JP2001097718A - Method for producing complex oxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a complex oxide by which the highly pure complex oxide can be produced by a low temperature process without being affected by the purity of a raw material. SOLUTION: This method for producing the complex oxide comprising immersing a first metal and a second metal having an ionization tendency smaller than that of the first metal in an aqueous solution containing at least one kind of an ion of a third metal and without containing the first or second metal to provide the objective complex oxide containing the first metal, and the third metal comprises electrically short-circuiting the first metal and the second metal. For example, mutually short-circuited Fe and Pt plates are immersed in an aqueous solution containing Zn(NO3)2 and the temperature of the aqueous solution is raised to 80 deg.C to elute Fe2+ ion, and to react Zn2+ ion in the solution with an acid and to provide ZnFe2O4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a composite oxide, and more particularly to a method for producing a composite oxide having a metal.

[0002]

2. Description of the Related Art For example, a conventional method for producing ferrite, which is one of composite oxides, is to mix powder of MnO ₂ or ZnO with Fe ₂ O ₃ , knead with a ball mill to form a slurry, and then dry. And calcined at 600 ° C to 800 ° C.
Main firing was performed at about ° C. to obtain a powder or a compact of ferrite such as MnFe ₂ O ₄ or ZnFe ₂ O ₄ .

[0003]

As described above, the above-described method for producing a composite oxide requires a high-temperature sintering step, and thus requires a large amount of heat energy in the production process.
The temperature control and the manufacturing process were also complicated. Further, the purity of the ferrite has been determined according to the purity of the raw material. Accordingly, the present invention has been made in view of the above-described problems, and has been developed in view of the above problems. The task is to provide.

[0004]

In order to solve the above-mentioned problems, the invention according to claim 1 includes a first metal M1 and a second metal M2 having a smaller ionization tendency than the first metal. A method for producing a composite oxide containing a first metal and a third metal by immersing the same in an aqueous solution containing ions M3 of at least one third metal other than the metal and the second metal. And electrically short-circuiting the first metal and the second metal. As a result, M1 is eluted as a cation, and an oxide of M1 ion and M3 ion in the solution, that is, a composite oxide can be produced.

According to a second aspect of the present invention, the first metal and the second metal having a lower ionization tendency than the first metal are combined with at least one type of third metal other than the first metal and the second metal. A method for producing a composite oxide containing a first metal and a third metal by immersion in an aqueous solution containing metal ions, wherein a voltage is applied between the first metal and the second metal. Is applied. As a result, the composite oxide production rate can be controlled by controlling the applied voltage.

The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the entire reaction field is heated. Here, the reaction field refers to the entire aqueous solution in which the metal is immersed. As a result, the reaction is promoted and the production speed of the composite oxide is increased.

According to a fourth aspect of the present invention, in any one of the first to third aspects, an alkali or an acid is added to the aqueous solution. As a result, it is possible to control the ionization of the metal, to control the production rate of the composite oxide,
For example, the compound form of the produced composite oxide can be changed. As the alkali, for example, Na ion, Li ion, NO ²⁻ can be used, and as the acid, for example, various acids including Cl ion, oxygen ion can be used.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the first metal is Fe and the second metal is P.
t, wherein the third metal is a Zn ion and / or a Mn ion. As a result, Fe ²⁺ ions are eluted from the Fe plate to produce ferrite (composite oxide) such as ZnFe ₂ O _4, MnFe ₂ O _4, or (Zn _0.5 Mn _0.5 ) Fe ₂ O ₄ .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
Will be explained. As shown in FIG.
Ion M3 of the genus M3^{n +}, For example, Zn ions and Cr ions
Aqueous solution 2 containing an appropriate amount of is charged and ionized therein.
Metal plates of a first metal M1 and a second metal M2 having different tendencies
3, 4, for example, Fe and Pt, or Cr and Au, or
Immerse a set of Zn and Cu to short-circuit each other, or ion
Voltage with the smaller tendency to increase
Then, ions of the metal M1 are eluted from the metal plate 3, and (M1)
_X(M3)_YO_ZComplex oxide 5 which can be represented by
This is deposited around the metal plate 3 and the bottom of the reaction vessel 1.

Factors that affect the formation rate, crystallinity, etc. of the composite oxide include the applied voltage, the pH of the aqueous solution, the temperature, the additives, or the concentration of the solution, and the electrical resistance.
The reaction can be promoted by raising the temperature of the aqueous solution, and metal M can be added by adding an alkali or acid to the aqueous solution.
Ionization of 1 or M2 can be promoted or suppressed. Further, by changing these conditions, the compound form of the product can be selected. For example, it is possible to control the spinel-type or perovskite-type compound form. Further, by gradually changing the ion of the third metal M3 in the aqueous solution during the reaction to another metal ion or adding another metal ion, the gradient composition of the composite oxide can be easily provided. When the reaction is nearing completion, the reaction can be further continued by adding metal ions.
A continuous process is possible.

As described above, a complex oxide can be produced by a low-temperature process without requiring a firing step and energy can be saved, and the reaction rate and the crystallinity can be controlled. Further, by controlling the crystallinity, it is possible to change the compound form of the produced composite oxide. In addition, since a composite oxide is produced by ionizing a metal, even if an impurity is contained in the metal body M1, the impurity is separated during ionization, so that a composite oxide containing M1 with high purity is obtained. be able to.

Hereinafter, embodiments of the present invention will be described. Example 1 A reaction vessel was charged with an aqueous solution containing 0.36 mol% of Zn (NO ₃ ) ₂ , and a Fe metal plate and a Pt metal plate were immersed therein and short-circuited with each other.
C. and held for 60 minutes. As a result, the ferrite ZnFe ₂ , which is a 3 μm thick composite oxide, was formed on the surface of the Fe plate.
An O ₄ film was formed.

EXAMPLE 2 0.36 mol% of Zn (NO_Three)_TwoAnd 0.3
6 mol% Mn (NO _Three)_TwoCharged with an aqueous solution containing
Immersion by short-circuiting a metal plate made of Fe and a metal plate made of Pt
And heat the reaction vessel to 120 ° C in an autoclave
And held for 60 minutes. As a result, the thickness 5
μm (Zn_0.5Mn_0.5) Fe_TwoO_FourForming a film, complex acid
Compound was obtained.

EXAMPLE 3 An aqueous solution containing 0.36 mol% of Zn (NO ₃ ) ₂ was charged into a reaction vessel, and a metal plate made of Fe and a metal plate made of Pt were immersed in the solution. A voltage of 1.0 V was applied with the positive electrode side being positive, and the aqueous solution was heated to 80 ° C. and held for 60 minutes. As a result, a 10 μm thick Zn
Fe ₂ O ₄ film was formed and 160 mg
Of ZnFe ₂ O ₄ powder was formed, to obtain a composite oxide.

[0015]

As described in detail above, according to the first to fourth aspects of the present invention, a complex oxide can be produced by a low-temperature process with low energy consumption without requiring a firing step. Further, since the ionization tendency is utilized, impurities can be eliminated, and a high-purity composite oxide can be obtained. According to the fifth aspect, in addition to the effects of the first to fourth aspects, ferrite can be manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for producing a composite oxide according to the present invention.

[Explanation of symbols]

1. Reaction vessel, 2. Aqueous solution, 3, 4, Metal plate, 5
..Compound oxides.

Continued on the front page (72) Inventor Tomoaki Nakamura 16 Izushimachi, Ishiki-cho, Hazu-gun, Hazu-gun, Aichi Higashimae-dori, 16 1-7-6 Chikubachi-cho, Ogaki-shi 2 (72) Inventor Toshiaki Imai 41-12 Fukuta, Nishio-shi, Aichi Pref. DC15

Claims (5)

[Claims] 1. A method according to claim 1, wherein the first metal and the second metal having a lower ionization tendency than the first metal contain ions of at least one third metal other than the first metal and the second metal. A method for producing a composite oxide containing a first metal and a third metal by immersing the first metal and the third metal, wherein the first metal and the second metal are electrically short-circuited. A method for producing a composite oxide. 2. A method according to claim 1, wherein the first metal and the second metal having a lower ionization tendency than the first metal contain ions of at least one third metal other than the first metal and the second metal. A method for producing a composite oxide containing a first metal and a third metal by immersing the composite oxide in an aqueous solution, comprising applying a voltage between the first metal and the second metal. A method for producing a composite oxide, which is characterized in that: 3. The method according to claim 1, wherein the whole reaction field is heated. 4. The method for producing a composite oxide according to claim 1, wherein an alkali or an acid is added to the aqueous solution. 5. The method according to claim 1, wherein the first metal is Fe, the second metal is Pt,
The method for producing a composite oxide according to any one of claims 1 to 4, wherein the third metal is a Zn ion and / or a Mn ion.