JPS6227160B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a dimensionally stable electrode, and more particularly to a dimensionally stable electrode for generating oxygen from an acidic electrolyte used in methods such as electrowinning of metals from an acidic electrolyte. Regarding the anode.

BACKGROUND OF THE INVENTION Lead or lead alloy anodes have been widely used in the electrowinning of metals from sulfuric acid solutions. Nevertheless, such lead alloy anodes had significant drawbacks. The disadvantages are that the oxygen overvoltage is high and
As a result of the loss of anode material, metal is deposited on the cathode and the electrolyte is contaminated.

Although the use of lead-silver alloy anodes reduces the oxygen overpotential to some extent and improves the current efficiency, such anodes still suffer from the same overall drawbacks.

For the anodic generation of oxygen, it has been proposed to use dimensionally stable titanium anodes with a coating of platinum metal oxide, but generally speaking such anodes are more or less titanium-based Passivation and oxidation will occur.

It has also been proposed to apply protective undercoatings containing platinum-based metals to the titanium base below the external coating, but such expensive coatings generally do not protect the titanium base sufficiently. The meaning of using precious metals is lost.

Since metal electrowinning cells typically require a large anode area and operate at low current densities to ensure uniform electrodeposition of the metal on the cathode, the cost of titanium-based cells is quite significant and requires consideration. It becomes a factor.

US Pat. No. 3,632,498 describes a dimensionally stable anode having a mixed oxide coating comprising a platinum metal and a valve metal. One embodiment of the above-mentioned US patent relates to a method for producing a Ti--Pd mixed oxide fine powder that is later transformed into rod-shaped soft titanium through a rolling or hammer forging process. However, in this way, the amount of noble metal included in the mixed oxide powder and applied to the electrode becomes prohibitively expensive for various industrial applications. Thus, if the entire surface of the electrode is to be coated with mixed oxide powder, and if the electrode is to be operated at relatively low current efficiencies such as those used for metal electrode harvesting, the mixed oxide powder may be The cost of the precious metals applied becomes prohibitively high.

DISCLOSURE OF THE INVENTION One object of the present invention is to provide an improved anode for generating oxygen from acidic electrolytes.

Another object of the present invention is to provide an improved anodic reactive method for removing oxygen from an acidic electrolyte to substantially prevent loss of anode material and thereby eliminate the aforementioned drawbacks of conventional lead or lead alloy anodes. The object of the present invention is to provide an anode with a lead or lead alloy base that has electrochemical properties that occur.

A further object of the invention is to provide a simple method of manufacturing such an electrode with improved properties.

The above objects are substantially achieved by the invention as defined in the claims.

The electrochemical properties of the electrode are improved according to the invention as follows. That is, titanium particles catalytically activated by ruthenium oxide and partially embedded in the surface of a lead or lead alloy anode base and thus firmly fixed and electrically connected to said base are used as an anode. is applied. The remaining unembedded portions of the catalyst particles protrude from the surface of the anode base, thereby providing a surface for oxygen evolution that has a significantly larger area than the underlying surface of the lead or lead alloy anode base. can.

The partially embedded catalyst particles described above are preferably arranged according to the invention for the following purposes: That is, to substantially cover the entire surface of the lead or lead alloy base, providing maximum surface area for oxygen evolution, and thereby substantially uniformly distributing the anodic current density.

According to the invention, it is particularly advantageous to use ruthenium for the catalytic activation of titanium particles. This is because ruthenium is an electrocatalyst for oxygen generation that is considerably cheaper and has excellent characteristics than other platinum metals.

Advantageously, the catalyst particles applied according to the invention consist of titanium sponge. The catalyst particles also have a particle size in the range of 150 to 1250 microns, preferably in the range of about 300 to 1000 microns.

In accordance with the present invention, the amount or load applied to a unit area of the anode base should generally be sufficient to substantially cover the anode base.

It has been found that producing electrodes with sufficient properties requires relatively high particle loadings, generally corresponding to 400 g/m ² or more. 1000
It has been found that g/m ² and above are equally advantageous even at high loadings.

It is advantageous for the catalyst particles to have a uniform distribution over a large area of a minimum amount of ruthenium, which corresponds to at most 6% of the weight of titanium in the particles.

Despite the above indicated, e.g. 500
High loadings of catalyst particles, such as ~1000 g/m ² , significantly increase the cost of ruthenium. Therefore, it is particularly important to minimize the loss of ruthenium during anode operation.

