JPS5933200B2 - Processing method for plating copper material - Google Patents

Description

[Detailed Description of the Invention] This invention removes tin and lead from tin-plated steel materials or solder-plated steel materials that are partially plated or attached with solder or lead, and uses them as raw copper materials. This invention relates to a processing method for making it recyclable.

As is well known, tin-plated copper wires, particularly tin-plated conductor insulated wires with an insulation coating of 20 mwL or less, are used for communication cables, IV cables, jumper wires for connecting equipment, etc.

It is preferable from the viewpoint of resource saving and the like to collect these electric wire cables and effectively reuse the copper wires that are the conductors. However, in order to reuse the removed tin-plated insulated wire, it is first necessary to remove the insulation coating from the tin-plated copper wire, and this method involves cutting the tin-plated insulated wire into short pieces of about 5 to 15 m1 and crushing them. A known method is to mechanically remove the insulation coating from tin-plated copper wire.

If the tin-plated copper wire whose insulation coating has been removed is melted and recycled into copper wire, etc., the conductivity will drop significantly because the copper contains a considerable amount of tin, so the tin must be removed. There is a need to. A known method for removing tin from tin-plated copper wire is to use soda treatment, phosphoric acid treatment, etc. in pyrometallurgical refining, but it is difficult to remove tin sufficiently with this method, and the furnace There are problems such as the lifespan of refractories is significantly shortened by treatment agents and the copper regeneration yield is low. It was difficult to adapt.

Also, as a method for removing tin from long tin-plated copper wires, a method is known in which the tin-plated copper wires are intertwined with each other and electrolytically treated in a sulfuric acid aqueous solution bath.
As mentioned above, when applying the tin removal method to tin-plated copper wire that has been crushed to about 5 to 15 nanometers to remove the insulation coating, the material to be treated, that is, the crushed tin-plated copper wire, is of small size and irregular shape. It is difficult to handle the material to be treated for electrolysis, it is difficult to completely remove tin, and there are also problems such as less electrolytic treatment per time, which increases the treatment cost. Therefore, it has been considered difficult to remove tin from pulverized tin-plated copper wire by electrolytic treatment.

Against the background of the above circumstances, the inventor of the present invention used an electrolyzer with a specific configuration to continuously electrolyze a large number of short tin-plated copper materials under specific electrolytic conditions in a sulfuric acid bath. We have developed a method to remove tin using this method.
According to this method, it has become possible to sufficiently remove tin from short and irregularly shaped tin-plated copper wires with high efficiency and at low cost.

However, common tin-plated copper wires are often soldered to connect their terminals, and are often pre-soldered to facilitate soldering of the terminals. Furthermore, solder-plated copper wire may also be used. Therefore, recovered materials after removal often have solder attached to them, and in order to process such recovered materials and reuse them for copper wire, etc., lead as well as tin must be removed. Must be. However, in this case, it has become clear that the electrolytic treatment method proposed by the inventors of the present invention as described above only removes tin, but it is difficult to sufficiently remove lead as well. Therefore, the inventor of the present invention further investigated the proposed technology and found that it is possible to remove both tin and lead from short to irregularly shaped tin-plated copper materials and solder-plated copper materials with high efficiency and low cost. This became possible and led to this invention. That is, the method of the present invention consists of a rotating hollow cylindrical insulating material having an inlet for the plated copper material formed at one end and an outlet at the other end, the outer peripheral surface of which is configured to allow the electrolyte to pass through. Using an electrolytic device in which a drum is arranged in an electrolytic cell so that its axis can be tilted from the input port to the discharge port, an anode is inserted into the rotating drum, and a cathode is arranged outside the rotating drum, While rotating the rotary drum in dilute sulfuric acid having a concentration of 1 to 6 N in the electrolytic device, a large number of short plated copper materials were continuously introduced into the rotary drum from the inlet, so that the apparent current density was 100 A. /Dm2 or less to first remove tin by electrolysis and continuously discharge the treated short material from the discharge port of the rotating drum,
Next, while rotating the rotating drum in a sodium hydroxide aqueous solution having a concentration of 2N or more in the electrolysis device or similar device, the copper material from which tin has been removed is sequentially introduced into the rotating drum from the inlet, and the voltage is 3V or less. It is characterized in that lead is removed by electrolysis at an electrolytic voltage and then continuously discharged from the discharge port of the rotating drum.

To explain this invention in detail below, FIGS. 1 to 3 are diagrams showing an example of an electrolytic device used in the method of this invention. It has a configuration in which a hollow cylindrical rotating drum 2 is disposed.

The outer circumferential portion of the rotating drum 2 is a hollow body made of an acid- and alkali-resistant and insulating hard resin material such as vinyl chloride, which has a large number of through holes 3 formed over almost the entire surface of the circumferential wall so that the electrolyte can flow therethrough. 120 on the inner peripheral surface of the cylindrical outer cylinder 4
It has a structure in which a cloth net 5 made of acid-resistant, chemical-resistant, and abrasion-resistant material such as polyvinylidene chloride fiber (trade name Saran) having a mesh size of about 1 to 140 meshes is attached. The cloth mesh 5 is attached to the inner circumferential surface of the outer cylinder 4 by a plurality of strip-shaped holding plates 6 made of vinyl chloride or the like, which are substantially parallel to the axial direction of the outer cylinder 4. A short cylindrical input side end frame 7 is provided at one end of the outer cylinder 4 (the right end in the figure).
are coaxially fitted, and a roller-shaped support 8 is fixed to the end surface of the input side end frame 7. The input side end frame 7 and the support body 8 are formed with an input port 9 that penetrates in the axial direction of the rotary drum 2 and is tapered to expand from the outside to the inside. In addition, in the input side end frame 7, there is an intake member 12 made of plated copper material, which has four propeller-like inclined blades 10 radially attached to a hollow cylindrical support shaft 11. A small chamber 13 is formed between the intake member 12 and the input port 9, and the plating Copper materials can now be delivered smoothly. Also, the other end of the outer cylinder 4 (
A discharge side end frame 14 similar to the input side end member 7 is fitted on the left end of the figure), and the outer wall surface of the discharge side end frame 14 is made of a hard insulating material such as Bakelite. A large-diameter gear 15 is fixed, and a roller-shaped support 1 similar to the input-side support 8 is disposed on the outer wall side of the large-diameter gear 15.
6 is fixed.

These discharge side end frame 14, large diameter gear 15 and support body 1
6 is formed with a discharge port 17 that passes through the outer cylinder body 4 in the axial direction and expands outward in a tapered shape. Similar to the input member 12, a discharge member 20 is fixedly provided, which is formed by four propeller-like inclined blades 18 radially attached to a hollow cylindrical support shaft 19. The rotating drum 2 configured as described above is rotatably supported by a pair of receiving frames 21 and 22 provided on the inner bottom surface of the electrolytic cell 1.

That is, receiving frames 21 and 22 each having an arcuate upper surface are provided at a predetermined interval on the inner bottom surface of the electrolytic cell 1.
1 and 22, supports 8 and 1 at both ends of the rotating drum 2;
6 is slidably mounted and held. In addition, receiving frame 21,
The upper surface of 22 is made of a material with low frictional resistance, such as poly 4
A film 23 made of fluorinated ethylene (trade name: Deflon) or the like is formed. Furthermore, the rotating drum 2 is installed so that its center axis 1 can be tilted downward at a small angle a from the input port side to the discharge port side with respect to the horizontal line H. On the other hand, at the top of the electrolytic cell 1, there is a rotation 5 drive device 2 such as a motor.
4 is arranged, and the drive shaft 2 of this rotation drive device 24
A sprocket 26 provided at 5 meshes with the large diameter gear 15 of the rotary drum 2 through an intermediate rotary gear 27, so that the rotary drum 2 rotates about an axis l inclined slightly downward.

Further, at the upper part of the electrolytic cell 1, a hopper 2 is provided for continuously feeding short lengths of solder, lead-containing tin-plated copper wire, and solder-plated copper wire as the material to be processed 28 into the input port 9 of the rotating drum 2.
9 is provided, and the lower part of this hopper 29 is guided to the input port 9 via an openable/closable shutter 37 and a material passage 30.

On the other hand, near the discharge port 17 of the rotating drum 2, the discharge port 17
An inclined discharge conveyor 32 is provided to receive the treated material falling from the electrolytic cell 1 and transport it to the outside of the electrolytic cell 1.
Further, below the discharge conveyor 32, a casing (not shown) having an opening on the top surface is provided to receive the treated material spilled from the conveyor 32. Note that an air jetting member (not shown) is provided above the conveyor 32 for blowing pressurized air onto the treated material being carried up by the conveyor 32 to drain water. Further, an anode 3 such as a rod-shaped anode 3 is inserted into the rotary drum 2 from the input port through the material passage 30 to be treated.
5 is inserted, and a cathode 36 is disposed outside the rotating drum 2 at a position surrounding the rotating drum 2 from below.

The anode 35 is in contact with the plated copper wire of the material to be treated within the rotating drum 2, and is made of a material such as copper, stainless steel, titanium, or the like. Similarly, materials such as copper, stainless steel, and titanium are used for the cathode 36. Next, using the electrolytic device as described above, the tin-plated copper wire or solder-plated copper wire (hereinafter referred to as the material to be treated) that has been cut into short lengths of approximately 5 to 15 mm and is plated or adhered with solder and lead is detined and A method for performing lead treatment will be specifically explained.

First, the electrolytic cell 1 is filled with an aqueous sulfuric acid solution.

The concentration of this sulfuric acid aqueous solution may be within the range of 1 to 6 normal. By putting a large number of materials 28 into the hopper 29 and opening the shutter 37 as appropriate, the materials 28 are transferred to the material path 30.
The liquid is then introduced into the small chamber 13 at the end of the rotating drum 2 through the inlet 9 of the rotating drum 2. The rotary drum 2 is a rotary drive device 2
4 rotates at a constant speed, the rotating drum 2
The propeller-shaped intake member 12 on the input side also rotates. At this time, the material to be processed 28 in the small chamber 13 rolls down the inner peripheral wall of the small chamber 1) due to its own weight due to the rotation of the rotating drum 2, but the material to be processed located between the blades 10 of the intake member 12 2
8 are sequentially introduced into the rotary drum 2, that is, to the left of the intake member 12, with the falling direction thereof being regulated by the blades 10. Once taken in, since the rotating drum 2 is inclined by a small angle a, it sequentially moves toward the discharge port side (to the left) as the rotating drum 2 rotates. The inside of the rotating drum 2 is communicated with the outside through the through holes 3 of the outer cylinder 4 and the texture of the cloth 5, so that the sulfuric acid aqueous solution flows inside and outside the rotating drum 2. Since the material to be treated moving within the rotating drum 2 comes into contact with the anode 35, tin on the surface of the material to be treated is first electrolyzed by the electrolytic current between the anode 35 and the cathode 36 outside the rotating drum 2. In this way, the material to be treated moves within the rotating drum 2 while gradually removing tin, and when the tin is almost completely removed, the material is located between the blades 18 of the discharge member 20. Therefore, the treated material is discharged to the outside of the discharge member 20 in the same manner as the action of the intake member 12 described above, and is conveyed upwardly by the discharge conveyor 32 through the discharge port 17, and is placed above the electrolytic cell 1, for example. High-pressure air is blown by the air blowing member to blow off the electrolyte adhering to the treated material, and the material is further carried out to the outside of the electrolytic cell 1. This post-treated material is washed with water and dried. The collecting member 12 allows the material to be processed to be smoothly introduced into the rotary drum 2, and even if the amount of material to be processed in the small chamber 13 varies, a fixed amount is fed into the drum as the rotary drum 2 rotates. It has the effect of adding energy to the Further, the discharge member 20 similarly functions to discharge the treated material in fixed amounts. Therefore, a certain amount of treatment material is always present between the income member 12 and the discharge member 20 of the rotating drum 2, that is, the area where electrolysis is effectively performed. The material to be treated from which tin has been removed as described above is subjected to an electrolytic treatment for removing lead using an electrolytic device similar to that described above.

That is, the electrolytic cell 1 of another electrolytic device having the same structure as the electrolytic device used for the tin removal treatment is filled with an aqueous sodium hydroxide solution having a concentration of 2N or more, and the hopper 29 of this electrolytic device is filled with a large number of cells that have been subjected to the tin removal treatment. Inject the material to be treated. When the rotary drum 2 is rotated at a constant speed in the same manner as described above, the material to be treated is continuously taken into the rotary drum 2 and sequentially moves within the rotary drum 2 toward the discharge port side while contacting the anode 35. .
Therefore, the material to be treated is electrolyzed in the sodium hydroxide aqueous solution by the electrolytic current between the anode 35 and the cathode 36, and lead on the surface of the material to be treated is electrolytically removed. At this time, a small amount of residual tin that could not be removed by electrolysis in the sulfuric acid bath is also electrolytically removed. When lead and residual tin have been almost completely removed in this way, they are discharged from the rotary drum 2 as it rotates, and are drained, washed, and dried in the same manner as described above, and almost all copper is removed. A recycled material containing only In the above description, it is desirable that the inclination angle a of the rotating drum 2 in each electrolytic treatment is about 1 to 10 degrees.

If it is less than 1, the material to be treated will not be transferred smoothly or sufficiently.
If it exceeds 0, the residence time of the material to be treated in the rotating drum 2 is too short, and therefore tin and lead may not be removed sufficiently.

Further, it is desirable that the rotational speed of the rotating drum 2 is set to about 5 to 20 revolutions per minute. Further, it is desirable that the amount of the material to be treated in the rotary drum 2 is set such that the material to be treated occupies 30 to 70% of the area in the cross-sectional view of the rotary drum 2. If it is less than 30%, it will not make sufficient contact with the anode 35, causing problems in power supply, and if it exceeds 70%, it may cause problems in electrolysis (detining, deleading).

Next, to explain the electrolytic conditions in the first electrolytic treatment, that is, electrolysis in a sulfuric acid bath for detining, the relationship between current density and tin dissolution current efficiency when the concentration of the sulfuric acid bath is changed at a bath temperature of 40°C. is as shown in FIG.

That is, the lower the sulfuric acid concentration, the higher the dissolution efficiency. Therefore, it is desirable that the sulfuric acid concentration be low, but if it is less than 1N, it will be difficult to absolutely increase the current density and the progress of electrolysis will be slow, so it is necessary to have a concentration of 1N or more. In addition, if the concentration is increased to exceed 6 regulated, as mentioned above, the dissolution current efficiency will decrease, resulting in large economic losses, and the high acid concentration of the effluent will cause problems such as difficulty in treating the effluent. be. Therefore, the sulfuric acid concentration must be within the range of 1 to 6 normal. On the other hand, the relationship between the current density and the tin dissolution current efficiency when the bath temperature is changed at a sulfuric acid concentration of 4 normal is as shown in FIG. As is clear from FIG. 5, the liquid temperature has little effect on the tin dissolution current efficiency, so any liquid temperature may be used. However, if the liquid temperature is raised, the liquid resistance is reduced and the loss is reduced, but on the other hand, there is a problem of generation of sulfuric acid mist, so it is desirable to set the temperature to about 30 to 50°C in consideration of the balance between the two. Furthermore, the apparent current density of the electrolytic current (the value obtained by excluding the total electrolytic current by the surface area of the aggregate of the treated material) is 20 to 30 A/Dm2.
The optimum range is 100 A/Dm2 or less. When it exceeds 100 A/Dm2, there is a problem that the dissolution current efficiency decreases and the economic cost increases.

Also, to explain the electrolytic conditions in the second electrolytic treatment, that is, electrolysis in a sodium hydroxide aqueous solution bath for deleading, in the electrolysis in a sodium hydroxide aqueous solution bath, unlike the aforementioned electrolysis in a sulfuric acid bath, the electrolytic voltage is It has a great effect on efficiency, especially if it exceeds 3V, the dissolution efficiency decreases rapidly, so it is necessary to keep it below 3V. Further, considering the problem of lead oxidation during electrolysis, it is desirable to set the voltage to about 2V. In addition, the specified concentration of the sodium hydroxide aqueous solution must be 2N or higher, and the upper limit is 8N.
It should be within the prescribed range. Especially if it is less than 2 regulations,
There is a problem that the dissolution current efficiency decreases depending on the temperature conditions.
FIG. 6 shows the relationship between dissolution current efficiency and current density when the current density is varied between 2 and 8 normal.

