JP2002327288A - Method for collecting hydrochloric acid and copper from copper chloride solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for collecting valuable substances from effluent of copper chloride etchant, which is suitable for a comparatively small factory or the case of collecting surplus effluent in the other location. SOLUTION: This method comprises adding a sulphuric acid solution to a copper chloride solution and concentrating it, collecting dilute hydrochloric acid, diluting the mixture of crystalline copper sulfate and aqueous solution of copper sulfate left after collecting hydrochloric acid in the concentration process, with water, redissolving the precipitated crystals into the aqueous solution without taking them out, collecting metallic copper by electrolyzing the aqueous solution containing the crystals redissolved in the dilution process, and circulating the aqueous solution after collecting metallic copper to the concentration process, to use it repeatedly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In the manufacturing process of printed wiring boards, it is industrially performed to form a desired pattern by corroding a copper foil with an etching solution mainly containing copper chloride and hydrochloric acid. At this time, the used etching solution is treated outside the factory as a waste solution. The present invention relates to a method for regenerating a used etching waste liquid by using a sulfuric acid substitution method and an electrolytic method.

[0002]

2. Description of the Related Art For the above-mentioned deteriorated etching solution,
In general, hydrogen peroxide water is injected as an oxidizing agent, and cuprous chloride or ferrous chloride generated along with dissolution of the material is oxidized and regenerated and diluted with water to replenish hydrochloric acid. Is being done. (Scheme oxidation of cuprous chloride with hydrogen _{peroxide) CuCl + 1 / 2H 2 O} 2 + HCl → CuCl 2 + H 2 O

[0003] However, such a method can restore the oxidizing power of copper ions, but requires the addition of hydrochloric acid to replenish chloride ions and dilutes with water without dissolving the dissolved copper component. Therefore, it is necessary to dispose excess etching liquid as waste liquid.

As a method of treating the above-mentioned etching waste liquid, a method of adding sulfuric acid and concentrating the same to recover copper sulfate crystals and hydrochloric acid (hereinafter referred to as a sulfuric acid substitution method) is disclosed in Japanese Patent Application Laid-Open No. Hei 5 (1993) -105.
No. 33168 is proposed. However,
It is difficult to obtain high quality copper sulfate recovered by this method because it contains a chlorine component.

According to the above-mentioned Japanese Patent Application Laid-Open No. 5-33168, it is disclosed that the obtained copper sulfate crystal is dissolved in an aqueous solution, recrystallized, and further washed with water to reduce the chlorine component. A great deal of cost is required to install a device for taking out crystals to the outside and performing centrifugal dehydration, particularly a device whose operation management is automated. In addition, there is a problem that treatment of washing wastewater is required separately.

On the other hand, the inventors of the present invention have disclosed in
JP-A-125564 and JP-A-5-117879 propose a regeneration method using a diaphragm electrolysis method, and the structure of an electrolytic cell used for these electrolytic regeneration processes is proposed and put to practical use in JP-A-6-158359. .

Further, in Japanese Patent Application No. 11-280011 or the like, an etching solution containing copper chloride and hydrochloric acid as main components is electrolyzed, copper ions in the etching solution are recovered as metallic copper, and chlorine gas generated is removed from the etching solution. A method and apparatus for use in reproduction have been proposed and put into practical use.

However, since the method of directly electrolyzing the copper chloride etching solution involves the generation of chlorine gas, it is necessary to consider the handling of the chlorine gas. In the above-mentioned regenerating method, this is replaced with the etching solution instead of the hydrogen peroxide. I'm going to use it for playback.

Therefore, in order to take advantage of the fact that hydrogen peroxide can be made unnecessary, when performing a relatively large amount of liquid treatment, this method is suitable for being incorporated into an etching process from which an etching waste liquid is discharged. When targeting relatively small factories that use less oxidizing agents such as hydrogen,
It is unsuitable when the surplus waste liquid is collected at another place away from the etching step.

[0010]

DISCLOSURE OF THE INVENTION In view of the above problems, a copper chloride etching waste solution suitable for a relatively small-scale factory or for recovering excess waste solution at another place. It is an object of the present invention to provide a valuable resource recovery method.

