JP4342522B2 - Method for homogenizing electrolyte concentration and electrolytic cell - Google Patents

Description

  The present invention relates to an electrolytic solution concentration homogenizing method and an electrolytic cell, and more particularly, an electrolytic solution concentration homogenizing method and electrolysis for preventing non-uniformity of metal ion concentration in an electrolytic solution in metal electrolytic refining. Regarding the tank.

  Electrolytic refining is a refining method that uses an electrode reaction, supplying the energy required for the reduction reaction in the form of electric energy, and using no fuel, reducing agent, oxidant, etc., so that a highly pure metal can be obtained. It is a refining method. The case where a crude metal is used for the anode and the anode reaction is a dissolution reaction of the target metal is called electrolytic purification. In electrolytic refining and electrolytic refining, in general, a plurality of cathode seed plates (cathode plates) and eared anodes (anode plates) are alternately arranged in parallel in a rectangular parallelepiped electrolytic cell in which an electrolytic solution is stored. It is carried out by immersing and applying a direct current to dissolve the target metal in the electrolytic solution from the anode side and deposit it on the cathode. For example, in the case of refining copper, it is usually carried out by installing a plurality of electrolytic cells in which about 20 to 50 anodes and cathodes are arranged as a set, adjacent to each other in the vertical and horizontal directions. The total number of water reaches several hundred tanks.

  In the electrolyte, the electrolyte near the anode surface dissolves metal ions from the anode, so that the concentration of metal ions increases and the liquid specific gravity increases and falls. On the other hand, in the electrolyte solution near the surface of the cathode seed plate, metal ions are deposited on the cathode seed plate, so that the concentration of the metal ions decreases and the specific gravity of the liquid decreases and rises. Therefore, since the concentration of the upper part of the electrolytic solution gradually decreases and the concentration of the lower part gradually increases, the concentration of the electrolytic solution tends to be non-uniform. Therefore, in order to prevent the electrolytic conditions in the electrolytic solution and the surfaces of both electrodes from changing locally, it is necessary to constantly circulate the electrolytic solution in the electrolytic cell to make the composition and temperature uniform. For this reason, a part of the electrolytic solution in the electrolytic cell is extracted and the composition is adjusted, and then the electrolytic solution is continuously supplied into the electrolytic cell. If drainage and supply of the electrolyte are not performed appropriately, the composition of the electrolyte in the electrolytic bath, the temperature distribution, etc. will be biased, and the electrolyte conditions will become uneven depending on the location. For example, if the electrolyte is supplied (upper) from the top of one end of the electrolytic cell and drained (up) from the upper end of the opposite side, the electrolyte will only flow through the upper layer of the electrolytic cell. Since the electrolyte solution at the bottom of the electrolytic cell remains, the electrolyte solution is conventionally supplied from the lower part of one end side in the longitudinal direction of the electrolytic cell. The drainage (upper drainage) was carried out from the upper part (for example, Unexamined-Japanese-Patent No. 10-183389 (patent document 1)).

  If the concentration of the electrolytic solution is not uniform, the target metal does not deposit uniformly on the cathode seed plate, so that a high-quality metal cannot be obtained and the product is not produced. In addition, when the concentration of metal ions in the vicinity of the anode becomes high, a metal salt is deposited on the surface of the anode, which causes problems such as inhibiting the dissolution of metal ions from the anode. Therefore, for example, in Japanese Patent Laid-Open No. 2002-105684 (Patent Document 2), an electrolysis method is performed in which an electrolytic solution is discharged in a direction parallel to the planes of the cathode plate and the anode plate and in a diagonal direction of top and bottom. Disclosure.