It has been substantially determined that activation of titanium particles with manganese together with ruthenium oxide increases the stability of the catalyst towards ruthenium oxide alone or in combination with ruthenium oxide and other compounds.

Under conditions where oxygen evolves in acidic media,
The improved electrocatalytic properties and stability of the Ru--Mn oxide system are largely due to the particularly advantageous properties of the catalytically activated titanium particles used on the lead base according to the invention.

It has also been found that the stability of the particles is further improved by forming titanium oxide by pyrolysis on the activated particles.

Furthermore, if the large activated particles are first pressed into the lead anode base and then the smaller particles, which advantageously have a higher ruthenium content than the larger particles, are pressed, the ruthenium can be utilized more efficiently. It is confirmed that it is possible.
It has been found that such a two-stage welding process improves the long-term stability of the catalyst activated particles as well as the degree of contact of the catalyst activated particles with the lead base.

Also, valve metal or valve metal oxide,
In particular, it has been found that the stability of the activated particles is further improved by carrying out a further pressing step to apply the non-activated particles of zirconium oxide. This means that poor conductivity
If MnO ₂ precipitates, the anode properties may be impaired.
This is particularly important in methods for electrowinning metals from electrolytes containing Mn ₂ ⁺ ions.

The following examples illustrate various modes of carrying out the invention.

Example 1 0.57 g RuCl ₃ · aq (hydration water) and 1.33 g Mn
An activation solution was prepared by dissolving (NO ₃ ) ₂ ·aq (water of hydration) in 4 ml of 1-butyl alcohol. Next, this solution was diluted with 1-butyl alcohol in an amount six times the above amount.

After degreasing 3.25 g of Ti sponge (particle size of 630 microns or more) with trichlorethylene and drying,
It was impregnated with the above activation solution. After each impregnation, the titanium sponge was dried at 100°C for approximately 1 hour. Next, first 10 at 200℃.
Heat treated for 1 minute, then under fresh air flow.
Heat treatment was performed at 400°C for about 10 minutes. This activation step was performed five times. thus obtained
The loading amount of Ru and Mn is 28.4mgRu and Ti per g of Ti.
reached 36.0 mg Mn per g.

The same activation solution was used for a new 4.9 g Ti sponge (particle size 315-630 microns). drying temperature,
The heating temperature and number of impregnations are the same as those applied in the previous case of large particles. However, the heat treatment time at 400°C was 12 minutes. The Ru and Mn loadings obtained in this case amounted to 27 mg Ru/g Ti and 34 mg Mn/g Ti.

These activated titanium sponge particles were pressed against a lead sheet coupon. That is, first, particles with a large particle size (630 microns or more) are pressed together at a pressure of 290 kg/cm ² and the particles are 322 g/m 2 and 11.5 g/m ² , respectively.
Ti, Mu and Ru loadings per unit lead sheet area of g/m ² and 9.1 g/m ² were obtained. Next, small activated titanium particles (315-630 microns) are added.
Pressed together at a pressure of 360Kg/ ^cm2 , each
Ti, Mn and Ru loadings of 13.7 g/ ^{m 2 and} 10.8 g/m ² were obtained.

In this way, 722g/m ² Ti sponge, 19.9
oxidation in amounts corresponding to g/m ² Ru and 25.2 g/m ² Mn.
An electrode sample (L62) with a lead base uniformly coated with Ru-Mn activated titanium sponge particles was obtained.

This electrode sample was tested as an anode for oxygen generation in H ₂ SO ₄ (150 g/). 500A/
The electrode potential (oxygen half-cell potential) at a current density of m ² reached 1.57 V vs. NHE after 68 days of anode operation, 1.59 V after 194 days, and 1.75 V after 210 days.

Incidentally, activated Ti with high Ru and Mn loadings corresponding to 27.9 g/m ² and 35.4 g/m ² respectively
Another anode sample (L61), obtained by pressing small sponge particles directly onto the lead, showed an anode potential of 1.62 V after 69 days of operation under comparable conditions, and anode potential of 1.62 V after 194 days of operation under the same conditions. When stopped, the potential was 1.63V.

Another anode sample (L76) was fabricated under the same conditions as L62. The only difference is that the activation process for large particles was repeated five times in L62, but
In L76, I limited it to 4 times. For L76,
The total Ru and Mn loading amounted to 22.1 g/m ² and 28.0 g/m ² , respectively. A similar test was performed on this anode and after 22 days of operation it showed 1.5V vs. NHE.
Furthermore, after 140 days of operation, it showed 1.8V.

