JPS5933199B2 - How to remove tin from tin-plated copper materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing tin from tin-plated copper or copper alloy materials, such as tin-plated copper wire.

As is well known, tin-plated copper wires, particularly tin-plated insulated wires with an insulation coating of 2.0 mm or less, are used for internal communication cables, IV cables, jumper wires for connecting equipment, and the like.

Such tin 5 plated insulated wires can be used to change the communication route,
If it is removed due to changes in load or number of lines, etc., it is desirable to effectively recover it and reuse it as raw copper material from the perspective of resource conservation. However, in order to reuse the tin-plated insulated wires that have been removed, it is first necessary to remove the insulation coating from the tin-plated wires.This method involves cutting the tin-plated insulated wires into short pieces of about 5 to 15 mm and crushing them. A known method is to mechanically remove the insulation coating from tin-plated copper wire.

If the tin-plated copper wire from which the insulation coating has been removed in this way is melted and recycled into copper wire, etc.,
Since copper contains a significant amount of tin, the conductivity is significantly reduced, so it is necessary to remove the tin. As a method for removing tin from tin-plated copper wire, methods have been proposed in which tin is removed by soda treatment, phosphoric acid treatment, etc. in 20 pyrometallurgical refining, but it is difficult to remove tin sufficiently with these methods. There are problems such as the lifespan of furnace refractories is significantly shortened by treatment agents, and the rate of copper regeneration is low.
25 Therefore, in the past, this method has only been carried out on a trial basis and has not been put into practical use.

Furthermore, 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 bath.
As mentioned above, when applied to the removal of tin from tin-plated copper wires that have been crushed to about 5 to 15 mm in order to remove the insulation coating, the material to be treated, that is, the crushed tin-plated copper wires, is of small size and irregular shape. It is difficult to handle the treated material for electrolysis, it is difficult to completely remove tin, and the amount of electrolytic treatment per time is small, which causes problems such as high treatment costs. Therefore, it has been considered difficult to remove tin from pulverized tin-plated copper wire by electrolytic treatment. This invention was made in view of the above-mentioned circumstances, and is a highly efficient and low-cost method for producing short and irregularly shaped tin-plated copper material by cutting or crushing tin-plated copper wire or tin-plated copper plate. The object of the present invention is to provide a method for removing tin from tin-plated copper material, which can be sufficiently removed by removing tin from the tin-plated copper material.

In other words, the method described here consists of a hollow cylindrical insulating material that has an inlet for tin-plated copper material formed at one end, an outlet for the tin-plated copper material at the other end, and an outer peripheral surface configured to allow the electrolyte to pass through. A rotating drum is arranged in the electrolytic cell so that its axis can be tilted downward from the inlet to the outlet, and an anode is inserted into the rotating drum, and a cathode is arranged outside the rotating drum. Then, the electrolytic cell was filled with an aqueous sulfuric acid solution with a concentration of 1 to 6 normal, and the tin-plated copper material was continuously introduced into the inlet while rotating the rotary drum at 100 A/D.
This method is characterized by removing electrolytic waste tin at an apparent current density of m2 or less, and continuously discharging and recovering the treated copper material from the discharge port.

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 provided with a large number of through holes 3 over almost the entire circumferential wall surface so that the electrolyte can flow therethrough.
The inner peripheral surface of the hollow cylindrical outer body 4 made of an acid-resistant hard insulating material such as vinyl chloride is coated with polyvinylidene chloride fiber (trade name Saran) having a mesh size of about 120 to 140 meshes. It has a structure in which a cloth net 5 made of acid-resistant and wear-resistant material is attached. The cloth mesh 5 is attached to the inner circumferential surface of the outer cylinder 4 by a plurality of strip-like holding plates 6 made of vinyl chloride or the like, which are substantially parallel to the axial direction of the outer cylinder 4. One end of the outer cylinder 4 (right end in the figure)
A short cylindrical input-side end frame 7 is fitted coaxially to the input-side end frame 7, 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 has a tapered shape that expands from the outside to the inside. Further, in the input side end frame 7, an intake member 12 is fixedly provided, which is made up of four blades 10 inclined like a propeller and radially attached to a hollow cylindrical support shaft 11. The intake member 12 is provided at a predetermined distance inwardly from the inner end of the input port 9, so that a small chamber 13 is formed between the intake member 12 and the input port 9. ing. Further, a discharge side end frame 14 similar to the input side end frame 7 is fitted to the other end (left end in the figure) of the outer cylinder 4, and the outer wall surface of this discharge side end frame 14 is fitted. A large-diameter gear 15 made of a hard insulating material such as Bakelite is fixed to the large-diameter gear 15, and a roller-shaped support 16 similar to the input-side support 8 is fixed to the outer wall of the large-diameter gear 15. ing.

