JP2011204596A - Raw material calcination method and raw material calcination device - Google Patents

Raw material calcination method and raw material calcination device Download PDF

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JP2011204596A
JP2011204596A JP2010073010A JP2010073010A JP2011204596A JP 2011204596 A JP2011204596 A JP 2011204596A JP 2010073010 A JP2010073010 A JP 2010073010A JP 2010073010 A JP2010073010 A JP 2010073010A JP 2011204596 A JP2011204596 A JP 2011204596A
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firing
furnace
raw material
precursor
temperature
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Kenichi Hamazaki
顕一 浜崎
Hajime Sato
肇 佐藤
Toshikazu Inaba
俊和 稲葉
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Mitsui Engineering and Shipbuilding Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

PROBLEM TO BE SOLVED: To provide a raw material calcination method in which, when manufacturing a secondary battery electrode material by calcinating a calcination precursor by a batch method, time necessary for calcination is shortened, and a calcination process can be carried out at a high efficiency and a low cost.SOLUTION: In the raw material calcination method, in which a process to calcinate the calcination precursor that is the raw material of the secondary battery electrode is repeatedly carried out by batch treatments in one calcination furnace, the calcination processed material obtained in the calcination process is transferred to an outer cooling part of the calcination furnace, and cooling is carried out without going through a process to decrease temperature of the calcination furnace, and at the same time, the calcination precursor for the next calcination process is put into the calcination furnace and the calcination is started in parallel with the cooling by the cooling part.

Description

本発明は、二次電池用電極材料を合成する際の原料焼成方法に関するものである。   The present invention relates to a raw material firing method for synthesizing a secondary battery electrode material.

金属リチウム電池、リチウムイオン電池、リチウムポリマー電池等に代表される二次電池の正極材料としては、コバルト酸リチウム（ＬｉＣｏＯ２）、マンガン酸リチウム（ＬｉＭｎＯ２）、ニッケル酸リチウム（ＬｉＮｉＯ２）、リン酸鉄リチウム（ＬｉＦｅＰＯ４）等のリチウム遷移金属が挙げられる。 As positive electrode materials of secondary batteries represented by metal lithium batteries, lithium ion batteries, lithium polymer batteries, etc., lithium cobaltate (LiCoO 2 ), lithium manganate (LiMnO 2 ), lithium nickelate (LiNiO 2 ), phosphorus Examples thereof include lithium transition metals such as lithium iron oxide (LiFePO 4 ).

このような二次電池用電極材料の多くは、原料を焼成することによって合成される。例えば、リン酸鉄リチウム系正極材料は、シュウ酸鉄（II）［（ＦｅＣ２Ｏ４）・２Ｈ２Ｏ］、リン酸二水素アンモニウム［ＮＨ４Ｈ２ＰＯ４］、水酸化リチウム一水和物［ＬｉＯＨ・Ｈ２Ｏ］等の原料を焼成することによって製造される。 Many of such electrode materials for secondary batteries are synthesized by firing raw materials. For example, lithium iron phosphate-based positive electrode materials include iron (II) oxalate [(FeC 2 O 4 ) · 2H 2 O], ammonium dihydrogen phosphate [NH 4 H 2 PO 4 ], lithium hydroxide monohydrate It is manufactured by firing raw materials such as a product [LiOH.H 2 O].

より具体的には、原料であるシュウ酸鉄（II）、リン酸二水素アンモニウム、水酸化リチウム一水和物等を、アルコール［例えばＩＰＡ（イソプロピルアルコール）］等を加えて粉砕・混合し、減圧下で乾燥して焼成前駆体を調製し、該焼成前駆体を炉焼成する。この焼成工程により、活物質であるリン酸鉄リチウムを合成することができる。   More specifically, raw materials such as iron (II) oxalate, ammonium dihydrogen phosphate, lithium hydroxide monohydrate, etc. are pulverized and mixed with an alcohol [eg IPA (isopropyl alcohol)] etc. A fired precursor is prepared by drying under reduced pressure, and the fired precursor is fired in a furnace. Through this firing step, lithium iron phosphate as an active material can be synthesized.

リン酸鉄リチウム系正極材料の場合、前記焼成前駆体の焼成は、温度を５００〜８００℃程度（好ましくは６００℃〜７００℃程度）の高温域まで昇温して行うことが必要であるが、特許文献１に記載の製造方法のように焼成工程を２つに分けることによって、より高い２次電池性能が得られることが知られている。すなわち、先に第１の焼成工程として３５０℃〜４００℃程度（中温域）にて０．５時間〜５時間程度の仮焼成を行い、一旦外部に仮焼成物を取り出して擂潰した後に、第２の焼成工程として５００〜８００℃程度（好ましくは６００℃〜７００℃程度）に０．５時間〜１０時間程度の本焼成を行うことによって、得られる正極材料のリン酸鉄リチウムの均一性が一層向上し、より高い２次電池性能が得られる。   In the case of a lithium iron phosphate-based positive electrode material, the firing precursor needs to be fired by raising the temperature to a high temperature range of about 500 to 800 ° C. (preferably about 600 ° C. to 700 ° C.). It is known that higher secondary battery performance can be obtained by dividing the baking step into two as in the manufacturing method described in Patent Document 1. In other words, as the first firing step, after preliminary firing at about 350 ° C. to 400 ° C. (medium temperature range) for about 0.5 hours to 5 hours, the temporarily fired product is once taken out and crushed. Uniformity of lithium iron phosphate as a positive electrode material obtained by performing main baking for about 0.5 to 10 hours at about 500 to 800 ° C. (preferably about 600 to 700 ° C.) as the second baking step. Is further improved, and higher secondary battery performance is obtained.

ここで、前記第１の焼成工程は、ロータリーキルン等の公知の焼成炉を用いて行われるが、第２の焼成工程に移行する前に第１の焼成工程で得られた前記仮焼成物を取り出して炭素被覆前処理するため、前記ロータリーキルンにおける第１の焼成工程はバッチ方式によって行われている。すなわち、原料（焼成前駆体）を焼成炉に投入し、該焼成炉内を３５０℃〜４００℃程度に昇温して０．５時間〜５時間の仮焼成を行った後、焼成炉を冷却して仮焼成物を取り出す、という一連の工程を１バッチとして前記焼成炉においてこの第１の焼成工程を繰り返し、バッチを重ねて量産する。   Here, although the first firing step is performed using a known firing furnace such as a rotary kiln, the temporary fired product obtained in the first firing step is taken out before moving to the second firing step. In order to perform the carbon coating pretreatment, the first firing step in the rotary kiln is performed by a batch method. That is, a raw material (firing precursor) is charged into a firing furnace, the temperature inside the firing furnace is raised to about 350 ° C. to 400 ° C., and calcined for 0.5 to 5 hours, and then the firing furnace is cooled. Then, a series of steps of taking out the temporarily fired product is taken as one batch, the first firing step is repeated in the firing furnace, and the batches are stacked for mass production.

したがって、前記焼成炉では、図７のように、常温（例えば約２０℃）から３５０〜４００℃程度までの範囲で温度を上昇および下降させる運転が繰り返して行われることになる。例えば、約４００℃で３〜４時間の仮焼成を行う場合、昇温および冷却にかかる時間を含めると、１バッチの反応を行うために要する時間は７〜８時間である（図７の符号ａの範囲）。そして、焼成炉内が常温になっている図７における符号ｂの範囲の間に焼成炉から仮焼成物を取り出し、次の焼成のための原料（焼成前駆体）を投入する。   Therefore, in the firing furnace, as shown in FIG. 7, the operation of raising and lowering the temperature in the range from room temperature (for example, about 20 ° C.) to about 350 to 400 ° C. is repeatedly performed. For example, when pre-baking is performed at about 400 ° C. for 3 to 4 hours, the time required to perform one batch of reaction is 7 to 8 hours, including the time required for heating and cooling (reference numeral in FIG. 7). a range). Then, the temporarily fired product is taken out from the firing furnace during the range indicated by symbol b in FIG. 7 where the inside of the firing furnace is at room temperature, and the raw material (firing precursor) for the next firing is introduced.