Example 2 An anode sample (L64) was produced under the same conditions as L62 of Example 1. The only difference is that the loading amounts of Ru and Mn were increased to 23.1 g/m ² and 29.3 g/m ² , respectively. This anode was tested in a Zn electrowinning solution containing Mn ²⁺ as the main impurity.

The potential after 60 and 120 hours of operation as an anode to generate oxygen from such a medium is respectively
Reached 1.68V vs. NHE and 1.73V vs. NHE. The current density was 400A/ ^m2 . During this period, no precipitation of manganese oxide occurred.

Incidentally, the total Ru and Mn loadings are 19 each.
After 60 hours of operation, lead samples containing either only large-sized particles (>630 microns) or only small-sized particles (315-630 microns) corresponding to ~20 g/ ^m2 and 24-25 g/ ^m2 were tested. Approximately 1.72~1.75V vs.
It showed a high anodic potential of NHE. Thick anodic deposition of manganese oxide was also observed in the case of both particles.

Example 3 A Ti sponge (particle size 315-630 microns) was activated under the same conditions as in Example 1. Next, this Ti sponge was pressed against lead at a pressure of 270Kg/cm ² to yield 427g/m ² , 15.1g/m 2 and 11.9g/m ² , respectively.
Ti, Mn and Ru loadings corresponding to g/m ² were obtained.
Finally, granular ZrO ₂ (particle size 150-500 microns) was pressed onto the top surface of the Ti sponge with a pressure of about 410 Kg/cm ² to obtain a ZrO ₂ loading corresponding to 248 g/m ² .

Electrode sample obtained in this way (L82)
was tested as an anode for oxygen evolution in H ₂ SO ₄ (150 g/). The electrode potential at a current density of 500 A/ ^m2 is 1.50 V vs. after 150 hours of anodic operation.
Reached NHE. After another 293 days, it reached 1.59V and was still operating. This corresponds to a voltage saving of 410 mV in the case of pure untreated lead.

Example 4 A Ti sponge (315-630 micron particle size) was first activated with a Ru and Mn containing solution as described in Example 1. The activation method is also the same as in Example 1.
The method was the same as that shown in .

After such activation, 1.78 g of Ti-butoxide was mixed with 3.75 ml of 1-butyl alcohol and 0.25 ml of Ti-butoxide.
A protective film was applied by impregnation with a solution containing Ti-butoxide prepared in HCl.

The sponge thus impregnated was dried at 100° C. for about 1 hour. Heat treatment was then carried out at 250°C for 12 minutes, and then at 400°C for about 12 minutes under an outside air flow.
Heat treatment was performed for 10 minutes.

Approximately 250 activated titanium particles were
It was pressed onto lead at a pressure of Kg/cm ² . As a result, 13.3gRu/m ² , 16.9gMn/m ² , 5.8gTi/
An electrode sample (L84) was obtained with a lead base uniformly coated with an oxidized Ru--Mn activated titanium sponge with a protective layer of titanium oxide with an amount corresponding to m ² and 515 g Ti sponge/m ² .

This electrode sample was tested as an anode for oxygen generation in H ₂ SO ₄ (150 g/). 500A/
The potential at a current density of m ² reached 1.49 V vs. NHE after 130 hours of anodic operation. This corresponds to a savings of 510 mV when using untreated lead. The anodic potential further reached 1.64V after 128 days. This corresponds to a savings of 360 mV when using untreated lead.

Example 5 A Ti sponge (particle size 315-630 microns) was first activated with a Ru-containing solution prepared by dissolving 134 g of _RuCl3H2O in 1 part butyl alcohol. This Ti sponge was impregnated with such a Ru-containing solution and the solution was evaporated for 120 min.
℃ for 20 minutes, then 250℃ for 15 minutes, and finally 450℃ for another 15 minutes.
Heat treatment was performed. This impregnation, drying and baking process was repeated four times. The ruthenium loading amount thus obtained reached 30 mg per gram of Ti sponge.

After such activation, a protective coating of TiO ₂ was applied to the activated particles by impregnation with a solution obtained by mixing 1.8 g of titanium butoxide with 3.75 ml of butyl alcohol. The drying, heating and baking steps were the same as for the Ru-containing activation solution described above.

The activated titanium particles were pressed onto a lead sheet coupon at a pressure of 250 kg/cm ² . In addition, 500
Of the particle loading of g/m ² , 15 g/m ² Ru and 2.5
Pressure welding was carried out such that g/m ² Ti was applied to the particles evenly distributed on the lead surface.

