JP2964440B2 - Treatment method of iron chloride solution containing nickel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an iron chloride solution containing nickel discharged from an etching step when a metal member made of nickel or a nickel alloy is processed with an etching solution containing ferric chloride as a main component. Hereinafter, it may be referred to as an etching waste liquid.) In particular, the present invention relates to a method of recovering and removing excess nickel and iron from the etching waste liquid and regenerating it as an etching liquid.

[0002]

2. Description of the Related Art In the manufacture of shadow masks used for cathode ray tubes and lead frames for electronic parts, a thin metal plate or metal foil made of nickel or a nickel alloy is used.
Processing into a desired fine pattern is performed using an etching solution containing ferric chloride as a main component. Therefore, in such an etching step, nickel or a nickel alloy is eluted into the etching solution as the etching proceeds, and the etching ability of the etching solution is reduced, and a large amount of etching waste liquid is generated. In addition to environmental pollution, the etching waste liquid is used to recover nickel or nickel alloy and iron in the waste liquid from the viewpoint of resource saving and economy, and to regenerate the etching waste liquid.

[0003] Regarding the method of regenerating the etching waste liquid, the present applicant has also previously disclosed Japanese Patent Application Nos. 5-26946 and 5-22.
No. 0114 proposes a method by electrolytic deposition. In the above method, a ferric chloride solution containing nickel, which is an etching waste liquid, is cooled to crystallize crystals containing ferric chloride as a main component, and further, the filtrate obtained by separating the crystals is subjected to electrolytic treatment, whereby the cathode side is removed. To precipitate an iron-nickel alloy, electrolytic oxidation of ferrous chloride contained in the solution to ferric chloride on the anode side, and contact of generated chlorine gas with an etching solution circulated in the etching process. Then, it is oxidized to ferric chloride and regenerated as an etching solution. According to the above method, the Ni / Fe ratio in the solution to be electrolyzed by crystallization is increased, and the conductivity of the solution is increased to reduce the power consumption in the electrolysis process. Since both components are effectively used for the regeneration of the etching solution, they are extremely economically advantageous.

[0004]

However, in the above-described method using both crystal crystallization and electrolysis, a high-temperature (about 60 ° C.) processing solution must be cooled to a low temperature of about 0 ° C. to 2 ° C. during crystallization. Therefore, the load on the cooling device is large and there is a problem in economy. Also in the electrolysis step, the Ni / Fe ratio in the filtrate after the crystal separation is determined by the Ni / Fe of the metal to be recovered.
Since the Fe ratio cannot be increased, the trivalent iron is electrolytically reduced to divalent iron on the cathode side, and then the divalent iron is converted to trivalent iron again on the anode side in order to regenerate as an etching solution. It has to be oxidized, with wasteful power consumption which is a drawback of the electrolysis method.

Further, since the etching rate and the amount of etching are controlled by the concentration of the etching solution, the concentration of the solution must be adjusted with high precision. However, the solution obtained by the electrolysis step is optimal for the etching solution. The concentration is usually different from the optimal solution concentration, and this must be adjusted to the optimum concentration. However, when the relative amounts of the ferric chloride crystals obtained by the crystallization step and the de-Ni solution obtained by the electrolysis step are compared, the concentration is lower than the liquid concentration usable as the etching liquid. Therefore, it is necessary to concentrate the solution obtained by the dissolving step to a concentration that can be used as an etching solution, and this is also not preferable because it consumes energy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and reduces the load on a cooling device when crystallizing crystals from an iron chloride solution containing nickel, for example, an etching waste solution, and also reduces power consumption in the electrolytic process. Provided is a method for treating an iron chloride solution containing nickel, which can achieve further power saving by reducing the concentration and which does not require a concentration step even when adjusting the concentration of a solution obtained as a dissolving step and regenerated as an etching liquid. With the goal.

[0007]

The above object is achieved by a concentration step of concentrating a solution mainly containing ferric chloride and nickel chloride discharged from an etching step, and cooling the concentrated liquid to remove the ferric chloride. A crystallization step of crystallizing a crystal as a main component; and electrolysis of the liquid after crystallization separation to precipitate an iron-nickel alloy on the cathode side, and divalent iron contained in the liquid on the anode side by 3%.
An electrolysis step of oxidizing to valent iron and generating chlorine gas, an oxidation step of bringing the chlorine gas obtained in the electrolysis step into contact with an etching solution circulated in the etching step, and an iron-nickel by the electrolysis step. A dissolving step of dissolving the crystal containing ferric chloride as a main component in the crystallization step in the liquid from which the alloy has been separated, and a concentration supplied to the etching step by adjusting the concentration of the liquid obtained in the dissolving step. And an adjusting step, which is achieved by a method for treating an iron chloride solution containing nickel.