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,
A film 23 made of a material with low frictional resistance, such as polyfluoroethylene (trade name: Teflon), is formed on the upper surface of the film 22 . Furthermore, the rotating drum 2 is held such that its central axis l is inclined downward by a small angle a from the input port 9 side toward the discharge port 17 side with respect to the horizontal line H. On the other hand, at the top of the electrolytic cell 1 is a rotary 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. Furthermore, a hopper 29 is provided at the top of the electrolytic cell 1 for continuously feeding short tin-plated copper wires as the material to be treated 28 into the input port 9 of the rotating drum 2. is led to the input port 9 via a shutter 37 that can be closed on the side and a passageway 30 for the material to be processed.

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. In addition, above the conveyor] 732,
An air blowing member (not shown) is provided for blowing pressurized air onto the treated material being carried up by the conveyor 32 to drain water. Further, an anode 35 is inserted into the rotary drum 2 from the input port through the material passage 30, and is located outside the rotary drum 2 and located outside the rotary drum 2.
A cathode 36 is disposed at a position surrounding from below.
The anode 35 is in contact with the tin-plated copper wire of the material to be treated within the rotating drum 2, and is made of copper, stainless steel, titanium, or the like. Further, as the cathode 36, copper, stainless steel, titanium, etc. are similarly used. Next, use an electrolytic device like the one mentioned above to create a 5-15m7! A method for detining a short length of tin-plated copper wire (hereinafter referred to as a material to be treated) will be specifically described.

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. When a large number of materials 28 are loaded into the hopper 29 and the shutter 37 is opened appropriately, the materials 28 are loaded into the small chamber 13 at the end of the rotary drum from the input port 9 of the rotary drum 2 via the material passage 30. entered. Since the rotary drum 2 is rotated at a constant speed by the rotary drive device 24, the propeller-shaped intake member 12 on the input side of the rotary drum 2 also rotates. At this time, Komuro 13
The material to be treated inside 28 rolls down the inner circumferential wall of the small chamber 13 due to its own weight as the rotating drum 2 rotates, but the material 28 inside the intake member 1
The falling direction of the material to be treated 28 located between each of the blades 10 of 2 is regulated by the blades 10, and the material 28 falls inside the rotating drum 2.
That is, they are taken in sequentially to the left of the intake member 12. Once taken in, the rotary drum 2 is tilted by a small angle a, so as the rotary drum 2 rotates, it sequentially moves toward the discharge port (to the left). Inside the rotating drum 2 is the outer cylindrical body 4.
The aqueous sulfuric acid solution flows inside and outside the rotating drum 2 because it communicates with the outside through the through holes 3 and the texture of the cloth 5. Since the material to be processed 28 moving within the rotating drum 2 comes into contact with the anode 35, the anode 35 is connected to the cathode 3 outside the rotating drum 2.
Tin on the surface of the material to be treated is electrolyzed by the electrolytic current between the two.

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 processed 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 falls onto the discharge conveyor 32 through the discharge port 17 to the soil. The treated material is then conveyed upward by the discharge conveyor 32, and high-pressure air is blown by an air blowing member above the electrolytic cell 1 to blow off the electrolyte adhering to the treated material, and further to the outside of the electrolytic cell 1. will be transported to. This post-treated material is washed with water and dried. The intake member 12 smoothly charges the material to be processed into the rotary drum 2, and even if the amount of material to be processed in the small chamber 13 fluctuates, the intake member 12 allows the material to be processed to be fed into the rotating drum 2 in constant amounts as the rotary drum 2 rotates. It has the function of charging into the drum. Also, the discharge member 2
0 also has the effect of discharging the treated material in fixed amounts.
Therefore, the inlet member 12 and the outlet member 20 of the rotating drum 2
In other words, a certain amount of treatment material is always present in the area where electrolysis is effectively performed. In the above description, it is desirable that the inclination angle a of the rotating drum 2 is about 1 to 100. If it is less than 1, the material to be treated will not be transferred smoothly, and if it exceeds 10, the residence time of the material to be treated in the rotating drum 2 will be too short, and therefore tin 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 so that the material to be treated occupies 30 to 70% of the area in the cross section of the rotary drum 2. If it is less than 30%, it will not make sufficient contact with the anode 35, causing trouble in power supply, and if it exceeds 70 (Ff), it may cause trouble in electrolysis.

