JP5518421B2 - Recycling method for nickel-plated copper or copper alloy scrap - Google Patents

Description

  The present invention is a recycling method in which nickel is continuously and efficiently peeled off from copper or copper alloy scraps subjected to nickel plating, and the copper or copper alloy wastes from which nickel plating is peeled is used as a raw material for producing copper or copper alloys. It is about the method.

Conventionally, plating layers of nickel, tin, copper, etc. have been formed on the surface of copper strips made of copper or copper alloys on lead frames, terminals, connectors, etc. used in semiconductor devices such as IC and LSI, and various electronic and electrical components. Plated copper strips are widely used.
Such plated copper strips are often processed by punching and used, and a large amount of scrap generated during punching is collected and recycled as a raw material for copper or copper alloy production. It is important from the point of view.
In this case, copper alloys used for electronic materials such as lead frames are close to pure copper due to their properties, and nickel-containing scraps can be thinned and reused, or they can be used as general scrap at a low price in the market. The current situation is that it must be sold.

Then, in patent document 1, paying attention to nickel plating especially, after peeling a nickel plating layer with a peeling liquid from the copper or copper alloy waste on which nickel plating was given, the surface of copper or copper alloy waste was further 0.2. A recycling method is disclosed that etches ~ 200 μm and is used as a copper or copper alloy raw material.
In Patent Document 2, as a method for separating a nickel solution and a stripping solution from a stripping solution containing nickel, a waste acid solution was supplied to a pressure dialysis machine and dialyzed to increase the concentration of the acid solution and the metal content. Separated into a metal concentrate, the metal concentrate is supplied to an ion exchange resin device, separated into an acid solution and a waste acid, and is discarded after improving the acid recovery rate and metal removal rate of the waste acid solution. A method for reducing the amount of liquid is disclosed.

JP 2001-123280 A JP 2003-144858 A

In the method disclosed in Patent Document 1, an expensive and short-life nickel stripping solution is used, and in order to remove contamination caused by the nickel stripping solution, copper or copper alloy scraps are further removed after the nickel plating stripping. Etching is performed. In addition, waste liquid treatment of the stripping solution after being subjected to stripping becomes a problem.
In this case, although the acid can be recovered from the waste liquid by the waste liquid treatment technique described in Patent Document 2, it is desired to recover nickel more efficiently as a recycling technique.

  The present invention has been made in view of such circumstances, and does not use an expensive and short-life stripping solution, and does not etch after stripping. Or, peel nickel from copper alloy scraps, use copper or copper alloy scraps from which nickel plating has been peeled off as a raw material for the production of copper or copper alloys, and also eliminate the problem of waste liquid treatment of the stripping solution. The purpose is to provide a recycling method in which nickel can also be collected.

As a result of diligent research, the inventors of the present invention have developed nickel sulfate by directly oxidizing nickel by electrolysis using an inexpensive and simple stripping solution based on sulfuric acid. Regarding the stripping solution, it was considered that if nickel sulfate was discharged out of the system, it could be used repeatedly and so-called zero emission could be achieved. In that case, in order to raise the efficiency at the time of discharging | emitting nickel sulfate from stripping solution, it discovered that it was effective to concentrate and isolate nickel sulfate from used stripping solution using a pressure dialysis apparatus. It has also been found that nickel can be efficiently recovered on the cathode surface by electrolyzing the concentrated and separated nickel sulfate in an electrolyte having a pH of 1 to 6 based on nickel sulfate.
Furthermore, since a simple stripping solution based on sulfuric acid was used, it was confirmed that there was no contamination due to residual sulfur (S) and the like, and etching after stripping was unnecessary.

In the production method of the present invention, a sulfuric acid solution is stored as a stripping solution, the sulfuric acid concentration of the sulfuric acid solution is 50 to 300 g / L, and the pH is -0.7 to 0. By immersing the nickel-plated copper or copper alloy scrap, the nickel plating is peeled off by a chemical reaction of Ni + H ₂ SO ₄ → NiSO ₄ + H ₂ , and the used stripping solution containing the peeled nickel is pressured In a dialyzer, the nickel sulfate solution is separated into a concentrated nickel sulfate solution and the concentrated nickel sulfate solution is electrolyzed in a second electrolytic cell to recover nickel and the concentrated The sulfuric acid solution is returned to the first electrolytic cell.
A pressure dialysis machine is a pressure-based membrane separation method that efficiently separates a used stripping solution containing stripped nickel into a concentrated nickel sulfate solution and a concentrated sulfuric acid solution, and has a spiral load membrane. Preferably it is.