The electrode sample was tested as an anode for ion generation in H ₂ SO ₄ (150 g/).
The electrode potential at a current density of 500 A/m ² reached 1.66 V vs. NHE after 2000 hours of anodic operation.

Example 6 Rutile with particle size range 513-630 microns
_TiO2 particles were impregnated with the following solution. That is,
0.54 g RuCl ₃ H ₂ O, 1.8 g butyl titanate,
A solution of 0.25 ml HCl and 3.75 ml butyl alcohol.

After impregnation, the particles were air-dried at 100°C.
Next, baking was performed at 440°C for 10 minutes under air flow. This process was repeated four times. The obtained particles
RuO ₂ -activated with TiO ₂ .

The particles were pressed against a lead sheet coupon by applying a pressure of 250 Kg/cm ² . Each particle loading amount is
A loading of 400 g/m ² was reached, corresponding to a loading of 15 g/m ² Ru and 16 g/m ² Ti. (Applied as RuO ₂ -TiO _2. ) The activated lead electrode thus obtained was heated at room temperature.
The applied anodic current density tested as an anode in an aqueous solution containing 150 g/H ₂ SO ₄ was
It was 500A/ ^m2 . 300 hours after operation
An oxygen half-cell potential of 1.75V vs. NHE was obtained. 1000
After a period of time, the anode potential reached the same value as that of a pure, untreated lead anode.

Example 7 An activation solution was prepared in the same manner as in Example 1.
The only difference is that in Example 1, the dilution was 6 times the amount, but in this case, the amount was 3 times the amount of n-butyl alcohol.
The reason is that the dilution was limited to double the amount.

Next, 4.11 g of Ti sponge (particle size 400-630 microns) was impregnated with the solution. After each impregnation, the titanium sponge was dried at 100° C. for approximately 1 hour. Next, heat treatment was performed at 250°C for about 10 minutes, and finally, heat treatment was performed at 400°C for about 10 minutes under an outside air flow. This activation step was performed three times. The amount of Ru and Mn loaded in this way was 36.2mgRu/g.
Ti and 45.8mgMn/gTi were reached.

Ti having a particle size of 630 microns or more in Example 1
The activation process for sponges was again applied to large particles (630 microns and above). However, the activation step was only repeated four times. The Ru and Mn loads thus obtained reached 23.5 mgRu/gTi and 29.9 mgMn/gTi.

The activated titanium sponge particles thus obtained are pressed onto the surface of the lead sheet coupon to partially embed it. Large particles (630 microns or more) were first pressed together at a pressure of 240 kg/cm ² . As a result, 350g/m ² and 10.5
Loadings of Ti, Mn and Ru are given per unit lead sheet area of g/m ² and 8.3 g/m ² . As a result, 760 g/m ² Ti sponge, 23.2 g/m ² Ru and
An electrode sample (L95) was obtained with a lead base uniformly coated with oxidized Ru-Mn activated titanium sponge particles in an amount corresponding to 29.3 g/m ² Mn. The electrode samples were tested as oxygen generating anodes in H ₂ SO ₄ (150 g/). The electrode potential at a current density of 500 A/ ^m2 was 287 days after the anode operation.
Reached 1.65V vs. NHE.

Incidentally, the Ru and Mn loads corresponding to 15.4 g/ ^{m 2 and} 19.5 g/m ² were obtained by directly pressing small particles of activated Ti sponge onto lead at a pressure of 280 Kg/cm 2 . Another anode sample (L93) was tested under similar conditions and the electrode potential after 289 days was 1.78V vs. NHE.

Yet another anode sample (L92) was fabricated under the same conditions as L95. The only difference is that small particles (400 to 630 microns) were activated under the same conditions as in Example 1 (L62). In this case, the total loading amount of Ti, Mn and Ru is respectively
726 g/m ² , 22.5 g/m ² and 17.7 g/m ² were reached. Large particles and small particles, respectively.
Welding was carried out at pressures of 290 Kg/cm ² and 410 Kg/cm ² . The resulting anode was tested under similar conditions and showed a potential of 1.78 V vs. NHE after 289 days of operation.

Example 8 An activation solution was prepared as in Example 7.
Next, 4.22 g of large particles (particle size 630 microns or more) were activated twice under the conditions specified in Example 7, resulting in 21.5 mg Ru/gTi and 27.4 mg Ru/gTi.
Mn/gTi was obtained.

Another activation solution was applied to a Ti sponge with a small particle size range of 400-630 microns. This activation solution corresponds to the activation solution described in Example 7, except that it is diluted with twice the amount of 1-butyl alcohol. Two activations were then performed according to Example 7. Ru and Mn per 1g of Ti
The loading amounts reached 25.9 mg and 32.9 mg, respectively.

