heater 14 is used to heat to a predetermined temperature. Next, as shown in FIG. 3A, the controller 21 opens the etching waste liquid supply valve 12 and starts supplying the etching waste liquid. Here, the control unit 21 monitors the pH of the solution in the neutralization reaction tank 10 using the pH meter 20, and the pH value is, for example, a predetermined value from 3.5 to 7.0 (for example, 4.0). Until only the etching waste liquid is supplied. In FIG. 3, the open supply valves 11, 12 are marked with “O”, and the closed valves are blacked out and marked with “S”.

  When the pH of the solution in the neutralization reaction tank 10 reaches a predetermined value, the controller 21 opens the sodium hydroxide supply valve 11 and starts supplying the sodium hydroxide aqueous solution, as shown in FIG. Then, neutralization of the etching waste liquid is started. And the opening degree of the sodium hydroxide supply valve 11 and the etching waste liquid supply valve 12 is adjusted, and the pH of the solution in the neutralization reaction tank 10 is maintained at a predetermined value of, for example, 3.5 to 7.0. Thus, the supply amount of the etching waste liquid and the sodium hydroxide aqueous solution is controlled. By these operations, the slurry generated by the neutralization reaction between the etching waste liquid and the sodium hydroxide aqueous solution is stored in the neutralization reaction tank 10.

  As a result of prior experiments, the inventor mixed the etching waste liquid and the aqueous sodium hydroxide solution under such conditions, and compared with the case where the neutralization was performed under other conditions, the slurry was filtered with the mother liquor and the solid content. It is easy to separate. This is because, for some reason, the particle size of the solid content to be generated becomes larger than in the case where an aqueous sodium hydroxide solution is added to the neutralization reaction tank 10 in which the etching waste liquid is previously spread. it is conceivable 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 brought to a predetermined pH. A method of supplying a sodium hydroxide aqueous solution so that the value does not fluctuate greatly after adjustment is adopted.

  Next, when the slurry in the neutralization reaction tank 10 reaches a certain amount, the control unit 21 closes the sodium hydroxide supply valve 11 and the etching waste liquid supply valve 12 as shown in FIG. And the sodium hydroxide aqueous solution are 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 opening / closing valve of the mother liquor extraction pipe 16b, discharges the supernatant in the neutralization reaction tank 10 as a mother liquor to an unshown post-treatment device, and then settles to the bottom of the neutralization reaction tank 10. The slurry is extracted toward a filter press (not shown). Thereafter, the apparatus for solid-liquid separation of the slurry and the apparatus for re-dissolving the solid content with hydrochloric acid are substantially the same as those described in FIG. In these devices, the slurry and solid content may be processed in batches, or may be processed continuously after a certain amount is accumulated.

  In FIG. 3, the case where the control unit 21 performs sequence control of a series of operations for neutralizing the etching waste liquid has been described as an example. However, a part or all of the above operations may be manually performed by a human. In this case, since the instrumentation installed in the apparatus can be reduced, the equipment cost can be reduced.

  Moreover, in embodiment, although the case where the copper chloride etching waste liquid (copper chloride solution) was refine | purified was demonstrated as an example of a copper salt solution, the copper salt solution refine | purified by this invention is not limited to what was illustrated. For example, the present invention can also be applied to a copper salt solution such as a copper sulfate solution that is a plating waste solution of a printed board.

(Experiment 1)
The influence of the pH during the neutralization reaction on the copper yield and the impurity removal rate was evaluated.
(Example 1-1)
500 g of etching waste liquid is put in advance in an experimental level apparatus (2 L beaker) that executes the neutralization step in a batch mode, and stirred at 70 ° C. Thereto, an aqueous sodium hydroxide solution was supplied at a constant supply rate using a tube pump while monitoring the pH of the solution. Then, when the pH of the solution reached a predetermined value (target value), the supply of the aqueous sodium hydroxide solution was stopped. Then, stirring was continued for 30 minutes, and the solid content obtained by solid-liquid separation of the obtained slurry by suction filtration was washed with water. Table 1 shows the experimental conditions.

(Table 1)
Experimental conditions of (Example 1-1)

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

(Table 2)
Effect of pH target on copper yield and calcium and barium removal rates

(Example 1-2, Comparative example 1-3)
Etching waste liquid was neutralized in the same manner as in Example 1-1 except that the pH target values were set to 5.0 and 7.0, respectively.