このように短いサイクルで、常温〜４００℃のような大きな温度変化を伴う運転が繰り返し行われると、焼成炉に大きな負担がかかり使用寿命が短くなってしまう。また、焼成前駆体投入後に常温から焼成温度にまで昇温するための時間、および、仮焼成終了後に焼成温度から常温にまで冷却する時間がかかるため、製造時間の短縮には限界があった。   When an operation with a large temperature change such as room temperature to 400 ° C. is repeatedly performed in such a short cycle, a large burden is applied to the firing furnace, and the service life is shortened. Further, since it takes time to raise the temperature from normal temperature to the firing temperature after charging the firing precursor and time to cool from the firing temperature to room temperature after the end of the pre-firing, there is a limit to shortening the manufacturing time.

特開２００８−２５７８９４号公報JP 2008-257894 A

本発明は、上記問題を解決し、バッチ方式で焼成前駆体の焼成を行って二次電池用電極材料を製造する際に、前記焼成に要する時間を短縮し、焼成工程を高効率且つ低コストで行うことができる原料焼成方法を提供することを目的とするものである。   The present invention solves the above-mentioned problems, shortens the time required for the firing when producing the electrode material for a secondary battery by firing the firing precursor in a batch system, and makes the firing process highly efficient and low cost. It aims at providing the raw material baking method which can be performed by this.

上記目的を達成するため、本発明の第１の態様に係る原料焼成方法は、一つの焼成炉において、二次電池用電極材料の原料である焼成前駆体を焼成する工程をバッチ処理によって繰り返し行う原料焼成方法であって、先の焼成工程によって得られる焼成処理物を前記焼成炉の温度を下げる工程を経ずに該焼成炉の外部の冷却部に移して冷却を実行し、且つ前記焼成炉に次の焼成工程用の焼成前駆体を入れて前記冷却部による冷却と並行して焼成を開始することを特徴とするものである。   In order to achieve the above object, the raw material firing method according to the first aspect of the present invention is such that a step of firing a firing precursor that is a raw material of an electrode material for a secondary battery is repeatedly performed by batch processing in one firing furnace. A raw material firing method, in which the fired product obtained in the previous firing step is transferred to a cooling unit outside the firing furnace without passing through the step of lowering the temperature of the firing furnace, and cooling is performed, and the firing furnace The firing precursor for the next firing step is put in and the firing is started in parallel with the cooling by the cooling section.

ここで、リン酸鉄リチウム系正極材料の場合、該リン酸鉄リチウム系正極材料の原型となる正極活物質（ＬｉＦｅＰＯ４）の原料となる物質［例えば、シュウ酸鉄（II）、リン酸二水素アンモニウム、水酸化リチウム等］のみからなる焼成前駆体を用いるほか、前記ＬｉＦｅＰＯ４の原料と他の物質（例えば、ＬｉやＦｅ以外の金属ハロゲン化物）とを混合して得られる焼成前駆体を用いる場合がある。本発明における「二次電池用電極材料の原料である焼成前駆体」とは、焼成することによって二次電池用電極材料を合成することが可能な物質の混合物を、「焼成前駆体」と称するものとする。 Here, in the case of a lithium iron phosphate-based positive electrode material, a material [for example, iron (II) oxalate, diphosphate phosphate serving as a raw material of a positive electrode active material (LiFePO 4 ) that is a prototype of the lithium iron phosphate-based positive electrode material In addition to using a calcining precursor composed only of ammonium hydrogen, lithium hydroxide, etc., a calcining precursor obtained by mixing the raw material of LiFePO 4 with another substance (for example, a metal halide other than Li or Fe) is used. May be used. The “firing precursor as a raw material of the secondary battery electrode material” in the present invention refers to a mixture of substances capable of synthesizing the secondary battery electrode material by firing as a “firing precursor”. Shall.

本態様によれば、先の焼成工程によって得られる焼成処理物を前記焼成炉の温度を下げる工程を経ずに該焼成炉の外部の冷却部に移すので、従来、焼成炉内の温度を焼成温度から常温にまで冷却するためにかかっていた時間を短縮することができる。   According to this aspect, since the fired product obtained in the previous firing step is transferred to the cooling section outside the firing furnace without going through the step of lowering the temperature of the firing furnace, conventionally, the temperature in the firing furnace is fired. The time taken for cooling from temperature to room temperature can be shortened.

また、焼成炉の温度を下げる工程を行わないため、前記焼成処理物を前記冷却部に移した後の焼成炉内の温度は、ほぼ焼成温度に維持されている。この焼成温度に維持された焼成炉内に次の焼成工程に用いる新たな焼成前駆体を入れるので、次の焼成工程をすぐに行うことができる。そして、当該次の焼成工程と、前記冷却部における先の焼成工程によって得られた焼成処理物の冷却とを並行して行う。   In addition, since the step of lowering the temperature of the firing furnace is not performed, the temperature in the firing furnace after the fired product is transferred to the cooling unit is maintained substantially at the firing temperature. Since the new baking precursor used for the next baking process is put in the baking furnace maintained at this baking temperature, the next baking process can be performed immediately. And the said next baking process and cooling of the baking processed material obtained by the previous baking process in the said cooling part are performed in parallel.

このように、先の焼成工程の焼成終了後、すぐに焼成処理物を取り出して次の焼成工程を開始するとともに、前記焼成処理物の冷却を前記焼成炉とは別の冷却部において前記次の焼成工程と並行して行うことにより、炉内温度を焼成温度から常温まで冷却、または常温から焼成温度まで昇温するためにかかっていた時間を短縮し、昇温にかかるエネルギーコストを抑え、バッチ処理のサイクルを短くすることができる。また、燃焼炉内の温度変化が少ないため、急激な温度変化が繰り返されることによって燃焼炉にかかる負荷が減少することが期待できる。   In this way, immediately after the completion of the firing in the previous firing step, the fired product is taken out and the next firing step is started, and cooling of the fired product is performed in the cooling section separate from the firing furnace. By performing in parallel with the firing process, the time required to cool the furnace temperature from the firing temperature to room temperature or to raise the temperature from room temperature to the firing temperature is shortened, and the energy cost for the temperature rise is reduced, and the batch The processing cycle can be shortened. Further, since the temperature change in the combustion furnace is small, it can be expected that the load applied to the combustion furnace is reduced by repeating the rapid temperature change.

尚、焼成処理物の取り出し時や新たな前駆体投入時には、焼成炉の加熱は止めることが望ましいが、焼成温度より２０℃程度以上低い温度に下がってしまう場合には、前記焼成工程における焼成温度を維持できるように焼成炉の加熱を続けてもよい。   In addition, it is desirable to stop the heating of the firing furnace when taking out the fired product or adding a new precursor, but if the temperature falls to about 20 ° C. or lower than the firing temperature, the firing temperature in the firing step The heating of the firing furnace may be continued so that the temperature can be maintained.

