JP2020019978A - Method for stopping treatment of iron chloride-based etching waste liquid - Google Patents

Abstract

To provide a method for stopping a treatment of an iron chloride-based etching waste liquid, which can easily and quickly stop and restart the regeneration treatment of an iron chloride-based etching waste liquid.SOLUTION: There is provided a method for stopping a treatment of an iron chloride-based etching waste liquid, in which the method stops temporarily the treatment performed by supplying the iron chloride-based etching waste liquid containing a metal ion having a smaller ionization tendency than iron and iron powder to a treatment tank equipped with stirring means and mixing them, thereby reacting the metal ion and the iron powder to reduce the metal ion to precipitate metal, including the steps of: (1) adjusting an amount of iron powder in a treatment tank to an amount capable of resuming stirring by the stirring means; (2) stopping supply of the iron chloride-based etching waste liquid and the iron powder; and (3) taking out a part of the iron powder treatment liquid in the treatment tank from an upper part of the treatment tank and circulating and supplying it to the bottom of the treatment tank.SELECTED DRAWING: None

Description

  The present invention relates to a method for stopping a process for removing a metal ion from an iron chloride-based etching waste liquid containing a metal ion having a smaller ionization tendency than iron in a state where the process can be restarted simply and quickly.

Conventionally, for lead frames and shadow masks for ICs and LSIs, for example, plate-like materials made of copper, iron-nickel alloy material and the like have been used, and these plate-like materials are etching solutions containing a large amount of ferric chloride. It is manufactured by partial corrosion treatment.
As a result of the etching treatment, ferric chloride contained in the etching solution is reduced to ferrous chloride, and the concentration of ferric chloride is reduced, thereby lowering the etching efficiency. Have been done.
The etching waste liquid, which is the waste liquid after the etching treatment, contains a considerable amount of metal ions having a lower ionization tendency than iron, such as copper ions and nickel ions, in addition to high-concentration iron ions. By removing metal ions having a smaller ionization tendency than the iron from the etching waste liquid and oxidizing the ferrous chloride, an etching liquid that can be reused can be obtained.
For example, Patent Documents 1 and 2 disclose mixing iron powder into an iron chloride-based etching waste liquid containing a metal ion having a smaller ionization tendency than iron, reacting the iron powder with the metal ion, reducing the metal ion, and converting the metal. It describes a method for regenerating an iron chloride-based etching waste liquid in which a treatment liquid is obtained by precipitation and removal, and then the obtained treatment liquid is oxidized.

JP-A-11-12768 JP 2000-199086 A

The method for regenerating an iron chloride-based etching waste liquid described in Patent Documents 1 and 2 is a method on the premise that the regenerating process is performed continuously, and corresponds to a case where the processing amount of the iron chloride-based etching waste liquid decreases. There was a drawback that it was difficult to do.
Specifically, when the supply of iron chloride-based etching waste liquid to the processing tank is reduced and the regeneration process is temporarily suspended, simply putting the iron chloride-based etching waste liquid or iron powder into the processing tank will stop the process. Since hydrogen ions have a smaller ionization tendency than specific ions (eg, nickel ions) among metal ions contained in the iron-based etching waste liquid, hydrogen ions are reduced at the same time when the metal ions are reduced, and hydrogen gas is reduced. This causes a problem that the pH of the liquid in the processing tank rises. Further, there is a problem that harmful iron hydroxide is generated with the rise of the pH.
Further, by stopping the stirring of the processing tank, iron powder having a large specific gravity sinks and accumulates at the bottom of the processing tank. Therefore, when a stirrer is used as the stirring means, there is a concern that the stirrer is buried in the iron powder, and a large amount of energy is required when the regeneration treatment of the iron chloride-based etching waste liquid is restarted, or that the stirrer is damaged. was there.
Furthermore, during the regeneration process, a part of the iron powder processing liquid in the processing tank is taken out from the upper part of the processing tank and circulated and supplied to the bottom part of the processing tank, also serving as stirring, in order to increase the reaction efficiency. However, if the stirring stops and the iron powder accumulates on the bottom of the processing tank, the inlet for supplying the removed iron powder processing liquid to the bottom of the processing tank may be blocked, making supply difficult. .

