JP2021195584A - Electrolytic reduction apparatus and electrolytic reduction method - Google Patents

Abstract

To provide an electrolytic reduction apparatus and an electrolytic reduction method in which pre-treatment equipment and a high temperature control device do not need to be used, and the capacity of a reduction facility can be reduced compared to the conventional art and methods in the electrolytic reduction of metal oxides.SOLUTION: An electrolytic reduction apparatus 1 comprises: a cathode 3 for holding a metal oxide 2; an anode 4; a bath salt 5; a reductant supplying salt 12; a container 6 for accommodating the bath salt 5; and a direct-current power supply 7 for energizing the cathode 3 and the anode 4. The bath salt 5 is an organic salt. The organic salt is composed of: an organic cation having two or more carbon chains each of which has a different number of carbons; and an organic anion having four or more fluorine functional groups.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electrolytic reduction device for reducing a metal oxide by passing an electric current between an anode immersed in a bath salt and a cathode holding a metal oxide to be reduced, and an electrolytic reduction method.

As an example of a non-aqueous system for extracting and regenerating actinide from a reprocessed fuel material, Patent Document 1 provides uranium and superuranium metals and metal oxides first dissolved in an ozone composition. The ozone solution is further dissolved in a second solution as tri-methyl-n-butylammonium n-bis (trifluoromethanesulfonylimide), which is a room temperature ion liquid, to form a second solution, and the metal in the second solution is removed. It is described that it is electrochemically precipitated.

Further, as an example of a technique for reducing the amount of waste generated between the operating temperature and the electrolytic purification step in the subsequent stage when the spent oxide fuel is reduced, Patent Document 2 describes the reduction target. It is equipped with a cathode that holds the oxide, an anode, a molten salt in which the oxide and the anode are immersed, a container that houses the molten salt, and a DC power supply that applies current to the cathode and the anode to reduce the oxide. , It is described that the molten salt is a lithium chloride-potassium chloride cocrystal salt.

Japanese Patent Publication No. 2016-507008 Japanese Unexamined Patent Publication No. 2003-166094

In addition to uranium and ultra-uranium elements, spent fuel generated from nuclear power plants contains fission products such as alkali metals, alkaline earth metals, and rare earths, which are used as fuel through a retreatment process. Can be reused.

Conventionally, as a reprocessing method, an electrolytic reduction method is known as a method of reducing a used oxide fuel and a mixed oxide fuel (MOX fuel) to a metal as a reduction target to obtain a metal fuel.

Patent Document 1 uses a reduction device including a pretreatment device and an electrolytic reduction device. The pre-processor, the U ₃ O ₈ is reduced target is contacted with the ozone is dissolved in the bath salt Uranasuion. A reduction facility has been developed in which both the anode and the cathode are immersed in a bath salt by an electrolytic reduction device, and the dissolved uranas ions are reduced and precipitated as metallic uranium at the cathode by energizing an electric current. Here, as the bath salt, an organic salt that is in a molten state at 30 ° C. or lower is used.

Further, in Patent Document 2, a reduction device including a high temperature control device and an electrolytic reduction device is used. The high temperature control device keeps the bath salt at a high temperature of 500 ° C. or higher to bring it into a molten state. Using an electrolytic reduction device, the cathode and anode holding the metal oxide to be reduced are immersed in bath salt, and a current is applied to the cathode and anode to reduce the metal oxide as a solid and reduce it to metallic uranium. Equipment is being developed. Here, as the bath salt, a lithium chloride-potassium chloride eutectic salt that is in a molten state at 500 ° C. or higher is used.

However, the problem of the technique described in Patent Document 1, a U ₃ O ₈ of reduced interest is contacted with ozone, it is necessary pretreatment system which is soluble in organic salts as uranyl ions, reducing equipment increases in size, and There is.

Further, in the technique described in Patent Document 2, an inorganic salt is used as a bath salt, but such an inorganic salt has a cation and an anion constituting the salt as a single atom, so that the temperature is 500 ° C to 800 ° C or higher. It has a high melting point. Therefore, a high temperature control device is required, and there is also a problem that the reduction equipment becomes large.

For these reasons, an electrolytic reduction device that does not require pretreatment or high temperature control is awaited in order to reduce the capacity of the reduction facility.

