JPS5817260B2 - Etching agent waste treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ammonia-alkaline copper etching process that is used in a copper etching process that is carried out as a final step to complete a conductor pattern on an insulating substrate in the manufacture of printed wiring boards, for example, and in various other copper etching processes. The present invention relates to a method for treating waste liquid of a chemical agent.

As is well known, in the manufacturing process of printed wiring boards, in order to complete the conductor pattern on the insulating substrate, it is necessary to dissolve and remove unnecessary copper coating parts of the wiring in the final process. Various copper-etched etching agents have been used in the past, such as ferric chloride-based, hydrogen peroxide-based, ammonium persulfate-based, and cupric chloride-based etching agents. The treatment of this waste liquid has become a problem.

Also, especially recently? Among these, ammonia-alkaline copper etching agents have attracted attention and have been widely adopted because they have good etching properties and do not contain heavy metals other than copper, and are therefore advantageous in waste liquid treatment. .

However, even with this ammonia alkaline copper etching agent, the waste liquid after its use contains a large amount of copper (0.1~
0.6 ton/m, 3) Therefore, it is required to treat this, but the measures actually taken so far have been limited to neutralization coagulation sedimentation methods, and the waste liquid has not been disposed of. Due to the presence of a large amount of ammonium ions in the copper hydroxide, the solubility of copper hydroxide requires strict pH adjustment during neutralization, and the precipitate of copper hydroxide is bulky and difficult to distinguish. For these reasons, it may not be possible to sufficiently reduce the residual copper ion concentration in treated wastewater, and copper is disposed of as copper hydroxide through ocean dumping and reused. The current situation is that the water is being released into the water and not being reused.

Therefore, there are still various problems with the processing method, such as the fact that resource saving and recycling, which are currently strongly desired, cannot be achieved with such a neutralization coagulation sedimentation method.

Furthermore, in addition to the neutralization coagulation-sedimentation method, metal replacement methods and electrolytic methods are also known as treatment methods for ammonia-alkaline copper etching agent waste liquid, but these treatment methods are rarely adopted in practice. In any case, no conventional recycling treatment method for the waste liquid of this type of ammonia-alkaline copper etching agent has been proposed.

The present invention was made to improve the above-mentioned situation, and uses a special copper etching agent characterized by an ammonium salt of an acid and aqueous ammonia to easily and reliably treat this ammonia-alkaline copper etching agent waste liquid. In addition to ensuring the detoxification of treated water and preventing the destruction of the natural environment due to harmful substances, we are also renovating the waste liquid by recovering almost 100% of the ammonia in the waste liquid and effectively reusing it as a raw material for etching agents. The purpose of the present invention is to provide a method for processing ammonia-alkaline copper etching agent waste liquid that can be easily carried out, and also recover most of the copper as a valuable substance, thereby achieving recycling and being effective as a resource saving measure. shall be.

That is, in order to achieve the above object, the present invention adds alkali hydroxide and/or alkali carbonate to the waste liquid of a copper etching agent whose main components are an ammonium salt of an acid and aqueous ammonia to form ammonia gas and copper oxide. and reacting this ammonia gas with an acid and aqueous arsenic to generate an ammonium salt of this acid and aqueous ammonia, respectively, and reusing the ammonium salt of this acid and aqueous ammonia as raw materials for the copper etching agent, The present invention also provides a method for treating ammonia-alkaline copper etching agent waste liquid, which is characterized in that the copper oxide is recovered.

Hereinafter, details of the present invention will be explained with reference to the drawings.

The ammonia-alkaline copper etching agent used in the present invention contains an acid ammonium salt and aqueous ammonia as main components, and does not contain any heavy metals other than copper.

Further, as the ammonium salt of the acid, ammonium salts of inorganic acids such as ammonium chloride and ammonium sulfate gas, ammonium acetate, and the like can be used alone or in combination of two or more kinds.

In the past, this etching agent was used for manufacturing printed wiring boards and other purposes.

And, during the etching process, what is contained in the waste liquid of the etching agent? Then, the ammonium salt of the acid and ammonia water react with copper, and a large amount of copper is contained in the form of a copper-aluminium complex.

In the present invention, the etching agent waste liquid containing a large amount of copper ammine complexes is treated. First, the etching agent waste liquid A discharged from the etching process and stored in the etching waste liquid storage tank 1 is put into the reaction tank 2, and then water is added to the reaction tank 2. Alkali hydroxides such as sodium oxide and potassium hydroxide (if necessary, alkali carbonates such as sodium carbonate and potassium carbonate may be used in place of the alkali hydroxide or in combination with the alkali hydroxide).

) Add B. As a result, as shown in reaction formulas (1) to (3) or (1') to (3') below, the copper ammine complex in waste liquid A is decomposed, and ammonia in this copper ammine complex and waste liquid ammonium salt remaining in A,
Ammonium hydroxide becomes ammonia gas C and is discharged from the reaction tank 2, and all of the copper becomes black and insoluble oxidized steel (CuO) D and precipitates.

Incidentally, when alkali carbonate is used, the generated carbon dioxide gas is discharged together with ammonia gas C.