  For this reason, conventionally, when the regeneration treatment is temporarily suspended, the iron chloride-based etching waste liquid, iron powder, and iron powder treatment liquid in the treatment tank are all discharged. Was re-introduced into the processing tank, and the regeneration processing conditions such as the pH of the liquid in the processing tank and the oxidation-reduction potential ORP (Oxidation-Reduction Potential) had to be readjusted, which required a great deal of trouble.

  An object of the present invention is to stop the processing of the iron chloride-based etching waste liquid, discharge the iron chloride-based etching waste liquid, iron powder, and iron powder processing liquid present in the processing tank, and to restart the processing. It is another object of the present invention to provide a method for stopping an iron chloride-based etching waste liquid treatment that does not require readjustment of the regenerating treatment conditions and that can easily and promptly interrupt and restart the regeneration processing of the iron chloride-based etching waste liquid.

  The present inventors have conducted intensive studies and found that the above-mentioned problems can be solved by the following means.

[1]
In a treatment tank provided with a stirring means, an iron chloride-based etching waste liquid containing a metal ion having a smaller ionization tendency than iron and iron powder are supplied and stirred to cause the metal ion and the iron powder to react with each other, thereby A method of stopping the treatment of an iron chloride-based etching waste liquid, which stops the treatment of an iron chloride-based etching waste liquid that reduces metal ions and precipitates a metal,
(1) Adjusting the amount of iron powder in the processing tank to an amount at which stirring by the stirring means can be restarted. (2) Stopping the supply of the iron chloride-based etching waste liquid and the iron powder. (3) A method for stopping treatment of an iron chloride-based etching waste liquid, comprising a step of taking out a part of an iron powder treatment liquid in the treatment tank from an upper part of the treatment tank and circulating and supplying it to a bottom part of the treatment tank.
[2]
The stirring means is a stirring means by a stirrer,
(4) The method for stopping the treatment of the iron chloride-based etching waste liquid according to [1], including a step of stopping the stirrer.
[3]
The method for stopping treatment of an iron chloride-based etching waste liquid according to [1] or [2], wherein the metal ion is a nickel ion.

  ADVANTAGE OF THE INVENTION According to this invention, the stop method of the iron-chloride-based etching waste liquid processing which can interrupt | interrupt and restart the reproduction | regeneration processing of the iron-chloride-based etching waste liquid easily and quickly can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual structure explanatory drawing of one aspect of the iron-chloride-based etching waste liquid treatment equipment to which the method for stopping the regeneration treatment of the iron-chloride-based etching waste liquid of the present invention is applied. It is a cross section of an example of a processing tank. FIG. 3 is a schematic cross-sectional view showing an example of a processing tank during regeneration processing (R) and processing stop (S).

The present invention
In a treatment tank provided with a stirring means, an iron chloride-based etching waste liquid containing a metal ion having a smaller ionization tendency than iron and iron powder are supplied and stirred to cause the metal ion and the iron powder to react with each other, thereby A method for stopping the treatment of the iron chloride-based etching waste liquid, which temporarily stops the treatment of reducing the metal ions to precipitate the metal,
(1) Adjusting the amount of iron powder in the processing tank to an amount at which stirring by the stirring means can be restarted. (2) Stopping the supply of the iron chloride-based etching waste liquid and the iron powder. (3) The present invention relates to a method for stopping the processing of an iron chloride-based etching waste liquid, comprising a step of taking out a part of the iron powder processing liquid in the processing tank from the upper part of the processing tank and circulating and supplying it to the bottom of the processing tank.