Japanese Patent Laid-Open No. 10-183389 JP 2002-105684 A

When the electrolyte is supplied from the lower side of the end face in the longitudinal direction of the electrolytic cell and drained from the top of the opposite end surface, the electrolyte is mainly on the bottom side of the electrolytic cell. Therefore, the concentration of metal ions in the vicinity of the liquid surface near the end surface on the liquid supply side is particularly likely to decrease.
However, if the amount of liquid supply is increased in order to maintain the concentration of metal ions, it becomes easier to wind up the anode slime precipitated at the bottom of the electrolytic cell due to the liquid flow. If the anode slime adheres to the cathode, the target metal will be contaminated and will not become a product.
For example, as shown in Table 1A), when the copper concentration on the liquid surface is reduced to 25 to 35 g / l, As, Sb, and Bi of electrolytic copper are reduced from twice the average normal value of electrolytic copper. It becomes a bad value of 100 times or more.
Further, as a countermeasure, when the amount of liquid supplied is increased and the flow rate is increased, impurities such as Pb, Se, Te, etc. become 2 to 10 times worse as shown in B) of Table 1. This is thought to be due to the winding up of the anode slime due to the increase in the liquid supply amount.

  On the other hand, the liquid supply method shown in the cited document 2 requires the installation of a liquid supply port and a liquid discharge port at positions completely different from the conventional ones, and the production must be stopped to make a major repair. Is cumbersome and cumbersome.

  Therefore, the present invention solves these problems, improves the decrease in the concentration of metal ions in the vicinity of the upper part of the electrolyte solution on the supply side generated by lowering the supply solution to the electrolytic cell, and It is an object of the present invention to provide an electrolytic solution concentration homogenization method and an electrolytic cell capable of improving electrodeposition on a cathode plate located in an upper layer portion.

The present invention of claim 1 in order to solve the above problems, the electrolytic solution which is stored in the electrolytic cell, alternately in a state in which the cathode plate and the anode plate is hooked on the side walls of the electrolyzer is arranged on the inner wall surface of the one longitudinal end of the electrolytic cell is immersed, together with the upper side and the lower side have the internal space which is open, in diameter for supplying the electrolytic solution to the upper portion of the electrolytic cell The electrolyte solution is 10-30 mm, and is located at a depth of 30-70 mm from the electrolyte surface, and the electrolyte solution is supplied from the upper opening of the liquid supply pocket having holes provided at a plurality of locations along the width direction of the electrolytic cell. By supplying 3 to 5% of the supplied amount from the hole to the upper layer of the electrolyte, and supplying the other from the lower opening to the lower layer of the electrolyte, the opposite side The electrolyte concentration is characterized by draining from the upper surface of the liquid surface near the edge of the electrolyte. To provide a uniform method.

The present invention according to claim 4 in order to solve the above problems, the electrolytic solution which is stored in the electrolytic cell, alternately in a state in which the cathode plate and the anode plate is hooked on the side walls of the electrolyzer It is disposed on the inner wall surface on one end side in the longitudinal direction of the immersed electrolytic cell, has an internal space where the upper side and the lower side are open, and has a diameter of 10 in order to supply the electrolytic solution to the upper layer side in the electrolytic cell. A liquid supply pocket having holes provided at a plurality of locations along the width direction of the electrolytic cell so as to be located at a depth of 30 to 70 mm from the electrolyte surface, and electrolysis from the upper opening. A liquid supply pocket for supplying new electrolyte from the hole to the upper part of the electrolyte and supplying the other from the lower opening to the lower part of the electrolyte by supplying the liquid a liquid supply means comprising, and, contrary to the liquid supply means are provided side Disposed at the end portion side of the electrolyzer, providing an electrolytic cell, characterized by comprising a drainage means for draining the electrolyte from the liquid level upper layer.

  According to the electrolytic solution concentration homogenizing method and the electrolytic cell according to the present invention, the electrolytic solution is supplied from one end side in the longitudinal direction of the electrolytic cell to each of the upper layer part and the lower layer part of the electrolytic solution. Thus, there is an effect that the electrolyte solution upper layer portion near the liquid supply side end of the electrolytic cell, in which the metal ion concentration is likely to decrease, can be brought close to the liquid supply concentration. Thereby, the electrodeposition of the metal ions in the upper part of the electrolytic solution is improved, and the quality of the target metal can be improved.