When sulfuric acid concentration is less than 50 g / L, primarily dissolved copper or copper alloy scrap of the base material than nickel hardly proceeds dissolution of nickel. If the sulfuric acid concentration exceeds 300 g / L, the peeling speed decreases due to the increase in viscosity, and it takes time for peeling. More preferably, the sulfuric acid concentration is 150 to 300 g / L. When the pH is less than −0.7, the solubility of nickel decreases, and when the pH exceeds 0, the dissolution rate of nickel decreases and it takes time to peel off.

Moreover, in the manufacturing method of this invention, the main component of the electrolyte solution of said 2nd electrolytic vessel is nickel sulfate, and pH is 1-6, It is characterized by the above-mentioned. Since the nickel sulfate solution recovered by peeling is electrolyzed, nickel sulfate is the most suitable as the main component of the electrolytic solution. When the pH of the electrolytic solution is less than 1, the current efficiency is low and the deposition rate of nickel on the cathode is slow, and when the pH exceeds 6, the adhesion of nickel on the cathode is deteriorated and the nickel is recovered. Will take time. The temperature of the electrolyte and the current density also affect the nickel recovery efficiency, but the temperature is preferably 45 to 55 ° C. and the current density is preferably ²⁰ to 50 A / dm ² .

  In the recycling method of the present invention, the stripping solution preferably contains 0.05 to 0.1% by volume of an oil removing agent. Copper or copper alloy scrap is, for example, stamped scrap at the time of press working, and most of the oil adheres to the surface. By removing this, nickel can be effectively peeled off in advance. Since the degreasing treatment can be omitted, efficiency is high.

  By using the recycling method of the present invention, without using an expensive and short-lived stripping solution, without etching after stripping, continuously and efficiently strips nickel from copper or copper alloy scraps with nickel plating, The peeled copper or copper alloy scrap can be used as a raw material for producing copper and copper alloy. Moreover, in parallel with the electrolytic stripping with the stripping solution, the stripping solution can be used semipermanently while efficiently separating and recovering nickel sulfate from the used stripping solution and recovering nickel from the nickel sulfate. So-called zero emissions can be achieved.

FIG. 1 is an overall view of an apparatus for carrying out the method for stripping nickel from scraped copper or copper alloy scraps according to the present invention.

Hereinafter, an embodiment of the recycling method of the present invention will be described with reference to the drawings.
FIG. 1 shows the overall configuration of a nickel plating stripping apparatus. The nickel plating stripping apparatus 1 includes a first electrolytic tank 2 storing a stripping liquid E, and a stripping solution used for electrolysis in the first electrolytic tank 2. A pressure dialysis apparatus 3 that separates E into concentrated nickel sulfate M and concentrated sulfuric acid solution R, and a second electrolytic layer 4 that recovers nickel D from the concentrated nickel sulfate M are provided.
In the first electrolytic cell 2, a drum cage 5 into which copper or copper alloy scrap C to be recycled is placed and a cathode 6 are immersed, and a power source is connected between the drum cage 5 and the cathode 6 via a rectifier 7. (Not shown) is connected.
The drum cage 5 is made of SUS or the like, and the cathode 6 is made of a metal such as SUS or Cu. Further, the drum cage 5 may be rotated in the electrolytic cell 2 in order to increase the contact area between the stripping solution E and the copper and copper alloy scrap C in the drum cage 5.

The composition of the stripping solution E stored in the first electrolytic cell 2 is a sulfuric acid solution having a sulfuric acid concentration of 50 to 300 g / L (10% sulfuric acid is 50 to 300 g with respect to 1 L of water), and the temperature is 20 to 80 ° C. And When the sulfuric acid concentration of the stripping solution E is less than 50 g / L, the base material copper or copper alloy scrap C is mainly dissolved rather than nickel, and the dissolution of nickel is difficult to proceed. If the sulfuric acid concentration exceeds 300 g / L, the peeling speed decreases due to the increase in the viscosity of the stripping solution E, which takes time. More preferably, the sulfuric acid concentration is 150 to 250 g / L. The pH of the stripping solution E is -0.7 to 0. This is because if it is less than −0.7, the solubility of nickel decreases, and if it exceeds 0, the dissolution rate of nickel decreases and it takes time to peel off.
Moreover, most of the supplied copper or copper alloy scrap C is stamped scraps by press working, and since processing oil is attached, 0.05 to 0.1% by volume of surface activity in the stripping solution E An oil removing agent such as an agent is added.

  The pressure dialysis apparatus 3 is connected to the first electrolytic cell 2 by a connecting pipe 9 having a high-pressure pump 8, and is concentrated by dialyzing the separation membrane 10 with the separation membrane 10 having the supplied stripping solution E inside. The sulfuric acid solution R and the concentrated nickel sulfate M that is not dialyzed are separated, the concentrated sulfuric acid solution R is returned to the first electrolytic cell 2 by the pump 11, and the concentrated nickel sulfate M is secondly pumped by the pump 13. A recovery pipe 14 for supplying to the electrolytic layer 4 is provided.