Next, explaining the electrolytic conditions, the relationship between the current density and the tin dissolution current efficiency when the concentration of the sulfuric acid bath is changed at a bath temperature of 4'C is shown in FIG.

That is, the lower the sulfuric acid concentration, the higher the 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. Furthermore, if the sulfuric acid concentration is increased to exceed 6N, the dissolution current efficiency will decrease as mentioned above, resulting in a large economic loss, and the high acid concentration of the effluent will make it difficult to treat the effluent. There is. 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 liquid 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 almost no effect on the current dissolution efficiency of tin, so the liquid temperature can be set arbitrarily. Since there is a problem of mist being generated, it depends on the balance between the two.
It is desirable to set the temperature to about 0°C. Further, the apparent current density of the electrolytic current (the value obtained by dividing the total electrolytic current by the surface area of the aggregate of sample pieces) is optimally in the range of 20 to 30 A/Dm2, but may be 100 Vdm2 or less. 100A/
If it exceeds Dm2, the dissolution current efficiency decreases and the economic cost increases.

Examples of the present invention using the apparatus shown in FIGS. 1 and 2 will be described below.

Example Length between intake member 12 and discharge member 20 is 500m7
! A rotary drum 2 having a size L and an inner diameter of 150 mm was used, and the rotary drum 2 was installed at an angle of 2 from the horizontal and rotated at 20 rpm.

Further, as a cathode, a copper plate having a side of 5001 U curved into a gutter shape was used, and this was fixed close to the lower surface side of the rotating drum 2. 4N dilute sulfuric acid is used as the electrolyte, and this is poured into the electrolytic tank 1 until the rotating drum 2 is almost completely submerged.
injected into. Crushed tin-plated copper wire (0.2 wt%
(Tin plating) was continuously introduced into the rotating drum 2 at a rate of 2.5 kg per minute and electrolyzed for 1 hour while being continuously discharged.

The electrolysis conditions were 8V and 300A. Rotating drum 2
When the crushed copper wire discharged from the was drained, washed with water, dried, and analyzed, the tin content was always 30 ppm or less. In other words, it became copper scrap corresponding to No. 2 scrap of JIS-H2lO9. As is clear from the above explanation, according to the present invention, tin can be easily removed from short and irregularly shaped tin-plated copper materials, and by using an inclined rotating drum, it is possible to continuously remove tin with high efficiency and low cost. Tin removal treatment can be performed at 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. FIGS. 4 and 5 are graphs showing the relationship between current density and dissolution current efficiency when the electrolytic solution concentration and temperature are changed. 1...--Electrolytic cell, 2... Rotating drum, 3
...Through hole, 9...Input port, 17...
···Vent.

Claims (1)

[Claims] 1. A rotary drum made of a hollow cylindrical insulating material, which has an inlet for tin-plated copper material at one end and an outlet at the other end, and is configured so that the electrolyte can freely pass through the outer circumferential surface. Arranged in the electrolytic cell so that the axis can be tilted from the inlet to the outlet, an anode is inserted into the rotating drum, a cathode is arranged outside the rotating drum, and the electrolytic cell is further inserted into the electrolytic cell. was filled with an aqueous sulfuric acid solution having a concentration of 1 to 6N, and while the rotating drum was being rotated, short pieces of tin-plated copper material were continuously introduced into the rotating drum from the inlet.
A tin-plated copper material characterized in that tin is removed by electrolysis at an apparent current density of 0 A/dm^2 or less, and the treated short material is continuously discharged and recovered from the discharge port of a rotating drum. How to remove tin.