The present invention provides an electrolytic reduction device and an electrolytic reduction method that do not require a pretreatment device or a high temperature control device in the electrolytic reduction of a metal oxide and can reduce the capacity of the reduction equipment as compared with the conventional case.

The present invention includes a plurality of means for solving the above problems, and one example thereof is an electrolytic reduction device that reduces the metal oxide by bringing the reducing agent into contact with the metal oxide to be reduced. A cathode holding the metal oxide, an anode, a bath salt, a reducing agent supply salt, a container for accommodating the bath salt, and a DC power source for energizing the cathode and the anode. The bath salt is an organic salt, and the organic salt is characterized by being composed of an organic cation having two or more different numbers of carbon chains and an organic anion having four or more fluorine functional groups. ..

According to the present invention, a pretreatment device and a high temperature control device are not required, and the capacity of the reduction equipment can be reduced as compared with the conventional case. Issues, configurations and effects other than those mentioned above will be clarified by the description of the following examples.

It is a figure which shows the schematic structure of the electrolytic reduction apparatus of Example 1 of this invention. It is a figure which shows the potential difference measurement of Li reduction at room temperature using an organic salt: 1-butyl-1-methylpyrrolidinium = bis (trifluoromethylsulfonyl) imide. It is a figure which shows the schematic structure of the electrolytic reduction apparatus of Example 3 of this invention. It is a figure which shows the schematic structure of the electrolytic reduction apparatus of Example 4 of this invention.

Hereinafter, examples of the electrolytic reduction apparatus and the electrolytic reduction method of the present invention will be described with reference to the drawings. In the drawings used in the present specification, the same or corresponding components may be designated by the same or similar reference numerals, and repeated description of these components may be omitted.

<Example 1>
The electrolytic reduction apparatus of the present invention and Example 1 of the electrolytic reduction method will be described with reference to FIGS. 1 and 2.

First, the overall configuration of the electrolytic reduction device will be described with reference to FIG. FIG. 1 is a diagram showing a schematic configuration of an electrolytic reduction device of this embodiment.

The electrolytic reduction device 1 shown in FIG. 1 accommodates a cathode 3 holding a metal oxide 2 to be reduced, an anode 4, a bath salt 5 in which the metal oxide 2 and the anode 4 are immersed, and a bath salt 5. The container 6 is provided with a DC power source 7 for reducing the metal oxide 2 by energizing the cathode 3 and the anode 4.

A reducing agent supply salt 12 is added / dissolved in the bath salt 5. Therefore, the reducing agent supply salt 12 becomes the reducing agent supply ion, and the potential difference is given between the cathode 3 and the anode 4 by the DC power source 7, so that the reducing agent supply ion is reduced at the cathode 3 and the reducing agent is generated. Generated. When the generated reducing agent comes into contact with the metal oxide 2, the metal oxide 2 is reduced as a solid.

Examples of the metal oxide 2 to be reduced include spent oxide fuel from a nuclear power plant and mixed oxide fuel products, and in this embodiment, for example, UO ₂ . In this way, uranium oxide and plutonium oxide contained in the spent oxide fuel and the mixed oxide fuel product are reduced. Therefore, it is a device capable of converting oxide fuel from the light water reactor fuel cycle into metal fuel.

The cathode 3 is an electrode composed of Pt (platinum), and in this embodiment, it has a basket 8 made of Pt. The anode 4 has a main body 9 made of Pt and a lead 10 made of Pt. The cathode 3 and the anode 4 can be electrodes made of a material containing any one or more of Ni, C, La, Zr, and Bi in addition to Pt. With such a configuration, the metal oxide 2 is reduced to a metal at the cathode 3. Further, when carbon other than carbon is used in the anode 4, oxygen is generated as bubbles 11 in the anode 4, and when carbon is used, carbon dioxide is generated as bubbles 11.

The bath salt 5 is an organic salt composed of an organic cation having two or more different numbers of carbon chains and an organic anion having four or more fluorine functional groups. For example, 1-butyl-1-methylpyrrolidinium. = An organic salt having a melting point of room temperature or lower, such as bis (trifluoromethylsulfonyl) imide.

