JP2006219708A - Electrolytic regeneration method for copper-etching deteriorated solution by ferric chloride and electrolytic regenerator therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic regeneration method in a non-diaphragm electrolytic solution tank for copper-etching deteriorated solution by a ferric chloride solution, and to provide an electrolytic regenerator therefor. <P>SOLUTION: In copper-etching reaction by a ferric chloride solution, copper is dissolved by ferric chloride, so as to be changed into cupric chloride, and the ferric chloride itself is reduced into ferrous chloride, and its etching capacity is deteriorated. The deteriorated solution is charged inside a non-diaphragm electrolytic solution tank, and reaction in a direction reverse to the etching reaction is allowed to occur. At that time, the cupric chloride in the deteriorated solution is decomposed and is returned to the original metal copper, and chlorine ions produced perform electrolytic regeneration reaction of oxidizing the ferrous chloride in the deteriorated solution and returning the same to the original ferric chloride, and self-feed a chlorine source required for the oxidation of the ferrous chloride, thus there is no need of feeding the whole quantity of the chlorine source required for the reaction such as hydrochloric acid and salt as in the case of a membrane electrolytic process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrolytic regeneration method and an electrolytic regeneration apparatus for regenerating a deteriorated liquid generated in a copper etching process using ferric chloride in printed circuit board production.

  At present, the copper etching deterioration liquid by ferric chloride is regenerated by the “chlorine gas blowing method” in which chlorine gas is directly blown into the deterioration liquid. Although the above chlorine is stored in the form of liquid chlorine, it is a toxic and dangerous substance that is subject to the Poisonous and Deleterious Substances Control Law, the High Pressure Gas Control Law, etc. They are not regenerated using chlorine at the site, but are transported and regenerated to a factory having a chlorine-using facility located away from the site.

  If the deterioration solution of copper etching can be safely regenerated at the copper etching site, it is possible not only to save the trouble of replacing the copper etching in the etching machine and the round-trip transportation with the recycling factory, By connecting and operating with an etching machine, it is possible to prevent the copper etching ability of the copper etching solution from decreasing with time, and to keep the copper etching rate constant throughout.

Therefore, chemical methods such as the sodium chlorate method and the ozone method can be used to eliminate the work of transporting the highly corrosive copper etching deterioration solution and regenerate the copper etching deterioration solution without using chlorine gas, which is a hazardous substance. A method using a chemical, and a diaphragm electrolysis method using an ion exchange membrane as a diaphragm as disclosed in Japanese Patent No. 2689076 and Japanese Patent Laid-Open No. 2000-178768 have been proposed.
Japanese Patent No. 2689076 Japanese Patent Laid-Open No. 2000-178768

However, in the case of the method for regenerating degraded liquids with the above chemicals, sodium chlorate is in contact with organic substances and may cause a fire, and the ozone method may cause explosion at an ozone concentration of 20% or more. The above danger may be unavoidable.
In addition, the method using a diaphragm electrolyte bath is to oxidize the anode surface by partitioning the anode and the cathode with a membrane made of an anion exchange membrane and allowing only chloride ions (Cl ⁻ ) to permeate from the cathode side to the anode side. In order to use the reaction, it is necessary to supply hydrochloric acid or a chlorine compound corresponding to the total amount of chlorine ions required for the reaction from the outside to the cathode side.

Further, in the diaphragm electrolyte bath, IR (voltage) drop due to the diaphragm is unavoidable, and there is a disadvantage that the power consumption increases accordingly.
The present invention has been made in view of the above points, and is to regenerate the copper etching deterioration liquid at a copper etching site, thereby eliminating the liquid reciprocal transport between the recycling factory and the copper etching machine. If the liquid circulation of sending a part of the deteriorated liquid generated in the tank to the electrolytic regeneration tank and sending the regenerated copper etching solution back to the copper etching machine is performed, the above copper etching reaction and regeneration reaction are performed in parallel. As a result, it is possible to prevent the copper etching solution from deteriorating and prevent the copper etching performance from being lowered. As a result, the second chloride chloride can keep the processing speed constant in the copper etching machine. It is an object of the present invention to provide an electrolytic regeneration method and an electrolytic regeneration apparatus for a copper etching deterioration solution using iron.