  In addition, according to the electrolytic solution concentration homogenizing method and the electrolytic cell according to the present invention, it is not necessary to increase the amount of liquid supply to prevent a decrease in the metal ion concentration near the surface of the electrolytic solution. There is an effect that it is possible to prevent the precipitation of the precipitated anode slime and to produce a higher quality metal.

  Hereinafter, a preferred embodiment of an electrolytic solution concentration homogenizing method and an electrolytic cell according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view showing an example of an electrolytic cell for carrying out the concentration homogenization method for an electrolytic solution according to the present invention, and FIG. 2 is a plan view.

  The illustrated electrolytic cell 1 has a rectangular parallelepiped shape with an open top, and is configured such that a concrete outer tub 1a is disposed on the outer side and a synthetic resin inner tub 1b is disposed on the inner side. An electrolytic solution 3 is stored inside the electrolytic cell 1. In the electrolytic solution 3, anode plates A and cathode plates K are arranged side by side so as to be alternately parallel. For example, in the case of copper refining, the anode plate A is formed by casting copper. The anode plate A includes ears (not shown) formed so as to protrude outward at both left and right ends on the upper side. Is immersed in the electrolytic solution 3 so as to be hooked on both side walls of the electrolytic cell 1 and in contact with an electrode (not shown) wired on the upper side of the side wall of the electrolytic cell 1. On the other hand, the cathode plate K is suspended from an electrode support rod (not shown) by a metal ribbon (not shown) on a thin SUS plate having a rectangular shape, for example. And is immersed in the electrolytic solution 3 so as to be in contact with an electrode (not shown) wired on the upper side wall of the electrolytic cell 1. Thus, the target metal is purified by dissolving the target metal in the electrolytic solution from the anode plate A side by flowing a direct current through the anode plate A and the anode and depositing it on the cathode plate K.

  A liquid supply pocket 20 which is a liquid supply means for supplying the electrolytic solution whose component has been adjusted is disposed at one end 10 (the left end in FIGS. 1 and 2) in the longitudinal direction of the electrolytic cell 1. Has been. And as shown in FIG. 1, the drainage path 30 for draining the electrolyte solution 3 from the upper layer part is standingly arranged in the edge part 12 side of the electrolytic cell 1 on the opposite side.

  The liquid supply pocket 20 has a rectangular tube shape having a space inside the open upper and lower sides, and one surface thereof is fixed to the inner tank 1b on the resin tank side on the end 10 side of the electrolytic cell 1. Yes. Then, by supplying the electrolytic solution 3 from the upper opening 21 side, the fresh electrolytic solution 3 is supplied into the electrolytic cell 1 from the lower opening 22 side. As shown in FIG. 4, the liquid supply pocket 20 further has a hole 23 formed on the surface thereof, and a part of the supplied electrolyte 3 flows out of the hole 23. A new electrolytic solution 3 is supplied into the electrolytic cell 1 also from the hole 23. Thereby, since the supplied electrolyte 3 flows also in the upper layer part of the electrolyte 3, the metal ion concentration near the liquid surface can be brought close to the supply concentration.

  The amount of liquid supplied to the upper layer side in the electrolytic cell 1 is preferably about 3 to 5% with respect to the total amount of liquid supplied. Therefore, the hole 23 provided in the liquid supply pocket 20 is preferably provided at least at one place, preferably at a plurality of places along the width direction of the electrolytic cell 1. And it is preferable to arrange | position the hole part 23 so that it may be located in the depth of about 30-70 mm from the liquid level of the electrolyte solution 3 stored in the electrolytic cell 1. FIG. The size of the hole 23 is preferably about 10 to 30 mm in diameter. By forming the hole 23 in this manner, 3 to 5% of the liquid supply amount can be supplied to the upper layer side of the electrolytic cell 1.