[0011]

SUMMARY OF THE INVENTION The present inventors have found that a factor that hinders the practical use of the sulfuric acid substitution method, particularly in or near a factory having an etching step, is to separate and collect the recovered copper sulfate crystals. Large cost is required for the installation of the equipment to be performed, and it is difficult to remove the chlorine component from the recovered copper sulfate crystal, and the sales profit of the copper sulfate crystal is obtained in proportion to the above equipment cost and the cost of sulfuric acid as the raw material. There is no
In order to solve the above problems, a concentration step of adding an aqueous solution containing sulfuric acid as a main component to an aqueous solution containing copper chloride as a main component and concentrating the solution to recover dilute hydrochloric acid, and recovering hydrochloric acid in the concentration process, A dilution step of diluting a mixture of crystals and an aqueous solution mainly containing copper sulfate and sulfuric acid with water, and dissolving the precipitated crystals in the aqueous solution without taking out the precipitated crystals to the outside, and dissolving the crystals in the dilution step An electrolysis step of electrolyzing an aqueous solution containing copper sulfate and sulfuric acid as a main component to recover metallic copper, and after recovering metallic copper in the electrolysis process, circulating an aqueous solution containing sulfuric acid as a main component in the concentration step, The inventors have found that the above problem can be solved by repeated use, and have completed the present invention.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In the equipment shown in FIG.
25g / l copper, 250g / l chlorine component
80 liters of copper chloride aqueous solution containing 1.25
I got it. On the other hand, the barrel electrolytic cell 5 feeds copper into the sulfuric acid measuring tank 2.
About 430 liters of dilute sulfuric acid after collection is received via sulfuric acid receiving tank 6.
I got it. Cu, Cl, SO in dilute sulfuric acid ₄Are 2.
1, 3.9, 179 g / liter, liquid specific gravity 1.12
Was.

The copper chloride aqueous solution and the dilute sulfuric acid were fed in a batchwise manner to a concentrated / dilution container 3 made of tempered glass having an internal volume of 200 liters at a fixed ratio. That is, a total of 170 liters of 26.7 liters of copper chloride and 143.3 liters of dilute sulfuric acid were simultaneously sent per time, divided into three times, and heated and concentrated by an electric heater (not shown) while mixing with the stirrer 4. .

The pressure in the concentration / dilution vessel 3 was set to a vacuum of 50 to 80 mmH ₂ O by using the ejector 8. The liquid temperature at the time of concentration in the concentration / dilution container 3 was 40 to 80 ° C. The amount of liquid sent was controlled by starting and stopping the pump with each level switch installed in the copper chloride waste liquid measuring tank 1 and the sulfuric acid measuring tank 2.

The vapor evaporated at the time of concentration was sucked by the ejector 8 and brought into direct contact with the dilute hydrochloric acid in the dilute hydrochloric acid receiving tank 7 to be liquefied.
The diluted hydrochloric acid was cooled by the cooler 9 to remove heat of condensation. The total amount of the diluted hydrochloric acid collected was 433.9 liters, and the Cl concentration was 45.
4 g / liter and specific gravity 1.03.

After the concentration step and the dilute hydrochloric acid separation / recovery step, the slurry containing creamy copper sulfate crystals remains in the concentration / dilution vessel 3. Dilution water is poured into the vessel 3 and stirred. While dissolving, the solution was sent to the sulfuric acid receiving tank 6. Dilution was performed three times in accordance with the number of times of concentration, and the total amount of injected dilution water was 371.1 liters. Sulfuric acid receiving tank 6
The total amount of the liquid sent to 419.9 liters was Cu, C
1 and SO ₄ concentrations were 25.7, 5.0 and 180 g / l, respectively, and the liquid specific gravity was 1.17.

The solution sent to the sulfuric acid receiving tank 6 is further sent to the barrel electrolytic tank 5, where it is electrolyzed and decopperized in a circulation returning to the sulfuric acid receiving tank 6 by overflow. The copper component in the solution is converted into cathode pellets (outside diameter 28) in a rotating hexagonal barrel.
It was deposited and recovered as metallic copper on the surface of a copper tube (mm × 30 mm long). The liquid (dilute sulfuric acid) after the removal of copper has a liquid volume of 417.1 liters, and the concentrations of Cu, Cl and SO ₄ are 1.9 and ₄ .
3, 181.2 g / l, liquid specific gravity 1.12. The recovered metallic copper was 10 kg, the electrolytic current and the voltage were each 500 A and 6.5 V, and the current efficiency with respect to the recovered copper was 93.7% when the energizing time was 18 hours. The diluted sulfuric acid after copper removal was sent to the sulfuric acid measuring tank 2 and used repeatedly.