For this reason, the electrolytic regeneration method of the copper etching deterioration solution with ferric chloride according to the first aspect of the present invention is the method of electrolytic regeneration of the copper etching deterioration solution with ferric chloride. And a drum-type rotating cathode rotating with a gap between them, and the stationary anode and the rotating cathode are formed in the copper etching deterioration solution, and there is no diaphragm separation between the electrodes. The ferric chloride is changed into ferrous chloride by the copper etching, and the copper etching deterioration solution in which the copper etching ability is deteriorated is put in the liquid tank as an electrolytic solution, and a part of the rotary cathode is the electrolytic solution. While rotating while immersed in the electrode, a voltage is applied between the two electrodes to oxidize the deteriorated ferrous chloride in the copper etching deterioration solution and to restore the original chloride chloride. Returning to iron, the fixed anode having the function of regenerating the copper etching degradation solution into a copper etching solution, and simultaneously decomposing the dissolved cupric chloride in the electrolyte solution by a reduction reaction to precipitate solid metal copper, While repeating the cycle operation of moving the deposited solid metal copper onto the electrolyte surface to remove and remove it, and submerging in the electrolyte again with the rotation of the rotating cathode to deposit the copper, the above-mentioned The above-mentioned diaphragm electrolyte bath equipped with the above-mentioned rotating cathode having a function of performing copper removal in the electrolyte solution is maintained at an electrolyte temperature of 15 to 35 ° C. and a free hydrochloric acid amount in the solution of 0.3 to 3.0%. The cathode current density is adjusted to a range of 10 to 25 A / dm ² and the operation is performed.

  According to a second aspect of the present invention, there is provided a method for electrolytic regeneration of a copper etching deterioration solution using ferric chloride according to the first aspect of the present invention. Since one end of the conductive cable is connected to the rotary cathode, the other end is connected to the rotary terminal of the sliding connector provided on the rotary shaft of the hollow structure, and the negative electrode conductive cable rotates together with the rotary cathode. The entire rotating cathode surface is energized during rotation, and the formed copper is formed in the electrolyte solution portion of the rotating cathode surface, and in the portion where the rotating cathode rotates and exits from the electrolyte solution surface, Since the electrolytic action is not performed, but the current is energized, the deposited copper adheres to the surface of the rotating cathode without being redissolved by the electrolytic solution accompanying the electrolytic solution. It is characterized by separating and removing.

  The method for electrolytic regeneration of a copper etching deterioration solution with ferric chloride according to the present invention as set forth in claim 3 is the method according to claim 1 or 2, wherein the copper is ferric chloride in the copper etching with ferric chloride. The ferric chloride itself is reduced to the ferrous chloride and the copper etching ability deteriorates and liquefies. By applying electric energy from the outside in a diaphragm electrolyte bath, a reaction for returning the copper etching reaction to the reverse direction is generated, and the cupric chloride in the copper etching deterioration solution is decomposed to decompose the original metal. Returning to copper, chlorine ions generated by the decomposition reaction at that time are self-supplied as a chlorine source to oxidize the ferrous chloride and return it to the original ferric chloride.

  The method for electrolytic regeneration of a copper etching deterioration solution using ferric chloride according to the present invention as set forth in claim 4 is the method according to any one of claims 1 to 3, wherein the regeneration electrolyte tank for the diaphragm electrolyte layer is used. The deterioration of the copper etching solution and the above are formed by forming a path so that the electrolyte solution circulates between the solution and the deterioration solution tank of the etching machine, and constantly replacing the copper etching deterioration solution and the regenerated electrolyte solution little by little. Regeneration of the copper etching deterioration solution proceeds simultaneously, and the copper etching rate is constantly stabilized.

The electrolytic regeneration apparatus for a copper etching deterioration solution using ferric chloride according to the present invention according to claim 5 is the fixed anode fixed in the copper etching deterioration liquid in the electrolytic regeneration apparatus for copper etching deterioration solution using ferric chloride. A drum-type rotating cathode installed at a distance between the fixed anode and the fixed anode, and a diaphragm for partitioning the fixed electrode and the rotating cathode in the copper etching deterioration liquid. There is not a diaphragm electrolyte bath, and the copper anode solution in which the ferric chloride is changed to ferrous chloride by the copper etching and the copper etching ability is deteriorated in the fixed anode is electrolyzed in the diaphragm electrolyte bath. Deterioration of copper etching by applying a voltage between the electrodes while rotating a part of the rotating cathode immersed in the electrolytic solution. The fixed anode having the function of oxidizing the deteriorated ferrous chloride and returning it to the original ferric chloride to regenerate the copper etching deterioration solution into a copper etching solution, and simultaneously dissolving in the solution by a reduction reaction The cupric chloride is decomposed, solid metal copper is deposited, the deposited solid metal copper is moved onto the electrolyte surface, peeled and removed, and again in the electrolyte solution along with the rotation of the rotating cathode. The above-mentioned diaphragm electrolyte bath having the above-mentioned rotating cathode having a function of removing copper in the electrolytic solution while repeating a cycle operation of immersing and depositing the copper is attached to an electrolytic solution temperature of 15 to 35 ° C. The operation is characterized in that the amount of free hydrochloric acid in the liquid is maintained at 0.3 to 3.0%, and the cathode current density is adjusted in the range of 10 to 25 A / dm ² .