本発明の第２の態様に係る原料焼成方法は、一つの焼成炉において、二次電池用電極材料の原料である焼成前駆体を焼成する工程をバッチ処理によって繰り返し行う原料焼成方法であって、先の焼成工程によって得られる焼成処理物を前記焼成炉の温度を焼成温度以下であって２００℃以上に下げる工程を経て該焼成炉の外部の冷却部に移して冷却を実行し、且つ前記焼成炉に次の焼成工程用の焼成前駆体を入れて前記冷却部による冷却と並行して焼成を開始することを特徴とするものである。   The raw material firing method according to the second aspect of the present invention is a raw material firing method in which a step of firing a firing precursor that is a raw material of an electrode material for a secondary battery is repeatedly performed by batch processing in one firing furnace, The fired product obtained by the previous firing step is transferred to a cooling unit outside the firing furnace through a step of lowering the temperature of the firing furnace to 200 ° C. or lower and lowering the temperature of the firing furnace, and cooling is performed. A firing precursor for the next firing step is put in a furnace and firing is started in parallel with cooling by the cooling unit.

本態様によれば、得られた焼成処理物を焼成炉内が常温まで下がる前に取り出し、該焼成炉の外部の冷却部に移して冷却をするので、従来、焼成炉内の温度を焼成温度から常温にまで冷却するためにかかっていた時間が短縮できる。   According to this aspect, the obtained fired product is taken out before the temperature in the firing furnace is lowered to room temperature, and is transferred to a cooling unit outside the firing furnace for cooling. Therefore, conventionally, the temperature in the firing furnace is the firing temperature. The time required for cooling to room temperature can be shortened.

前記焼成処理物の取り出しは、焼成炉内の温度を焼成工程における焼成温度以下、２００℃以上に維持した状態で行われる。前記焼成炉の温度を焼成温度以下、２００℃以上に下げる工程を行った後、焼成処理物を取り出すために焼成炉の取り出し口を開けたこと等によって炉内温度が２００℃より低い温度に低下する場合には、焼成炉を加熱して炉内温度が２００℃以上になるようにする。   The calcination treatment is taken out in a state where the temperature in the calcination furnace is maintained below the calcination temperature in the calcination step and at 200 ° C. or more. After performing the step of lowering the temperature of the firing furnace below the firing temperature and above 200 ° C., the temperature inside the furnace is lowered to a temperature lower than 200 ° C. by opening the outlet of the firing furnace to take out the fired product. In order to do so, the firing furnace is heated so that the furnace temperature becomes 200 ° C. or higher.

続いて、次の焼成工程に用いる新たな焼成前駆体を前記焼成温度以下、２００℃以上に維持した状態の焼成炉内に入れ、次の焼成工程を行うために焼成炉を加熱し、該炉内の温度を焼成温度まで昇温する。そして、当該次の焼成工程と、前記冷却部における先の焼成工程によって得られた焼成処理物の冷却とを並行して行う。   Subsequently, a new firing precursor used in the next firing step is placed in a firing furnace maintained at a temperature equal to or lower than the firing temperature and 200 ° C., and the firing furnace is heated to perform the next firing step. The temperature inside is raised to the firing temperature. And the said next baking process and cooling of the baking processed material obtained by the previous baking process in the said cooling part are performed in parallel.

このように、先の焼成工程の焼成終了後、焼成炉内を常温にまで下げる前に焼成処理物を取り出して次の焼成工程を開始するとともに、前記焼成処理物の冷却を前記焼成炉とは別の冷却部において前記次の焼成工程と並行して行うことにより、炉内温度を焼成温度から常温まで冷却、または常温から焼成温度まで昇温するためにかかっていた時間を短縮し、昇温にかかるエネルギーコストを抑え、バッチ処理のサイクルを短くすることができる。以って、二次電池用電極材料の原料焼成を高効率且つ低コストで行うことができる。   As described above, after the firing of the previous firing step is completed, before the inside of the firing furnace is lowered to room temperature, the fired product is taken out and the next firing step is started, and cooling of the fired product is referred to as the firing furnace. By performing in parallel with the next firing step in another cooling section, the time required for cooling the furnace temperature from the firing temperature to room temperature or raising the temperature from room temperature to the firing temperature is shortened, and the temperature is raised. Energy cost can be reduced and the batch processing cycle can be shortened. Accordingly, the raw material firing of the secondary battery electrode material can be performed with high efficiency and low cost.

また、焼成温度よりも低い温度の焼成炉内に焼成前駆体を入れるので、焼成温度の炉内に焼成前駆体を入れる場合よりも反応を穏やかに開始することができる。また、従来よりも燃焼炉内の温度変化が少ないため、燃焼炉にかかる負荷が減少することが期待できる。   Further, since the firing precursor is placed in a firing furnace having a temperature lower than the firing temperature, the reaction can be started more gently than in the case where the firing precursor is placed in a furnace having a firing temperature. Further, since the temperature change in the combustion furnace is less than that in the prior art, it can be expected that the load applied to the combustion furnace is reduced.

本発明の第３の態様に係る原料焼成方法は、第２の態様において、前記焼成炉の温度を焼成温度以下であって２００℃以上に下げる工程で該焼成炉から放出される熱エネルギーを、次工程以降の焼成前駆体の予熱に利用することを特徴とするものである。   In the raw material firing method according to the third aspect of the present invention, in the second aspect, the thermal energy released from the firing furnace in the step of lowering the temperature of the firing furnace to not more than the firing temperature and to 200 ° C. or more, It is characterized in that it is used for preheating the firing precursor after the next step.

本態様によれば、先の焼成工程終了後に前記焼成炉の温度を下げる工程で該焼成炉から放出される熱エネルギーを、次の焼成工程に用いる新たな焼成前駆体の予熱に利用し、予熱された焼成前駆体を焼成炉内に入れることができる。このことによって、新たな焼成前駆体を焼成炉内に入れたときの炉内温度の低下を小さくすることができる。   According to this aspect, the thermal energy released from the firing furnace in the step of lowering the temperature of the firing furnace after the end of the previous firing process is used for preheating the new firing precursor used in the next firing process, and preheating. The finished firing precursor can be placed in a firing furnace. By this, the fall of the furnace temperature when a new baking precursor is put in a baking furnace can be made small.

本発明の第４の態様に係る原料焼成方法は、第３の態様において、次工程以降の焼成前駆体を前記焼成炉に接触させて前記熱エネルギーを吸収することを特徴とするものである。   The raw material firing method according to a fourth aspect of the present invention is characterized in that, in the third aspect, a calcining precursor subsequent to the next step is brought into contact with the calcining furnace to absorb the thermal energy.

本態様によれば、効率よく焼成炉の温度を下げることができるとともに、熱交換器等の装置を必要とせず、新たな焼成前駆体を予熱するために前記焼成炉の廃熱を簡単に利用することができる。   According to this aspect, the temperature of the firing furnace can be efficiently reduced, and a heat exchanger or the like is not required, and the waste heat of the firing furnace is easily used to preheat a new firing precursor. can do.

本発明の第５の態様に係る原料焼成方法は、第１の態様または第２の態様において、前記焼成工程は、前記焼成炉内を不活性雰囲気にする不活性ガスを流しつつ行われ、前記焼成炉内を通過して加熱された前記不活性ガスの熱エネルギーを次工程以降の焼成前駆体の予熱に利用することを特徴とするものである。   In the raw material firing method according to the fifth aspect of the present invention, in the first aspect or the second aspect, the firing step is performed while flowing an inert gas that makes the inside of the firing furnace an inert atmosphere, The heat energy of the inert gas heated through the firing furnace is used for preheating the firing precursor in the subsequent steps.