First, the particles with the above particle size are 210Kg/cm ²
360g/m ² and 9.8g/m 2 , respectively.
Anode samples (L120) were fabricated by obtaining Ti, Mn, and Ru loadings of g/m ² and 7.7 g/m ² . Next, small activated titanium particles (400-630 microns) were pressed together at a pressure of 320 Kg/cm ² to give Ti of 420 g/m ² , 13.9 g/m ² and 10.9 g/m ² , respectively. The loading amounts of Mn and Ru were obtained.
The total Ti, Mn and Ru loadings thus obtained were 780 g/m ² , 23.7 g/m ² and 18.6 g/m 2 , respectively.
Reached m ² .

The electrode samples were tested as oxygen generating anodes in H ₂ SO ₄ (150 g/). 500A/
The electrode potential at a current density of m ² reached 1.58 V vs. NHE after 218 days of anodic operation.

Example 9 Titanium sponge (400-630 microns) was oxidized
It was oxidized as shown below before activation with Ru-Mn.

4.74 g of titanium sponge was activated once with the activation solution described in Example 1. After drying this Ti sponge at 100℃, it was heated to 400℃ under an outside air flow.
Heat treatment was performed at ℃ for 13 minutes. The loading amounts of Ru and Mn are 5.2mg/gTi sponge and 6.6mg/g, respectively.
It was hot with gTi sponge. These sponges were subjected to heat treatment at 480°C for 45 minutes under an outside air flow to convert them into the respective oxides.

3.5 g of the Ti oxide sponge thus obtained was activated under the conditions described in Example 1. The only difference is that after each activation process, intermediate heat treatment is performed.
This was done at 250℃ instead of 200℃. The loading amount of Mn and Ru per 1g sponge is 32.8 each.
mg and reached 25.8 mg.

This pre-oxidized activated Ti sponge was press-fitted in two steps as follows. i.e. first
Mn was injected at a pressure of 230 Kg/cm ² and then at a pressure of 290 Kg/cm ² to produce 21.1 g/m ² and 16.6 g/m ² of Mn, respectively.
The loading amount of Ru was obtained. The loading amount of this Ti oxide sponge reached 643 g/m ² . Ti oxide before final activation
Considering the loading amount of Mn and Ru in the
The Ru loading amount is 25.3g/ ^m2 and 19.9g/ ^m2 , respectively.
will reach.

This electrode was tested at a current density of 500 A/m ² in 150 g/H ₂ SO ₄ and reached a potential of 1.65 V vs. NHE after 275 days of operation.

Example 10 Greater than the Mn/Ru ratio described in Example 1
Two types of solutions with Mn/Ru ratios were prepared as follows.

Solution A: 0.537 in 3.75ml n-butyl alcohol
g of RuCl ₃ ·aq (water of hydration) and 2.0819 g of Mn
(NO ₃ ) ₂ ·aq (hydration water) was dissolved.

Solution B: 0.537 in 3.75ml n-butyl alcohol
g of RuCl ₃ ·aq (water of hydration) and 4.6844 g of Mn
(NO ₃ ) ₂ ·aq (hydration water) was dissolved.

These solutions A and B were diluted with three times the amount of n-butyl alcohol before application as follows. Solution A corresponds to a molar ratio of MnO ₂ /RuO ₂ =4, and solution B corresponds to a molar ratio of MnO ₂ /RuO ₂ =9.

4.27g Ti sponge (particle size 315-630 microns)
was impregnated with diluted activation solution A. After each impregnation, the titanium sponge was dried at 100° C. for approximately 7 hours. Next, heat treatment was performed at 250°C for 14 minutes, and finally, heat treatment was performed at 400°C for about 14 minutes under an outside air flow. This activation step was performed three times. The amount of Ru and Mn loaded in this way was 29.3mgRu/
gTi and 63.8 mgMn/gTi were reached.

4.16g Ti sponge (particle size 315-630 microns)
was impregnated with diluted activation solution B. The activation step was carried out in the same manner as for activation solution A. The Ru and Mn loading amount thus obtained was 19.9mg/gTi
and 97.4mgMn/gTi.