[In the case of alkali hydroxide]

Cu (NH3)7++ 20H-+4NH3+ Cu
O+)I2゜・・・・・・・・・(1) NH4++＋OH−→NH3+H20・・・・・・・・・
(2) NH40H→NH3+H20・・・・・・・・・
(3) [In the case of alkali carbonate] Cu(NI(3)x+→4NH3+CuO+C02...
...(1')2NH,,++ coi -→2NH
3+H20+CO2...(2')NH40H+NH3
+H20...(3',) In this case, waste liquid A
The reaction between IJB and Alka IJB is preferably carried out under heating and stirring at 60 to 120°C, whereby the copper ammine complex is reliably decomposed and the reactions (1) to (3) or (
1') to (3') also proceed rapidly.

In addition, water vapor is also generated by heating to 100° C. or higher, and the waste liquid A is concentrated.

This water vapor is discharged from the reaction tank 2 together with the ammonia gas C.

In addition, the alkali is used for the reactions (1) and (2).
) It is preferable to add about 5 to 30 parts more than the amount consumed.

The ammonia gas C discharged from the reaction tower 2 is sent to the first ammonia absorption tank 4 after condensing water vapor if necessary.
Lead inward.

This absorption tank 4 contains an acid E such as hydrochloric acid, sulfuric acid, acetic acid, or a mixture thereof, and ammonia gas C reacts with the acid E to generate an ammonium salt F of the acid E.

(When acid E is used diluted with water, ammonia gas is absorbed by this water and ammonium hydroxide is also produced.

(In this case, as acid E, it is preferable to use an acid corresponding to the acid ion (anion) of the ammonium salt of the acid constituting the etching agent (for example, if the ammonium salt of the acid in the etching agent is ammonium chloride) For example, it is preferable to use hydrochloric acid as the acid E.

), and the concentration of acid E is appropriate.

Further, it is preferable that the ammonia gas is reacted with an acid corresponding to its equivalent number, and in particular, the generated acid ammonium salt E and unreacted ammonia gas are reacted with water (the dilution water of the acid E and the second The equivalence ratio of ammonium hydroxide (ammonium water) produced by absorption into water present in the ammonia absorption tank 5 is equal to the equivalence ratio of ammonium salt of acid in the self-etching agent to ammonium hydroxide. Preference is given to reacting with acid E accordingly.

The unreacted ammonia gas C' in the first absorption tank 4 is
Next, it is guided into the second ammonia absorption tank 5 containing water, where most of the unreacted ammonia gas is absorbed into water to generate ammonium hydroxide (ammonium water) G.

Incidentally, the carbon dioxide gas generated when alkali carbonate is added during the decomposition of the etching waste liquid A becomes ammonia carbonate unless it is removed by absorption with an alkali or the like after being discharged from the reaction tower.

Some ammonia gas C" leaking out of the absorption tank 5 is led to a deodorizing tower 6 for treatment.

The acid ammonium salt and aqueous ammonia in the first and second ammonia absorption tanks 4 and 5 (including this carbonate if ammonia carbonate is generated) are in the etching agent mother liquor storage tank 7.
At the same time, the copper etching agent is introduced from the storage tank 7 to an etching agent production tank 8, and if there is a shortage of water, ammonia, or ammonium salt, the insufficient amount is filled up to produce a copper etching agent.

This etching agent is used in the same manner as the copper etching agent described above, and its waste liquid is treated and recycled in the same manner as described above.

Note that ammonia leaked from the etching agent production tank 8 is led to the deodorizing tower 6 and treated.

On the other hand, the copper oxide in the reaction tank 2 is extracted from the reaction tank 2, placed in a sedimentation cleaning tank 9 such as a sedimentation type, and after removing most of the supernatant liquid, washing water H is supplied to sufficiently remove the copper oxide. Wash with water,
After solid-liquid separation, the copper oxide is transferred to a dehydrator 1 such as a filter press.
Dehydrate at 0 to form a copper oxide cake.

This copper oxide cake D' is dried in a dryer 11 and recovered as copper oxide powder D''.

This copper oxide has a high purity and can be used as a reagent or pigment in itself, but if it is dissolved in an acid such as sulfuric acid or hydrochloric acid to form an aqueous solution of copper sulfate or copper chloride, it can be used for printing again by electrolysis. It can also be used to manufacture copper foil for wiring boards.

In addition, the supernatant liquid (treated water) in the sedimentation cleaning tank 9 is as follows.

The suspended solids (copper oxide) D"' are removed using a precision tear filter 12 or the like, and this copper oxide D"' is combined with the copper oxide cake D'), and then discharged from the filter press 10 in G). The wastewater is sent to the wastewater management tank 13 together with ■, where p
Adjust H to 5.8 to 8.6 and discharge.

According to the treatment method according to the present invention described above, ammonia gas is produced by adding alkali hydroxide and/or alkali carbonate to the waste liquid of an ammonia-alkaline copper etching agent whose main components are an ammonium salt of an acid and aqueous ammonia. Since this ammonia gas is reacted with acid and water, the ammonia content in the etching agent waste liquid is reliably fixed as the ammonium salt of the acid and ammonium hydroxide (ammonia water), which are valuable raw materials for the copper etching agent. , the ammonia content in the waste liquid is approximately 1. o o% recovered.