二次電池用電極材料の焼成前駆体の焼成は、焼成炉内に窒素、アルゴン、二酸化炭素等の不活性ガスをブローしながら該不活性ガス雰囲気下において行われる。焼成炉を通過して排出される不活性ガス（排気）は焼成温度とほぼ同じ温度である。
本態様によれば、焼成炉内のパージに用いた不活性ガスの熱エネルギーを前記新たな焼成前駆体の予熱に利用し、予熱された焼成前駆体を焼成炉内に入れることができる。このことによって、新たな焼成前駆体を焼成炉内に入れたときの炉内温度の低下を小さくすることができる。 Firing of the firing precursor of the electrode material for the secondary battery is performed in an inert gas atmosphere while blowing an inert gas such as nitrogen, argon, carbon dioxide or the like into the firing furnace. The inert gas (exhaust gas) discharged through the firing furnace is at the same temperature as the firing temperature.
According to this aspect, the heat energy of the inert gas used for purging in the firing furnace can be used for preheating the new firing precursor, and the preheated firing precursor can be placed in the firing furnace. By this, the fall of the furnace temperature when a new baking precursor is put in a baking furnace can be made small.

本発明の第６の態様に係る原料焼成方法は、第１の態様から第５の態様のいずれか一つの態様において、前記焼成前駆体は不活性ガスによるパージ部において不活性ガスでパージされて前記焼成炉内に入れられることを特徴とするものである。   The raw material firing method according to a sixth aspect of the present invention is the raw material firing method according to any one of the first to fifth aspects, wherein the firing precursor is purged with an inert gas in a purge portion with an inert gas. It is put into the said baking furnace, It is characterized by the above-mentioned.

高温の焼成炉内に焼成前駆体を入れると、該焼成前駆体中の原料はすぐに反応し始める。その際、前記焼成炉内に酸素が存在すると２価の鉄原料が酸化され、３価の鉄化合物（ＦｅＰＯ４、Ｆｅ２Ｏ３）等の不純物が生成してしまう。本態様によれば、焼成前駆体供給時に焼成炉内へ酸素が混入することを防ぎ、Ｆｅ２Ｏ３等の不純物の生成を抑えることができる。 When the firing precursor is placed in a high-temperature firing furnace, the raw materials in the firing precursor start to react immediately. At that time, if oxygen is present in the firing furnace, the divalent iron raw material is oxidized, and impurities such as trivalent iron compounds (FePO 4 , Fe 2 O 3 ) are generated. According to this aspect, it is possible to prevent oxygen from being mixed into the firing furnace when supplying the firing precursor, and to suppress the generation of impurities such as Fe 2 O 3 .

本発明の第７の態様に係る原料焼成装置は、二次電池用電極材料の原料である焼成前駆体を焼成炉に入れてバッチ処理によって繰り返し焼成する構成の原料焼成装置であって、前記焼成炉と別に冷却部を備え、先の焼成処理によって得られる焼成処理物を前記焼成炉の温度を下げる工程を経ずに該焼成炉の外部の冷却部に移して冷却を実行し、且つ前記焼成炉に次の焼成工程用の焼成前駆体を入れて前記冷却部による冷却と並行して焼成を開始するように構成されていることを特徴とするものである。   A raw material firing apparatus according to a seventh aspect of the present invention is a raw material firing apparatus having a configuration in which a firing precursor, which is a raw material of an electrode material for a secondary battery, is placed in a firing furnace and repeatedly fired by batch processing. A cooling part is provided separately from the furnace, the fired product obtained by the previous firing process is transferred to the cooling part outside the firing furnace without passing through the step of lowering the temperature of the firing furnace, and cooling is performed. A firing precursor for the next firing step is placed in a furnace, and firing is started in parallel with cooling by the cooling unit.

本態様によれば、焼成前駆体を焼成炉に入れてバッチ処理によって繰り返し焼成する際、先の焼成処理によって得られる焼成処理物を、前記焼成炉の温度を下げる工程を経ずに該焼成炉の外部の冷却部に移し、該冷却部において常温まで冷却することができる。
また、焼成炉の温度を下げる工程を行わないので、次の焼成工程用の焼成前駆体は、ほぼ焼成温度に維持された焼成炉内に入れられる。そして、この冷却部における先の焼成処理によって得られた焼成処理物の冷却と並行して、次の焼成処理を行う。 According to this aspect, when the firing precursor is placed in a firing furnace and repeatedly fired by a batch process, the fired product obtained by the previous firing process is not subjected to the step of lowering the temperature of the firing furnace. It can move to the external cooling part of this, and can cool to normal temperature in this cooling part.
Moreover, since the process of lowering the temperature of the firing furnace is not performed, the firing precursor for the next firing process is placed in a firing furnace maintained at substantially the firing temperature. And the next baking process is performed in parallel with cooling of the baking processed material obtained by the previous baking process in this cooling part.

このように、先の焼成処理終了後の焼成炉の冷却にかかる時間と、次の焼成処理を行うための焼成炉の昇温にかかる時間を短縮できるとともに、先の焼成工程の焼成処理物の冷却と、次の焼成工程とを並行して行うので、一つの焼成炉において前記焼成工程をバッチ処理によって繰り返して行う二次電池用電極材料の原料焼成を効率よく行うことができる。   As described above, the time required for cooling the baking furnace after the completion of the previous baking process and the time required for heating the baking furnace for performing the next baking process can be shortened, and the baking processed product of the previous baking process can be reduced. Since the cooling and the next firing step are performed in parallel, the raw material firing of the secondary battery electrode material can be efficiently performed by repeating the firing step by batch processing in one firing furnace.

本発明の第８の態様に係る原料焼成装置は、第７の態様において、前記焼成前駆体を不活性ガスによってパージするパージ部を備え、該パージ部において不活性ガスでパージされた焼成前駆体を前記焼成炉内に入れるように構成されていることを特徴とするものである。   According to an eighth aspect of the present invention, there is provided a raw material firing apparatus according to the seventh aspect, further comprising a purge unit that purges the firing precursor with an inert gas, wherein the firing precursor is purged with an inert gas in the purge unit. Is placed in the firing furnace.

本態様によれば、焼成前駆体を不活性ガスでパージして焼成炉に入れることができ、以って、焼成炉内への酸素の混入を防ぐことができる。   According to this aspect, the firing precursor can be purged with an inert gas and put into the firing furnace, thereby preventing oxygen from being mixed into the firing furnace.

本発明によれば、バッチ方式で原料（焼成前駆体）の焼成を行って二次電池用電極材料を製造する際に、焼成前駆体の焼成工程に要する時間を短縮し、高効率且つ低コストを達成することができる。   According to the present invention, when a raw material (firing precursor) is fired in a batch process to produce an electrode material for a secondary battery, the time required for the firing step of the calcining precursor is shortened, and high efficiency and low cost are achieved. Can be achieved.

実施例１および実施例２の原料焼成方法に用いる焼成装置の概略図である。3 is a schematic view of a firing apparatus used in the raw material firing method of Example 1 and Example 2. FIG. 実施例３の原料焼成方法に用いる焼成装置の概略図である。6 is a schematic view of a firing apparatus used in the raw material firing method of Example 3. FIG. 実施例４の原料焼成方法によって焼成前駆体の予熱を行っている焼成装置の概略図である。6 is a schematic view of a firing apparatus that preheats a firing precursor by the raw material firing method of Example 4. FIG. 実施例５の原料焼成方法に用いる焼成装置の概略図である。6 is a schematic view of a firing apparatus used in the raw material firing method of Example 5. FIG. 実施例１の原料焼成方法により焼成前駆体の焼成を行った場合の焼成炉内の経時的な温度変化を示す図である。FIG. 3 is a view showing a change in temperature over time in a firing furnace when a firing precursor is fired by the raw material firing method of Example 1. 実施例２の原料焼成方法により焼成前駆体の焼成を行った場合の焼成炉内の経時的な温度変化を示す図である。FIG. 6 is a view showing a temperature change with time in a firing furnace when a firing precursor is fired by the raw material firing method of Example 2. 従来の原料焼成方法により焼成前駆体の焼成を行った場合の焼成炉内の経時的な温度変化を示す図である。It is a figure which shows the time-dependent temperature change in a baking furnace at the time of baking a baking precursor by the conventional raw material baking method.

