JPH0633482B2 - Method for manufacturing anode material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an anode material, particularly an anode material for producing electrolytic manganese dioxide, or an anode material for plating and electrolysis.

[Conventional technology]

Electrolytic manganese dioxide is mainly used as an active material for dry batteries, and this manganese dioxide is generally used as manganese sulfate.
It is produced by electrolysis of a sulfuric acid / manganese sulfate aqueous solution having a concentration of 0.5 to 1.0 mol / and a free sulfuric acid concentration of 0.2 to 0.6 mol /.

That is, by electrolyzing the above aqueous solution with a direct current of about 0.8 A / dm ² , manganese dioxide is deposited on the anode, and when it is accumulated to some extent, it is peeled off and manganese dioxide is collected.

At that time, hydrogen is generated from the cathode.

Recently, titanium has been used as an anode material for producing such electrolytic manganese dioxide. This is because the titanium electrode has excellent corrosion resistance, specific strength and workability.

[Problems to be Solved by the Invention]

However, when the current density of the titanium anode is increased, a passivation film on the surface grows and the bath voltage rises,
Further, there is a problem that if the power is still applied, the power cannot be finally applied. Therefore, it was necessary to keep the current density at around 0.8 A / dm ² .

In this way, current density is a problem that directly leads to productivity in the electrolysis industry.If the same electrolytic cell has a higher current density, mass production becomes possible. Can be reduced, and the facility cost for constructing the electrolytic cell can be reduced.

Furthermore, titanium is used as an anode other than the anode material for the production of electrolytic manganese dioxide, but as mentioned above, when the current density is increased, a passive film on the surface grows, and current cannot be supplied. It is used by plating precious metals.

However, such a treatment imposes a heavy economic burden due to the use of a very expensive precious metal, which has been a serious problem in industrial use.

The present invention has been made in view of the above circumstances, and in place of the titanium anode material that has been conventionally used, it is possible to inexpensively provide a titanium alloy anode material characterized by allowing a higher current density to flow. Has an aim.

[Means for Solving the Problems]

The present inventors have completed the present invention as a result of earnest research to solve the above problems.

A feature of the present invention is that a titanium alloy heat-treated to a β transformation temperature or higher is 0.1 Wt% or more and 10 Wt% or less, and the balance is titanium and unavoidable impurities.
This is a manufacturing method in which an excellent anode material can be obtained by heat treatment at a temperature of 800 ° C. or lower.

The present invention adds nickel to titanium because
The purpose is to form an intermetallic compound of Ti ₂ Ni. The Ti ₂ Ni Unlike titanium, anodic oxidation even by applying a current at a high current density Okizu has a characteristic that does not disable energization by the Ti ₂ Ni is present in the titanium, more Can flow current.

However, if the content of nickel is less than 0.1 wt%, the amount of Ti ₂ Ni formed will be small and the effect will not appear clearly, so the lower limit of nickel was made 0.1 wt%. Also, if the nickel content exceeds 10 wt%, the workability will be extremely poor.
The upper limit was set to 10 wt%.

Further, in manufacturing, in order to process into a shape that is generally used as an anode material, heating in a temperature range beyond the β transformation point such as hot forging and hot rolling is absolutely necessary. It has been found that such a material does not have a sufficient effect even if it contains nickel, and in order to improve this, it is subsequently heat treated at a temperature of 400 ° C or higher and 800 ° C or lower to obtain fine Ti ₂ Ni particles (several (μm) was deposited in titanium, and it became possible to flow a high current.

Example 1 Next, the present invention will be described based on specific examples.

First, in order to examine the effect of heat treatment, Ti-3% Ni containing 3 wt% of nickel was melted by arc melting, and then 9
After forging at 00 ° C., heating at 950 ° C. again, and hot rolling, a hot rolled plate having a thickness of 6 mm was produced. The material temperature at the end of this hot rolling was 840 ° C.

Further, this material was heat-treated in accordance with the method of the present invention and a comparative material heat-treated other than that was used as a test material in the experiment.

The experimental method was to conduct a constant current electrolysis test in a 0.35 mol / H ₂ SO ₄ aqueous solution at room temperature using a platinum electrode as the cathode and a buff-polished test material as the anode. It was investigated whether it would occur, and the anode characteristics were evaluated.

Tables 1 and 2 show the results of each test material obtained by the above experimental method.

The change with time of the bath voltage generally rises with time, but the time until the bath voltage exceeds 4 V was adopted as the criterion for judging the superiority and inferiority of the anode characteristics.

[Manufacturing conditions] Ingot (Ti-3% Ni) → forging (900 ° C.) → hot rolling (950 ° C.) → heat treatment → test material.

Table 1 shows changes in the bath voltage increase when the Ti-3% Ni hot rolled material is heat-treated, and the effect of the heat treatment is beginning to be clearly seen from the temperature of 400 ° C.

On the other hand, at 800 ° C., the effect was lower than that at 600 ° C., and it was found that at 900 ° C., the effect of heat treatment was completely lost.

As a result, it was confirmed that the heat treatment temperature needs to be 400 ° C to 800 ° C.

[Production conditions] Ingot → Forging (900 ° C) → Hot rolling (950 ° C)
→ Heat treatment (3 hours at 600 ℃) → Specimen.

Table 2 shows the test results for examining the effect of the added amount of nickel. It can be seen that the bath voltage rising time becomes longer than the nickel addition amount of 0.1 wt%, and this tendency becomes more remarkable as the nickel addition amount increases.

From this result, it was confirmed that the lower limit of nickel should be 0.1 wt% and the upper limit should be 10.0 wt% from the viewpoint of workability.

Example 2 Next, an anode material in the case of electrolytic manganese dioxide production will be described.

At present in the production of electrolytic manganese dioxide, pure titanium is used as an anode material, but how much current can be passed when using a test material manufactured by the method according to the present invention as the anode material The examined results are shown in Table 3.

The test method is 95 ° C 0.35mol / H ₂ SO ₄ + 0.55mol / MnS
Using a carbon dioxide as the cathode and a sandblasted test material as the anode in an O ₄ aqueous solution, a current density of 0.8 A / dm ² which is usually applied to pure titanium and a current density higher than that were applied, and the bath voltage exceeded 7V. The time was measured.

As a result, when using pure titanium as the anode, 1.2
The bath voltage exceeds 7 V within 100 hours when A / dm ² is passed, whereas the test material (manufacturing condition) produced by the method of the present invention has a bath voltage of 1.4 A / dm ² It was found that the anode material was a very excellent anode material without any increase.

It was also found that even with the same Ni concentration, the anode material produced by the method of the present invention can flow a higher current density than the hot rolled material.

In addition, MnO ₂ produced at high current density in this way
When assembled into a battery and measured the discharge characteristics,
It was found that a discharge characteristic equal to or better than that of MnO ₂ was obtained and that it could be used industrially.

〔The invention's effect〕

As described above, Ti produced by the method of the present invention
When Ni alloy is used as an anode material, it can pass a much higher current density than pure titanium, and it can be used as an anode for electrolytic manganese dioxide production, other plating, and an anode for electrolysis. An excellent anode material can be obtained.

Claims (1)

[Claims] 1. Nickel that has been heat treated to a β transformation point or higher.
A titanium alloy containing 1 Wt% or more and 10 Wt% or less and the balance of titanium and undesired impurities, and then 400 ° C. or more 8
A method for producing a material for an anode made of a titanium alloy, which comprises performing heat treatment at a temperature of 00 ° C. or less.