Here, since the melting point of the organic salt used for the bath salt 5 is room temperature (25 ° C.) or lower, electrolytic reduction can be realized at an operating temperature lower than 500 ° C., and the number of high temperature control devices can be reduced. The reduction equipment can be downsized, and the corrosion of the container 6, the cathode 3, and the anode 4 due to fluorine, oxygen, etc., which has been a particular problem during high-temperature operation, can be suppressed by operating at room temperature as compared with the conventional case. Further, the effect that the consumption of heat energy can be reduced can be obtained.

In order to suppress the operating temperature to, for example, 25 ° C., an organic salt composed of an organic cation having two or more carbon chains having different numbers and an organic anion having four or more fluorine functional groups is used.

The organic salt cations that achieve the low temperature melting point of the bath salt 5 are linear or branched groups such as tetraalkylammonium ion, tetraalkylphosphonium, N, N'-disubstituted imidazolium, N, N'. There are -disubstituted pyrrolidinium, N, N'-disubstituted piperidinium and the like, and the alkyl group is typically a cation having a different chain length and an asymmetric molecular structure.

Here, as the cation of the organic salt that realizes the low temperature melting point of the bath salt 5, the cation having one carbon chain having a different number or the cation having two carbon chains having the same number guarantees the asymmetry of the structure. However, since the bath salt 5 cannot have a low melting point to the room temperature level, the organic cation needs to have two or more carbon chains having different numbers of carbon chains.

The upper limit of the number of carbon chains having different numbers of cations of the organic salt is preferably 14 or less in consideration of the fact that they can be procured at a level that can be used in industrial fields.

The anion of the organic salt that realizes the low temperature melting point of the bath salt 5 is bis (trifluoromethanesulfonyl) imide or n-bis (perfluoroalkanesulfonylimide), more specifically 1-butyl-1-methyl. Piperidinium bis (trifluoromethylsulfonyl) imide, butyltrimethylammonium bis (trifluoromethylsulfonyl) imide, ethyldimethylpropylammonium bis (trifluoromethylsulfonyl) imide, trioctylmethylammonium bis (trifluoromethylsulfonyl) imide, etc. A typical example is an anion having 4 or more fluorine functional groups.

Here, when there are three "fluorine functional groups" with high electron attraction, there are those with a melting point of room temperature or higher, and chlorine, which has the second highest electric attraction after fluorine, has a melting point at room temperature. Since it does not exist, the anion of the organic salt needs to have four or more fluorine functional groups.

The upper limit of the number of fluorine functional groups of the anion of the organic salt is preferably 6 or less in consideration of the fact that it can be procured at a level that can be used in industrial fields.

Further, the bath salt 5 composed of an organic salt composed of an organic cation and an organic anion is referred to as -2.7V (Ag (I) / Ag (0)) in order to stably electrolyze and reduce the metal oxide 2. It is desirable to have the following potential window (electrode).

FIG. 2 is a diagram showing the potential difference measurement of Li reduction at room temperature using an organic salt: 1-butyl-1-methylpyrrolidinium = bis (trifluoromethylsulfonyl) imide. FIG. 2 shows the background (intermittent line) of 1-butyl-1-methylpyrrolidinium-bis (trifluoromethylsulfonyl) imide corresponding to the electrochemical response (solid line) of lithium ions at room temperature. ..

As shown in FIG. 2, a reduction wave by voltammetry measurement is detected in the vicinity of about -2.7V, which corresponds to the reduction potential of lithium ions to metallic lithium. Since metallic lithium, which is a reducing agent, _{can be reduced as a solid by coming into contact with UO 2} , which is a metal oxide 2, pretreatment that was conventionally required becomes unnecessary, and the number of pretreatment devices can be reduced.

By using lithium oxide as the reducing agent supply salt 12, the gas generated from the anode 4 becomes oxygen, but the operating temperature can be set to room temperature, and the corrosion of the container 6 and the electrode material due to the oxygen generated from the anode can be suppressed. ..

Returning to FIG. 1, the container 6 for containing the bath salt 5 as described above is made of glass, but the container 6 is not limited to this, and stainless steel, ceramic, or the like can be used.

The reducing agent supply salt 12 added to the bath salt 5 is an inorganic salt containing any one or more of Li, K, Ca, and Mg, and lithium oxide is used in this embodiment. The reducing agent supply salt 12 is dissolved in the bath salt 5 and reduced to a zero-valent reducing agent at the cathode 3, and the reducing agent reduces the metal oxide 2 to a metal.