  In the second electrolytic layer 4, a cathode 15 and an anode 16 are immersed, and a power source (not shown) is connected via a rectifier 17, and the concentrated nickel sulfate M supplied through the recovery pipe 14 is electrolyzed, It is strongly deposited as nickel D on the cathode 15.

Then, the nickel plating copper or copper alloy scrap C is accommodated in the drum cage 5 of the nickel plating peeling apparatus 1, and the peeling solution E is stored in the electrolytic cell 2, and the drum cage 5 and the cathode 6 are stored. Are immersed in the stripping solution E, and a current is passed between the power source and the rectifier 7 between them to melt and peel the nickel from the copper or copper alloy scrap C in contact with the drum cage 5.
At this time, the sulfuric acid concentration of the stripping solution E in the first electrolytic cell 2 is 50 to 300 g / L. The liquid temperature is 20 to 80 ° C. and the pH is −0.7 to 0.

In the stripping solution E, in the copper or copper alloy scrap C in the drum cage 5, Ni releases ions (Ni → Ni ²⁺ + 2e ⁻ ) and becomes Ni ions and dissolves in the stripping solution E. On the other hand, in the vicinity of the cathode 6, hydrogen is generated at 2H ⁺ + 2e ⁻ → H ₂ .
Therefore, it is expressed as the following reaction between the sulfuric acid of the stripping solution E and the nickel plating film of copper or copper alloy scrap C.
Ni + H ₂ SO ₄ → NiSO ₄ + H ₂
Thereby, nickel on the surface of copper or copper alloy scrap C becomes nickel sulfate and dissolves in stripping solution E.

  On the other hand, the stripping solution E in the first electrolytic cell 2 has an osmotic pressure of 0.1 to 0.1 in the separation membrane 10 of the pressure dialysis device 3 through a connecting tube 9 having a high-pressure pump 8 connected to the bottom thereof. A constant amount is supplied so as to be 10 MPa. As the pressure dialysis apparatus 3, it is preferable to use, for example, a metal having a spirally charged membrane as disclosed in Patent Document 2 and good metal removal efficiency. The concentrated sulfuric acid solution R obtained by dialysis of the separation membrane 10 is a pump 11. Then, it is returned to the first electrolytic layer 2 through the circulation system 12 again. The concentrated nickel sulfate M that does not dialyze the separation membrane 10 is supplied to the second electrolytic layer 4 through the recovery pipe 14 by the pump 13. For example, when the stripping solution E is supplied to the pressure dialysis apparatus 3 at 100 L / hr, the concentrated nickel sulfate M is separated through the separation membrane 10 at a rate of 30 L / hr and the concentrated sulfuric acid solution R is 70 L / hr.

Further, a cathode 15 and an anode 16 are immersed in the second electrolytic layer 4, and a power source (not shown) is connected via a rectifier 17, and the composition shown in Table 1 is preferable as the composition of the electrolytic solution. The concentrated nickel sulfate M supplied into the second electrolytic layer 4 is electrolyzed under the conditions shown in Table 1. The material of the cathode 15 is preferably nickel. Especially as nickel collection | recovery conditions, pH is important and it is preferable that it is 1-6. If the pH is less than 1, the current efficiency is low and the nickel deposition rate is slow, and if it exceeds 6, the nickel deposited on the cathode 15 becomes powdery and the recovery efficiency decreases. When the current density is less than 20 A / dm ² , the deposition rate is slow, and when it exceeds 50 A / dm ² , hydrogen generation during electrolysis becomes intense, and the deposition of nickel on the cathode 15 becomes worse due to bubble adhesion. If the temperature is less than 45 ° C., the current efficiency is low and the deposition rate of nickel is slow, and if it exceeds 55 ° C., the homogeneity of the deposited nickel is deteriorated.

  In this way, the cathode 15 from which the nickel D has been recovered is sent to a nickel refining factory and used as a raw material for nickel refining. In addition, the electrolytic solution F overflowing the second electrolytic layer 4 is preferably reused by being returned to the first electrolytic layer 2 through the liquid return pipe 19 by the pump 18 from the viewpoint of a closed system to the environment. Reference numeral 20 denotes a water supply system, and the concentration of the stripping solution E is adjusted by supplying water to the first electrolytic cell 2 as necessary.

As described above, when the energization between the drum cage 5 and the cathode 6 is stopped after a predetermined time from immersing the drum cage 5 in the stripping solution E, the nickel of the copper or copper alloy scrap C in the drum cage 5 is stopped. The plating is dissolved and peeled off, and the peeled nickel is firmly deposited on the cathode 15 of the second electrolytic layer 4.
The copper or copper alloy scraps from which this nickel plating has been peeled are free from sulfur and other contaminants, and can then be used as raw materials for copper or copper alloy melting and casting without being subjected to an etching process or the like and recovered. Nickel can be effectively used as a valuable metal.