The thus activated Ti sponge particles were pressed onto a lead sheet coupon. Large particles (630 microns or more) activated as in Example 8
were first pressed together at a pressure of 230Kg/cm ² , resulting in 44g/m ² , 12.0g/m 2 and 9.4g/m ² , respectively.
Ti, Mn and Ru loadings per unit lead sheet area of m ² were obtained. Next, activated small Ti particles (315-630 microns) (with diluted solution A) were pressed together at a pressure of 350 Kg/cm ² to yield 399 g/m ² and 25.5 g/m 2 , respectively. ² and 11.7g/ ^m2
The loading amounts of Ti, Mn and Ru were obtained.

As a result, 848g/ ^m2 Ti sponge, 20.8g/m2
Oxidation in amounts corresponding to m ² of Ru and 37.5 g/m ² of Mn
Electrode sample (L164) with lead base uniformly coated with Ru-Mn activated titanium sponge particles
I got it.

This electrode sample was tested as an oxygen generating anode in 150 g/H ₂ SO ₄ . The potential at a current density of 500 A/ ^m2 is 1.50 V after 36 days of anode operation.
Reached against NHE.

For comparison, another anode sample (L161) was fabricated. The manufacturing method consists of 320% activated Ti sponge small particles (in diluted solution A).
531 each by direct pressure contact with lead at a pressure of Kg/cm ²
g/m ² , corresponding to 15.6 g/m ² and 34.0 g/m ²
This was done to obtain the loading amounts of Ti, Ru, and Mn.

When this electrode L161 was tested as described above,
After 70 days of operation, the potential was 1.60 V vs. NHE.

In another set of experiments, activated Ti sponge particles with a particle size of 630 microns or more as in Example 8 were first pressed together at a pressure of 230 Kg/cm ² to yield 428 g/m ² and 11.5 g/m 2 , respectively. Ti, Mn and Ru loadings per unit lead sheet area of m ² and 9.0 g/m ² were obtained. Next, small activated titanium sponge particles (particle size 315 to 630 microns) obtained using activation solution B were pressed together at a pressure of 350 Kg/cm ² to yield 493 g/m ² and 48.0 g/m ² , respectively. and 9.8 g/m ² of Ti,
Mn and Ru loading amounts were obtained. As a result, 921g/m ²
An electrode sample (L163) with a lead base uniformly coated with oxidized Ru-Mn activated titanium sponge particles in an amount corresponding to 59.5 g/ ^m2 of Ti, 59.5 g/m2 of Mn and 18.8 g/ ^m2 of Ru was obtained. Ta.

This electrode was tested as an oxygen generating anode in 150 g/H ₂ SO ₄ . The potential after 33 days of operation is
Reached 1.57V vs. NHE.

Example 11 Another anode sample (L162) was fabricated for comparison (with L163 of Example 10). The manufacturing method is to press small particles (315-630 microns) activated (with diluted solution B) directly onto lead at a pressure of 290 kg/cm ² to produce 652 g/m 2 and 13.0 g/m ² , respectively.
Ti, Ru and Mn equivalent to g/m ² and 63.6 g/m ²
This was done to obtain the load amount.

This electrode was placed in 150g/H ₂ SO ₄ and at 500A/
Tested at a current density of ^m2 , the operating time was 18 days (430
time) showed a potential of 1.74V vs. NHE.

Example 12 0.54 g RuCl ₃ (aqueous) (38% Ru) and 0.12 g
An activation solution was prepared by dissolving PdCl ₂ in 15 ml of butyl alcohol. The solution was stirred until all salts were dissolved, then 1.84 g of butyl titanate was added.

After impregnating 3.5 g of titanium sponge with a particle size range of 315-630 microns with this activation solution,
It was dried at 140°C for 20 minutes, then heat treated at 250°C for 15 minutes, and finally at 450°C for 15 minutes. All of these heating steps were performed in air. After cooling, the above impregnation, drying, and heat treatment steps were repeated six times. Thus obtained on the particles
The loading amount of Ru and Pd is 30mgRu/gTi and 11mgPd/
gTi has been reached. The activated titanium sponge particles were composed of 500 g/m ² of Ti, 15 g/m ² of Ru, respectively.
250Kg/cm ² to obtain a Pd loading of 5.5g/m ²
It was pressed onto a lead sheet coupon at a pressure of .

This electrode sample was tested as an oxygen generating anode in H ₂ SO ₄ (150 g/m) and at a current density of 500 A/m ² . Electrode potential (oxygen half-cell potential)
reached 1.78V vs. NHE after 208 days of anode operation.

Example 13 7 g of titanium sponge (particle size 315-630 microns) was impregnated with 1.4 ml of a solution of Ir in the form of IrCl ₃ (aqueous) at a rate of 7 mg/ml in isopropyl alcohol. After impregnating, this titanium sponge
It was dried at 15°C for 15 minutes, then heat treated at 250°C for 10 minutes, and then at 450°C for 10 minutes. All these steps were performed in air.