In this way, for example, lithium oxide is added and dissolved as a reducing agent supply salt 12 to the bath salt 5 made of an organic salt to form lithium ions, and a potential difference is given between the cathode 3 and the anode 4 to give lithium to the cathode 3. By reducing the ions to metallic lithium as a reducing agent and bringing the metallic lithium into contact with the solid metal oxide 2, the metal oxide 2 can be reduced as a solid, so that the pretreatment apparatus can be omitted.

Next, an example of the procedure of the electrolytic reduction method of the metal oxide 2 according to the present embodiment, which is preferably carried out by the electrolytic reduction device 1 described above, will be described.

1-Butyl-1-methylpyrrolidinium-bis (trifluoromethylsulfonyl) imide of the bath salt 5 to which 1 wt% or more of lithium oxide is added and dissolved as the reducing agent supply salt 12 is placed in the container 6.

The lithium oxide of the reducing agent supply salt 12 added to the bath salt 5 dissolves in the bath salt 5 as lithium ions which are the reducing agent supply ions.

_{UO 2} , which is a metal oxide 2, is housed in the basket 8 of the cathode 3 and immersed in the bath salt 5. The anode 4 is also immersed in the bath salt 5.

A DC power supply 7 is connected to the anode 4 and the cathode 3, and a voltage of 3.1 volts is applied to energize the current. By applying a voltage, lithium ions dissolved from lithium oxide dissolved in the bath salt 5 are reduced to metallic lithium as a reducing agent. This reducing agent, metallic lithium, reduces UO ₂ , which is the metal oxide 2 to be reduced, to U.

Next, the effect of this embodiment will be described.

The above-mentioned electrolytic reduction apparatus 1 of the first embodiment of the present invention is an apparatus for reducing the metal oxide 2 by bringing the reducing agent into contact with the metal oxide 2 to be reduced, and holds the metal oxide 2. The cathode 3, the anode 4, the bath salt 5, the reducing agent supply salt 12, the container 6 containing the bath salt 5, and the DC power source 7 for energizing the cathode 3 and the anode 4 are provided, and the bath salt is provided. Reference numeral 5 is an organic salt, and the organic salt is composed of an organic cation having two or more different numbers of carbon chains and an organic anode having four or more fluorine functional groups.

As a result, the melting point of the bath salt 5 is at room temperature or lower, and the metal oxide 2 can be reduced as a solid, so that no pretreatment device is required. In addition, electrolytic reduction can be realized at a lower operating temperature than before, there is no need to use a high temperature environment, the number of high temperature control devices can be reduced, and the reduction is greatly simplified compared to the conventional device configuration. Equipment can be downsized. In addition, it can be expected that the energy consumption is reduced and the corrosion of the constituent materials constituting the device such as the container 6 is suppressed.

Such an electrolytic reduction device 1 is very suitable for reducing oxide fuels, mixed oxide fuels, and minerals of nuclear power plants to metals.

Further, since the potential window of the organic salt described in the bath salt 5 is -2.7 V (Ag (I) / Ag (0) reference electrode) or less, electrolysis of the bath salt 5 does not occur and the metal oxide is formed. 2 can be electrolytically reduced more efficiently.

Further, the anion of the organic salt is either bis (trifluoromethanesulfonyl) imide or n-bis (perfluoroalkanesulfonylimide), and the cation of the organic salt is N, N'-disubstituted imidazolium, N. , N'-disubstituted pyrrolidinium, N, N'-2-substituted piperidinium, tetraalkylammonium, tetraalkylphosphonium, the equipment can be further miniaturized.

Further, the reducing agent supply salt 12 is an inorganic salt containing any one or more of Li, K, Ca, and Mg, so that the equipment can be miniaturized. Further, since a halogen salt such as conventional lithium chloride is not used, no halogen gas is generated, and it is possible to suppress the corrosion of the container and the electrode material due to the halogen gas.

<Example 2>
The electrolytic reduction apparatus and the electrolytic reduction method of Example 2 of the present invention will be described.

The electrolytic reduction device of this embodiment is basically the same as the configuration of the electrolytic reduction device 1 of Example 1 shown in FIG. The difference is that an organic salt containing at least one of Li, K, Ca, and Mg, for example, lithium bis (trifluoromethylsulfonyl) imide, is used as the reducing agent supply salt 12 in the bath salt 5. By using lithium bis (trifluoromethylsulfonyl) imide as the reducing agent supply salt 12, lithium ions having a high concentration of 1000 mM or more can be dissolved in the bath salt 5. Due to the high concentration of lithium ions, the reduction and precipitation rate of lithium ions can be increased, and the reduction rate of metal oxides can be improved.