The effect by the method of the present invention was verified.
A stripping apparatus 1 similar to that shown in FIG. 1 was used, and a sulfuric acid solution having a sulfuric acid concentration of 100 g / L, a pH of −0.3, and a temperature of 45 ° C. was used as the stripping solution E for the first electrolytic layer 2. As a sample of copper or copper alloy scrap C, copper alloy scrap with nickel plating having a thickness of 1 μm was used on both sides, and this was placed in a 2.6 kg drum cage 5 and immersed in the stripping solution E.
The drum cage 5 was immersed in the stripping solution E, and electricity was supplied between the drum cage 5 and the cathode 6. The drum cage 5 was made of SUS, and a SUS electrode was also used for the cathode 6. The drum cage 5 was rotated in the stripping solution E at a predetermined speed.

The pressure dialyzer 3 was a standard specification product of Nosaka Manufacturing Co., Ltd., and the stripping solution E was separated into concentrated nickel sulfate M and concentrated sulfuric acid solution R at an osmotic pressure of 3 MPa.
The concentrated nickel sulfate M was supplied to the second electrolytic cell 4, and the concentrated sulfuric acid solution R was circulated to the first electrolytic cell 2 for reuse.
The second electrolytic cell 4 is energized between the anode 16 and the cathode 15, electrolyzes concentrated nickel sulfate M using a nickel plate as the cathode 15 under the conditions shown in Table 2, and nickel D is deposited on the cathode 15. Precipitated.
Further, the electrolytic solution F overflowing from the second electrolytic cell 4 was circulated to the first electrolytic cell 2 for reuse.

Two hours after the drum 5 is immersed in the stripping solution E, the energization between the drum 5 and the cathode 6 is stopped, the sample is taken out from the drum 5 and the SEM (Scanning Electron Microscope: scanning electron microscope). ), The surface of the copper or copper alloy scrap C was observed, and it was confirmed that nickel was completely peeled off.
Moreover, when the copper or copper alloy scrap surface from which the nickel plating was peeled was analyzed by EPMA (Electron Probe Micro Analyzer), there was no contamination due to residual sulfur (S) or the like. The copper or copper alloy scrap from which the nickel plating was peeled was used for melting and casting as a part of the raw material for producing the copper alloy, and when the hot-rolled copper alloy sheet was visually examined, no cracks were produced.

On the other hand, 10 g of nickel was firmly deposited on the cathode 15 of the second electrolytic layer 4 and analyzed by IPC (Ion-Pair Chromatography). As a result, the Cu content was 100 ppm or less, and no other metal elements were detected.
As described above, according to the method of the present invention, the nickel plating is efficiently peeled from the nickel-plated copper or copper alloy scrap, and it is not necessary to perform an etching process after the peeling. It turns out that copper alloy waste can be recycled as it is as a raw material for melting and casting. It was also confirmed that nickel can be separated and collected effectively from the stripping solution and can be recycled as a valuable resource.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Nickel plating peeling apparatus 2 1st electrolysis tank 3 Pressure dialysis apparatus 4 2nd electrolysis tank 5 Drum tank 6 Cathode 7 Rectifier 8 Pump 9 Connecting pipe 10 Separation membrane 11 Pump 12 Circulation system 13 Pump 14 Recovery piping 15 Cathode 16 Anode 17 Rectifier 18 Pump 19 Liquid return pipe 20 Water supply system R Concentrated sulfuric acid solution M Concentrated nickel sulfate D Nickel E Stripping liquid C Copper or copper alloy scrap

Claims (3)

A copper solution having a surface plated with nickel in a first electrolytic cell in which a sulfuric acid solution is stored as a stripping solution, the sulfuric acid concentration of the sulfuric acid solution is 50 to 300 g / L, and the pH is -0.7 to 0 Alternatively, by immersing the copper alloy scrap, the nickel plating is peeled off by a chemical reaction of Ni + H ₂ SO ₄ → NiSO ₄ + H ₂ , and the used stripping solution containing the peeled nickel is concentrated with a pressure dialysis machine. The nickel sulfate solution and the concentrated sulfuric acid solution are separated, and the concentrated nickel sulfate solution is electrolyzed in a second electrolytic cell to recover nickel, and the concentrated sulfuric acid solution is used for the first electrolysis. Nickel-plated copper or copper alloy waste recycling method characterized by returning to the tank   The copper or copper alloy scrap recycling method according to claim 1, wherein the main component of the electrolytic solution in the second electrolytic cell is nickel sulfate, and the pH is 1 to 6. The method for recycling copper or copper alloy waste according to claim 1 or 2, wherein the stripping solution contains 0.05 to 0.1% by volume of an oil removing agent.

Images