The activated titanium sponge particles
A pressure of 250 kg/cm ² was applied to the lead sheet coupon. The selection of particle amounts was made to obtain titanium and iridium loadings of 700 g/m ² and 1 g/m ² respectively.

A second activation solution was applied to the electrode samples described above as follows. First, 5.0g of Mn
(NO ₃ ) ₂ 4H ₂ O and 0.32 g Co(NO ₃ ) ₂ 6H ₂ O to 0.5
A solution was prepared by dissolving it in ml of ethanol. This solution was applied to the surface of the electrode, dried at 140°C for 15 minutes, and then baked at 250°C (10 minutes) in air. After cooling, this coating, drying, and baking process was repeated five times, resulting in a final weight of 240 g/ ^m2 .
A loading of MnO ₂ and 12 g/m ² of cobalt oxide (calculated as Co ₃ O ₄ ) was obtained.

This electrode sample was tested as an oxygen generating anode in H ₂ SO ₄ (150 g/). 500A/ ^m2
Electrode potential (oxygen half-cell potential) at a current density of
reached 1.78 volts (vs. NHE) after 7 months of anode operation.

Example 14 An electrode sample was manufactured under the same conditions as Example 13.
The only difference is that instead of IrCl ₃・aq (hydration water)
By using RuCl ₃ ·aq (water of hydration) (14 mg/ml Ru) and repeating the impregnation process twice, a ruthenium loading of 4 g/m ² for a titanium sponge loading of 700 g/m ² was applied. This is what I got.

When this sample was tested under the same conditions as in Example 13, the oxygen half-cell potential was
It reached 1.80V (vs. NHE).

Example 15 0.44 g RuCl ₃ aq (water of hydration) (38 wt% Ru),
0.090 g SnCl ₂ 2H ₂ O and 0.52 g Mn
An activation solution was prepared by dissolving (NO ₃ ) ₂ ·4H ₂ O in 4 ml of butyl alcohol.

2.5 g of titanium sponge (particle size 315-630 microns) was impregnated with the above activation solution as follows. That is, 0.77ml of the solution was applied uniformly to a titanium sponge, dried at 140°C for 15 minutes, and then heated at 250°C.
℃ for 10 minutes, and finally 420℃ for 10 minutes.
It was baked for 1 minute. All of these drying and baking steps were performed in air. After cooling, the titanium sponge was activated again twice. Activation was performed using 0.5 ml of activation solution each time. It was then dried and baked as described above.

250Kg/cm ² of titanium particles activated in this way
lead-calcium alloy (0.06%
Ca) Ti700g/m ² in pressure contact with the surface of the coupon,
Loadings of Ru 20 g/m ² , Sn 5.8 g/m ² and Mn 13.7 g/m ² were obtained.

This electrode sample was tested as an oxygen generating anode at a current density of 500 A/m ² and in H ₂ SO ₄ (150 g/). Electrode potential after 7 months of operation
Reached 1.67V vs. NHE.

As can be seen from the above examples, the anode according to the invention can be formed in a simple manner and at a potential significantly lower than the anode potential corresponding to oxygen evolution in lead or lead alloys under similar operating conditions. Can be used for long-term oxygen generation.

It is noteworthy that when lead or lead alloy reference samples were tested under similar conditions, a significant amount of lead was lost from the electrodes when the electrolyte was observed; When such anode samples were tested as in the Examples above, no loss of lead from the base was observed.

Furthermore, when the valve metal particles are partially embedded in the lead or lead alloy on the surface of the anode base, applying heat and pressure at the same time promotes fixation.
It has been found that the disadvantage of the particles being completely embedded in the base and/or lying flat on the base is eliminated.

What should also be noted is that the anode according to the present invention has
Further improvements can be expected in the above embodiments by determining the best conditions for maximizing the saving of the amount of noble metal and providing optimally stable electrochemical properties.

In addition to using a press as in the above embodiments, suitable
It is clear that the catalyst particles can also be applied and fixed to the lead or lead alloy base of the anode by means such as, for example, a pressure roller.

It has been found that the application of heat (eg, 250° C.) during the welding process promotes partial embedding of the catalyst particles into the surface of the lead or lead alloy.

The present invention provides various advantages as described below.