(Consideration of Experiment 1)
(Table 2) shows that the higher the pH target value, that is, the higher the amount of aqueous sodium hydroxide 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 that these impurities are mixed in the solid content. However, with respect to calcium, a removal rate of about 90% or more is maintained within a pH target value range of 4.0 to 7.0. Moreover, about barium, it 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 about half of the barium is removed even when the pH target value becomes 7.0. Is done. From the above, it can be said that by neutralizing the etching waste liquid, the yield of copper is 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 liquid and the aqueous sodium hydroxide solution on the filterability (ease of solid-liquid separation) of the slurry was evaluated.
(Example 2-1)
In an experimental level apparatus (3 L beaker) corresponding to the apparatus shown in FIG. 3, 1,000 g of ion-exchanged water is spread in advance and heated to 70 ° C. and stirred. The etching waste liquid was supplied there, and when the pH reached the target value, the supply of the sodium hydroxide aqueous solution (10 wt%) was started at a constant flow rate (8 mL / min) while the supply of the etching waste liquid was continued. 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 sodium hydroxide aqueous solution was stopped. Thereafter, stirring was continued for 1 hour while maintaining the temperature condition, heating was stopped, and the resulting slurry was allowed to stand overnight. 400 mL 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 suction filtered to obtain a predetermined amount of mother liquor was measured and used as an index for evaluating 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 and Sodium Hydroxide Solution on Slurry Filterability

(Comparative Example 2-1)
Into a 1 L beaker, 400 g of etching waste liquid is put in advance and heated to 70 ° C. and stirred. Thereto, an aqueous sodium hydroxide 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 the same as in (Example 2-1). Thereafter, stirring was continued for 30 minutes while maintaining the temperature condition, heating was stopped, and the resulting slurry was allowed to stand overnight. A suction filtration experiment similar to (Example 2-1) was performed on 400 mL of the slurry thus obtained.

(Consideration of Experiment 2)
From (Table 4), while adjusting the pH value to be constant as in (Example 2-1), the slurry obtained by mixing the etching waste liquid and the aqueous sodium hydroxide solution little by little is ( The time required for filtration is about 30 times shorter than the slurry obtained by adding the aqueous sodium hydroxide solution to the etching waste liquid filled in the container as in Comparative Example 2-1) until the predetermined pH is reached. It can be seen that the solid-liquid separation property is good and it is advantageous in an actual process for handling 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)
Except that the temperature at the time of mixing was 40 ° C., a suction filtration experiment similar to (Example 2-1) was performed using a slurry obtained by a method substantially similar to (Example 2-1). The results are shown in (Table 5). In Table 5, the results of Examples 3-2 to 3-3 and Comparative Examples 3-1 to 3-2 are also shown.

(Table 5)
Effect of mixing temperature on slurry filterability

(Examples 3-2 and 3-3)
A suction filtration experiment was performed using the slurry obtained under the same conditions as in Example 1-1 except that the temperature during mixing was 50 ° C. and 70 ° C., respectively.
(Comparative Examples 3-1, 3-2)
A suction filtration experiment was performed using the slurry obtained under the same conditions as in Example 1-1 except that the temperature during mixing was 20 ° C. and 30 ° C., respectively.

(Consideration of Experiment 3)
From Table 5, it can be seen that the higher the temperature when mixing 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, the case where mixing is performed in a temperature range of 40 ° C. or higher, in which half of a 400 mL slurry can be filtered in about 3 minutes, achieves the target value of the present inventors.

  As described above, according to the embodiment of the present invention, when the etching waste liquid and an alkali such as an aqueous sodium hydroxide solution are mixed so that the pH is in the range of 3.5 to 7.0, for example, A solid-liquid mixture (slurry) in which a solid content containing copper in dicopper and a liquid content containing impurities such as calcium are mixed can be obtained. Thus, 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 at which the etching waste liquid and the alkali are mixed and neutralized is 40 ° C. or higher, it is possible to generate a solid-liquid mixture that is easily separated into solid and liquid by a filter or the like. As a result, for example, when solid-liquid separation is industrially performed using a filter press or the like, the filter is less likely to be clogged, thereby reducing pressure loss and reducing power consumed by a pump or the like. it can.

  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 a target range. Can be purified.

  In addition, in a refining device that performs batch-type neutralization, neutralization is performed so that the pH value falls within the target range while mixing the etching waste liquid and alkali in small amounts in a neutralized reaction tank filled with water. . It has been experimentally found that the slurry obtained by this method can be easily separated into a solid and a liquid as compared with a slurry obtained by adding alkali to a reaction tank filled with etching waste liquid, for example. For this reason, it is possible to reduce the power consumed in the subsequent solid-liquid separation step. In the case of a purifier that continuously neutralizes the etching waste liquid, the same effect can be obtained because the neutralization is performed so that the pH value falls within the target range.