According to the method for electrolytic regeneration of a copper etching deterioration solution with ferric chloride according to the present invention as set forth in claim 1, in the method for electrolytic regeneration of a copper etching deterioration solution with ferric chloride, a fixed anode and a rotation are placed in the copper etching deterioration solution. A drum-type rotating cathode with a gap between the electrodes, and the fixed anode and the rotating cathode are formed in the copper etching deterioration solution, and there is no diaphragm separating the two electrodes. In addition, the ferric chloride is changed into ferrous chloride by the copper etching, and the copper etching deterioration solution in which the copper etching ability is deteriorated is put as an electrolytic solution, and a part of the rotating cathode is put in the electrolytic solution. While rotating in the immersed state, by applying a voltage between the electrodes, the ferrous chloride deteriorated in the copper etching deterioration solution is oxidized to the original ferric chloride. Then, the fixed anode having a function of regenerating the copper etching deterioration solution into a copper etching solution, and simultaneously decomposing the dissolved cupric chloride in the electrolytic solution by a reduction reaction to precipitate solid metal copper, The above-mentioned electrolyte solution is repeatedly removed by moving the solid metal copper onto the electrolyte surface, peeling off and removing it, and immersing it again in the electrolyte solution with the rotation of the rotating cathode to deposit the copper. The above-mentioned diaphragm electrolyte bath provided with the above-mentioned rotating cathode having a function of performing copper removal inside is maintained at an electrolyte temperature of 15 to 35 ° C. and the amount of free hydrochloric acid in the solution at 0.3 to 3.0%, Since the cathode current density is adjusted to the range of 10 to 25 A / dm ² and the operation is performed, when the dissolved copper dissolved in the electrolytic electrolyte is deposited on the rotating cathode surface, the chlorine ions separated from the copper are Bonded with ferrous chloride produced by copper etching In combination, this can be easily and electrolytically regenerated into ferric chloride.

  According to the method for electrolytic regeneration of a copper etching deterioration solution using ferric chloride according to the present invention described in claim 2, in the method according to claim 1, the cathode conductive cable is installed in the cathode rotating shaft having a hollow structure, One end of the cathode conductive cable is connected to the rotary cathode, and the other end is connected to a rotary terminal of a sliding connector provided on the rotary shaft of the hollow structure, and the cathode conductive cable rotates together with the rotary cathode. Therefore, the entire rotating cathode surface is energized during rotation, and the deposited copper is formed in the portion of the rotating cathode surface in the electrolyte solution, and the rotating cathode rotates to leave the electrolyte solution surface. Then, since the electrolysis is not performed, but the current is energized, the deposited copper adhered to the surface of the rotating cathode without being redissolved by the electrolyte accompanying the electrolyte is removed with a scraper. As described above, the entire rotating cathode surface is energized during rotation as described above, and the deposited copper is formed in the portion of the rotating cathode surface in the electrolyte, and the rotating cathode In the portion that is rotated out of the liquid surface, the electrolytic action is not performed, but the current is applied. Therefore, the deposited copper is separated and recovered without being redissolved by the accompanying electrolytic solution. be able to.

  According to the method for electrolytic regeneration of a copper etching deterioration solution using ferric chloride according to the third aspect of the present invention, in the method according to claim 1 or 2, in the copper etching using ferric chloride, the copper is chlorinated. It is dissolved in ferric and converted to cupric chloride, and the ferric chloride itself is reduced to the ferrous chloride and the copper etching ability is deteriorated and liquefied. Is put into a non-diaphragm electrolyte bath to give electric energy from the outside, thereby causing a reaction to reverse the copper etching reaction, and decomposing the cupric chloride in the copper etching deterioration solution to It returns to the metallic copper, and the chlorine ion generated in the decomposition reaction at that time is self-supplied as a chlorine source to oxidize the ferrous chloride and return it to the original ferric chloride. The above in the deteriorated liquid In order to decompose cupric chloride and return it to the original copper metal, the chlorine ion generated in the decomposition is self-supplied as a chlorine source to oxidize ferrous chloride and regenerate it into ferric chloride. A chlorine source is unnecessary and safe.

  According to the method for electrolytic regeneration of a copper etching deterioration solution using ferric chloride according to the present invention as set forth in claim 4, in the method according to any one of claims 1 to 3, regeneration electrolysis of the diaphragm electrolyte layer is performed. Deterioration of the copper etching solution by forming a path so that the electrolyte circulates between the solution tank and the deterioration solution tank of the etching machine and constantly replacing the copper etching deterioration solution and the regenerated electrolyte solution little by little. And the regeneration of the copper etching deterioration solution proceed at the same time, and the copper etching rate can be constantly stabilized.