It is preferable to use waste heat of the electrolysis step as a heat source of the concentration step. In the concentration adjusting step, it is preferable to adjust the concentration of the liquid by using the vapor obtained in the concentration step.

[0009]

According to the present invention, the crystallization temperature of ferric chloride is increased by concentrating the processing solution before crystallizing ferric chloride-based crystals from the nickel-containing iron chloride solution. And the energy required for cooling can be reduced. In addition, since the waste heat of the electrolysis step is used as a heat source required for the concentration, the present invention can be performed without requiring a new heat source. In addition, by the concentration,
Since the crystallization separation efficiency of iron is improved and the nickel concentration of the processing solution sent to the electrolysis step is relatively increased, the electrolysis power in the electrolysis step can be reduced. Furthermore, since a large amount of ferric chloride crystals can be crystallized in the crystallization step, a high-concentration ferric chloride solution can be obtained in the dissolving step. A regenerated etching solution can be obtained only by diluting with the steam generated in the process. Therefore, not only the concentration can be easily adjusted, but also the material balance and energy consumption are superior.

Hereinafter, a method for treating an iron chloride solution containing nickel according to the present invention will be described with reference to a flowchart conceptually shown in FIG. The etching waste liquid discharged from the etching process includes nickel and ferric chloride, and ferrous chloride reduced to divalent iron by dissolution of nickel.
It is a mixed solution containing iron as a main component, and a part thereof (a waste liquid in the figure) is sent to a concentration step.

The concentration step is a step for increasing the crystallization temperature of ferric chloride in the crystallization step described below by concentrating the etching waste liquid. The degree of concentration is not particularly limited, but the higher the liquid concentration, the higher the crystallization temperature can be. However, considering the amount of heat required for the concentration, it is preferable to concentrate the ferric chloride contained in the waste liquid to a concentration at which the ferric chloride is saturated at room temperature (15 to 25 ° C.). Various known methods can be used for the concentration. However, according to the method of evaporating and separating steam by heating under reduced pressure, the generated steam can be used for dilution (concentration adjustment) of the liquid in a dissolving step described later, so that it is particularly preferable. .

The concentrated solution obtained in the above-mentioned concentration step is led to a crystallization step, and is cooled to a saturation temperature or less to form a second chloride.
Crystals mainly composed of iron precipitate. Here, the crystallization temperature is increased from the conventional 0 to 2 ° C. to the ordinary temperature (15 to
Since the temperature is raised to 25 ° C.), the load on the cooling device can be reduced. At this time, the temperature is raised and cooled again, and the crystal is grown to a large diameter, whereby the crystal can be separated more easily.

The filtrate after the crystal separation is led to an electrolysis step, where iron ions and nickel ions are reduced and electrodeposited on the cathode side, and are recovered as respective metals. As the electrolysis method, a diaphragm electrolysis method using a synthetic resin filter cloth is preferable, and since the anode is required to have a function of reducing an overvoltage when generating chlorine gas, platinum or a dimensionally stable electrode (D
(Ru-Sn) O ₂ / Ti called (SE electrode) or (I
(r-Pt) O ₂ / Ti and RuO ₂ / Ti can be preferably used, and a titanium plate can be suitably used for the cathode. As the material of the diaphragm, it is preferable to use polyester having excellent heat resistance, acid resistance, and chlorine resistance. Further, the electrolysis can be performed in a continuous current density and voltage range (for example, 7.5 A / dm ² and 3.5 V at an electrolyte temperature of 70 ° C.). On the other hand, chlorine gas generated on the anode side is sent to the absorption tower, and comes into contact with an etching waste liquid (a waste liquid in the figure) circulated and used in the etching step. With this contact,
In the etching waste liquid, ferrous chloride in the liquid is oxidized to ferric chloride which is an effective component of etching, and is reused as an etching liquid. In addition, pure water may be supplied to the electrolytic cell in order to maintain a constant amount of the solution during electrolysis.

