JPH07150385A - Method for measuring liquidity fluctuation of copper electrolyte and device therefor - Google Patents

Abstract

PURPOSE:To easily and labor-savingly measure the liquidity fluctuation of a copper electrolyte and to control the electrolytic refining of copper by supplying a sampled copper electrolyte to a single electrolytic cell and applying a constant current to measure the inter-electrode potential. CONSTITUTION:A copper electrolyte is supplied to >=1 electrolytic cell from its feed pipe, and a current is applied to plural anode and cathode plates which are alternately arranged. In this electrolytic reforming of copper, the electrolyte is sampled from the feed pipe through a sampling branch pipe 8 and a pump 9 and supplied to a single measuring electrolytic cell 2 arranged in a water bath 1. One insoluble anode 5 and one cathode 4 are arranged in the cell 2. A constant current is applied to the cell 2 through a rectifier 6 to measure the inter-electrode potential when the current is applied. In this case, the pump 9 and the rectifier 6 are alternately operated by a timer 7, and the supply of electrolyte to the cell and the application of the constant current are not conducted at the same time but preferably conducted alternately.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method and apparatus for controlling the electrorefining operation of copper.

[0002]

2. Description of the Prior Art When electrolytically refining copper, the properties of the electrolytic solution, such as copper / sulfuric acid concentration, additive amount, temperature, etc.
Has a great influence on the product copper. Therefore, in order to maintain the quality of electrolytic copper, it is important to keep the optimum properties of the electrolytic solution stable. As a method to know the properties of the electrolyte,
Conventionally, by observing the appearance of electrolytic copper products, the excess and deficiency of additives can be determined and the amount of additive added can be increased or decreased.
Sulfuric acid concentration has been analyzed, and management such as supplementation or removal has been performed so that it falls within a certain range.

However, it is difficult to say that the properties of the electrolytic solution can be completely controlled by these methods. That is, it usually takes about 10 days for the electrolytic copper to be pulled up, and it is often too late to respond after observing the appearance of the electrolytic copper. Further, it is very laborious and labor intensive to constantly measure the concentration of copper, sulfuric acid and impurities in the electrolytic solution. In addition, some additives are difficult to analyze. The polarization of the electrolyte is also measured to analyze and control the additive. These examples are described in, for example, JP-A-60-500453 and "C".
cyclic Voltammetry for Mon
itoring Addition Agent Co
ncentrations in Copper Ele
ctrefining "(TMS 1991, P3
65-P386) and the like. However,
All of the devices used for these are expensive and large-scale, and the measurement takes too much time, but the device becomes complicated to be automated.

Regarding the relationship between the composition / temperature of the electrolytic solution and the liquid resistance, some empirical formulas are known as shown below. When the composition, temperature, etc. of the electrolytic solution changes, the liquid resistance of the electrolytic solution changes. Liquid resistance Ω · cm = 1 / conductivity = 1 / {0.66 + 0.
006 (T-55) +0.003 ( CH 2 SO 4 -18
0) -0.006 (C _Cu- 40) -0.007 (C _Ni-
10) -0.0006 (C _As -3)} (C _Cu , _Ni , _As , H ₂ SO ₄ : electrolytic solution copper, Ni, A
s, sulfuric acid concentration g / l, T: liquid temperature ℃) (Source: "Chemistry of industrial electrolysis" Masao Takahashi, Noboru Masuko, p.
41, published by Agne) In addition, if the anode / cathode polarization changes depending on the composition of the electrolyte, the concentration of the additive, the temperature, etc., the potential difference caused thereby also changes. That is, the change in liquidity appears as a potential difference. The potential between the anode and the cathode, such as the liquid resistance of the electrolyte and the potential difference due to polarization, can be measured as the cell voltage together with the voltage drop due to the resistance between the contacts and electrodes. Therefore, it is considered that the change in the electrolytic solution can be known by using only the portion of the inter-electrode potential obtained by subtracting the voltage drop due to the contact resistance from the cell voltage of the electrolytic cell.

However, there are the following problems in using the cell voltage of the electrolytic cell in actual operation as it is. In electrolytic refining, the anode is melted and electrodeposited on the cathode, so the distance between the electrode plates is not constant and changes with the energization time. In addition, during the electrolytic operation, a short circuit occurs due to bending of the electrode plate. When a short circuit occurs, the resistance between the cells decreases and the cell voltage decreases. Also, when a person moves up on the electrolytic cell to detect or correct a short circuit, the resistance between the electrode plate and the contact changes depending on the weight, and the cell voltage changes. As described above, the cell voltage has many changing factors other than the electrolytic solution, and processing of the obtained data becomes complicated in order to remove these changing factors and measure only the state change of the electrolytic solution. Further, the capacity of the electrolytic cell is usually 4 to 10 m ^3, and it takes several hours or more for the liquid to be replaced. When the state change of the electrolytic solution occurs abruptly, it may be delayed in detecting the change. Therefore, conventionally, there was a problem in using it as it is for the management of the electrolytic solution.