It is a flowchart explaining the purification method of the copper chloride solution which concerns on this invention. It is a block diagram which shows an example of the refiner | purifier of the copper chloride solution which concerns on 1st Embodiment. It is explanatory drawing which shows the operation procedure of the neutralization reaction tank of the refiner | purifier of the copper chloride solution which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sodium hydroxide tank 2 Etching waste liquid tank 3 Post-processing apparatus 4 Hydrochloric acid tank 5 Purified copper chloride solution tank 10 Neutralization reaction tank 11 Sodium hydroxide supply valve 11a Sodium hydroxide supply pipe 12 Etching waste liquid supply valve 12a Etching waste liquid supply pipe 13 Mixer 14 Heater 15 Level gauge 16 Bottom pump 16a Bottom piping 16b Mother liquor extraction piping 17 Sampling pot 17a Return piping 18 Extraction valve 18a Extraction piping 19 Thermometer 20 pH meter 21 Controllers 22 to 26
Signal line 30 Filter press 30a Solid content conveyance path 30b Mother liquor pipe 40 Redissolving tank 40a Hydrochloric acid supply pipe 41 Mixer 42 Level gauge 43 Bottom pump 43a Bottom pipe 44a Return pipe 45 Extraction valve 45a Extraction pipe 46 Signal line

Claims (9)

Neutralizing the copper salt solution with alkali so that the pH is in the range of 3.5 to 5.0, and obtaining a solid-liquid mixture;
A solid-liquid separation step for solid-liquid separation of the solid-liquid mixture into a solid containing copper and a liquid containing calcium;
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, and a method for purifying a copper salt solution. Neutralizing the copper salt solution with alkali so that the pH is in the range of 3.5 to 5.0, and obtaining a solid-liquid mixture;
A solid-liquid separation step for solid-liquid separation of the solid-liquid mixture into a solid content containing copper and a liquid content containing barium;
A re-dissolution step of re-dissolving the solid content in an inorganic acid to obtain a copper salt solution from which barium has been removed, and a method for purifying a copper salt solution. The said neutralization process is performed in the temperature range in which the said solid-liquid mixture becomes 40 degreeC or more, The purification method of the copper salt solution of Claim 1 or 2 characterized by the above-mentioned. The said copper salt solution is a copper chloride etching waste liquid, The purification method of the copper salt solution as described in any one of Claim 1 thru | or 3 characterized by the above-mentioned. A neutralization reactor,
Solution supply means capable of continuously supplying to the neutralization reaction tank while increasing or decreasing the supply amount of the copper salt solution;
Alkali supply means capable of continuously supplying to the neutralization reaction tank while increasing or decreasing the supply amount of alkali;
PH measurement means for measuring the pH of the solid-liquid mixture which is a reaction product in the neutralization reaction tank;
Extraction means for continuously extracting the solid-liquid mixture from the neutralization reaction tank;
The measurement result of the pH measurement means is 3.5 to 5 through at least one of the solution supply means and the alkali supply means. Control means for performing control to increase or decrease the supply amount of at least one of the copper salt solution and the alkali so as to be within a range of 0;
Solid-liquid separation means for solid-liquid separation of the solid-liquid mixture extracted from the neutralization reaction tank by the extraction means into a solid content containing copper and a liquid content containing calcium;
And a re-dissolution means for obtaining a copper salt solution from which calcium has been removed by re-dissolving the solid content in an inorganic acid. 6. The copper salt according to claim 5 , wherein barium is contained in the liquid component that is solid-liquid separated by the solid-liquid separation means, and barium is removed from the copper salt solution obtained by the re-dissolution means. Solution purification equipment. A neutralization reactor,
Solution supply means capable of continuously supplying to the neutralization reaction tank while increasing or decreasing the supply amount of the copper salt solution;
Alkali supply means capable of continuously supplying to the neutralization reaction tank while increasing or decreasing the supply amount of alkali;
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;
The neutralization reaction tank is filled with water in advance, and then the pH of the solution in the neutralization reaction tank is 3.5 to 5 . Control for controlling the supply amount of at least one of the copper salt solution and the alkali so that the copper salt solution is supplied until it falls within the range of 0, and then the pH of the solution maintains a value within the range. Means,
Solid-liquid separation means for solid-liquid separation of the 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;
And a re-dissolution means for obtaining a copper salt solution from which calcium has been removed by re-dissolving the solid content in an inorganic acid. The apparatus for purifying a copper salt solution according to any one of claims 5 to 7 , further comprising temperature adjusting means for adjusting the solution in the neutralization reaction tank to a temperature of 40 ° C or higher. . The alkali is sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, claims 1, characterized in that it is selected from the alkali group consisting of sodium hydrogen carbonate or potassium hydrogen carbonate 4 The method for purifying a copper salt solution according to any one of the above.

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