According to the electrolytic regeneration apparatus for ferric chloride copper etching deterioration liquid of the present invention according to claim 5, in the electrolytic regeneration apparatus for ferric chloride copper etching deterioration liquid, the copper etching deterioration liquid is fixed in the copper etching deterioration liquid. A fixed anode and a drum-type rotating cathode installed at a distance between the fixed anode and a gap, and the fixed anode and the rotating cathode are partitioned between the electrodes disposed in the copper etching deterioration solution. The diaphragm electrolyte bath without the diaphragm, and the copper degradation solution in which the ferric chloride is changed to ferrous chloride by the copper etching on the stationary anode and the copper etching ability is deteriorated is the diaphragm electrolyte bath. The copper etchant by applying a voltage between the two electrodes while rotating a part of the rotating cathode immersed in the electrolytic solution. The fixed anode having a function of oxidizing the deteriorated ferrous chloride in the deterioration solution and returning it to the original ferric chloride to regenerate the copper etching deterioration solution into a copper etching solution; The dissolved cupric chloride is decomposed, solid metal copper is precipitated, the deposited solid metal copper is moved onto the electrolyte surface, peeled and removed, and again with the rotation of the rotating cathode, the electrolyte solution again. The diaphragm electrolyte bath having the rotating cathode having the function of removing copper in the electrolyte while repeating the cycle operation of depositing and adhering the copper by submerging in the electrolyte, the electrolyte temperature being 15 to 35 ° C, the amount of free hydrochloric acid in the liquid is maintained at 0.3 to 3.0%, and the cathode current density is adjusted to the range of 10 to 25 A / dm ² , so that the dissolved copper dissolved in the electrolytic solution is operated. Is deposited on the surface of the rotating cathode. Chlorine ions decomposed from monocopper can be combined with ferrous chloride produced by the above copper etching, and this can be easily electrolytically regenerated into ferric chloride.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic plan view of a diaphragm electrolyte bath for regenerating the copper etching deterioration solution of the present invention, and FIG. 2 shows a main part of a cross section taken along line 2A-2A in FIG. FIG. 3 is a schematic explanatory view showing a state in which dissolved copper in the liquid is deposited on the surface of the rotating cathode and peeled off on the surface of the electrolytic solution. FIG. 3 is a schematic side view of FIG. FIG. 4 is a process flow sheet showing the simultaneous operation method of the diaphragm electrolyte bath and the etching machine in FIG. 3. 3 is a schematic explanatory view of a three-dimensional perspective view, and FIG. 5 is an adjusting means for adjusting the level of the electrolyte in the non-diaphragm electrolyte bath of the present invention shown in FIGS.

As shown in FIG. 1, in a diaphragm electrolyte bath 1 which is a square bath with an open top, a bearing mount 6 is installed on the two opposite wall surfaces, and a bearing 7 of a support shaft 4A thereon is a drum type. The rotary conductive shaft 4 of the rotary cathode 3 is supported. The liquid inlet account 16 of the diaphragm electrolyte bath 1 is a pipe, and the electrolyte outlet account 13 is an overflow type so that the height of the diaphragm electrolyte liquid surface is always kept constant.
2 and 3, the fixed anode 2 is fastened to the bottom surface 1a of the diaphragm electrolyte bath 1 by bolts B and nuts N via bolts B and nuts N via support members 2S. The rotating cathode 3 and the rotating conducting shaft 4 rotate together in an integral structure, but the liquid discharge account 13 of the diaphragm electrolyte bath 1 is rotated by the overflow method as shown in FIGS. A part of the drum-type rotary cathode 3 below the shaft 4 is immersed in the electrolytic solution, and the remaining part protrudes upward from the liquid surface.

The rotary conductive shaft 4 accommodates the cathode-side conductive cable 12B in the hollow shaft 4a, and the rotary cathode surface 3 and the conductive cable 12B conduct while rotating together with the drum-type rotary cathode 3 having an integral structure. .
As shown in FIGS. 1 and 2, the conductive cable 12A on the fixed anode 2 side connected to the + side terminal of the DC power supply is electrically connected to the fixed anode 2 side installed vertically in the non-diaphragm electrolyte bath 1. The bus 17 is connected at one end 17a. The other end 17 b is fastened to the fixed anode 2 on the bottom surface of the diaphragm electrolyte bath 1 with bolts B and nuts N.

  The cathode side conductive cable 12B connected to the negative terminal of the DC power source is connected to the fixed terminal side of the sliding connector 11 on the rotary conductive shaft 4 as shown in FIG. The rotary conductive shaft 4 is connected to the conductive cable 12B installed in the hollow portion of the hollow shaft 4a. The other end of the conductive cable 12B is fastened with a bolt B and a nut N to the connection terminal portion 3C inside the drum-type rotary cathode 3, so that the drum-type rotary cathode that rotates with one side terminal of the DC power supply. 3 is electrically connected.

  When the copper etching deterioration solution is put in the diaphragm electrolyte bath 1 and a voltage is applied to the fixed anode 2 and the rotating cathode 3, the ferrous chloride in the solution is oxidized on the surface of the fixed anode 2 and is chlorinated. It becomes ferric iron and copper etching ability is regenerated. On the other hand, on the surface of the rotating cathode 3, cupric chloride formed by dissolving copper metal by copper etching is reduced to deposit metallic copper and adhere to the surface of the rotating cathode 3 in the electrolytic solution. As the rotating cathode 3 rotates, the deposited copper adhering to the rotating cathode 3 leaves the electrolytic solution surface and comes into contact with air, but this portion is energized but does not reach the electrolytic reaction. As shown in FIG. While repeating the above-described cycle operation of the fixed anode 2 and the rotating cathode 3, regeneration of the deteriorated liquid proceeds.