The crystal mainly composed of ferric chloride separated in the crystallization step is sent to the dissolving step, in which the iron, nickel and chloride ions are reduced in the electrolytic step and dissolved in the de-Ni solution discharged. A high-concentration ferric chloride solution is obtained, and the concentration is adjusted by diluting with steam mainly composed of steam generated in the concentration step. Then, the liquid whose concentration has been adjusted is sent to an etching step as an etching liquid, and is reused. Here, the crystallization amount of the ferric chloride crystal obtained in the crystallization step is larger than that in the case where the conventional concentration step is not performed. can get. Therefore, the concentration can be adjusted by adding water vapor, and an etching regenerating solution can be obtained without requiring concentration as in the conventional case.

In the above series of steps, if the waste heat generated in the electrolysis step is recovered and used as a heat source required in the concentration step, the energy consumption for the concentration can be advantageously reduced. This can be easily implemented by using a suitable heat exchanger.

[0016]

The present invention will be described in detail below with reference to examples and comparative examples. ○ Example Divalent iron component as a sample solution of etching waste liquid 21.
4 g / liter, trivalent iron component 222.0 g / liter, nickel component 33.0 g / liter, chlorine component 48
740.5 g of water was added to 9 g / l to give a specific gravity of 1.50.
Solution 7 (A) was prepared and processed according to the flowchart shown in FIG. 4000 ml of this solution (A) was concentrated under reduced pressure at 60 ° C., and water vapor corresponding to 535.2 ml liquid, 24.7 g / liter of divalent iron component, 256.3 g / liter of trivalent iron component, nickel Component 38.1 g / liter, chlorine component 563.6 g /
3464.8 milliliters of concentrate (B) having a composition of 1 liter was obtained.

Next, this concentrated liquid (B) is cooled to 20 ° C., and the divalent iron component is 1.35% and the trivalent iron component is 19.4.
%, A nickel component of 0.76% and a chlorine component of 38.6% were precipitated and separated. Here, the cooling load required for cooling the concentrated liquid (B) (from 60 ° C. to 20 ° C.) is about 48 kcal per liter of the processing liquid, and when converted into electric power, the continuous processing is performed at a processing liquid amount of 100 liter / h. In this case, the power consumption of the cooling device was 1.7 kwh. The weight of the crystals was 2509.8 g.
The filtrate (C) after the crystal separation had a divalent iron component of 26.7.
g / liter, trivalent iron component 207.1 g / liter,
Nickel component 58.3 g / liter, chlorine component 508.
It consisted of 0 g / l and had a liquid volume of 1937 ml and a specific gravity of 1.538.

The filtrate (C) is led to an electrolytic cell, and Fe
296.1 g of Ni alloy, 486.6 chlorine gas on the anode side
g was obtained. The composition of the Fe—Ni alloy is 3 nickel components.
1.1%. Electric power required for electrolysis is 1 g of recovered metal
4.5 wh per unit. Further, chlorine gas generated on the anode side was supplied to an absorption tower to be absorbed in 35.8 liters of the above solution (A). As a result, 243.4 g / liter of a trivalent iron component, 33.0 g / liter of a nickel component, A solution (D) having a composition of a chlorine component of 502.6 g / liter was obtained. No divalent iron component was detected, and it was confirmed that all the iron components contained in the solution (D) were trivalent.
In addition, pure water was replenished to the electrolysis tank, and the liquid volume during electrolysis was kept constant.

On the other hand, the crystals obtained by the crystallization separation contained 0.49 g / liter of a divalent iron component discharged from the electrolytic cell, 127.8 g / liter of a trivalent iron component, and 10.2 g of a nickel component.
Dissolved in a de-Ni solution (specific gravity: 1.27, liquid volume: 1937 ml) having a composition of 8 g / liter and a chlorine component of 256.8 g / liter, and further diluted with steam obtained in the concentration step to obtain a divalent iron component. .8 g / l, trivalent iron component 1
As a result, 3983 ml (specific gravity: 1.383) of a solution (E) having a composition of 84.4 g / l, a nickel component of 10.1 g / l, and a chlorine component of 369.0 g / l was obtained. This solution (E) was returned to the etching step as a regenerating solution.

The above material balance is shown in Table 1.

[0021]

[Table 1]

[0022]

[Table 2]

Comparative Example The same sample solution (A) as in the example was processed according to the flowchart shown in FIG. The solution (A) was cooled to 2 ° C., and the divalent iron component was 0.5%, the trivalent iron component was 19.4%,
Crystals having a composition of 0.76% nickel component and 38.5% chlorine component were precipitated and separated. Here, the cooling load for cooling the solution (A) from 60 ° C. to 2 ° C. is about 70 kcal per liter of the treatment liquid,
al) about 1.5 times. In addition, in power conversion, the power consumption of the cooling device in the case of continuous processing at a processing liquid volume of 100 liter / h is 6.0 kwh, and the embodiment (1.7 kW)
h) required about 3.5 times. The weight of this crystal is 187
It was 6.8 g, and the crystallization amount was about 74% as compared with the example (2509.8 g). The filtrate (C) after the crystal separation was 27.2 g / liter of a divalent iron component, 186.9 g / liter of a trivalent iron component, and 42.0 g of a nickel component.
/ Liter, chlorine component 440.0 g / liter, the liquid volume was 2803 ml, and the specific gravity was 1.481.