FIG. 2 shows the above processing as a process flow, and Table 1 summarizes the processing in a table.

[Table 1]

EXAMPLE 2 Referring again to FIG. 1, 80 liters of an aqueous copper chloride solution having a specific gravity of 1.25 and containing 125 g / l of copper and 250 g / l of a chlorine component was received in the copper chloride waste liquid measuring tank 1.
On the other hand, 407.9 liters of diluted sulfuric acid after copper recovery in the barrel electrolytic tank 5 was received in the sulfuric acid measuring tank 2 via the sulfuric acid receiving tank 6. Cu in dilute sulfuric acid, C1, SO ₄ each 1.1,5.
It was 2,179.2 g / liter and the liquid specific gravity was 1.12.

The above-mentioned copper chloride solution and dilute sulfuric acid were fed to the concentration / dilution container 3 in a batchwise manner at a fixed ratio. That is, a total of 162.7 liters of 26.7 liters of copper chloride and 136.0 liters of dilute sulfuric acid were simultaneously sent per one batch in three portions, and the mixture was heated and concentrated by an electric heater while mixing with the stirrer 4.

The control of the pressure in the concentration / dilution vessel, the control of the liquid temperature during the concentration and the control of the amount of liquid sent are exactly the same as those in the first embodiment. The vapor evaporated at the time of concentration was sucked by the ejector 8 and brought into direct contact with dilution water in the dilute hydrochloric acid receiving tank 7 to be liquefied. The aqueous solution dilutely containing the liquefied hydrochloric acid was cooled by the cooler 9 to remove heat of condensation. The total amount of the aqueous solution recovered and increased (used as dilution water in the dilution step) is 281.4 liters, and the Cl concentration is 2
At 9.5 g / l and a specific gravity of 1.025, the diluted sulfuric acid was fed to the sulfuric acid measuring tank 2 after discharging it.

The concentrate obtained after the above-mentioned concentration step and separation / recovery step of the dilution water was further concentrated (second-stage concentration), and the diluted hydrochloric acid was recovered. The vapor evaporated at the time of concentration is sucked by the ejector 8 as in the case of the first-stage concentration, and the diluted hydrochloric acid receiving tank 7 is used.
Liquefied by direct contact with dilute hydrochloric acid as a residual liquid at the time of the first-stage concentration, and further dilute hydrochloric acid containing a liquefied component is cooled by a cooler 9;
The heat of condensation was removed. The total amount of dilute hydrochloric acid recovered was 138.1
Liter, Cl concentration 118g / liter, specific gravity 1.05
It was 5.

Since the slurry containing creamy copper sulfate crystals remained in the concentration / dilution vessel 3 after the second-stage concentration, the dilution water fed to the sulfuric acid measuring tank 2 during the first-stage concentration was used. Was sent into the concentration / dilution vessel 3 to dissolve the copper sulfate crystals with stirring, and the dissolved copper sulfate aqueous solution was sent to the sulfuric acid receiving tank 6. The total amount of dilution water injected into the concentration / dilution container 3 is 281.4 liters, which is the same as the amount recovered during the first-stage concentration. The total amount of the liquid sent to the sulfuric acid receiving tank 6 was 410.7 liters, and the concentrations of Cu, Cl and SO ₄ were 27.0 and 13.
4, 178 g / liter and liquid specific gravity 1.17.

The solution sent to the sulfuric acid receiving tank 6 is further sent to the barrel electrolytic tank 5 and electrolyzed and copper-removed under circulation returning to the sulfuric acid receiving tank 6 by overflow. The copper component in the solution is converted into cathode pellets (outer diameter 28) in a rotating hexagonal barrel.
It was deposited and recovered on the surface of a copper tube (mm × 30 mm length) as metallic copper. The liquid (dilute sulfuric acid) after the removal of copper had a liquid volume of 407.9 liters, and the concentrations of Cu, Cl and SO ₄ were 2.7 and 12 respectively.
7, 179.2 g / liter and liquid specific gravity 1.12. The recovered metallic copper was 10 kg, the electrolytic current and the voltage were 500 A and 6.3 V, respectively, the energizing time was 18.5 hours, and the current efficiency with respect to the recovered copper was 91.2%. The diluted sulfuric acid after copper removal was sent to the sulfuric acid measuring tank 2 and used repeatedly.