  As shown in FIGS. 1, 2, and 4, the diaphragm electrolyte tank 1 for regenerating the copper etching deterioration solution is provided as an accessory of the diaphragm electrolyte tank 1 and outside the diaphragm electrolyte tank 1. There is a circulation pump 14, and a circulation pipe RP for extracting a part of the electrolyte in the diaphragm electrolyte tank 1 and returning it to the diaphragm electrolyte tank 1 is installed. A freshly regenerated electrolytic solution is always supplied to the electrode surface, and a liquid temperature indicator / regulator TIC and a free hydrochloric acid amount are supplied to the liquid tank return pipe on the discharge side of the circulation pump 14 of the circulation pipe RP shown in FIGS. A liquid specific gravity indicator / regulator DIC is incorporated in the piping for the indicator / adjuster AIC and the etching machine E, and the electrolyte properties are automatically adjusted and maintained so as to meet the electrolyte conditions of the above-mentioned claim 1. Time to regenerate the entire amount of the above-mentioned deteriorated liquid stuck to the liquid tank 1 as one batch In the case of playback is shown. Since the current etching machine is a batch operation, regeneration is also performed for each of the deteriorated liquids supplied as one batch.

  As shown in FIG. 4, the automatic adjustment and holding means that the liquid temperature detected at the detection end of the liquid temperature indicating adjuster TIC is converted into an electric signal and sent to the operation panel 30a. The valve opening degree is instructed to the water adjustment valve 40a by a signal, and a required amount of cooling water is supplied to automatically adjust the liquid temperature. The hydrochloric acid concentration detected at the detection end of the free hydrochloric acid amount indicating regulator AIC is converted into an electric signal and sent to the operation panel 30b. The required amount of hydrochloric acid is supplied to automatically adjust the hydrochloric acid concentration.

On the other hand, the continuous regeneration is to regenerate the deteriorated solution simultaneously with the copper etching of FIG. 3 and claim 5.
In the operation of the copper etching machine E, the copper etching solution is gradually deteriorated. However, when a small amount of the deterioration solution is put into the electrolytic regeneration device 100 as shown in FIG. 3, the deteriorated portion is immediately regenerated. If this is returned to the copper etching machine E, the copper etchant will not deteriorate. The copper etching machine E and the diaphragm electrolyte bath 1 of the present invention are connected by two pipes P1 and P2 as shown in FIG. 3, and a small amount of liquid is passed from the copper etching machine E to the diaphragm electrolyte solution. If the same amount of the regenerated liquid flows back to the tank 1 and returns to the etching machine E, the above-described etching and regeneration proceed simultaneously and simultaneously, so that continuous regeneration is achieved.

  The diaphragm electrolyte bath 1 is made of a material such as vinyl chloride resin that is resistant to copper etchant and does not pass electricity, and the fixed anode 2 is resistant to electrolyte, such as carbon having good conductivity. Made with. The electrode surface of the drum-type rotating cathode 3 uses a highly conductive metal excluding titanium alone. The titanium cathode has a characteristic that the surface becomes inactive and cannot be energized, and is not suitable as a cathode material. It is an electrochemically well-known fact that metals are not corroded at all during energization. Therefore, after the operation is completed, a small amount of anticorrosive current cathode is energized to protect the drum.

Further, the rotating cathode 3 continuously repeats repetitive movements, but a part of the rotating cathode 3 needs to be in a state where it protrudes above the electrolytic solution surface for peeling the upper deposited copper. Further, the fixed anode 2 can be changed to a shape having a circular arc surface concentric with the rotating cathode 3 so as to keep the distance between the electrodes substantially constant, thereby reducing the current resistance.
In the electrolytic regeneration method and the electrolytic regeneration apparatus of the copper etching deterioration solution of the present invention, since the diaphragm electrolyte bath is used, there is no distinction between the anolyte and the catholyte in the electrolyte, and the copper etching deterioration solution is directly used. Unlike the diaphragm electrolytic cell, the reaction mechanism is a method of causing the reaction in the opposite direction to the copper etching reaction to return to the original copper etching solution. As such, the copper etching reaction is as follows.
The standard electrode potentials (V vs SHE) E ⁰ of cupric ions (Cu ²⁺ ) and ferrous and ferric ions (Fe ²⁺ , Fe ³⁺ ) involved in the etching reaction are as follows.

Since the flow of electrons (e ⁻ ) moves from the lower potential (unstable side) to the higher potential (stable side), ferric iron dissolves metallic copper and is reduced to ferrous iron. It is clear that the etching reaction of becoming a cupric ion is a natural reaction. In other words, this reaction direction does not change unless energy is given from the outside.
The present invention moves the electrons (e ⁻ ) in the opposite direction (the direction of the arrow is reversed) by applying a necessary voltage to the copper etching degradation liquid of the copper etching reaction termination liquid from the outside, By causing a reaction in the opposite direction to the etching, maintaining the temperature and free hydrochloric acid amount acidity constant, and adjusting and controlling the cathode current density in the range of 10 to 25 A / dm ² , It is something to regenerate.