本発明は、原料となる焼成前駆体を焼成して合成される二次電池用電極材料の製造に用いられる。以下の実施例では、二次電池用電極材料としてリン酸鉄リチウム系正極材料の製造を例に挙げて説明するが、本発明はこれらの実施例に限られるものではない。   INDUSTRIAL APPLICABILITY The present invention is used for manufacturing a secondary battery electrode material synthesized by firing a firing precursor as a raw material. In the following examples, production of a lithium iron phosphate-based positive electrode material will be described as an example of an electrode material for a secondary battery, but the present invention is not limited to these examples.

リン酸鉄リチウム系正極材料は、リン酸二水素アンモニウム［ＮＨ４Ｈ２ＰＯ４］等のリン酸導入用の原料（ＰＯ４を含むもの）と、シュウ酸鉄（II）［（ＦｅＣ２Ｏ４）・２Ｈ２Ｏ］等の鉄導入用原料（Ｆｅを含むもの）と、水酸化リチウム一水和物［ＬｉＯＨ・Ｈ２Ｏ］等のリチウム導入用の原料（Ｌｉを含むもの）を含む焼成前駆体を焼成することによって製造される。 Lithium iron phosphate-based cathode material, the raw material for phosphate introduction of such ammonium dihydrogen phosphate [NH 4 H 2 PO 4] ( those containing PO 4), iron oxalate (II) [(FeC 2 O 4 ) Including raw materials for introducing iron (including Fe) such as 2H 2 O] and raw materials for introducing lithium (including Li) such as lithium hydroxide monohydrate [LiOH.H 2 O] It is manufactured by firing a firing precursor.

本発明に係る原料焼成方法は、前記焼成前駆体の焼成を第１の焼成工程と第２の焼成工程の二段階で行う場合の第１の焼成工程において用いることができる。また、焼成工程を二段階に分けず、一段階の焼成によって行う方法をバッチ方式で行う場合にも用いることができる。   The raw material firing method according to the present invention can be used in a first firing step in which the firing precursor is fired in two stages of a first firing step and a second firing step. Moreover, it can use also when performing the method performed by one-step baking by a batch system, without dividing a baking process into two steps.

リン酸鉄リチウム系正極材料の焼成前駆体の焼成は、５００〜８００℃程度の高温域での一回の焼成（一段階の焼成）によって行うことも可能であるが、本発明では、３００℃〜４００℃程度の低温の温度範囲で焼成を行う第１の焼成工程（仮焼成）と、前記第１の焼成よりも高温域（５００℃〜８００℃程度、より好ましくは６００℃〜７００℃程度）で焼成を行う第２の焼成工程（本焼成）とを行うことによって製造する場合について主に説明する。すなわち、二段階の焼成工程で原料焼成を行う場合の前記第１の焼成工程（仮焼成）について説明する。   Firing of the firing precursor of the lithium iron phosphate-based positive electrode material can be performed by one firing (one-step firing) in a high temperature range of about 500 to 800 ° C., but in the present invention, 300 ° C. A first firing step (temporary firing) for firing in a low temperature range of about ~ 400 ° C, and a higher temperature range (about 500 ° C to 800 ° C, more preferably about 600 ° C to 700 ° C) than the first firing. ) In the second baking step (main baking) in which baking is performed will be mainly described. That is, the first firing step (preliminary firing) in the case where raw material firing is performed in a two-stage firing step will be described.

［実施例１］
図１は、実施例１の原料焼成方法に用いる焼成装置１の概略図である。図５は、実施例１の原料焼成方法により焼成前駆体の焼成を行った場合の焼成炉内の経時的な温度変化を示す図である。図７は、従来の原料焼成方法により焼成前駆体の焼成を行った場合の焼成炉内の経時的な温度変化を示す図である。 [Example 1]
FIG. 1 is a schematic view of a firing apparatus 1 used in the raw material firing method of Example 1. FIG. 5 is a view showing the temperature change with time in the firing furnace when the firing precursor is fired by the raw material firing method of Example 1. FIG. FIG. 7 is a diagram showing a temperature change with time in the firing furnace when the firing precursor is fired by the conventional raw material firing method.

本実施例において用いる焼成装置１は、焼成炉２と、該焼成炉２内を加熱する加熱装置３と、焼成前駆体を不活性ガスでパージするパージ部４と、前記焼成炉２と別に配設される冷却部５を備えている。焼成炉２としては、ロータリーキルン、ローラーハースキルン等の公知の焼成炉が用いられる。   The firing apparatus 1 used in this embodiment is arranged separately from the firing furnace 2, the heating apparatus 3 for heating the inside of the firing furnace 2, the purge unit 4 for purging the firing precursor with an inert gas, and the firing furnace 2. A cooling unit 5 is provided. As the firing furnace 2, a known firing furnace such as a rotary kiln or a roller hearth kiln is used.

前記第１の焼成工程によって得られる焼成処理物７は、第２の焼成を行う前に粉砕混合したり、炭素被覆原料を添加して均一に混合するために、前記焼成炉２外に一旦取り出す必要がある。そのため、前記焼成装置１における第１の焼成工程はバッチ方式によって行われる。   The fired product 7 obtained by the first firing step is once taken out of the firing furnace 2 in order to pulverize and mix before performing the second firing, or to add and uniformly mix the carbon coating raw material. There is a need. Therefore, the 1st baking process in the said baking apparatus 1 is performed by a batch system.

まず、前記焼成装置１が停止している状態（焼成炉２内が常温の状態）から1回目の焼成［以下、焼成（１）］を始めるときには、常温の焼成炉２内に焼成前駆体６を入れる。焼成炉２内に入れる焼成前駆体６は、パージ部４において純窒素等の不活性ガス８によってパージされたものを用いることが望ましい。このことによって、焼成炉２内に酸素等が混入するのを防ぐことができる。   First, when the first firing [hereinafter referred to as firing (1)] is started from the state where the firing apparatus 1 is stopped (the firing furnace 2 is at room temperature), the firing precursor 6 is placed in the firing furnace 2 at room temperature. Insert. As the firing precursor 6 put into the firing furnace 2, it is desirable to use the one that has been purged with an inert gas 8 such as pure nitrogen in the purge unit 4. This can prevent oxygen and the like from being mixed into the firing furnace 2.

焼成前駆体６を入れた焼成炉２内に純窒素ガス等の不活性ガス９を通気しながら昇温し、所定の温度（例えば４００℃）にして焼成を行う。符号１０は焼成炉２から排出される不活性ガス（焼成炉内での反応によって発生するガスを含む排気）である。所定の時間（例えば０．５〜５時間）の焼成終了後、焼成処理物７が得られる。   The temperature is raised while an inert gas 9 such as pure nitrogen gas is passed through the firing furnace 2 containing the firing precursor 6, and firing is performed at a predetermined temperature (for example, 400 ° C.). Reference numeral 10 denotes an inert gas (exhaust gas including a gas generated by a reaction in the firing furnace) discharged from the firing furnace 2. After the firing for a predetermined time (for example, 0.5 to 5 hours), the fired processed product 7 is obtained.

