KR20130009550A - Noble metal electrolysis collecting method - Google Patents

Abstract

PURPOSE: An electrolysis recovering method for precious metal is provided to improve a recovering speed by electrolysis of a precious metal ion in plating waste water and bath by setting the rotating speed of a rotary cathode drum of the rotary type electrolysis recovering apparatus greater than 1.12 m/sec, in a constant current value. CONSTITUTION: An electrolysis recovering method for precious metal can improve the recovering efficiency of precious metal in precious metal containing solution by setting the rotating speed of the rotary cathode drum included in an electrolysis recovering apparatus for precious metal as 1.21m/sec to 1.8m/sec, the rotating time as 3-4 hours. The final concentration for precious metal in the precious metal containing solution is to be less than 110 mg/L. When the power is on, current starts flow from the output side of a current rectifier, and the current starts to react with the object solution for precious metal recovery in a cathode drum(3) and an outer anode(2). As a result, in the surface of the rotating cathode drum, gold, silver, platinum, palladium and et cetera are attached, so that the precious metal can be collected. [Reference numerals] (AA) Au concentration; (BB) Time

Description

Precious metal electrolytic recovery method {NOBLE METAL ELECTROLYSIS COLLECTING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noble metal recovery method for improving the noble metal recovery efficiency by providing a function of changing the rotational speed of the rotating cathode drum accompanying the noble metal electrolytic recovery device for recovering noble metals such as gold, silver, platinum, and palladium. .

Conventionally, precious metal plating such as gold, silver, platinum, and palladium has been used in a wide range of fields such as semiconductor-related parts and ornaments, but in addition to reducing the amount of material used, both in terms of resource saving and manufacturing cost reduction. In addition, there is a strong demand for reduction of expensive precious metals from being taken out or distributed out of the system.

When recovering the noble metal dissolved in these plating waste water and the washing | cleaning liquid after plating, there also exists a method of making metal complex salt adsorb | suck to an ion exchange resin and collect | recovering. Due to running costs such as cost, labor of maintenance work, etc., a method of recovering by electrolytic reduction as a metal on a negative electrode is generally used by an electrolytic method.

In this case, as disclosed in Japanese Patent Laid-Open No. 11-92985 (Patent Document 1) as a drum electrode rotating precious metal electrolytic recovery device, precious metal plating such as gold, silver, platinum, palladium, and the like is disclosed. In the recovery of wastewater and precious metals taken out of the system, by removing the oxide film on the front and back surfaces of the rotating cathode drum accompanying the precious metal electrolytic recovery device, a rotating cathode drum was used to prevent peeling and dropping of electrodeposited metal. The noble metal electrolytic recovery apparatus which collect | recovers the noble metal contained in waste water by electrolysis is proposed.

As for the recovery of the precious metals carried out of the system, the recovery tank or the washing tank is provided in the next step of the plating tank, and the role of these tanks is the precious metal ions, conductive salts, polishes, and organic substances, which are plating liquid components attached to the plating target. Since it washes away etc., precious metal ion which is a plating liquid component mixes in a collection tank and a washing tank. In order to recover the expensive precious metal mixed therein, a liquid circulation is performed between the drum electrode rotating type precious metal electrolytic recovery device and the recovery tank of the subsequent step of the plating tank, the washing tank, or the replacement of these liquids with another tank. Expensive precious metals carried out of the system are electrodeposited onto a rotating cathode drum (drum cathode) to recover them.

This drum electrode rotation type electrolytic recovery apparatus arrange | positions a tube-shaped drum cathode in the center, arrange | positions the anode which coated Ti-based Pt plating or indium oxide from all directions, and electrolyzes the metal ion contained in a liquid. By electrodeposition as a metal on the drum cathode surface. The drum cathode is rotated at the time of electrolysis to increase the contact efficiency of metal ions between the electrodes by the liquid stirring effect, to increase the electrolytic reaction efficiency, to smooth the deposited metal, and to deposit the metal with strong adhesion. The effect can be obtained.

In addition, this drum cathode electrode has a structure that can be easily separated from the electrolytic apparatus, and is entrusted to a professional who refines the precious metal, thereby easily reproducing the expensive precious metal deposited on the drum cathode, thereby making it valuable as a precious metal. In addition, the precious metal recovered by peeling and recovering from the drum surface can be regenerated by a material such as a noble metal chemical used in the plating and used again in the plating step.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. 2011-58087 (Patent Document 2) and International Publication No. WO2008 / 153001 (Patent Document 3), an apparatus for recovering metal by electrolyzing a metal-containing solution is disclosed. And a collecting device for a solution and a positive electrode, a negative electrode and a driving mechanism by water flow, and either or both of the positive electrode and the negative electrode rotate by the driving mechanism, a column-shaped or tube-shaped rotating negative electrode, A metal recovery device has been proposed which has an anode facing the rotating cathode and a conductor having a mesh or porous shape, and wherein at least a part of the surface of the rotating cathode is covered with a conductor.