  As described above, the electrolytic regeneration reaction of the copper etching deterioration solution of the present invention proceeds in the opposite direction to the copper etching reaction this time with respect to the copper etching deterioration solution after completion of the copper etching reaction. Therefore, the chlorine source necessary for the oxidation of the fixed anode 2 is not newly supplied from the outside, but the cupric chloride in the copper etching deterioration solution generated by the copper etching reaction is the chlorine source. This is a chlorine self-supply type electrolytic reaction, and the following regenerative electrolytic reaction formula supports it. If the copper metal deposited on the rotary cathode 3 is peeled and removed from the electrolytic solution, ferric chloride remains to be the regenerated solution itself.

  In the rotating cathode 3, the field of electrolysis is a portion where the rotating cathode 3 is immersed in the electrolyte solution. Here, the metallic copper is deposited on the cathode surface, and from the liquid surface into the air as the rotating cathode 3 rotates. Although it comes out, since the rotating cathode 3 is in an energized state, the deposited copper does not re-dissolve. In addition, since the air contact portion of the rotating cathode surface is away from the field of electrolysis, the deposited copper can be recovered by mechanically peeling it with a scraper. The surface of the rotating cathode 3 after peeling of the deposited copper is rotated and repeatedly cycled so that it is immersed again in the electrolyte and deposits the deposited copper.

In addition to the cupric chloride (CuCl ₂ ) produced by the copper etching in the electrolyte, the substance is chemically unstable even if there is a small amount of cuprous chloride (CuCl). In the presence of hydrochloric acid, a stable complex salt ([CuCl ₂ ] ⁻ ) is formed. However, since the complex salt is decomposed into each element by electrolytic action, it does not hinder regeneration. That is, the presence of free hydrochloric acid has the effect of stabilizing cuprous chloride.

Free hydrochloric acid itself does not etch the copper, but has the property of accelerating the copper etching of the ferric chloride. Therefore, as defined by JIS, the etching solution inherently contains free hydrochloric acid. However, volatilization disappears gradually during the copper etching. Therefore, it is rather necessary that free hydrochloric acid is present in the regenerated solution.
Another effect of the presence of free hydrochloric acid is to prevent the formation of ferric hydroxide (Fe (OH) ₃ ). When the amount of hydrochloric acid in the liquid becomes 0.3% or less (pH of liquid> 2, 25 ° C.) during the regeneration electrolysis, a part of the ferric chloride (FeCl ₃ ) in the liquid is hydrolyzed and solidified. Begins to produce ferric hydroxide. This material is not electrolyzed and remains as an impurity after regeneration.

  As described above, free hydrochloric acid in the electrolytic solution is indispensable for the operation of the electrolytic cell of the present invention. However, hydrochloric acid has a property that it is likely to volatilize suddenly when the liquid temperature exceeds 35 ° C. It is necessary to keep the electrolyte temperature at 35 ° C. or lower for the purpose of preventing the volatilization of hydrochloric acid. Since the loss of electric power in the electrolytic action becomes thermal energy and causes the electrolyte temperature to rise, the liquid temperature is held and adjusted by a cooler. Conversely, when the liquid temperature is 15 ° C. or lower due to excessive cooling, the conductivity of the liquid is lowered.

The state of copper deposited on the rotating cathode surface varies depending on the current density. The cathode material can be iron, carbon, stainless steel copper, or copper. In the case of iron or stainless steel, the surface is plated with copper. When the cathode current density is low, the deposited copper becomes fine and strongly adheres to the cathode. When the current density is high, coarse granular copper adheres loosely and peeling becomes easy. A suitable cathode current density level for operation is 10-25 A / dm ² .

Since the copper etching solution indirectly measures the ferric chloride concentration by the liquid specific gravity, it is important to manage the liquid specific gravity of the regenerating liquid. In the etching and regeneration process, water is not added, but rather it evaporates and water always runs short. Therefore, a water-type automatic specific gravity adjustment meter is installed at the regeneration solution outlet. The specific gravity value is the user's management value.
If the copper etching machine and the regenerative electrolyte bath are connected by piping and the electrolyte is circulated between them, the copper etchant is immediately regenerated as much as the copper etch deteriorates. It is obvious that the absence of the state is realized, but if the operation is performed in this state, the copper etching rate can be kept constant, and the stable copper etching state can be provided.

  Since it is not necessary to remove until there is no dissolved copper in the electrolytic solution, the reaction is terminated with some copper remaining.