Further, the ammonia content in the waste liquid can be effectively reused as a raw material for an etching agent as an acid ammonium salt and aqueous ammonia, and the waste liquid can be regenerated efficiently without waste.

Moreover, during the treatment and rehabilitation of this waste liquid, are there any impurities mixed in that have a negative effect on the etching agent? This is not the case at all, and the refurbished etching agent is used successfully, and the etching agent components are effectively recycled.

Furthermore, all of the copper content in the waste liquid can be effectively recovered, and
Copper has low solubility and can be recovered as copper oxide (Cub), which has low bulk and is easily cooled, so there is almost no leakage of copper in the supernatant liquid (processed water), and the treated water has a low pH. It can be released by simply making adjustments.

As described above, according to the present invention, by using a special ammonia-alkaline etching agent, the waste liquid can be effectively treated, valuable components can be recovered, and recycling can be achieved. This can be reliably prevented from occurring.

In addition, 1. The method of the present invention is easy to operate, and the etching agent waste liquid can be treated easily and reliably, and as mentioned above, valuable components can be reused and recycled, making it possible to treat it economically. It has various advantages such as

The present invention will be explained in more detail with reference to Examples below.
The invention is not limited to this example.

ExamplesThe following compositionWater 61.7% by weightAmmonium chloride 22.5 tt' (4.2 mol)Ammonium hydroxide 15.8 tt (4,
The waste liquid after using 5 mol of copper etching agent was treated according to the steps shown in the drawing.

That is, - A copper etching agent waste solution containing 1013 Kp of cupric ammonium chloride, 10.7 tt of ammonium hydroxide, and 175 tt of ammonium hydroxide in a single treatment amount of 5 m3 was heated to 115°C, and 90% of sodium hydroxide was added to the solution, By stirring for 1 hour, this reaction produces 740% ammonia gas and 9% water vapor.
1.25 ma Copper oxide 795 images Sodium chloride 1170 tt Sodium hydroxide 100〃 were obtained.

The ammonia gas and water vapor were reacted with 1.75 m3 of concentrated hydrochloric acid and water to produce a product of approximately 4.5 mB (containing 1124 kg (4°66 mol) of ammonium chloride and 788 kg (5.0 mol) of ammonium hydroxide). I got it.

This product had the same molar ratio of ammonium chloride and ammonium hydroxide as the copper etching agent, and was used as it was as the river stone for the button 1 etching agent, and the etching agent was obtained by simply diluting it with water.

One power, 7 to the copper oxide 795, 11 um of chloride l-+7
70 to 9, 75 m3 of concentrated slug IJ-3 containing 100 kg of sodium hydroxide was once sedimented, the supernatant liquid was removed, and thoroughly washed with 4.4 m3 of washing water, and then the precipitated copper oxide was extracted again and filter press The powder was dehydrated and dried to obtain 795 g of copper oxide powder.

Further, the supernatant liquid in which the copper oxide 1 was precipitated and the waste water from the filter press were adjusted to pH 7.0 by adding hydrochloric acid, and then discharged.

8. The etching agent obtained using ammonium chloride and ammonia water obtained by the reaction of ammonia gas with hydrochloric acid and water could be used satisfactorily.

[Brief explanation of the drawing]

The drawing is a flow sheet showing one embodiment of the present invention. 1...Etching waste liquid storage tank, 2...Reaction tank, 4...First ammonia absorption tank, 5...
... Second ammonia absorption tank, 7 ... Etching agent mother liquor storage tank, 8 ... Etching agent production tank, 9
... Sedimentation cleaning tank, 10 ... Dehydrator, 1
3...Drainage management tank, A...Etching agent waste, B...Alkali hydroxide, C, C'...
...Ammonia gas, D, I)', D/
／ , D／／／・・・・・・Copper oxide, E・・・・・・
Inorganic acid, F... Ammonium salt of inorganic acid, G.
...Ammonium hydroxide.

Claims (1)

[Claims] 1. Ammonia gas and copper oxide are produced by adding alkali hydroxide and/or alkali carbonate to the waste liquid of a copper etching agent whose main components are an ammonium salt of an acid and aqueous ammonia. The ammonium salt of this acid and the aqueous ammonia are respectively produced by reacting with the acid and water, and the produced ammonium salt of the acid and the aqueous ammonia are reused as raw materials for the copper etching agent, and the copper oxide is A method for treating etching agent waste, the method comprising recovering the etching agent waste. 2. The ammonium salt of the acid constituting the copper etching agent is one or more selected from the group consisting of ammonium chloride, ammonium sulfuric acid, and aqueous ammonium acetate, and the acid to be reacted with ammonia gas is selected from hydrochloric acid, sulfuric acid, and acetic acid. The method for treating etching agent waste according to claim 1, wherein the etching agent is one or more selected from the group consisting of: