KR20160113609A - Method for producing α-lithium aluminate - Google Patents

Abstract

The present invention provides an industrially advantageous method of lithium? -Aluminate having various physical properties preferable as an electrolyte retention plate of an MCFC excellent in thermal stability, even if it has a BET specific surface area of 10 m < 2 > / g or more. The transition alumina and lithium carbonate are mixed in a ratio of Al / Li molar ratio of 0.95 to 1.01, the resulting mixture (a) is subjected to a first firing reaction to obtain a fired product, (B) in which the molar ratio (Al / Li) of Al atoms in the aluminum compound to Li atoms in the fired product is from 0.001 to 0.05 is provided for the second firing reaction. .

Description

TECHNICAL FIELD The present invention relates to a method for producing lithium α-aluminate,

The present invention relates to lithium α-aluminate (LiAlO ₂ ) particularly useful as an electrolyte holding plate for a molten carbonate fuel cell (MCFC) and a method for producing the same.

The electrolyte holding plate of the MCFC is used for maintaining the mixed molten carbonate such as lithium carbonate (Li ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), sodium carbonate (Na ₂ CO ₃ ) at a high temperature region near 650 ° C. do. Therefore, properties such as high retention to molten carbonate, stability of particle shape, alkali resistance, and heat resistance are required. Lithium aluminate is used as a constituent material of the electrolyte retention plate as a material satisfying such a demand property, and particularly, a fine lithium? -Aluminate having a relatively large specific surface area and excellent in electrolyte retention has been preferably used.

It is also known that fine a-aluminate lithium is also useful as an electrolyte retention plate for MCFC. The following patent document 1 discloses a process for producing highly crystalline? -Aluminate. Patent Document 2 discloses a method of heat-treating a mixture of an alumina powder having a specific surface area of 100 m 2 / g or more and a carbonate containing lithium carbonate in a molten carbonate at 700 to 800 ° C. Further, Patent Document 3 discloses a method of heat-treating a mixture of an aluminum hydroxide powder having a specific surface area of 100 m < 2 > / g or more and a carbonate containing lithium carbonate in a molten carbonate at 700 to 800 ° C.

The above method is to heat-treat alumina or lithium aluminate as a raw material in a molten carbonate in any of these methods. This method not only requires a long reaction time from 50 hours to 100 hours, but also includes a step of washing and drying the product in order to remove the carbonate, due to the nature of the production process, thereby avoiding the complication and costly process I can not.

In Patent Document 4, it is proposed that porous? -Alumina and a lithium compound are dry mixed at a Li / Al molar ratio in the vicinity of a stoichiometric ratio and fired to produce? -Aluminium oxide. However, when this process is used to produce fine? -Aluminates having a BET specific surface area of at least 10 m 2 / g, it is not possible to obtain the necessary thermal stability of the electrolyte holding plate of the MCFC.

Japanese Unexamined Patent Publication No. 2-80319 Japanese Unexamined Patent Application Publication No. 2-243511 Japanese Patent Application Laid-Open No. 10-112329 Japanese Patent Application Laid-Open No. 2000-195531

Under such a technical background, there has been a demand for the development of lithium α-aluminate having a high retainability and excellent heat resistance, which has a BET specific surface area of 10 m 2 / g or more and aims to improve the longevity of the MCFC.

The inventors of the present invention have conducted intensive studies in order to solve the above problems. As a result, they have found that transition alumina is used, and the resulting alumina and lithium carbonate are mixed at a molar ratio of Al / Li to a ratio of about 1, a) is subjected to the first firing reaction, and a mixture (b) in which an aluminum compound is added to the resulting fired product in a specific range of molar ratio (Al / Li) of Al atoms in the aluminum compound to Li atoms in the fired product ) Is added to the second firing reaction, even if the BET specific surface area is 10 m < 2 > / g or more, the lithium a-aluminate is excellent in thermal stability and has various physical properties preferable as an electrolyte- And reached the completion of the present invention.

The present invention has been accomplished on the basis of the above-described findings. An object of the present invention is to provide a method for producing an electrolytic solution of an MCFC having an excellent thermal stability in a molten carbonate of MCFC, even if it has a BET specific surface area of 10 m & It is an object of the present invention to provide an industrially advantageous method of lithium? -Aluminate having various physical properties preferable as a plate.