Other examples of organic salts include, for example, potassium bis (trifluoromethylsulfonyl) imide, calcium bis (trifluoromethylsulfonyl) imide, magnesium bis (trifluoromethylsulfonyl) imide and the like.

Also in the electrolytic reduction device of this embodiment, by applying a potential difference between the cathode 3 and the anode 4, lithium ions are reduced to metallic lithium as a reducing agent at the cathode 3, and metallic lithium and solid metal oxide 2 are separated. The metal oxide 2 can be reduced as a solid by contacting the metal oxide 2.

Other configurations and operations are substantially the same as those of the electrolytic reduction apparatus and the electrolytic reduction method of Example 1 described above, and details thereof will be omitted.

The electrolytic reduction device and the electrolytic reduction method of Example 2 of the present invention also have substantially the same effects as the electrolytic reduction device and the electrolytic reduction method of Example 1 described above.

<Example 3>
The electrolytic reduction apparatus and the electrolytic reduction method of Example 3 of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing a schematic configuration of the electrolytic reduction device of this embodiment.

As shown in FIG. 3, the electrolytic reduction device 1A of the present embodiment further includes a stirring device 13 for stirring the bath salt 5 in addition to the configuration of the electrolytic reduction device 1 of FIG.

The stirring device 13 in FIG. 3, is in the form of introducing poor gas into the reaction with the inert gas or Yokushio 5 such as N ₂ gas or a rare gas into Yokushio 5, physically Yokushio A stirring blade or the like for stirring 5 can be used.

Other configurations and operations are substantially the same as those of the electrolytic reduction apparatus and the electrolytic reduction method of Example 1 described above, and details thereof will be omitted.

The electrolytic reduction device and the electrolytic reduction method of Example 3 of the present invention also have substantially the same effects as the electrolytic reduction device and the electrolytic reduction method of Example 1 described above.

Further, by further providing the stirring device 13 for stirring the bath salt 5, the bath salt 5 is stirred, and the diffusion rate of the lithium ion and the oxygen ion which are the bases of the reducing agent in the bath salt 5 can be increased. , The reduction rate of the metal oxide 2 can be improved.

Also in the electrolytic reduction apparatus and the electrolytic reduction method of this example, an organic salt can be used as the reducing agent supply salt 12 as in Example 2.

<Example 4>
The electrolytic reduction apparatus and the electrolytic reduction method of Example 4 of the present invention will be described with reference to FIG. FIG. 4 is a diagram showing a schematic configuration of the electrolytic reduction device of this embodiment.

As shown in FIG. 4, the electrolytic reduction device 1B of the present embodiment includes an off-gas treatment device 14 that collects gas generated when an organic salt is electrolyzed, in addition to the configuration of the electrolytic reduction device 1 of FIG. Further prepared.

The off-gas treatment device 14 includes an N _{2 gas pipe 18 for inflowing N 2} as an inert gas of the off-gas treatment device 14, a fluorine detector 15 and a three-way cock 16 at an out-of-system discharge destination, and F ₂ adsorption of activated alumina or the like. Agent 17 is provided.

In this embodiment, _{N 2} gas flows _{from the installed N 2} gas pipe 18 toward the outside discharge destination. The fluorine detector 15 and the three-way cock 16 are connected by an electric signal line 19. The tip of the three-way cock 16 is _{connected to the container in which the F 2} gas adsorbent 17 is housed and the outside of the system.

When the electrolytic reduction of the metal oxide 2 is normally performed, the fluorine gas is not detected by the fluorine detector 15, and the three-way cock 16 is open to the outside of the system.

However, in the unlikely event that the organic salt, which is the bath salt 5, is electrolyzed and fluorine gas is generated, the generation is detected by the fluorine detector 15, and the three-way cock 16 is generated by an electric signal via the electric signal line 19. The connection direction is changed, and fluorine gas flows into the container side containing the _{F 2 gas adsorbent 17.} The fluorine gas that has flowed into the container _{is collected by the F 2} gas adsorbent 17, and is configured to prevent the fluorine gas from being released to the outside of the system.