FIG. 3 shows the above processing as a process flow, and Table 2 summarizes the processing in a table.

[Table 2]

[0026]

According to the present method, it is convenient to recover as metallic copper which can obtain a sales profit more than a copper sulfate crystal containing a chlorine component without consuming sulfuric acid as a raw material.

Further, an electrolysis apparatus using a rotating barrel is:
Compared with an automatic centrifugal dehydrator for separating and recovering copper sulfate crystals having the same copper component recovery capability, it can be manufactured at least at a cost of 1/3 or less.

The number of personnel required for operation management of the apparatus is also 10
It is almost unnecessary other than changing the cathode pellets once a day, which is more convenient.

The concentration of dilute hydrochloric acid that can be used in the etching step usually needs to be 10% or more. However, if the concentration step is performed in two steps, it is easy to secure such a concentration.
In the concentration step, it is conceivable to use a batch type vessel equipped with a stirring means. However, when the concentration is performed in two steps, the same vessel can be used in both steps.

[Brief description of the drawings]

FIG. 1 is a diagram conceptually showing equipment for carrying out a method for recovering hydrochloric acid and copper according to the present invention.

FIG. 2 is a flowchart showing a process of a collection method according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing a process of a collection method according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Copper chloride waste liquid measuring tank 2 Sulfuric acid measuring tank 3 Concentration / dilution container 4 Stirrer 5 Barrel electrolytic tank 6 Sulfuric acid receiving tank 7 Dilute hydrochloric acid receiving tank 8 Ejector 9 Cooler

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/58 C02F 1/62 ZABC 5E339 1/62 ZAB C23F 1/46 C23F 1/46 C25C 7/06 301A C25C 7/06 301 H05K 3/06 Z H05K 3/06 C02F 1/46 101B (72) Inventor Yuji Tanimura 8-1 Hiraicho Hiraicho, Nishitama-gun, Tokyo Nippon Steel Mining Co., Ltd. F-term (reference) 4D034 AA27 BA01 CA12 4D038 AA08 AB39 AB68 BA02 BA04 BB02 BB10 4D061 DA08 DB18 EA02 EA05 EB02 EB04 EB16 EB31 EB33 FA02 FA05 4K057 WB04 WE08 WH01 WH07 WM19 WN01 4K058 AA22 BA21 BB04 FC04 FA17 BE13 FC13 BC01 FC13

Claims (4)

[Claims] 1. A concentration step of adding an aqueous solution containing sulfuric acid as a main component to an aqueous solution containing copper chloride as a main component and concentrating the aqueous solution to recover dilute hydrochloric acid, and forming a crystal of copper sulfate after collecting hydrochloric acid in the concentrating process. A dilution step of diluting a mixture of an aqueous solution mainly containing copper sulfate and sulfuric acid with diluting water, and re-dissolving the precipitated crystals in the aqueous solution without taking them out, and dissolving the crystals in the dilution step. An electrolysis step of electrolyzing an aqueous solution containing copper sulfate and sulfuric acid as a main component and recovering metallic copper, and after recovering the metallic copper in the electrolysis process, circulating the aqueous solution containing sulfuric acid as a main component in the concentration step, A method for recovering hydrochloric acid and copper from a copper chloride solution, wherein the method is used repeatedly. 2. The method according to claim 1, wherein the concentration step is performed in two stages, and an aqueous solution containing hydrochloric acid diluted in the first concentration step is used as dilution water in the dilution step. 2. The method for recovering hydrochloric acid and copper from a copper chloride solution according to claim 1, wherein the aqueous solution that is more concentrated than in one step is recovered as dilute hydrochloric acid. 3. The method for recovering hydrochloric acid and copper from a copper chloride solution according to claim 1, wherein in the concentration step, one or a plurality of batch-type vessels provided with a stirring means are used. . 4. The method according to claim 1, wherein in the electrolysis step, an electrolytic cell having a rotating barrel containing a plurality of flowing cathode pellets is used. How to recover copper.