ここで、焼成（１）が終了してその焼成処理物７を焼成炉２外に取り出す場合、従来は、図７に示されるように焼成炉２内の温度を常温近傍（例えば２０℃〜５０℃）にまで放冷した後に前記焼成処理物７の回収を行い、続いて２回目の焼成［以下、焼成（２）］の焼成前駆体６を焼成炉２に投入していた。図７の符号ａの範囲が従来の１バッチの工程における炉内温度の変化である。   Here, when the firing (1) is completed and the fired processed product 7 is taken out of the firing furnace 2, conventionally, the temperature in the firing furnace 2 is set to near room temperature (for example, 20 ° C. to 50 ° C.) as shown in FIG. The fired product 7 was recovered after being allowed to cool to (° C.), and then the firing precursor 6 of the second firing [hereinafter referred to as firing (2)] was put into the firing furnace 2. The range of the symbol a in FIG. 7 is the change in the furnace temperature in the conventional one-batch process.

本実施例では、前記所定の時間の焼成終了後、前記焼成処理物７を前記焼成炉２の温度を下げる工程を経ずに前記焼成炉２の外部に配設された冷却部５に移して冷却する。すなわち、前記焼成炉２内の温度がほぼ前記焼成温度（本実施例では４００℃）のままの状態の焼成炉２の取り出し口を開けて前記焼成処理物７を回収する（図５を参照）。図５の符号ａ'の範囲が１バッチの焼成工程における炉内温度の変化である。すなわち、焼成（１）によって得られた焼成処理物７を焼成の終了後すぐに取り出す。このことによって、焼成炉２内の温度を焼成温度から常温にまで冷却するためにかかっていた時間を短縮することができる。   In this embodiment, after the firing for the predetermined time, the fired product 7 is transferred to the cooling unit 5 disposed outside the firing furnace 2 without going through the step of lowering the temperature of the firing furnace 2. Cooling. That is, the discharge port of the baking furnace 2 in a state where the temperature in the baking furnace 2 is substantially the same as the baking temperature (400 ° C. in the present embodiment) is opened to collect the baking processed product 7 (see FIG. 5). . The range of the sign a ′ in FIG. 5 is the change in the furnace temperature in one batch of the firing process. That is, the fired product 7 obtained by firing (1) is taken out immediately after the completion of firing. As a result, the time taken to cool the temperature in the firing furnace 2 from the firing temperature to room temperature can be shortened.

尚、焼成処理物７の取り出しは、焼成炉２の加熱を止めて行うことが望ましい。焼成炉２から焼成処理物７の取り出しを行うと、図５に示されるように焼成炉２内の温度は若干低下する。焼成処理物７の取り出し操作中に焼成炉２内の温度が下がりすぎる場合（例えば焼成温度より２０℃程度以上低い温度に下がってしまう場合）には、前記焼成工程における焼成温度を維持できるように焼成炉２の加熱を続けることもできる。   In addition, it is desirable to take out the fired product 7 while stopping the heating of the firing furnace 2. When the fired product 7 is taken out from the firing furnace 2, the temperature in the firing furnace 2 slightly decreases as shown in FIG. When the temperature in the firing furnace 2 is too low during the operation of taking out the fired product 7 (for example, when the temperature is lowered by about 20 ° C. or more from the firing temperature), the firing temperature in the firing step can be maintained. The heating of the firing furnace 2 can be continued.

また、焼成炉２の温度を下げる工程を行わないため、焼成（１）の焼成処理物７を取り出した後、ほぼ前記焼成温度に維持された状態の焼成炉２内に、次の焼成［焼成（２）］に用いる新たな焼成前駆体６を入れることができるので、焼成炉２内を速やかに焼成温度にすることができ、焼成（２）の工程をすぐに開始することができる。図５の符号ｂ'の範囲は、焼成炉２からの焼成処理物７の取り出しと、次の焼成のための焼成前駆体６の投入を行うために要する時間である。   Further, since the step of lowering the temperature of the firing furnace 2 is not performed, after the fired processed product 7 of the firing (1) is taken out, the next firing [firing] is performed in the firing furnace 2 in a state of being substantially maintained at the firing temperature. Since the new baking precursor 6 used for (2)] can be put in, the inside of the baking furnace 2 can be rapidly made into baking temperature, and the process of baking (2) can be started immediately. The range of symbol b ′ in FIG. 5 is the time required for taking out the fired product 7 from the firing furnace 2 and charging the firing precursor 6 for the next firing.

すなわち、焼成（１）の焼成終了後、すぐに焼成（２）が開始され、焼成（１）の焼成処理物の冷却は、前記焼成（２）と並行して冷却部５において行われる。このことによって、従来、焼成前駆体６の投入後の炉内温度を常温から焼成温度にまで昇温するためにかかっていた時間を短縮し、昇温にかかるエネルギーコストを抑えるとともに、バッチ処理のサイクルを短くすることができる。以って、二次電池用電極材料の原料焼成を高効率且つ低コストで行うことができる。また、燃焼炉２内の温度変化が少ないため、急激な温度変化が繰り返されることによって燃焼炉２にかかる負荷が減少することが期待できる。   That is, immediately after the firing of the firing (1), the firing (2) is started, and the fired product of the firing (1) is cooled in the cooling unit 5 in parallel with the firing (2). This shortens the time conventionally required to raise the temperature in the furnace after the firing precursor 6 is charged from room temperature to the firing temperature, suppresses the energy cost for the temperature rise, The cycle can be shortened. Accordingly, the raw material firing of the secondary battery electrode material can be performed with high efficiency and low cost. Moreover, since the temperature change in the combustion furnace 2 is small, it can be expected that the load applied to the combustion furnace 2 is reduced by repeating the rapid temperature change.

［実施例２］
次に、本発明に係る原料焼成方法の他の実施例について説明する。本実施例に用いる焼成装置としては、実施例１と同様、図１に示す焼成装置１を用いることができる。図６は、実施例２の原料焼成方法により焼成前駆体の焼成を行った場合の焼成炉内の経時的な温度変化を示す図である。 [Example 2]
Next, another embodiment of the raw material firing method according to the present invention will be described. As the baking apparatus used in this embodiment, the baking apparatus 1 shown in FIG. FIG. 6 is a diagram showing a change in temperature over time in the firing furnace when the firing precursor is fired by the raw material firing method of Example 2. FIG.

前記焼成装置１が停止している状態（焼成炉２内が常温の状態）から１回目の焼成［以下、焼成（１）］を始める場合の操作は実施例１と同じであるためその説明は省略する。図６の符号ａ''の範囲が１バッチの焼成工程における炉内温度の変化である。次に、本実施例における焼成（１）が終了した後の焼成処理物７の取り出し、および新たな焼成前駆体６の投入について説明する。   Since the operation when starting the first baking [hereinafter referred to as baking (1)] from the state where the baking apparatus 1 is stopped (the temperature in the baking furnace 2 is normal temperature) is the same as that of the first embodiment, the explanation thereof is as follows. Omitted. The range of the symbol a ″ in FIG. 6 is the change in the furnace temperature in one batch of the firing process. Next, taking out of the fired processed product 7 after the firing (1) in the present embodiment is completed and introducing a new firing precursor 6 will be described.

本実施例では、焼成（１）の所定の時間の焼成終了後、焼成炉２内の温度を焼成工程における焼成温度以下であって２００℃以上に下げる工程を行い、該焼成炉２の温度が焼成温度以下、２００℃以上の状態で前記焼成処理物７の取り出しを行う。取り出した焼成処理物７は、冷却部５に入れて常温まで冷却する。焼成炉２内の温度は、例えば焼成炉２内に低温の不活性ガスを吹き込んだり、焼却炉２の外部に冷却材を接触させたりすることによって下げることができる。   In the present embodiment, after the firing for a predetermined time of firing (1), a step of lowering the temperature in the firing furnace 2 below the firing temperature in the firing step to 200 ° C. or higher is performed. The fired product 7 is taken out at a temperature not higher than the baking temperature and not lower than 200 ° C. The fired product 7 taken out is put in the cooling unit 5 and cooled to room temperature. The temperature in the firing furnace 2 can be lowered, for example, by blowing a low-temperature inert gas into the firing furnace 2 or bringing a coolant into contact with the outside of the incinerator 2.