That is, the present invention relates to a method for producing a fired product, comprising the steps of mixing transition alumina and lithium carbonate in a molar ratio of Al / Li of 0.95 to 1.01 in a molar ratio and then subjecting the resulting mixture (a) to a first firing reaction to obtain a fired product, (B) in which an aluminum compound is added in an amount of 0.001 to 0.05 in terms of a molar ratio (Al / Li) of Al atoms in an aluminum compound to a Li atom in the fired product is subjected to a second firing reaction. And a process for producing lithium aluminate.

Further, the present invention provides a process for producing? -Aluminate having a calcination temperature of 650 to 850 ° C in the first calcination reaction.

The present invention also provides a process for producing lithium? -Aluminate having a calcination temperature of 750 to 900 占 폚 in the second calcination reaction.

The present invention also provides a process for producing a-alumina, wherein the transitional alumina is a transition alumina or? -Alumina containing the? -Phase.

Further, the present invention provides a process for producing? -Aluminate, wherein the transition alumina is? -Alumina.

The present invention also provides a process for producing alpha -alumina lithium wherein the transition alumina has a BET specific surface area of 50 m < 2 > / g or more.

In addition, the present invention provides a process for producing? -Aluminate, wherein the aluminum compound is transition alumina.

The present invention also provides a process for producing lithium? -Aluminate used as an electrolyte holding plate of a molten carbonate fuel cell.

Since the present invention is constituted as described above, it is possible to industrially advantageously use lithium? -Aluminate having various properties preferable as an electrolyte retention plate of an MCFC excellent in thermal stability even if the BET specific surface area is 10 m < .

1 is an X-ray diffraction diagram of? -Alumina used in Example 1. Fig.
2 is an X-ray diffraction chart of a fired product (a-lithium aluminate (1)) obtained after the first firing reaction of Example 1. Fig.
3 is an X-ray diffraction chart of lithium? -Aluminate (2) obtained after the second firing reaction of Example 1. Fig.
4 is an SEM photograph of lithium? -Aluminate (2) obtained after the second firing reaction of Example 1. Fig.
5 is an X-ray diffraction chart after thermal stability test of lithium? -Aluminate (2) obtained in Example 1. Fig.
6 is an X-ray diffraction chart after thermal stability test of lithium? -Aluminate obtained in Comparative Example 2. Fig.

Hereinafter, the present invention will be described based on its preferred embodiments.

(Hereinafter sometimes referred to as " lithium a-aluminate (2) ") obtained by the present process is characterized in that in X-ray diffraction analysis substantially containing no lithium? -Aluminate, lithium? -aluminate (2).

In the X-ray diffraction analysis, the? -Aluminate (2) obtained by the present process can be obtained by heating the? -Aluminate (2) sample in an atmospheric environment at 750 ° C. for 200 hours, Lithium aluminate (2) which is substantially free of lithium adduct and excellent in thermal stability.

In addition, the BET specific surface area of the lithium? -Aluminate (2) obtained by the present process is not particularly limited, but in consideration of the advantageous effect of the lithium? -Aluminate (2) obtained by the present process, the BET specific surface area is 10 M 2 / g or more, and preferably 10 to 40 m 2 / g.

The process for producing lithium? -Aluminate (2) according to the present invention is characterized in that transition alumina and lithium carbonate are mixed at a molar ratio of Al / Li in a ratio of about 1 and the resulting mixture (a) is subjected to a first firing reaction (Hereinafter may be referred to as " lithium alpha -aluminate (1) "), and an aluminum compound is added to the resulting fired product in such a manner that the mole ratio of Al atoms in the aluminum compound to Li atoms in the fired product Al / Li) in a range of 0.001 to 0.05, and the mixture (b) is subjected to a second firing reaction. The present production method basically comprises the following steps (a) to (d) will be.

  (A): Mixture (a) Preparation process

  (B): First firing reaction process

  (C): Mixture (b) Preparation process

  (D): Second firing reaction process

(A): mixture (a) preparation process;

The preparation process of the mixture (a) is a process for preparing a homogeneous mixture (a) in which transition alumina and lithium carbonate are mixed at a molar ratio of Al / Li of 0.95 to 1.01 at a ratio of 1 near.

Alumina has various types of crystals such as?,?,?, And?, And alumina having a crystal form of?,?,? Other than? Is called a transition alumina at a low temperature phase of? -Alumina. ; Heating the boehmite represented by 4 [AlO (OH)] causes the phase change from the boehmite phase? The? Phase? Delta phase? The? Phase? Phase to the? Phase, Transitional alumina, such as the? -phase, the? -phase and the? -phase, is also known.

The transition alumina to be used in the present production method may be either a crystal form of?,? Or?, A single phase of?,?,?, Or a mixed phase of these crystalline forms. transitioned alumina containing the? phase is preferable, and use of transition alumina containing the? phase is particularly preferable from the viewpoint of obtaining lithium? -aluminate which further improves chemical stability.

The transition alumina containing the? phase is a mixture of the? phase, the? phase and the? phase, and the? phase, the? phase and the? phase are used as the phase transition phase. Of these,? phase alumina is particularly excellent in thermal stability, It is preferably used from the viewpoint of obtaining lithium alpha -aluminate having a further improved stability and further having a BET specific surface area of 10 m 2 / g or more, and preferably 10 to 40 m 2 / g. Further, it is confirmed by X-ray diffraction analysis that the mixed phase transition alumina is a mixed phase (see, for example, JP-A-07-96186).

The preferable physical properties of the transition alumina related to the preparation (a) preparation process are as follows. From the viewpoint of producing a -aluminium lithium (2) having a BET specific surface area of 10 m 2 / g or more, preferably 10 to 40 m 2 / g , And a BET specific surface area of 50 m < 2 > / g or more, preferably 60 to 200 m < 2 > / g.

The production of such transition alumina is known per se. For example, transition alumina containing the? Phase can be obtained by heat treatment of? -Alumina at 800 to 1100 占 폚, preferably 900 to 1050 占 폚. The transition alumina used in the present invention is also commercially available.

The lithium carbonate involved in the preparation of the mixture (a) is not particularly limited as far as it is industrially available, but its physical properties and the like are not particularly limited. However, from the viewpoint of improving the reactivity with transition alumina, Or less, preferably 10 m or less, is preferably used.

In the preparation process of the mixture (a), the transition alumina and lithium carbonate are mixed at a molar ratio of Al / Li of 0.95 to 1.01, preferably 0.97 to 1.00, in order to obtain lithium? -Aluminate (1).

This is because when the molar ratio of Al / Li is out of the above range, single-phase a-aluminates (1) can not be obtained in an X-ray diffraction pattern with a desired composition, it is difficult to obtain an excellent thermal stability even in the case of the? -aluminic acid lithium (2).

The mixing method of the transition alumina and lithium carbonate in the preparation (a) preparation process may be dry or wet, and there is no particular limitation.

In the case of dry mixing, when the mutual dispersion among the powders is insufficient, the particles of the? -Aluminous acid lithium (1) coagulate partly in the first firing reaction step (b) and are granulated. Therefore, in order to obtain a uniform mixed dispersion state of the raw materials, it is preferable to use a high-speed dispersion mixer such as a Henschel mixer or a super mixer.

In the case of wet mixing, since the lithium carbonate eluted in water is present on the filtrate side when the slurry is filtered, the desired? -Aluminium lithium (1) can not be obtained easily. For this reason, it is preferable to dry the whole amount of the slurry containing the raw material blended at an equivalent ratio close to the stoichiometry with a spray dryer.

(B): first firing reaction step;

The mixture (a) obtained by the process (a) preparing the mixture (a) is supplied to the first firing reaction process (b) to obtain a fired product.

The fired product itself obtained by the first firing reaction is lithium? -Aluminate (1), but in the? -Aluminate (1) itself obtained by the first firing reaction, the BET specific surface area is preferably 10 m2 / g or more, preferably 10 to 40 m < 2 > / g, is lower than that of the a-aluminic acid lithium (2) subjected to the second firing reaction described later from the viewpoint of thermal stability. However, in the present production method, the fired product (? -Aluminate (1)) obtained by the first firing reaction is used in the preparation process (b) of the mixture (c) to be described later and the second firing reaction process Lithium aluminate (1) can be converted to? -Aluminate lithium (2) having excellent thermal stability.

In this first firing reaction step, it is particularly important to obtain a single-phase? -Aluminate (1) as a fired product in the X-ray diffraction analysis from the viewpoint of obtaining excellent heat stability.

The firing temperature involved in the first firing reaction process is 650 to 850 deg. C, preferably 700 to 800 deg. When the firing temperature of the first firing reaction is less than 650 ° C, the single phase lithium aluminate (1) is not easily obtained. On the other hand, when the firing temperature of the first firing reaction exceeds 800 ° C, Phase are mixed together, which is not preferable.

Further, in the relationship between the firing temperature and the firing time, even when the same raw material mixture is subjected to the reaction at the same firing temperature, there is a case where the crystal form of the lithium aluminate (1) obtained according to the firing time is different. Generally, long-time firing tends to generate some? -Forms other than? -Forms. Further, this tendency tends to be more likely to occur in a short time in the γ type as the temperature is increased. Therefore, it is preferable to perform firing while appropriately checking whether or not the single-phase? -Aluminate (1) is obtained by performing X-ray diffraction analysis. Generally, if firing is carried out at the firing temperature for 0.5 to 40 hours, a single-phase? -Alumina lithium (1) can be produced as a fired product.

The firing atmosphere is not particularly limited, and may be any one of an atmosphere in an inert gas atmosphere, a vacuum atmosphere, and an atmosphere of an oxidizing gas atmosphere.

The first firing reaction may be performed several times as desired. After completion of the first firing reaction, the resulting fired product can be pulverized and / or pulverized according to need.

(C): mixture (b) preparation process;

The calcined product obtained in the first calcination reaction step (b) is provided in the preparation step (b) of the mixture (c) to obtain a mixture (b) in which the calcined product and the aluminum compound are uniformly mixed.

Examples of the aluminum compound related to the mixture (b) preparation process include transition alumina of γ-alumina, δ-alumina, θ-alumina, or a mixed phase containing two or more phases of γ phase, δ phase, Among them, the transition alumina exemplified in the process (a) for preparing the mixture (a) can be preferably used. Among them, transition alumina, aluminum hydroxide, ammonium dolonite and alum. In the case of using transitional alumina, the kind of transitional alumina is not particularly limited and may be the same as or different from that used in the above-mentioned preparation process of the mixture (a).

The aluminum compound related to the preparation process of the mixture (a) is preferably an aluminum compound in which? -Alumina has a BET specific surface area of 10 m 2 / g or more, preferably 10 to 40 m 2 / g and excellent thermal stability and chemical stability. It is particularly preferable from the viewpoint of obtaining lithium myristate.

The form of addition of the aluminum compound to the fired product can be added to the fired product as a slurry in which the aluminum compound is dispersed in a powder, solution or water medium.

The addition amount of the aluminum compound in the mixture (b) is 0.001 to 0.05, preferably 0.002 to 0.02, in terms of molar ratio (Al / Li) of Al atoms in the aluminum compound to Li atoms in the fired product in the preparation process is important in obtaining lithium? -aluminate (2). This is because when the addition amount of the aluminum compound is less than 0.001 as the molar ratio (Al / Li) of Al atoms in the aluminum compound to the Li atom in the fired product, the thermal stability becomes insufficient. On the other hand, By weight is not preferable because it contains an unreacted material.

The mixing means of the fired product and the aluminum compound can be used without particular limitation as far as the mixture (b) in which the respective raw materials are uniformly dispersed can be obtained. For example, the mixing method (a) Method can be used. Concretely, for example, a method of dry treatment using a high-speed dispersing mixer such as a Henschel mixer or a super mixer, or a method of drying the whole amount of the slurry by a spray dryer when wet mixing is used.

(D) a second firing reaction step;

The mixture (b) obtained in the preparing step (b) and the mixture (b) obtained in the preparing step (c) are supplied to the second calcination step to obtain the objective lithium aluminate (2).

In the present production method, the second firing reaction is carried out on the mixture (b) which is uniformly mixed, whereby the thermal stability is significantly improved as compared with the fired product obtained by the first firing reaction (? -Aluminate (1) to give lithium? -aluminate (2).

In the second firing reaction step (d), it is particularly important to obtain a single-phase? -Aluminate (2) from the viewpoint of obtaining excellent heat stability.

The firing temperature involved in the second firing reaction process is 750 to 900 占 폚, preferably 770 to 830 占 폚. This is because when the firing temperature of the second firing reaction is less than 750 캜, the single-phase lithium aluminate (2) is not easily obtained by X-ray diffraction, while the firing temperature of the second firing reaction exceeds 830 캜 It tends to contain a? -Phase, which is not preferable.

Further, in the relationship between the firing temperature and the firing time as described above, even when the same raw material mixture is subjected to the reaction at the same firing temperature, there is a case where the crystal form of the lithium aluminate (2) obtained according to the firing time is different . Generally, long-time firing tends to generate some? -Forms other than? -Forms. Further, this tendency tends to be more likely to occur in a short time in the γ type as the temperature is increased. Therefore, it is preferable to perform firing while appropriately checking whether or not the single-phase? -Aluminate (2) can be obtained by X-ray diffraction analysis. Generally, if firing is performed at the firing temperature for 0.5 to 40 hours, it is satisfactory and single-phase lithium a-aluminate can be produced.

The firing atmosphere is not particularly limited, and may be any one of an atmosphere in an inert gas atmosphere, a vacuum atmosphere, and an atmosphere of an oxidizing gas atmosphere.

The second firing reaction may be performed several times as desired. After completion of the second firing reaction, the resulting fired product is pulverized and / or pulverized according to need to obtain a product.

The lithium? -Aluminate (2) obtained by the production method of the present invention is? -Aluminic acid lithium (2) which is X-ray in a single phase substantially not containing lithium? -Aluminate and has a BET specific surface area of 10 m 2 / g or more. Therefore, the lithium? -Aluminate (2) obtained by the production method of the present invention can be preferably used as an electrolyte retention plate of the MCFC even if the BET specific surface area is 10 m 2 / g or more.

Example

Hereinafter, examples of the present invention will be described concretely in comparison with comparative examples. However, the scope of the present invention is not limited to these examples.

(Example 1)

(A): mixture (a) preparation process;

Alumina (XRD; Fig. 1) having a BET specific surface area of 92 m < 2 > / g and an average particle diameter of 30 mu m by laser method and lithium carbonate having an average particle diameter of 5 mu m by a laser method, Li) was 1.00, and sufficiently mixed with a Henschel mixer to prepare a homogeneous mixture (a).

(B): first firing reaction step;

The uniform mixture (a) was charged into an alumina crucible and subjected to a first firing reaction at 700 占 폚 for 25 hours in an air atmosphere to obtain a fired product. As a result of X-ray diffraction analysis on the obtained fired product, the fired product was a single-phase? -Aluminate (1) (see Fig. 2).

(C): mixture (b) preparation process;

The same θ-alumina as used in the preparation process of the mixture (a) was added to the fired product so as to have a molar ratio (Al / Li) of 0.015 to Li in the lithium α-aluminate (1), and the mixture was sufficiently mixed with a Henschel mixer, A homogeneous mixture (b) was prepared.

(D) a second firing reaction step;

The uniform mixture (b) was charged into an alumina crucible and subjected to a second firing reaction at 800 占 폚 for 7 hours in an atmospheric environment to obtain a sample of lithium? -Aluminate (2). As a result of X-ray diffraction analysis of the obtained sample of lithium a-aluminate (2), it was found that it was a lithium α-aluminate single phase (see FIG. 3) and the BET specific surface area was 21.5 m 2 / g. An SEM photograph of a sample of lithium? -Aluminate (2) is shown in FIG.

(Example 2)

(A): mixture (a) preparation process;

A commercially available? -Alumina having a BET specific surface area of 147 m < 2 > / g and an average particle diameter of 30 mu m by laser method and lithium carbonate having an average particle diameter of 5 mu m by a laser method was used and the molar ratio (Al / Li) And the mixture was sufficiently mixed with a Henschel mixer to prepare a homogeneous mixture (a).

(B): first firing reaction step;

The uniform mixture (a) was charged into an alumina crucible and subjected to a first firing reaction at 700 占 폚 for 25 hours in an air atmosphere to obtain a fired product. As a result of the X-ray diffraction analysis of the obtained fired product, the fired product was a single-phase? -Aluminate (1).

(C): mixture (b) preparation process;

The same γ-alumina as used in the preparation process (a) was added to the fired product so as to have a molar ratio (Al / Li) of 0.015 to Li in the lithium α-aluminate (1), and sufficiently mixed with a Henschel mixer, A homogeneous mixture (b) was prepared.