Japanese Patent Laid-Open No. 11-92985 Japanese Laid-Open Patent Publication No. 2011-58087 International Publication WO2008 / 153001

In the above-mentioned Patent Document 2, there is a description that the circumferential speed is performed at 1 m / sec in the embodiment in rotating the cathode, but no further circumferential speed and time relationship are explained. Moreover, similarly to patent document 2, patent document 3 is the example of the circumferential speed of a negative electrode only 1m / sec and 2m / sec, and has not elucidated the relationship between a circumferential speed and time.

Therefore, as described above, the metals carried out of systems such as precious metal plating wastewater, precious metal plating recovery tanks, and water washing tanks are expensive metals such as gold, silver, platinum, palladium, and the amount of money for resource saving and precious metal plating products. In order to reduce the red load, it is a problem to recover the metal ion concentration remaining efficiently and in a short time to a low level, without changing the electrolytic recovery device shape, volume, and rectifier output of this drum electrode rotation type, Partial functional changes have raised the question of whether to improve the metal recovery capacity, i.e., improve the current efficiency.

In order to solve the above problems, the present invention has been developed in detail, and as a result, by varying the rotational speed of the drum cathode, the rate of electrolytic precipitation of metal ions in the liquid on the surface of the drum cathode without changing the value of the electrolytic current. Came to discover that it improved.

The gist of the invention,

(1) The recovery speed of the noble metal in the noble metal-containing solution is improved by setting the rotational speed of the rotating cathode drum accompanying the precious metal electrolytic recovery device to 1.21 m / sec to 1.8 m / sec and the rotation time to 3 to 4 hours. The precious metal electrolytic recovery method characterized by the above-mentioned.

(2) The method according to (1), wherein the final noble metal concentration in the noble metal-containing solution is 110 mg / L or less.

As described above, by setting the rotational speed of the rotating cathode drum of the electrolytic recovery apparatus of the drum electrode rotation type to 1.21 m / sec or more, the electrolytic decomposition of the noble metal plating wastewater and the noble metal ions in the washing tank at a constant current value. It was possible to increase the recovery rate. In addition, changing the rotational speed of the drum cathode is connected to controlling the recovery rate by the electrolysis of the plating wastewater and the noble metal ions in the water washing tank, so that an effect of preventing excessive electrolysis can be obtained. It shows an excellent effect.

1 is an external view of a precious metal electrolytic recovery apparatus according to the present invention.
2 is a diagram showing the rotational speed on the horizontal axis and the current density on the vertical axis in the case of a hard gold plating solution.
3 is a diagram showing the rotational speed on the horizontal axis and the current density on the vertical axis in the case of a soft gold plating solution.
Fig. 4 is a diagram showing time on the horizontal axis and Au concentration on the vertical axis in the case of a hard gold plating solution.
FIG. 5 is a diagram showing time on the horizontal axis and Au concentration on the vertical axis in the case of a soft gold plating solution.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail according to drawing.

1 is an external view of a noble metal electrolytic recovery apparatus according to the present invention. As shown in this figure, inside the electrolytic cell 1, a rotating cathode drum 3 rotatably disposed in the center thereof is disposed, and the rotational speed of the rotating cathode drum 3 is provided on the side of the apparatus. The rotation controller has a function of changing the rotation speed. On the outer circumference of the rotary cathode drum 3, four outer circumferential anodes 2 of plural plates which are arranged at regular intervals are arranged. The code | symbol "4" is a control panel, and controls the electric current in the control panel 4.

In the above noble metal electrolytic recovery apparatus, when a power is turned on, a current flows from the rectifier output side, and this current starts an electrolytic reaction with the noble metal recovery target liquid between the rotating cathode drum 3 and the outer anode 2. As a result, precious metals, such as gold, silver, platinum, and palladium, adhere to the surface of the rotating cathode drum 3, and collect | recover the precious metal.

Regarding the rotation of the rotary cathode drum 3, precious metal plating liquid components are loaded into the metal plating wastewater and the metal plating recovery tank and the water washing tank, and metal ions, conductive salts, polishes, organic substances, and the like are contained in each tank. When the metal ions therein are recovered using the noble metal electrolytic recovery device, the metal ions are precipitated on the drum cathode as the metal by electrolysis of the metal ions. May be electrolyzed and the washing water of the washing tank may turn brown. In this case, in order to avoid excessive electrolysis, the recovery rate of the metal ions in the washing water is controlled. Therefore, this electrolytic recovery apparatus has a function of varying the drum cathode main speed of the present drum electrode rotation type electrolytic recovery apparatus by transmissions such as inverters, pulleys, and gears.

The reason for limiting the rotational speed of the rotating cathode drum accompanying the noble metal electrolytic recovery device to 1.21 m / sec to 1.8 m / sec is less than 1.21 m / sec when the final target achievement concentration is set to 110 mg / L or less, It takes a long rotation time to reach the target achievement density | concentration, and the cost rises by excessive current consumption. On the other hand, since it turns out that recovery efficiency improves rapidly by making rotation speed into 1.21 m / sec or more, the minimum was made into 1.21 m / sec. However, when the rotational speed exceeds 1.8 m / sec, the reduction rate of the noble metal electrolysis recovery falls compared with the rotation time, and since the reduction rate becomes almost parallel, the upper limit was made 1.8 m / sec.

In addition, about rotation time, it set to 3 hours-4 hours. The reason is that when the target attainment concentration is set at 110 mg / L or less, in order to achieve the shortest time and the best efficiency and low cost, it is simply required that the rotation time takes the final recovery of the precious metal recovery concentration in the precious metal-containing solution in the plating wastewater. Although the reduction is possible, however, in order to achieve the target efficiently with the minimum time to achieve the final target concentration and at low cost, as described above, the lower limit is 1.21 m / sec and the rotation time is 3 hours as described above. It was made.

That is, in less than 3 hours, even if the rotation speed is increased, the target 110 mg / L or less cannot be achieved. On the other hand, if the rotation time exceeds 4 hours, the recovery concentration can be reduced. However, since the recovery speed is lowered due to excessive electrolysis and the cost is increased, the recovery time is as short as possible, and 4 hours from the need for efficient recovery. It was set as. That is, in less than 3 hours, recovery efficiency is inadequate, and when it exceeds 4 hours, since cost will rise, it was set as 3 to 4 hours.

Table 1 and Table 2 show the current efficiency when the above-mentioned rotational speed is 1.21 m / sec to 1.8 m / sec and the rotation time is 3 to 4 hours. The change of the value shown to this Table 1 and Table 2 is shown to FIG. 2 and FIG. 2 is a diagram showing the rotational speed on the horizontal axis and the current density on the vertical axis in the case of a hard gold plating solution. As shown in this figure, in the recovery of gold from the hard gold plating wastewater, the current efficiency (%) at the rotational speed of 1.21 m / sec or more is equal to the equilibrium state when the rotation time is 3 hours and 4 hours. In particular, it can be seen that the current efficiency after 3 hours is clearly shown.

3 is a figure which shows the rotational speed on a horizontal axis and a current density on a vertical axis in the case of a soft gold plating liquid. As shown in this figure, in the recovery of gold from the soft gold plating wastewater, the same tendency is observed as in the case of the hard gold plating wastewater shown in FIG. 2, and the current at the rotational speed of 1.21 m / sec or more. The efficiency (%) is in equilibrium when the rotation time is 3 hours and 4 hours, and it can be seen that the current efficiency after 3 hours is particularly apparent.

[Table 1]

[Table 2]

As for Table 1 and Table 2, No. 1-3 is a comparative example, No. 4-6 is an example of this invention.

(Example 1)

Hereinafter, an Example demonstrates this invention concretely.

Gold potassium cyanide containing hard gold plating wastewater Plating wastewater (acid): Gold potassium cyanide (Au): 1 to 4 g / L, citrate: 40 g / L, citric acid: 40 g / L, each test liquid amount 10 L, temperature room temperature, rotation Each drum rotation speed was set to 0.3 m / sec, 0.61 m / sec, under conditions of a current of 5 A, and placed in a tank in a noble metal electrolytic recovery device of a rotary electrode type having a function of varying the rotation speed of the cathode drum. The relationship between time and Au concentration at the time of changing to 0.91 m / sec, 1.21 m / sec, 1.7 m / sec and 1.8 m / sec was measured. The results are shown in Table 3. The change of the value shown in this Table 3 is shown in FIG. In addition, the number of device structures, rotating drum cathode was constant conditions:: (4dm ² × width 65 × height 160㎜ 4, the effective area) (diameter 116 × height 160㎜, effective area 5.8dm ^2), the anode.