(Treatment of iron chloride etching waste liquid)
First, treatment of an iron chloride-based etching waste liquid to which the stopping method of the present invention is applied will be described.
In the treatment (regeneration treatment) of the iron chloride-based etching waste liquid to which the method of stopping the treatment of the present invention is applied, the iron chloride-based etching waste liquid includes ferrous chloride (FeCl ₂ ) and ferric chloride (FeCl _3). ) Means an aqueous solution such as an etching waste liquid containing metal ions having a lower ionization tendency than iron such as copper and nickel due to the following reaction in the etching process.
2FeCl ₃ + Cu → 2FeCl ₂ + CuCl ₂
2FeCl ₃ + Ni → 2FeCl ₂ + NiCl ₂

  Note that the iron chloride-based etching waste liquid to which the method of the present invention is applied may be any as long as it contains metal ions having a lower ionization tendency than at least one type of iron. Therefore, it is not limited to the waste liquid itself generated after the etching treatment, but is subjected to a treatment for removing at least one kind of metal ion contained in the waste liquid, and still has a metal ion having a smaller ionization tendency than at least one kind of iron. What is necessary is just to include.

  The iron powder is, for example, powdered iron having a particle diameter of 44 to 250 μm, and includes a spherical shape, a porous shape, and the like, but is not limited thereto. Applicable to manufactured iron powder, iron powder obtained by grinding iron, and the like.

  The fluidized bed, which will be described later, is an area where the iron powder supplied into the processing tank is balanced by its own gravity and viscous resistance due to the flow supplied from the lower part, and floats and flows in a certain space with a high density of iron powder. Say.

  The iron powder treatment liquid is mainly composed of an aqueous solution in which metal ions that have a lower ionization tendency than iron such as copper and nickel that have passed through the fluidized bed and flowed out into the upper region have been reduced and removed. It is defined to include a small amount of, for example, about 20% by mass or less of powder, precipitated metal, and unreacted iron chloride-based etching waste liquid.

  In the regeneration treatment of the iron chloride-based etching waste liquid to which the present invention is applied, an iron chloride-based etching waste liquid containing a metal ion having a smaller ionization tendency than iron and iron powder are supplied to a treatment tank provided with stirring means and mixed. By reacting metal ions with iron powder to reduce the metal ions and obtain an iron powder treatment liquid in which the metal is deposited, regenerate an iron chloride etching waste liquid that removes the metal from the iron powder treatment liquid. Processing.

  As the stirring means provided in the processing tank, for example, a circulating device that takes out a part of the iron powder processing liquid from the upper part of the processing tank and circulates and supplies it to the bottom of the processing tank, a stirrer having a stirring blade, and the like, .

  From the viewpoint of increasing the degree of contact between the iron chloride-based etching waste liquid and the iron powder to increase the processing speed, it is preferable to provide the above-described circulation device as a stirring means. By taking out part of the iron powder processing liquid from the top of the processing tank and supplying it from the bottom, it forms a fluidized bed in which iron powder is dispersed and suspended without creating a dead space that does not contribute to the reaction in the processing tank Thus, the removal efficiency of metal ions having a lower ionization tendency than iron in the supplied iron chloride-based etching waste liquid can be increased.

  In addition, the circulating supply of the iron powder treatment liquid (step (3)) in the method of stopping the treatment of the present invention may be performed using the circulating device.

  It is also preferable that the stirring means include both the circulation device and the stirrer.

  Examples of the metal ion having a lower ionization tendency than iron include a copper ion and a nickel ion, and a nickel ion is preferable.

  That is, the treatment of the iron chloride-based etching waste liquid to which the treatment stopping method of the present invention is applied is performed by supplying an iron chloride-based etching waste liquid containing nickel ions to a treatment tank and iron powder, and mixing them. It is preferable to reduce the nickel ions by reacting the iron powder with the iron powder to remove nickel from the iron powder treatment liquid in which nickel is deposited.

  Hereinafter, with respect to a preferred embodiment of an iron chloride-based etching waste liquid treatment to which the stopping method of the present invention is applied, a conceptual configuration explanatory view of an iron chloride-based etching waste liquid treatment facility shown in FIG. 1 and a cross-sectional view of a processing tank shown in FIG. This will be described with reference to FIG.