Further, FIG. 7 shows the relationship between dissolution current efficiency and current density when the temperature of the sodium hydroxide aqueous solution bath is changed. As is clear from FIG. 7, the optimal temperature is about 40 to 50°C, but 20°C is sufficient. Furthermore, if the temperature exceeds 80°C, the problem of liquid evaporation will occur, so setting the temperature above 80°C is problematic. Furthermore, although the current density of the electrolytic current is arbitrary, it is preferably up to about 30 A/Dm2. In addition to the tin-plated copper material which is partially solder-plated,
It can be applied to tin-plated copper materials to which solder is simply attached, solder-plated copper materials, copper materials to which solder is attached, copper materials with two layers of lead and tin plating, etc. It can also be applied to mixed materials such as tin-plated copper mixed with solder pieces or lead pieces, or mixed materials of two or more of the above-mentioned materials. Applicable to copper materials including solder).

The following describes the results of sulfuric acid bath electrolysis and sodium hydroxide aqueous solution electrolysis performed on a crushed tin-plated copper wire of about 5 to 15 mm with 1560 ppI1 of tin and 300 ppm of lead attached. The first stage of sulfuric acid bath electrolysis was carried out at a sulfuric acid concentration of 2N, a bath solution of 20°C, a current density of 8A/Dm2, and a SUS3 counter electrode.
When carried out using O4, as shown in FIG. 8, tin was rapidly removed within 10 minutes, while lead was hardly removed, and there was almost no change after 14 minutes. In addition, for the treated material that had been subjected to sulfuric acid bath electrolysis for 14 minutes, the second stage of sodium hydroxide aqueous solution bath electrolysis was carried out under the electrolysis conditions of sodium hydroxide concentration of 6N, bath temperature of 60℃, and constant voltage of SUS3O42V counter electrode. As shown in Figure 9, lead decreased to 30 ppm or less in about 20 minutes, and tin (about 70 pprn) remaining during the electrolysis in the sulfuric acid bath decreased to 1.
It was confirmed that the concentration decreased to 10 ppm or less in about 0 minutes.
As is clear from the above explanation, according to the present invention, tin and lead can be easily removed from short tin-plated copper materials or solder-plated copper materials to which solder and lead are attached by terminal soldering work or solder plating. Furthermore, by using an inclined rotating drum, tin and lead can be continuously removed with high efficiency and low cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of an electrolytic device used in the present invention, FIG. 2 is a sectional view taken along the - line in FIG. Figures 4 to 7 are diagrams showing the relationship between current density and melting current efficiency when various conditions are changed, and Figures 8 and 9 are diagrams showing the relationship between tin and lead. It is a graph showing the removal state in correspondence with the electrolysis time. 1... Electrolytic cell, 2... Rotating drum, 3
...Through hole, 9...Input port, 17...
···Vent.

Claims (1)

[Claims] 1. A hollow cylindrical shape having an input port for supplying solder, lead-containing tin plating or solder plating copper material at one end, and a discharge port at the other end so that the electrolyte can freely pass through the outer circumferential surface. A rotating drum made of insulating material,
An electrolytic device is used, which is arranged in an electrolytic cell so that its axis can be tilted from the input port to the discharge port, an anode is inserted into the rotating drum, and a cathode is arranged outside the rotating drum. , the electrolyzer is filled with sulfuric acid with a concentration of 1 to 6 normal, and while the rotary drum is being rotated, the short pieces of the plated copper material are continuously introduced into the drum from the inlet;
First, tin was removed by electrolysis at an apparent current density of 00 A/dm^2 or less, and then the copper material from which the tin was removed was filled into the electrolytic device or another electrolytic device with a similar structure. Solder and tin plating containing lead, which are characterized by being continuously electrolyzed at an electrolytic voltage of 3 V or less in a sodium hydroxide solution with a concentration of 2 or higher to remove lead while being removed from the discharge port of a rotating drum. Or a method for processing solder-plated copper materials.