[Table 3]

As shown in Table 3, No. 1-3 is a comparative example, and No. 4-6 is an example of this invention.

The result shown in Table 3 is shown in FIG. As shown in Fig. 4, time is plotted on the horizontal axis and Au concentration (mg / L) on the vertical axis. Au contained 1700 mg / L in the wastewater changed the main speed, and the drum rotation speed was rapidly decreased at 1.21 m / sec after 3 hours, compared with the case of 2 hours. Similarly, it can be seen that the drum rotation speeds of 1.7 m / sec and 1.8 m / sec are also rapidly decreased compared with the case of 2 hours. As described above, by reducing the drum rotation speed to 1.21 m / sec or more and the rotation time to 3 hours or more, reduction in the Au concentration remaining in the liquid can be achieved very efficiently. For this reason, in the present invention, the drum rotational speed was 1.21 m / sec to 1.8 m / sec, and the rotation time was 3 to 4 hours. This confirmed that the Au in the plating wastewater was reduced to 110 mg / L or less. That is, it was confirmed that the electrolytic precipitation on the drum cathode.

(Example 2)

In the same manner as in Example 1, gold potassium cyanide-containing plating wastewater (alkali bath) of soft gold plating wastewater: gold potassium cyanide (Au): 10 g / L, potassium cyanide: 30 g / L, potassium hydrogen phosphate: 30 g / L, potassium carbonate : 15 g / L, temperature at room temperature, and placed in each of the tanks in the noble metal electrolytic recovery device of the rotary electrode type having the function of varying the rotational speed of the rotating cathode drum, and each drum rotational speed was 0.3 under conditions of a current carrying current of 7 A. The relationship between time and Au concentration at the time of changing into m / sec, 0.61 m / sec, 0.91 m / sec, 1.21 m / sec, 1.7 m / sec and 1.8 m / sec was measured. The results are shown in Table 4. The change of the value shown in this Table 4 is shown in FIG. In addition, the number of device structures, rotating drum cathode was constant conditions:: (4dm ² × width 65 × height 160㎜ 4, the effective area) (diameter 116 × height 160㎜, effective area 5.8dm ^2), the anode.

[Table 4]

As shown in Table 4, No. 1-3 is a comparative example, and No. 4-6 is an example of this invention.

The result shown in Table 4 is shown in FIG. As shown in Fig. 5, Au containing 10100 mg / L in the wastewater changes the rotational speed so that the drum rotational speed is 1.21 m / sec, and after 3 hours, the 10100 mg / L is 100 mg / L. Decreases. If the rotational speed is increased to 1.8 m / sec, the rate decreases to 20 mg / L. On the other hand, if the rotation time was continued from 3 hours to 4 hours, the value decreased to one digit. As can be seen, similarly to Example 1, when the drum rotational speed is 1.21 m / sec or more and the rotation time is 3 hours or more, it can be seen that the effect of reducing the Au concentration remaining in the liquid is greatly improved. have. In particular, it shows a significant reduction compared with the case of the hard gold plating wastewater of Example 1. As described above, by regulating the drum rotation speed at 1.21 m / sec to 1.8 m / sec and the rotation time to 3 to 4 hours, it was confirmed that Au in the plating wastewater was reduced to 100 mg / L or less in a very short time. That is, it was confirmed that the electrolytic precipitation on the drum cathode.

As described above, by increasing the rotational speed of the rotating cathode drum of the drum-electrode electrolytic recovery apparatus by a certain level or more, the recovery rate by electrolysis of the noble metal plating wastewater and the noble metal ions in the washing tank at a constant current value. Made it possible to rise. On the other hand, the rotation time therefor was also very efficient time, 3 to 4 hours. In addition, by changing the rotational speed of the drum cathode in this way, it is connected to controlling the recovery rate by the electrolysis of the plating wastewater and the noble metal ions in the water washing tank, so that excessive electrolysis can be achieved in a short rotation time. You can get a very good effect, such as the effect to prevent.

1: electrolytic cell
2: outer anode
3: rotating cathode drum
4: control panel
5: wastewater

Claims (2)

The recovery speed of the noble metal in the noble metal-containing solution was improved by setting the rotational speed of the rotating cathode drum accompanying the noble metal electrolytic recovery device to 1.21 m / sec to 1.8 m / sec and the rotation time to 3 to 4 hours. Precious metal electrolytic recovery method. The method of claim 1,
A noble metal electrolytic recovery method, wherein the final noble metal concentration in the noble metal-containing solution is 110 mg / L or less.

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