[0006]

DISCLOSURE OF THE INVENTION The present invention proposes a method for controlling the liquidity of a copper electrolyte solution at the interelectrode potential and an easy and labor-saving measuring device.

[0007]

In order to solve the above problems, the present invention provides one or more anode plates and cathode plates which are alternately arranged and electrically connected to each other. The electrolytic solution is separated from the liquid supply pipe to the electrolytic cell, and the separated electrolytic solution is supplied to a single electrolytic cell in which one insoluble anode and one cathode are arranged, Conducting electricity at a constant current in the electrolytic cell, and measuring the inter-electrode potential during conduction at the constant current,
Further, it is characterized in that the liquid supply to a single electrolytic cell and the energization at a constant current are not performed simultaneously but alternately.

Further, the present invention is directed to a sorting pipe provided in a liquid supply pipe, a liquid feed pump, a single electrolytic cell provided with one insoluble anode plate and one cathode plate, It is provided with a rectifier for supplying a constant current to a single electrolytic cell, and a timer for alternately operating the liquid feed pump and the rectifier, and here, the single electrolytic cell has a relative inside thereof. It is characterized in that it is an electrolytic cell provided with an inner box having opening portions in two walls and a plate fixing tool provided inside the other opposing walls.

[0009]

FIG. 1 is a diagram showing the outline of the configuration of the liquid property variation measuring device for a copper electrolyte according to the present invention. In FIG. 1, a measuring electrolytic cell 2 is installed inside a water bath 1 with an inner box 3 having an anode 5 and a cathode 4 built therein. The electrolyte for measuring the liquidity is absorbed by the liquid sending pump 9 through the preparative branch pipe 8 connected to the liquid supply pipe (not shown) for supplying a large number of electrolytic cells during the electrolytic refining operation of copper, The liquid is sent to the electrolytic cell for measurement 2 through the liquid supply pipe 10, is discharged from the liquid discharge pipe 11, and is returned to the liquid supply pipe for supplying liquid to a large number of electrolytic baths. Electricity is supplied to the electrolytic cell for measurement 2 by a rectifier 6, and the operation of the rectifier 6 is controlled by a timer 7. The timer 7 also controls the operation of the liquid feed pump 9 and is set so that the rectifier 6 is not operated when the liquid feed pump 9 is operating.

It is conceivable to measure the liquid property while continuously supplying electricity while supplying liquid, as in the actual operation. However, if supplying liquid during supplying electricity, the reaction on the electrode surface may be disturbed. Since it is possible to detect changes in the actual operation simply by making periodical measurements at appropriate intervals, it is better to make intermittent measurements at appropriate intervals determined by research.
Also, if the energization time is made too long, the surface condition will be deteriorated such that large particles will be generated on the electrodeposited surface of the electrode and the reaction on the electrode surface will be affected, resulting in an error, but not 30 to 60 seconds after energization. Therefore, the energization time is preferably about 60 seconds because the cell voltage is not stable.

In order to measure the ever-changing change in liquidity, it is preferable to install a measuring cell in close proximity to the flow path of the electrolytic solution and to frequently feed the electrolytic solution. However, even if the measurement is performed before the liquid in the measuring tank is replaced, it is difficult to clearly recognize the change in the state. Therefore, it is desirable to measure the inter-electrode potential after the electrolyte solution has been completely replaced. For this purpose, a timer is used for this purpose, and the liquid transfer pump and the rectifier are alternately operated.

FIG. 2 (a) shows the structure of the measuring electrolytic cell 2 and FIG. 2 (b) shows the structure of the inner box 3. As shown in FIG. The electrolytic solution whose liquidity is to be measured is sent to the measuring electrolytic cell 2, enters the inside of the inner box 3 through the opening 12, and contacts the anode 5 and the cathode 4.

FIG. 3 is a view showing an example of a structure for mounting the cathode 4 on the inner wall of the inner box 3. The cathode 4 is fixed by the protrusion 13 so that the distance between the anode and the cathode does not change even when the cathode 4 is deformed when the liquid is measured.

When it is attempted to measure the electrolytic solution property by the inter-electrode potential of the electrolytic cell, it is necessary to measure the inter-electrode potential under the condition that the influence of factors other than the change of the liquid property is not applied.
In the present application, the anode and the cathode are fixed in one box as described above, and the box is placed in the electrolytic solution to ensure the verticality of the anode and the cathode, and also minimize the error when mounting the electrode plate. Can be suppressed to Further, since the electrode plate can be replaced in the absence of the electrolytic solution, workability is improved.

In principle, the face-to-face distance between the anode and the cathode can be made quite small, but the face-to-face distance in actual operation is 3
It is suitable to perform the measurement at about 3 mm because the measured voltage value and the tank voltage in the actual operation can be easily compared. By widening the distance between the electrodes in this manner, it is possible to prevent the change in the distance between the electrodes from affecting the liquid resistance. In addition, when an insoluble anode such as lead is used for the copper electrolytic solution, the anode is not ablated, the distance between the electrodes does not change much, and the labor for replacing the anode can be omitted.