(a) The anodes of the present invention can operate at potentials significantly lower than those of conventional lead or lead alloy anodes used in industrial cells for the electrowinning of metals from acidic solutions. Therefore, the cell voltage and energy costs for electrowinning metals can be reduced.

(b) Contamination of the electrolyte caused by materials coming out of the anode and precipitation on the cathode can be almost prevented. This is because it has been experimentally confirmed that oxygen is generated from the catalyst particles at low potentials which effectively prevents corrosion of the lead or lead alloy of the anode base.

(c) Resin-like crystals form at the cathode, causing a short circuit with the anode and burning the pores leading to the anode;
No deterioration is observed in the characteristics of the anode according to the present invention. This is because oxygen evolution from the catalyst particles occurs at low potentials that do not cause significant corrosion of any exposed lead or lead alloy base.

(d) retrofitting industrial metal electrowinning cells to improve their properties in a very simple and inexpensive manner since conventional lead or lead alloy anodes can be easily converted to improved anodes according to the invention; becomes possible.

(e) The low cell voltage obtained with the anode according to the invention can be easily monitored, so that any significant rise in the anode potential can be immediately detected. The catalyst particles on the lead or lead alloy base can therefore be easily reactivated or replaced whenever necessary.

(f) Ruthenium can be used as a catalyst in the most economical way when synthesized in very small proportions with titanium sponge particles applied in multiple quantities on a lead or lead alloy anode base. Therefore,
Judging from the degree of improvement in the characteristics of the obtained anode,
Ruthenium costs will be at a reasonable level.

(g) Ruthenium can be used in very low amounts and can be synthesized into inexpensive and stable materials.

(h) Short circuits observed in copper electrowinning plants equipped with anodes according to the invention are reduced. This improves the current density at the cathode, thereby increasing the energy savings already achieved by the low cell voltage of the present invention due to anodic operation at low oxygen half-cell potentials.

Industrial Applicability The anode of the present invention can be used to reduce the energy costs required for industrial electrowinning of metals such as zinc, copper, cobalt, and nickel and to increase the purity of the metal produced at the cathode. This is advantageous because it can be applied in place of the current lead or lead alloy anodes.

Such an anode is useful because it can be applied to various processes requiring oxygen generation at low overpotentials.

Claims (1)

[Claims] 1. Titanium sponge particles consisting of a lead support or a lead alloy support and an electrochemically active layer provided thereon, the active layer being catalytically activated by ruthenium and manganese in the form of oxides. An oxygen anode for electrolytic refining of metal, characterized in that the particles are partially embedded and fixed in the surface of a support. 2. The anode according to claim 1, wherein the ruthenium oxide and manganese oxide are obtained by thermal decomposition of a ruthenium compound and a manganese compound. 3. The anode according to claim 1, wherein the active layer further includes valve metal particles or valve metal oxide particles that are not catalytically activated. 4 (a) providing a lead or lead alloy support; (b) distributing catalytically activated titanium sponge particles containing ruthenium and manganese in oxide form on the surface of the support; and (c) ) Pressing catalyst-activated titanium sponge particles into the surface of a lead support or lead alloy support and embedding and fixing a part of the particles; An oxygen anode characterized by the above steps (a) to (c). Manufacturing method. 5. The manufacturing method according to claim 4, wherein the ruthenium oxide and manganese oxide are obtained by thermal decomposition of a ruthenium compound and a manganese compound added to titanium sponge particles. 6 300 catalytically activated titanium sponge particles
having a particle size of microns or more, first part of the particles larger than 600 microns is pressed into the surface of said support, and then part of the particles of 300-600 microns is pressed into the surface of said support. The manufacturing method described in claim 4. 7. Said particles having a particle size of 300 to 600 microns,
7. The method of claim 6, wherein a larger amount of ruthenium oxide is added than said particles of particle size greater than 600 microns. 8. The method of claim 4, wherein said catalytically activated titanium sponge particles comprise more than 400 grams of titanium per square meter of anode support surface. 9 After forming ruthenium and manganese in the form of oxides on the titanium sponge particles, a titanium compound is further applied on the catalyst-activated titanium sponge particles to form a titanium oxide by thermal decomposition.Claim 4 The manufacturing method described in section. 10 After fixing a portion of catalyst-activated titanium sponge particles within the surface of the support, a portion of the valve metal particles and/or valve metal oxide particles are fixed within the surface of the support. The manufacturing method described in Scope No. 4. 11. The manufacturing method according to claim 10, wherein a portion of the catalyst-activated titanium particles are fixed within the surface of the support, and then a portion of the zirconium dioxide particles are fixed within the surface of the support.