本実施例によれば、前記焼成処理物７の取り出しが前記焼成炉２内の温度が常温に下がる前に行われるので、焼成炉２内の温度を焼成温度から常温にまで冷却するためにかかっていた時間が短縮できる。   According to the present embodiment, since the removal of the fired product 7 is performed before the temperature in the firing furnace 2 falls to room temperature, it takes time to cool the temperature in the firing furnace 2 from the firing temperature to room temperature. The time spent can be shortened.

続いて、次の焼成［焼成（２）］に用いる新たな焼成前駆体を前記焼成温度以下、２００℃以上の状態の焼成炉２内に入れ、次の焼成工程を行うために焼成炉２を加熱し、該焼成炉２内の温度を焼成温度まで昇温し、焼成（２）を開始する。
図６の符号ｂ''の範囲は、焼成炉２からの焼成処理物７の取り出しと、次の焼成のための焼成前駆体６の投入を行うために要する時間である。 Subsequently, a new firing precursor used for the next firing [firing (2)] is placed in the firing furnace 2 having a temperature equal to or lower than the firing temperature and equal to or higher than 200 ° C., and the firing furnace 2 is used to perform the next firing step. It heats, the temperature in this baking furnace 2 is heated up to baking temperature, and baking (2) is started.
The range of b ″ in FIG. 6 is the time required for taking out the fired product 7 from the firing furnace 2 and charging the firing precursor 6 for the next firing.

すなわち、焼成（１）の焼成終了後、焼成炉２内を常温にまで下げる前に焼成（２）が開始され、焼成（１）の焼成処理物７の冷却は、前記焼成（２）と並行して冷却部５において行われる。このことによって、従来、炉内温度を焼成温度から常温まで冷却、または常温から焼成温度まで昇温するためにかかっていた時間を短縮することができるとともに、昇温にかかるエネルギーコストを抑え、バッチ処理のサイクルを短くすることができる。以って、二次電池用電極材料の原料焼成を高効率且つ低コストで行うことができる。   That is, after the firing of firing (1) is finished, firing (2) is started before the inside of firing furnace 2 is lowered to room temperature, and cooling of the fired product 7 of firing (1) is parallel to firing (2). Then, it is performed in the cooling unit 5. This makes it possible to shorten the time conventionally required to cool the furnace temperature from the firing temperature to room temperature or to raise the temperature from room temperature to the firing temperature, while reducing the energy cost for the temperature rise, and batching The processing cycle can be shortened. Accordingly, the raw material firing of the secondary battery electrode material can be performed with high efficiency and low cost.

また、焼成温度よりも低い温度の焼成炉２内に焼成前駆体６を入れるので、焼成温度の炉内に焼成前駆体６を入れる場合よりも反応を穏やかに開始することができる。また、従来よりも燃焼炉２内の温度変化が少ないため、燃焼炉２にかかる負荷が減少することが期待できる。   Moreover, since the firing precursor 6 is put in the firing furnace 2 having a temperature lower than the firing temperature, the reaction can be started more gently than in the case where the firing precursor 6 is placed in the furnace having the firing temperature. Moreover, since the temperature change in the combustion furnace 2 is less than that in the prior art, it can be expected that the load applied to the combustion furnace 2 is reduced.

［実施例３］
本発明に係る原料焼成方法の更に他の実施例について説明する。本実施例は、実施例２のように、先の焼成処理を行った後、焼成炉２の温度を下げる工程を行う際に該焼成炉２から放出される熱エネルギーを、次工程以降の焼成前駆体の予熱に利用するものである。 [Example 3]
Still another embodiment of the raw material firing method according to the present invention will be described. In the present embodiment, the thermal energy released from the firing furnace 2 when performing the step of lowering the temperature of the firing furnace 2 after performing the previous firing treatment as in Embodiment 2 is fired in the subsequent steps. It is used for preheating the precursor.

本実施例に用いる焼成装置としては、図２に示す焼成装置２１が用いられる。本実施例において、前記焼成装置が停止している状態（焼成炉内が常温の状態）から1回目の焼成［焼成（１）］を開始し、焼成（１）の終了後、焼成処理物を取り出し、次の焼成［焼成（２）］に用いる焼成前駆体を投入して焼成（２）を開始する一連の工程は、実施例２と同様に行われる。焼成装置２１において、図１の焼成装置１と同様の部材には同じ符号を付し、その説明は省略する。   As a baking apparatus used in this embodiment, a baking apparatus 21 shown in FIG. 2 is used. In this example, the first firing [firing (1)] is started from the state where the calcining apparatus is stopped (the temperature in the calcining furnace is normal temperature). A series of steps of taking out and introducing the firing precursor used for the next firing [firing (2)] and starting the firing (2) are performed in the same manner as in Example 2. In the baking apparatus 21, the same code | symbol is attached | subjected to the member similar to the baking apparatus 1 of FIG. 1, and the description is abbreviate | omitted.

前記焼成装置２１において、パージ部４に不活性ガスを送り込むための焼成前駆体パージ用ライン２２は焼成炉２の放熱を吸収できるように構成され、該焼成前駆体パージ用ライン２２内を流通する不活性ガス８が加熱されるように構成されている。この加熱された不活性ガス８がパージ部４に導入され、該パージ部４内の焼成前駆体６を予熱する。焼成を行っている間は、バルブ２３を閉めて不活性ガス８の流通を停止する。   In the firing apparatus 21, a firing precursor purge line 22 for sending an inert gas into the purge unit 4 is configured to absorb heat radiation from the firing furnace 2, and flows through the firing precursor purge line 22. The inert gas 8 is configured to be heated. The heated inert gas 8 is introduced into the purge unit 4 to preheat the firing precursor 6 in the purge unit 4. During firing, the valve 23 is closed and the flow of the inert gas 8 is stopped.

本実施例によれば、先の焼成工程終了後に焼成炉２内の温度を下げる工程で放出される熱エネルギーを、次の焼成工程以降に用いる新たな焼成前駆体６の予熱に利用し、予熱された焼成前駆体６を焼成炉２内に入れることができる。このことによって、新たな焼成前駆体６を焼成炉２内に入れたときの炉内温度の低下を小さくすることができる。   According to the present embodiment, the thermal energy released in the step of lowering the temperature in the firing furnace 2 after the end of the previous firing step is used for preheating the new firing precursor 6 used after the next firing step. The fired precursor 6 thus prepared can be placed in the firing furnace 2. By this, the fall of the furnace temperature when a new baking precursor 6 is put in the baking furnace 2 can be made small.

尚、本実施例に用いる焼成装置２１は、パージ部４に導入する不活性ガス８を温めて焼成前駆体６を予熱する構成の他、パージ部４を加熱するように熱交換器を配設して焼成前駆体を予熱する構成とすることも可能である。   The calcining apparatus 21 used in the present embodiment has a configuration in which the inert gas 8 introduced into the purge unit 4 is warmed to preheat the calcining precursor 6 and a heat exchanger is provided so as to heat the purge unit 4. Thus, the firing precursor can be preheated.