[0016]

EXAMPLE An electrolytic cell made of PVC having an inner diameter of 100 mm in width, 100 mm in length, and 100 mm in depth as shown in FIG. Attached. An acrylic box having a length of 70 mm, a width of 70 mm, and a depth of 100 mm and having an opening shown in FIG. (All dimensions are inner diameter) Lead box anode (100mm x 50mm,
A thickness (5 mm) and a cathode (rolled copper plate 100 mm in length, 65 mm in width, 0.3 mm in thickness) were placed so as to face each other with one surface closely attached to the wall. Masking tape is wrapped around the surface of the cathode to insulate it, and the side that is not in close contact with the wall is 40 mm in length and 50 mm in width and 5 mm from the top.
The tape was peeled off only the part. The tape peeled portion was degreased with acetone. The surface of the anode was washed with water and used as it was.

As shown in FIG. 1, this electrolytic cell was kept at 60 ± 0.5 ° C. in a water bath. The electrolytic solution was directly collected from the liquid supply pipe of the electrolytic cell with a metering pump. The flow rate of the metering pump is 45 ml / min. As the rectifier, a commercially available rectifier of 18V3A (PR18-3 type manufactured by Kenwood Co., Ltd.) was used.
The applied current was 1A. Cathode current density is 500A /
It becomes m ² . Using a timer, the metering pump and the rectifier were operated alternately. The pump was operated for 14 minutes by a timer, then stopped, and energized for 1 minute. After that, the power went out and 1 again
The pump was operated for 4 minutes and the solution was replaced.

In order to reproduce the change in the electrolytic solution (initial composition: C _u : 45 g / l, free sulfuric acid: 190 g / l, glue: 10 mg / l), an electrolytic solution supplemented with sulfuric acid was supplied from the liquid supply port. (Free sulfuric acid concentration in the liquid after supply: 250 g /
l). As a result, as shown in FIG. 4, the electric potential increased and the inter-electrode potential decreased.

1 liter of an electrolytic solution in which glue as an additive was dissolved at a concentration of 1 g / l was supplied. As a result, as shown in FIG. 4, the cathodic polarization was increased and the inter-electrode potential was significantly increased.

When the electrolyte diluted with water was supplied (copper concentration in the liquid after the supply: 30 g / l), the inter-electrode potential increased as shown in FIG. As described above, by using the present invention, a change in the properties of the electrolytic solution can be recognized as a change in the inter-electrode potential. Fig. 5 shows the actual operation measured with this device (26 anodes, 27 cathodes, DK250
A / m ² ) shows the change in inter-electrode potential.

[0021]

According to the present invention, it has become possible to easily measure the change in the property of the electrolytic solution and use it for the control of additives, compositions and the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an apparatus according to the present application.

FIG. 2 (a) shows the structure of a measuring electrolytic cell 2 in the device according to the present application, and FIG. 2 (b) shows the structure of an inner box 3.

FIG. 3 is a diagram showing an example of a structure in which a cathode 4 is attached to an inner wall of an inner box 3 in the device according to the present application.

FIG. 4 shows the results of measuring the liquidity of an electrolytic solution by the device according to the present application, and in particular, the changes in the cell voltage were measured intentionally when diluted with water, added sulfuric acid, or supplemented with glue. It is a figure.

FIG. 5 is a diagram showing a result of measuring a change in inter-electrode potential in actual operation by the device according to the present application.

[Explanation of symbols]

 1 Water bath 2 Electrolysis tank for measurement 3 Inner box 4 Cathode 5 Anode 6 Rectifier 7 Timer 8 Branch pipe for preparative 9 Liquid feed pump 10 Liquid feed pipe 11 Drain pipe 12 Opening hole 13 Projection

Claims (4)

[Claims] 1. An electrolytic solution is collected from a liquid supply pipe to one or more electrolytic cells in which a plurality of anode plates and cathode plates are alternately arranged and electrically connected to each other. The separated electrolytic solution is supplied to a single electrolytic cell in which one insoluble anode and one cathode are arranged, and the single electrolytic cell is energized with a constant current to obtain the constant current. A method for measuring liquidity fluctuations of a copper electrolyte, which comprises measuring an inter-electrode potential when electricity is applied. 2. The method for measuring the liquidity variation of a copper electrolytic solution according to claim 1, wherein the supply of liquid to a single electrolytic cell and the energization at a constant current are not performed simultaneously but alternately. 3. A single electrolytic cell provided with a preparative branch pipe provided in a liquid supply pipe, a liquid feed pump, a single insoluble anode plate and a single cathode plate, and the single electrolytic cell. A liquid variation measuring device for a copper electrolyte, comprising: a rectifier that applies a constant current to an electrolytic cell; and a timer that alternately operates the liquid feed pump and the rectifier. 4. A single electrolyzer has two opposing internal electrolytic cells.
4. The liquid fluctuation measuring device for a copper electrolytic solution according to claim 3, which is an electrolytic cell having an inner box having an opening portion on one wall and an electrode plate fixture provided on the inside of the other opposing wall.