Other configurations and operations are substantially the same as those of the electrolytic reduction apparatus and the electrolytic reduction method of Example 1 described above, and details thereof will be omitted.

The electrolytic reduction device and the electrolytic reduction method of Example 4 of the present invention also have substantially the same effects as the electrolytic reduction device and the electrolytic reduction method of Example 1 described above.

In addition, by further providing an off-gas treatment device 14 that collects the gas generated when the organic salt is electrolyzed, even if a toxic gas such as fluorine gas is generated, it is released to the outside of the system. It can be prevented and safer operation becomes possible.

Also in the electrolytic reduction device and the electrolytic reduction method of this embodiment, an organic salt can be used as the reducing agent supply salt 12 as in Example 2, and the stirring device 13 can be provided as in Example 3. can.

<Others>
The present invention is not limited to the above examples, and includes various modifications. The above-mentioned examples have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations.

It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is also possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

For example, in this embodiment, the spent oxide fuel of the nuclear power plant is used as the metal oxide to be reduced, but the present invention is not limited to this, and for example, a mixed oxide fuel or a mineral may be used.

1,1A, 1B ... Electrolytic reduction device 2 ... Metal oxide 3 ... Cathode 4 ... Anode 5 ... Bath salt 6 ... Container 7 ... DC power supply 8 ... Basket 9 ... Main body 10 ... Lead 11 ... Bubbles 12 ... Reducing agent supply salt 13 ... Stirrer 14 ... Off-gas processing device 15 ... Fluorine detector 16 ... Three-way cock 17 ... F ₂ Gas adsorbent 18 ... N ₂ Gas piping 19 ... Electric signal line

Claims (10)

An electrolytic reduction device that reduces the metal oxide by bringing the reducing agent into contact with the metal oxide to be reduced.
The cathode that holds the metal oxide and
With the anode
With bath salt,
Reducing agent supply salt and
The container for accommodating the bath salt and
The cathode and the anode are provided with a DC power source for energizing the current.
The bath salt is an organic salt and is
The organic salt is an electrolytic reduction device characterized by being composed of an organic cation having two or more carbon chains having different numbers of carbon chains and an organic anion having four or more fluorine functional groups. In the electrolytic reduction apparatus according to claim 1,
The organic salt described in the bath salt is an electrolytic reduction device having a potential window of -2.7 V (Ag (I) / Ag (0) reference electrode) or less. In the electrolytic reduction apparatus according to claim 1,
An electrolytic reduction apparatus, wherein the anion of the organic salt is either bis (trifluoromethanesulfonyl) imide or n-bis (perfluoroalkanesulfonylimide). In the electrolytic reduction apparatus according to claim 1,
The cation of the organic salt is characterized by any one of N, N'-disubstituted imidazolium, N, N'-2-substituted pyrrolidinium, N, N'-2-substituted piperidinium, tetraalkylammonium, and tetraalkylphosphonium. Electrolytic reduction device. In the electrolytic reduction apparatus according to claim 1,
The electrolytic reducing apparatus, wherein the reducing agent supply salt is an inorganic salt containing any one or more of Li, K, Ca, and Mg. In the electrolytic reduction apparatus according to claim 1,
The electrolytic reducing apparatus, wherein the reducing agent supply salt is an organic salt containing any one or more of Li, K, Ca, and Mg. In the electrolytic reduction apparatus according to claim 1,
An electrolytic reduction apparatus, wherein the cathode and the anode are made of a material containing any one or more of Pt, Ni, C, La, Zr, and Bi. In the electrolytic reduction apparatus according to claim 1,
An electrolytic reduction device further provided with a stirring device for stirring the bath salt. In the electrolytic reduction apparatus according to claim 1,
An electrolytic reduction device further provided with an off-gas treatment device that collects gas generated when the organic salt is electrolyzed. It is an electrolytic reduction method for metal oxides.
Holding the metal oxide at the cathode,
Using an organic salt composed of an organic cation having two or more different numbers of carbon chains and an organic anion having four or more fluorine functional groups as a bath salt,
A DC power source is used to energize the cathode and anode to reduce the ions of the reducing agent supply salt dissolved in the bath salt, and bring them into contact with the metal oxide to be reduced as a reducing agent to cause a reaction. A characteristic electrolytic reduction method.

Images