The processing tank 119 shown in FIG. 2 is a processing tank provided in the denickelizer 14 shown in FIG. 1, and is used to supply and mix an iron chloride-based etching waste liquid and iron powder to reduce nickel ions. Processing tank.
A stirring blade 128a for stirring the supplied iron chloride-based etching waste liquid and the iron powder as necessary is provided inside the processing tank 119 and at a lower position, and the stirring blade 128a is rotationally driven above the stirring blade 128a. Motor 129 is provided. Further, a circulating device is provided which takes out the iron powder processing liquid 2E from the upper part of the processing tank 119 and supplies it by a circulating pump 126 to the lower part.
When the stirring blade 128a is not used, the stirring blade 128a can be removed from the processing tank 119.

The first partition portion 130, which is the uppermost portion of the processing tank 119, is a region formed of a straight cylindrical portion having a maximum horizontal cross-sectional area, and its upper end opening is open to the atmosphere. The iron powder 150 can be put into the inside.
A processing liquid inlet 145b is provided on the side wall of the fifth partition 134 so that the iron powder processing liquid 2E and the iron chloride etching waste liquid taken out from the upper part of the processing tank 119 are supplied to the processing tank 119. Has become.
Then, in the third to fifth compartments 132 to 134, as shown by hatching in FIG. 2, the iron powder supplied and the iron powder treatment liquid 2 </ b> E and the iron chloride-based etching waste liquid supplied from the lower part, A fluid bed with a high powder density is formed.
In the first and second compartments 130 and 131 having a low ascending flow speed, the descending speed of the iron powder is faster than the flow speed of the iron powder processing liquid, and therefore, the iron powder separating portion (free board) having an extremely small iron powder density. Is formed.

  The first partitioning section 130 and the second partitioning section 131 forming the iron powder separating section are provided with processing liquid partial outlets 145 and 145a, respectively, on the side walls, and the fifth partitioning forming the lower part of the fluidized bed. A processing liquid inlet 145b is provided on the side wall of the portion 134. The processing liquid partial outlets 145 and 145a and the processing liquid inlet 145b are connected to each other by a processing liquid circulation pipe 145d having a circulation pump 126 on the way. Therefore, by driving the circulating pump 126, the iron powder processing liquid 2E having a low iron powder content is respectively discharged from the first and second compartments 130 and 131 through the processing liquid partial outlets 145 and 145a. The iron powder treatment liquid 2E is taken out and then flows into the fifth partition 134 through the treatment liquid circulation pipe 145d and the treatment liquid inflow port 145b, thereby forming a self-circulating flow in the treatment tank 119. Fluidized beds are formed in the third to fifth compartments 132 to 134.

  In addition, the processing liquid discharge ports 145e and 145f are provided on the side walls of the first partition 130 and the second partition 131 forming the iron powder separating unit, respectively, and the iron powder processing liquid 2B is discharged.

  The above-mentioned reaction of reducing nickel ions by reacting nickel ions with iron powder is performed by changing the oxidation-reduction potential ORP and the hydrogen ion concentration coefficient pH of the iron powder treatment liquid in the treatment tank 119 measured by using a sensor. It is preferable that the circulating amount and the residence time of the powder treatment liquid are adjusted so as to be maintained in a predetermined range (ORP = -250 to -450 mV, pH = 1 to 3). Under the above conditions, the reduction treatment of nickel ions can be performed efficiently.

  The temperature of the iron powder treatment liquid in the treatment tank is preferably 50 ° C or higher, more preferably 70 to 80 ° C. By setting the temperature at 50 ° C. or higher, the reduction reaction of nickel ions proceeds. Further, by setting the temperature to 80 ° C. or lower, the material of the processing tank can be easily protected.

The reduction reaction of the nickel ions is a reaction represented by the following chemical reaction formula.
NiCl ₂ + Fe → FeCl ₂ + Ni ↓

  An iron powder treatment liquid obtained by reacting nickel ions and iron powder in a treatment tank, containing nickel precipitated, is discharged from the treatment tank and then contained using a liquid cyclone, a classifier, or the like. Iron powder, nickel, and other impurities are removed to obtain a nickel-removing solution containing a large amount of ferrous chloride (15 in FIG. 1). By supplying chlorine gas or blowing chlorine gas or by bubbling chlorine gas, a part or all of the contained ferrous ions is oxidized to ferric ions, whereby a regenerated etching solution 17 can be obtained.