  The result of refining copper by the electrolytic cell 1 having the above configuration is shown in FIG. This is a graph showing the relationship between the number of anode plates A (anodes) arranged in order from the liquid supply pocket 20 side and the copper concentration of the upper layer portion of the electrolytic solution 3 at that position. The copper concentration after implementation (after improvement) is higher than that before implementation (before improvement) of the electrolytic solution concentration homogenization method and the electrolytic cell according to the present invention, but close to the supply pocket 20 On the side, the increase rate of the copper concentration is high, and it can be seen that the concentration imbalance is improved. In addition, since the electrolyte 3 also flows from both sides of the anode plate A and the cathode plate K (arrows shown in FIG. 2), conventionally, if a very wide electrode plate is used, the flow is obstructed. Although it could not be used because it may cause further concentration non-uniformity, according to the present invention, it is possible to use such a wide electrode plate because it is possible to prevent such uniform concentration of the electrolyte 3 from being generated. It is possible to increase production.

Width of outer tank 1a: 1,110mm
Inner tank 1b width size: 1,060 mm
Size of cathode plate K: 1050 mm × 960 mm
Copper was subjected to electrolytic refining under the above conditions, and the relationship between the hole 23 provided in the liquid supply pocket 20 at that time and the copper concentration in the upper portion of the liquid surface having a depth of about 20 to 30 mm from the liquid surface was confirmed by experiments. . The results are shown below. The diameter of each hole 23 was 20 mm.

Number of holes (Liquid supply amount (%)) Cu on the liquid supply side
0 31.8 Comparative Example 1
1 (1%) 36.0 Invention 1
2 (2%) 37.7 Invention 2
3 (3%) 42.4 Invention 3

As described above, when a hole is made, the copper concentration at the upper part of the liquid supply side increases. In particular, as shown in the present invention 3, when three holes are opened, the liquid supply amount is 3%, and the desired copper concentration is 40 g / l. That's it.

  As described above, it can be seen that by providing a plurality of holes 23 along the width direction of the electrolytic cell 1, a decrease in the copper concentration in the upper layer portion of the electrolytic solution 3 is prevented.

It is side surface sectional drawing which shows one Embodiment of the electrolytic cell which concerns on this invention. It is a top view of the electrolytic cell shown in FIG. It is a front view of a liquid supply pocket. It is a perspective view of a liquid supply pocket. It is the graph which showed the relationship between the hole part in an electrolyte upper layer part, and copper concentration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolytic tank 1a Outer tank 1b Inner tank 3 Electrolytic solution 10 Electrolytic cell end 12 Electrolytic cell end 20 Liquid supply pocket 21 Upper opening 23 Hole 30 Drainage path A Anode plate K Cathode plate

Claims (2)

In the electrolyte stored in the electrolytic cell , the cathode plate and the anode plate are alternately immersed in a state of being hooked on both side walls of the electrolytic cell. It is arranged, as well as have the internal space in which the upper side and the lower side opened, with a diameter to supply electrolyte to the upper portion of the electrolytic cell is 10 to 30 mm, a depth of 30~70mm from the electrolyte surface 3-5% of the amount of liquid supplied from the hole by supplying the electrolyte from the upper opening of the liquid supply pocket having holes provided at a plurality of locations along the width direction of the electrolytic cell so as to be positioned While supplying new electrolyte to the upper layer of the electrolyte and from the lower opening to the lower layer of the electrolyte, the other is drained from the upper surface near the end opposite to the electrolyte. A method for homogenizing the concentration of an electrolytic solution. In the electrolyte stored in the electrolytic cell , the cathode plate and the anode plate are alternately immersed in a state of being hooked on both side walls of the electrolytic cell. It has an internal space where the upper side and the lower side are open and has a diameter of 10 to 30 mm and a depth of 30 to 70 mm from the electrolyte surface in order to supply the electrolyte to the upper layer side in the electrolytic cell. to way along the width direction of the electrolytic cell a supply fluid pocket having a hole provided in a plurality of locations, 3 of the liquid supply amount from the hole by supplying the electrolytic solution from the upper opening A liquid supply means having a liquid supply pocket for supplying 5% of the electrolyte to the upper layer of the electrolyte and the other from the lower opening to the lower layer of the electrolyte ; and
A drainage means disposed on the end side of the electrolytic cell opposite to the side on which the liquid supply means is provided, and drains the electrolyte from the upper surface of the liquid surface;
An electrolytic cell comprising:

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