  Using the above ferric chloride aqueous solution having a concentration of 43%, an etching waste solution having a copper concentration of 60 g / liter obtained by etching a printed circuit board was regenerated using an electrolytic cell having the same structure as that shown in FIG. . 2 liters of waste liquid was put into the electrolytic bath liquid tank, and the liquid was removed from the liquid tank by the circulation pump 14 and returned to the liquid tank so that the liquid could always wash the electrode surface and contact the fresh liquid with the electrode. .

The specifications of the regenerated electrolyte tank and the properties of the used deterioration liquid in the examples are described below.
Electrolyzer bath: 165 mm x 280 mm, 100 mm high hard vinyl chloride anode: 220 mm x 100 mm, 5 mm thick hard graphite carbon cathode: drum type stainless steel (SUS316L) with a diameter of 114.3 mm and a width of 200 mm 1-5 revolutions per minute (variable)
Minimum distance between electrodes: 5mm
Rectifier: Primary side 200V 2-phase AC secondary side 0-100A DC constant voltage / constant current switching circulation pump: 400ml per minute
Heat exchanger: Cylindrical type with a diameter of 200mm x height of 500mm Cooling water temperature 23 ° C
Coil winding length of plastic pipe with an inner diameter of 4 mm: 3 meters Outer water-cooled hydrochloric acid concentration meter: 1 piece Liquid thermometer: 1 piece The copper etching deterioration liquid collected from the etching line was used, but 60 grams of copper per liter of liquid It was dissolved. This was applied as an electrolytic solution to an electrolytic cell so that the liquid immersion rate of the drum was 30%. When the liquid temperature was maintained at 23 ° C. with a cooler and the hydrochloric acid concentration was adjusted to about 0.5%, the electrolyte bath was operated, and the operation was terminated at a regeneration rate of about 95%.

At this time, the operation result of the electrolytic solution tank was as follows.
Voltage: 3.5V
Current: 30A
Current density: 14.3 A / dm ²
Chlorine was not generated and the deposited copper was easy to peel off.

According to the present invention, a non-diaphragm electrolyte bath provided with the flat fixed anode and the rotating drum type rotating cathode is used, and a copper etching deterioration solution is used as an electrolyte, and hydrochloric acid is added thereto to add a hydrochloric acid concentration. The electrolyte bath was operated at a current density of 20 A / dm ² while keeping the liquid temperature at 30 ° C. or less with a cooler while keeping the liquid temperature at 0.3 to 4%. Can be regenerated into the above-described copper etching solution containing ferric chloride as a main component.

  Therefore, if the etching machine and the electrolytic solution tank are connected by piping and the liquid is circulated between the two apparatuses, the regeneration can be continued while the copper etching is performed, so the copper etching ability of the electrolytic solution is reduced. This can be kept constant without making it happen.

It is a schematic plan view of the diaphragm electrolyte bath which reproduces | regenerates the copper etching deterioration liquid of this invention. FIG. 2 is a cross-sectional view taken along line 2A-2A in FIG. 1, and schematically shows a state in which dissolved copper in the electrolytic solution is deposited on the surface of the rotating cathode and peeled off on the electrolytic solution surface in the non-diaphragm electrolytic solution tank. It is an explanation. FIG. 2 is a schematic explanatory view showing a schematic side view of FIG. 1 and simultaneously operating a diaphragm membrane electrolytic bath and an etching machine that simultaneously perform regeneration of the copper etching deterioration solution while performing the copper etching. It is a schematic explanatory drawing of the three-dimensional perspective of the structure which the process flow sheet | seat which shows the simultaneous operation method of the non-diaphragm electrolyte solution tank in FIG. 3 and the said etching machine shows. It is the adjustment means which adjusts the level of the electrolyte solution of the said diaphragm membrane electrolyte tank of this invention shown in FIG. 2, FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Non-diaphragm electrolyte bath 2 Fixed anode 3 Drum-type rotating cathode 4 Rotating conductive shaft 4a Hollow shaft 5 Reduction motor 6 Bearing mount 7 Bearing 8 Scraper fixing bar 9 Scraper 10 Scraper presser 11 Sliding connector 12A Anode-side fixed conductive cable 12B Cathode-side rotating conductive cable 13 Overflow-type circulating liquid tank outlet 14 Circulating pump 16 Waste liquid inlet (shared batch and continuous operation)
17 Anode conductive bus 19 Precipitated copper meter TIC Liquid temperature indicating controller AIC Free hydrochloric acid amount indicating controller DIC Liquid specific gravity indicating controller c
P1 Main circulation piping P2 Main circulation piping (recycled liquid outlet / for continuous operation)
RP circulation piping

Claims (5)