The filtrate (C) was led to an electrolytic cell, and Fe
345.4 g of a Ni alloy was obtained. In this electrolysis step, trivalent iron was once electrolytically reduced to divalent iron on the cathode side, and then the divalent iron was oxidized again to trivalent iron on the anode side. The composition of the Fe—Ni alloy is 2 nickel components.
8.0%. The power required for this electrolysis was recovered metal 1
The weight was 9.5 wh per g, which was about 2.1 times that of the example (4.5 wh). In addition, pure water was replenished to the electrolysis tank, and the liquid volume during electrolysis was kept constant.

On the other hand, the crystals obtained by the crystallization separation contained 0.0g / liter of divalent iron component discharged from the electrolytic cell, 126.6g / liter of trivalent iron component, and 7.5g of nickel component.
Per liter, a chlorine component of 250.2 g / liter, dissolved in a de-Ni solution (specific gravity: 1.283, liquid volume: 2803 ml), and further concentrated and diluted with pure water to adjust the concentration. Ingredient 2.35 g / l,
4000 ml (solution: specific gravity 1.368) of a solution (E) having a composition of 179.8 g / liter of a trivalent iron component, 8.8 g / liter of a nickel component, and 356.0 g / liter of a chlorine component was obtained. This solution (E) was returned to the etching step as a regenerating solution.

Table 2 shows the above material balance.

[0027]

[Table 3]

[0028]

[Table 4]

[0029]

As described above, according to the present invention,
The crystallization temperature of ferric chloride is increased by concentrating the processing solution before crystallizing ferric chloride-based crystals from the nickel-containing ferric chloride solution, thereby increasing the energy required for cooling. Can be reduced. In addition, since the waste heat of the electrolysis step is used as a heat source required for the concentration, the present invention can be performed without requiring a new heat source. Also,
The concentration improves the crystallization separation efficiency of ferric chloride,
Since the nickel concentration of the processing solution sent to the electrolysis step is relatively increased, the electrolysis power in the electrolysis step can be reduced. Furthermore, since a large amount of ferric chloride crystals can be crystallized in the crystallization step, a high-concentration ferric chloride solution can be obtained in the dissolving step. A regenerated etching solution can be obtained only by diluting with the steam generated in the process. Therefore, not only the concentration can be easily adjusted, but also the material balance and energy consumption are superior. As described above, the present invention can treat an iron chloride solution containing nickel in a very superior manner in terms of both energy balance and mass balance.

[Brief description of the drawings]

FIG. 1 is a flowchart schematically showing a method of treating an iron chloride solution containing nickel according to the present invention.

FIG. 2 is a flowchart schematically showing a method for treating an iron chloride solution containing nickel according to a comparative example.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mikami Yashuya 8-10-16 Shimorenjaku, Mitaka-shi, Tokyo Japan Iron Mining Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) C23F 1/46 C02F 1/461

Claims (3)

(57) [Claims] 1. A second chloride discharge from an etching step.
A concentration step of concentrating a solution mainly composed of iron and nickel chloride; a crystallization step of cooling the concentrated solution to crystallize crystals mainly composed of ferric chloride; and electrolyzing the liquid after crystallization separation. An electrolytic process of depositing an iron-nickel alloy on the cathode side, oxidizing divalent iron contained in the solution to trivalent iron on the anode side, and generating chlorine gas, and the electrolytic process, An oxidation step of bringing a chlorine gas into contact with an etching solution circulated in the etching step; and a liquid containing iron-nickel alloy separated by the electrolysis step. And a concentration adjusting step of adjusting the concentration of the solution obtained in the dissolving step and supplying the solution to the etching step. 2. The method for treating an iron chloride solution containing nickel according to claim 1, wherein the heat source of the concentration step utilizes waste heat of the electrolysis step. 3. The method for treating an iron chloride solution containing nickel according to claim 1, wherein in the concentration adjusting step, the concentration of the liquid is adjusted using the vapor obtained in the concentration step.