The iron chloride-based etching waste liquid containing metal ions having a lower ionization tendency than iron is subjected to the nickel ion deposition and removal treatment in the above-described nickel removal apparatus 14 before being reduced in the iron chloride-based etching waste liquid in the reduction apparatus 12 shown in FIG. It is preferable to perform a treatment for reducing ferric ions to ferrous ions.
In the reduction device 12, the iron chloride-based etching waste liquid is brought into contact with iron powder in a fluidized state, and the ferric ions in the liquid can be reduced to ferrous ions by elution of iron, that is, ionization of iron.

  The reduction reaction of ferric ion is preferably performed under the condition of pH = 2 or less and oxidation-reduction potential ORP = −350 to +700 mV. The lower limit of the pH is preferably a negative value measured by a pH meter.

In the case where the copper chloride ion is contained in the iron chloride-based etching waste liquid in addition to the nickel ion, a part or all of the copper ion is reduced by the reduction device 12 and at the same time, the reduction of the ferric ion is performed. Then, the remaining nickel ions can be reduced in the next nickel removing device 14 so that copper and nickel can be separated from each other.
Further, a copper removal device may be provided between the reduction device 12 and the nickel removal device 14.

  The copper ions are reduced by contacting the iron chloride-based etching waste liquid with iron powder in a fluidized state under conditions of pH = 3 or less and oxidation-reduction potential ORP = -250 to -450 mV, and reacting the iron powder with copper ions. Is preferred. The lower limit of the pH is preferably a negative value measured by a pH meter.

The reduction reaction of ferric ion and copper ion is a reaction represented by the following chemical reaction formula.
2FeCl ₃ + Fe → 3FeCl ₂
CuCl ₂ + Fe → FeCl ₂ + Cu ↓

(How to stop the treatment of iron chloride-based etching waste liquid)
The method of stopping the treatment of the iron chloride-based etching waste liquid of the present invention includes:
(1) Adjusting the amount of iron powder in the processing tank to an amount at which stirring by the stirring means can be restarted. (2) Stopping the supply of the iron chloride-based etching waste liquid and the iron powder. (3) A step of taking out a part of the iron powder processing solution in the processing tank from the upper part of the processing tank and circulating and supplying it to the bottom of the processing tank.

  In the step (3), the flow rate of the iron powder treatment liquid to be circulated is such that the reaction between the metal ions and the iron powder does not occur, and the iron powder treatment liquid taken out from the upper part of the treatment tank is used. It is preferable that the flow rate is such that the processing liquid inlet for supplying the part to the processing tank does not block the processing liquid inlet.

When the stirring means is a stirrer, the stopping method of the present invention further comprises:
(4) It is preferable to include a step of stopping the stirrer.

In the stopping method according to the present invention, the order of the steps (1) to (3) does not matter.
When the stopping method according to the present invention includes the step (4), the order of the steps (1) to (4) does not matter.

  The supply of the iron chloride-based etching waste liquid and the iron powder is stopped, the circulation flow rate of the iron powder treatment liquid is adjusted, and, if a stirrer is provided as a stirring means, the stirrer is stopped to obtain an iron powder having a large specific gravity. Settles down and accumulates at the bottom of the treatment tank. As a result, a fluidized bed in which the iron powder is dispersed and suspended is not formed, and the reaction between the iron chloride-based etching waste liquid and the iron powder stagnates, causing an increase in the pH of the iron powder treatment liquid in the processing tank and generation of harmful iron hydroxide. Can be suppressed. That is, the regeneration treatment can be simply interrupted without discharging the iron chloride-based etching waste liquid, iron powder, and iron powder treatment liquid in the treatment tank. Further, it is not necessary to readjust the processing conditions such as the pH and the ORP when the regeneration processing is restarted.