In the electrolytic regeneration method of a copper etching deterioration solution by ferric chloride, a fixed anode and a rotating drum-type rotating cathode are installed in the copper etching deterioration solution with a distance between the electrodes with a space therebetween. And a rotating cathode formed in the copper etching deterioration solution, and a diaphragmless electrolyte solution tank that separates the electrodes from each other, the ferric chloride is changed to ferrous chloride by the copper etching, and the copper etching ability The copper etching deterioration solution is applied as an electrolytic solution, and the copper etching is performed by applying a voltage between the electrodes while rotating a part of the rotating cathode immersed in the electrolytic solution. The fixed positive electrode has a function of oxidizing the deteriorated ferrous chloride in the deterioration solution and returning it to the original ferric chloride to regenerate the copper etching deterioration solution into a copper etching solution. And at the same time, the dissolved cupric chloride in the electrolytic solution is decomposed by a reduction reaction, solid metal copper is deposited, the deposited solid metal copper is moved onto the electrolytic solution surface, peeled and removed, and rotated. The diaphragmless electrolysis comprising the rotating cathode having a function of performing copper removal in the electrolyte while repeating a cycle operation in which the copper is deposited again by being immersed in the electrolyte again with rotation of the cathode. The liquid tank is operated with an electrolyte temperature of 15 to 35 ° C., a free hydrochloric acid amount in the liquid of 0.3 to 3.0%, and a cathode current density adjusted to a range of 10 to 25 A / dm ^2. A method for electrolytic regeneration of a copper etching deterioration solution using ferric chloride, which is characterized.   A cathode conductive cable is installed in a hollow structure cathode rotating shaft, one end of the cathode conducting cable is connected to the rotating cathode, and the other end is provided on the rotating shaft of the hollow structure. Since the cathode conductive cable is connected to the terminal and rotates together with the rotating cathode, the entire rotating cathode surface is energized during rotation, and the deposited copper is formed in the portion of the rotating cathode surface in the electrolyte. In the portion where the rotary cathode rotates and exits from the electrolyte surface, the electrolytic action is not performed but the current is applied. Therefore, the deposited copper is redissolved by the electrolyte solution accompanying the electrolyte solution. 2. The method for electrolytically regenerating a copper etching deterioration solution with ferric chloride according to claim 1, wherein the deposited copper adhering to the surface of the rotating cathode without mechanically peeling is removed mechanically with a scraper.   In the copper etching with ferric chloride, the copper is dissolved in ferric chloride and converted into cupric chloride, and the ferric chloride itself is reduced to the ferrous chloride so that the copper etching ability is reduced. Deteriorated and liquefied, but the copper etching deterioration solution is placed in a diaphragm electrolyte bath and electric energy is applied from the outside to cause a reaction to return the copper etching reaction in the reverse direction. The cupric chloride in the etching deterioration solution is decomposed and returned to the original metallic copper. Chlorine ions generated by the decomposition reaction at that time are self-supplied as a chlorine source to oxidize the ferrous chloride and oxidize the original The method for electrolytic regeneration of a copper etching deterioration solution with ferric chloride according to claim 1 or 2, wherein the ferric chloride is returned to ferric chloride.   A path is formed so that the electrolyte circulates between the regeneration electrolyte tank of the non-membrane electrolyte layer and the deterioration tank of the etching machine, and the copper etching deterioration solution and the regeneration electrolyte are constantly replaced little by little. The chlorination according to any one of claims 1 to 3, wherein the deterioration of the copper etching solution and the regeneration of the copper etching deterioration solution proceed simultaneously to stabilize the copper etching rate at all times. Electrolytic regeneration method of copper etching deterioration liquid by ferric iron. In an electrolytic regeneration apparatus for a copper etching deterioration solution by ferric chloride, a fixed anode fixed in the copper etching deterioration solution, and a drum-type rotating cathode installed with a distance between the fixed anode and the fixed anode; The fixed anode and the rotating cathode are disposed in the copper etching deterioration solution, and the non-diaphragm electrolyte solution tank that separates the electrodes from each other, and the ferric chloride is chlorided on the fixed anode by the copper etching. An electrolytic solution in which the copper deterioration solution changed to ferrous iron and the copper etching ability has deteriorated is embedded as an electrolytic solution in the diaphragm electrolyte bath, and a part of the rotating cathode is in the electrolytic solution. While rotating in a state immersed in the electrode, by applying a voltage between the electrodes, the ferrous chloride deteriorated in the copper etching deterioration solution is oxidized and returned to the original ferric chloride. Copper etch The above-described fixed anode having a function of regenerating the degradation solution into a copper etching solution, and simultaneously dissolving the cupric chloride dissolved in the solution by a reduction reaction to precipitate solid metal copper, and the precipitated solid metal copper The copper is removed from the electrolyte solution by repeating a cycle operation in which the copper electrode is moved to the surface of the electrolyte solution, peeled and removed, and immersed in the electrolyte solution again with the rotation of the rotating cathode to deposit the copper. The above-mentioned diaphragm electrolyte bath having the above-mentioned rotating cathode having the function of carrying out the above operation is maintained at an electrolyte temperature of 15 to 35 ° C., the amount of free hydrochloric acid in the solution at 0.3 to 3.0%, and a cathode current density of 10 An electrolytic regeneration apparatus for a copper etching deterioration solution by ferric chloride, which is adjusted to operate in a range of ˜25 A / dm ² .

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