(2) a second firing reaction step;

The uniform mixture (b) was charged into an alumina crucible and subjected to a second firing reaction at 800 占 폚 for 7 hours in an atmospheric environment to obtain a sample of lithium? -Aluminate (2). As a result of X-ray diffraction analysis of the obtained sample of lithium? -Aluminate (2), it was found that it was a lithium α-aluminate single phase and had a BET specific surface area of 31.2 m 2 / g.

(Comparative Example 1)

? -Alumina having a BET specific surface area of 70 m < 2 > / g, an average particle diameter of 30 m by laser method and lithium carbonate having an average particle diameter of 5 m by a laser method were weighed and mixed in the same manner as in Example 1, a) was obtained.

Subsequently, the uniform mixture (a) was charged into an alumina crucible and fired at 700 占 폚 for 25 hours in an atmospheric environment, and this was used as a sample of? -Aluminate. The obtained? -Aluminate sample was analyzed by X-ray diffractometry and found to be a lithium α-aluminate single phase and had a BET specific surface area of 18.7 m 2 / g.

(Comparative Example 2)

A BET specific surface area of 70 m 2 / g, θ-alumina having an average particle diameter of 30 μm by the laser method, and lithium carbonate having an average particle diameter of 5 μm by a laser method were used in amounts such that the molar ratio (Al / Li) And this was put into a bead mill to perform wet mixing and pulverization. The resulting slurry was dried in a total amount with a spray dryer to prepare a homogeneous mixture.

This uniform mixture was charged into an alumina crucible and subjected to a firing reaction at 740 占 폚 for 7 hours and further at 800 占 폚 for 7 hours in an air atmosphere to obtain a fired product. As a result of X-ray diffraction analysis of the obtained fired product, the fired product was a lithium α-aluminate single phase and had a BET specific surface area of 20.1 m 2 / g.

<Evaluation of stability>

The evaluation of the thermal stability and the chemical stability of each of the? -Aluminate samples obtained in Examples and Comparative Examples were evaluated.

<Thermal Stability Test>

10 g of the respective samples of the lithium a-aluminate obtained in Examples and Comparative Examples were placed in an electric furnace in an atmospheric environment and heated at 750 DEG C for 200 hours to perform X-ray diffraction analysis to confirm presence or absence of lithium? -Aluminate . Figs. 5 and 6 show X-ray diffraction charts of the? -Aluminate sample of Example 1 and Comparative Example 2 after the heat treatment.

<Chemical stability test>

A lithium a-aluminate sample obtained in Examples and Comparative Examples and an electrolyte (component composition: Li ₂ CO ₃ : K ₂ CO ₃ = 53: 47 mol%) were mixed at a weight ratio of 1: 2 and air / nitrogen / CO ₂ = 50/40/10 in an electric furnace maintained at a temperature of 670 캜 for 200 hours, and X-ray diffraction analysis was performed to confirm the presence or absence of lithium γ-aluminate.

From Table 2, it can be seen that the lithium? -Aluminate obtained by this production method has excellent thermal stability. It is also found that the use of transition alumina containing the? Phase as the starting material alumina for the transition improves the chemical stability.

Industrial availability

According to the present invention, even if the BET specific surface area is 10 m &lt; 2 &gt; / g or more, it is possible to industrially advantageously provide lithium alpha -aluminate having various properties preferable as an electrolyte holding plate of an MCFC having excellent thermal stability.

Claims (8)

The transition alumina and lithium carbonate are mixed in a ratio of Al / Li molar ratio of 0.95 to 1.01, the resulting mixture (a) is subjected to a first firing reaction to obtain a fired product, (B) in which the molar ratio (Al / Li) of Al atoms in the aluminum compound to Li atoms in the fired product is from 0.001 to 0.05 is provided for the second firing reaction. . The method according to claim 1,
Wherein the firing temperature of the first firing reaction is 650 to 850 ° C. The method according to claim 1,
Wherein the firing temperature of the second firing reaction is 750 to 900 占 폚. The method according to claim 1,
Wherein said transition alumina is transitioned alumina or gamma -alumina containing a phase of?. The method according to claim 1,
Wherein the transition alumina is? -Alumina. The method according to claim 1,
Wherein the transition alumina has a BET specific surface area of 50 m &lt; 2 &gt; / g or more. The method according to claim 1,
Wherein the aluminum compound is a transition alumina. 8. The method according to any one of claims 1 to 7,
A method for producing lithium? -Aluminate, which is used as an electrolyte holding plate of a molten carbonate fuel cell.

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