However, as described above, since iron powder accumulates at the bottom of the processing tank, a part of the iron powder processing liquid taken out from the top of the processing tank may be circulated and supplied to the bottom of the processing tank depending on the adjusted circulation flow rate. There is a concern that the processing liquid inflow port is blocked and a large amount of energy is required when the regeneration process is restarted, or the regeneration process cannot be restarted.
In addition, when a stirrer is provided, depending on the structure of the processing tank and the stirrer, the stirrer may be buried in the accumulated iron powder, requiring a large amount of energy at the time of resuming the regeneration process, or damaging the stirrer. There is.

Therefore, the method for stopping the treatment according to the present invention includes a step (step (1)) of adjusting the amount of the iron powder in the treatment tank to an amount capable of restarting the stirring by the stirring means (that is, the circulation device or the stirrer). And a step (step (3)) of adjusting the circulation flow rate to a flow rate at which the processing liquid inlet is not blocked.
As a result, the above-mentioned concerns are resolved, and the reproduction process can be quickly resumed.

  As a method of adjusting the amount of iron powder in the treatment tank in the step (1), for example, the amount of iron powder is adjusted in advance to an amount capable of restarting the stirring, and then the iron chloride-based etching waste liquid is regenerated. And a method in which iron is consumed to a desired amount by a reaction between metal ions and iron. Specifically, the components of the liquid are analyzed, and the amount of iron powder added is calculated based on the values.

  Here, the amount at which stirring by the stirring means can be restarted is an amount that does not block the processing liquid inlet in the circulation device, and an amount that does not bury the stirrer in the iron powder in the stirrer. The amount of these iron powders depends on the size of each device, but if it is a normal industrial scale, it is preferably 4 to 5 tons without any problem if it is up to about 10 tons.

In the step (3), the flow rate of the iron powder treatment liquid to be circulated is such that the reaction between the metal ions and the iron powder does not occur, and a part of the iron powder treatment liquid taken out from the upper part of the treatment tank. It is preferable that the flow rate is such that the processing liquid inlet for supplying the processing tank does not block.
The specific flow rate depends on the size and shape of the processing tank used, but is preferably ^{3 to} 7.5 m ³ / h. By setting the flow rate to ³ m ³ / h or more, it is possible to avoid closing the processing liquid inlet at the bottom of the stirring tank. In addition, when the content is 7.5 m ³ / h or less, a fluidized bed in which the iron powder is dispersed and suspended is not formed, and the treatment liquid and the iron powder come into contact with each other, so that the reaction can be prevented from proceeding.

  FIG. 3 is a diagram schematically illustrating a cross section of the processing tank during the regeneration processing and a cross section of the processing tank during the stop of the processing to which the method of stopping the processing of the present invention is applied. During the regeneration treatment, as shown in (R), the iron powder fluidized bed (X) is formed by the circulating device of the treatment tank 119 and the stirring means such as the stirring blade 128a. By applying (1), as shown in (S), iron powder is deposited on the bottom of the processing tank to form an iron powder deposited layer (Y), so that the reaction between iron and metal ions can be suppressed. Further, the iron powder deposited layer (Y) does not hinder the restart of stirring by the stirring blade 128a. Further, since the circulation of the iron powder treatment liquid 2E is maintained by the circulation pump 126, the treatment liquid inlet 145b is not blocked.

  Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples.

(Example 1)
A method for stopping the treatment of an iron chloride-based etching waste liquid according to an embodiment of the present invention will be described in detail below with reference to FIGS.

First, the processing tank 119 used in the first embodiment will be described.
As shown in FIG. 2, the processing tank 119 has a volume of 17 m ³ , which is composed of five regions of a first partition 130 to a fifth partition 134 each having a different horizontal cross-sectional area in the vertical direction, and has a maximum inner diameter. Is a reaction vessel of about 3.2 m, and can hold about 21 tons of iron powder for etching waste liquid treatment.
Each member included in the processing tank 119 is as described above.

(Iron chloride-based etching waste liquid treatment)
The iron chloride-based etching waste liquid and the iron powder were continuously supplied to the processing tank 119 shown in FIG.
As the iron powder, an iron powder having a particle size of 44 to 250 μm was used.
In addition, a shadow mask, a lead frame, or the like is etched into the iron chloride-based etching waste liquid to reduce the concentration of ferric chloride (FeCl ₃ ) in the liquid and to contain an aqueous solution containing metal ions of copper and nickel. Is brought into contact with iron powder in a fluidized state to reduce ferric ions to ferrous ions and, at the same time, to reduce copper ions. Using.

The iron chloride-based etching waste liquid and the iron powder were supplied to the treatment tank 119 to reduce nickel ions.
The pH of the iron powder treatment liquid in the treatment tank in the reduction reaction of nickel ions was 1 to 3, the oxidation-reduction potential was −440 to −250 mV, and the temperature was 50 to 80 ° C.
The circulating flow rate was 7.2 m ³ / h, and the input amount of the iron chloride-based etching waste liquid was 6 m ³ / h at the maximum.

(Stop iron chloride etching waste liquid treatment)
Next, the supply of the iron chloride-based etching waste liquid and the iron powder to the processing tank 119 during the processing operation was stopped, and the stirring blade 128a was stopped.
The circulation flow rate of the iron powder treatment liquid 2E was set to 7.2 m ³ / h.
The amount of iron powder was calculated by analyzing the liquid components and calculating the required amount.

  Twelve hours after the stop operation, the treatment of the iron chloride-based etching waste liquid was restarted. The processing liquid inlet 145b was not blocked by the iron powder, and the stirring blade 128a was not buried in the iron powder, and the processing could be resumed without any problem.

The pH of the iron powder treatment liquid in the treatment tank at the time of restart was 1.5 to 2.5, and the temperature of the liquid at 70 ° C. dropped to 55 ° C. The pH and oxidation-reduction potential were almost unchanged from before the stop operation. Further, the temperature is maintained at a temperature at which the reduction reaction of nickel can proceed, and the process can be easily restarted without having to readjust conditions such as pH, oxidation-reduction potential, and temperature when the operation is restarted. .
The amount of iron hydroxide was 22000 ppm, which was not a problem (generally, a problem may occur if it exceeds 35000 ppm).

DESCRIPTION OF SYMBOLS 11 Iron-chloride etching waste liquid 12 Reduction device 13 Reduced iron chloride aqueous solution 14 Nickel removal device 15 Nickel removal treatment solution 16 Chlorine treatment device 17 Etching solution 119 Treatment tank 126 Circulation pump 128a Stirrer blade 129 Motor 130 1st section 131 Second section Part 132 Third partition part 133 Fourth partition part 134 Fifth partition part 145 Partial outlet for processing liquid 145a Partial outlet for processing liquid 145b Inlet 145d Processing liquid circulation pipe 145e Processing liquid outlet 145f Processing liquid outlet 146a Discharge pipe 147 Supply pipe for iron chloride-based etching waste liquid 150 Iron powder 1B Copper removal treatment liquid (iron chloride-based etching waste liquid)
2A Fluidized bed of iron powder (slurry)
2B Iron powder treatment liquid 2E Iron powder treatment liquid X Iron powder fluidized bed Y Iron powder deposition layer

Claims (3)

In a treatment tank provided with a stirring means, an iron chloride-based etching waste liquid containing a metal ion having a smaller ionization tendency than iron and iron powder are supplied and stirred to cause the metal ion and the iron powder to react with each other, thereby A method of stopping the treatment of an iron chloride-based etching waste liquid, which stops the treatment of an iron chloride-based etching waste liquid that reduces metal ions and precipitates a metal,
(1) Adjusting the amount of iron powder in the processing tank to an amount at which stirring by the stirring means can be restarted. (2) Stopping the supply of the iron chloride-based etching waste liquid and the iron powder. (3) A method for stopping treatment of an iron chloride-based etching waste liquid, comprising a step of taking out a part of an iron powder treatment liquid in the treatment tank from an upper part of the treatment tank and circulating and supplying it to a bottom part of the treatment tank. The stirring means is a stirring means by a stirrer,
(4) The method for stopping treatment of an iron chloride-based etching waste liquid according to claim 1, comprising a step of stopping the stirrer.   3. The method according to claim 1, wherein the metal ions are nickel ions.

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