［実施例４］
実施例４の原料焼成方法は、焼成炉２の温度を下げる工程で該燃焼炉２から放出される熱エネルギーを新たな焼成前駆体の予熱に用いるにあたり、より効率的に焼成炉２の廃熱を利用することができる原料焼成方法である。「焼成（１）の開始」、「焼成（１）を行った後の焼成処理物の取り出し」、「焼成（２）に用いる焼成前駆体の投入」、および「焼成（２）の開始」の一連の工程は実施例２と同様に行われる。図３は、本実施例の原料焼成方法によって焼成前駆体の予熱を行っている焼成装置３１の概略図である。 [Example 4]
In the raw material firing method of Example 4, when the thermal energy released from the combustion furnace 2 in the step of lowering the temperature of the firing furnace 2 is used for preheating a new firing precursor, the waste heat of the firing furnace 2 is more efficiently used. This is a raw material firing method that can utilize this. "Start of firing (1)", "Removal of fired product after firing (1)", "Input of firing precursor used for firing (2)", and "Start of firing (2)" A series of steps is performed in the same manner as in Example 2. FIG. 3 is a schematic view of a firing apparatus 31 that preheats the firing precursor by the raw material firing method of the present embodiment.

本実施例では、焼成（１）で得られた焼成処理物７を取り出し、焼成（２）に用いる焼成前駆体６を入れる際に、前記新たな焼成前駆体６を入れたパージ部４を、図３に示されるように、前記焼成炉２に接触させることによって当該焼成炉２の温度を下げる。前記パージ部４は、原料焼成を行っている間は焼成炉に接触しないように構成されている。   In this example, when the fired product 7 obtained in the firing (1) is taken out and the firing precursor 6 used for the firing (2) is put, the purge section 4 containing the new firing precursor 6 is As shown in FIG. 3, the temperature of the firing furnace 2 is lowered by contacting the firing furnace 2. The purge unit 4 is configured not to contact the firing furnace while the raw material is fired.

本実施例によれば、焼成前駆体６を焼成炉３に接触させることによって効率よく焼成炉２の温度を下げることができるとともに、熱交換器等の装置を必要とせず、新たな焼成前駆体６を予熱するために前記焼成炉２の廃熱を簡単に利用することができる。尚、実施例４では焼成前駆体６をパージ部４に入れ、該パージ部４を介して焼成前駆体６と焼成炉２を間接接触させて予熱しているが、焼成炉２に焼成前駆体６を直接接触させて予熱する構成としてもよい。   According to the present embodiment, the temperature of the firing furnace 2 can be efficiently lowered by bringing the firing precursor 6 into contact with the firing furnace 3, and a new firing precursor is not required without requiring a device such as a heat exchanger. In order to preheat 6, the waste heat of the firing furnace 2 can be easily used. In Example 4, the firing precursor 6 is put into the purge section 4 and the firing precursor 6 and the firing furnace 2 are indirectly contacted via the purge section 4 and preheated. It is good also as a structure which makes 6 contact directly and preheats.

［実施例５］
実施例５の原料焼成方法は、焼成炉において焼成を行っているときの廃熱を新たな焼成前駆体の予熱に利用することができるものである。「焼成（１）の開始」、「焼成（１）を行った後の焼成処理物の取り出し」、「焼成（２）に用いる焼成前駆体の投入」、および「焼成（２）の開始」の一連の工程は、実施例１または実施例２と同様に行われる。 [Example 5]
In the raw material firing method of Example 5, waste heat generated during firing in a firing furnace can be used for preheating a new firing precursor. "Start of firing (1)", "Removal of fired product after firing (1)", "Input of firing precursor used for firing (2)", and "Start of firing (2)" A series of steps is performed in the same manner as in Example 1 or Example 2.

図４は、本実施例に用いる焼成装置４１の概略図である。本実施例では、焼成炉２内に純窒素等の不活性ガス９を流しつつ焼成を行い、高温の焼成炉２内を通過して加熱された不活性ガス（排気１０）の熱エネルギーを、新たな焼成前駆体の予熱に利用する。焼成装置４１には、焼成炉２内を通過した不活性ガス（排気１０）の熱によって、パージ部４に送り込む不活性ガス８が温められるように熱交換器４２が配設されている。   FIG. 4 is a schematic view of a baking apparatus 41 used in this embodiment. In the present embodiment, firing is performed while flowing an inert gas 9 such as pure nitrogen in the firing furnace 2, and the thermal energy of the inert gas (exhaust gas 10) heated through the high-temperature firing furnace 2 is It is used for preheating new firing precursors. In the baking apparatus 41, a heat exchanger 42 is arranged so that the inert gas 8 sent to the purge unit 4 is warmed by the heat of the inert gas (exhaust gas 10) that has passed through the baking furnace 2.

本実施例によれば、焼成炉２内のパージに用いた不活性ガス（排気１０）の熱エネルギーを前記新たな焼成前駆体６の予熱に利用し、予熱された焼成前駆体６を焼成炉２内に入れることができる。このことによって、新たな焼成前駆体６を焼成炉２内に入れたときの炉内温度の低下を小さくすることができる。また、前記焼成前駆体６の予熱のためにかかるエネルギーコストを抑えることができる。   According to this embodiment, the thermal energy of the inert gas (exhaust gas 10) used for purging in the firing furnace 2 is used for preheating the new firing precursor 6, and the preheated firing precursor 6 is used in the firing furnace. 2 can be included. By this, the fall of the furnace temperature when a new baking precursor 6 is put in the baking furnace 2 can be made small. Moreover, the energy cost required for preheating the firing precursor 6 can be suppressed.

次に、本発明の原料焼成方法によって合成することができるリン酸鉄リチウム系正極材について詳細に説明する。   Next, the lithium iron phosphate positive electrode material that can be synthesized by the raw material firing method of the present invention will be described in detail.

＜リン酸鉄リチウム系正極材料＞
本実施例において、リン酸鉄リチウム系正極材料とは、例えば、一般式Ｌｉ１−ｎｙ（ＭａｘＭｂｙＦｅ１−ｘ−ｙ）ＰＯ４で表され、オリビン型結晶構造を有し、前記式中のＭａ、ＭｂはＦｅを置換しうる金属元素であり、前記Ｍａは価数が２の元素であり、且つ元素周期表において２族、１１族、１２族に属する金属元素の群から選ばれる１種以上の金属元素であり、前記Ｍｂは価数が３以上の元素であり、且つ元素周期表において３族、４族、５族、６族、１３族、１４族に属する金属元素の群から選ばれる１種以上の金属元素であり、各置換量である前記ｘとｙは、０≦ｘ、ｙ≦０．０５の数であり、前記ｎは前記Ｍｂの平均価数をｆとして、ｎ＝ｆ−２である。特に、前記Ｍａは、カドミウム（Ｃｄ）、マグネシウム（Ｍｇ）、コバルト（Ｃｏ）、ニッケル（Ｎｉ）、ストロンチウム（Ｓｒ）、カルシウム（Ｃａ）、銅（Ｃｕ）、亜鉛（Ｚｎ）の群から選ばれる１種以上の金属元素であり、前記Ｍｂは、ニオブ（Ｎｂ）、タングステン（Ｗ）、マンガン（Ｍｎ）、スカンジウム（Ｓｃ）、イットリウム（Ｙ）、チタン（Ｔｉ）、バナジウム（Ｖ）、クロム（Ｃｒ）、モリブデン（Ｍｏ）、アルミニウム（Ａｌ）、インジウム（Ｉｎ）、スズ（Ｓｎ）よりなる群から選ばれる１種以上の金属元素である。 <Lithium iron phosphate positive electrode material>
In the present embodiment, the lithium iron phosphate-based cathode material, for example, is represented by the general formula Li 1-ny (Ma x Mb y Fe 1-x-y) PO 4, has an olivine-type crystal structure, wherein Ma and Mb in the formula are metal elements capable of substituting Fe, and Ma is an element having a valence of 2 and is selected from the group of metal elements belonging to Groups 2, 11, and 12 in the periodic table One or more metal elements, and Mb is an element having a valence of 3 or more, and a metal element belonging to Group 3, Group 4, Group 6, Group 13, Group 14 in the Periodic Table of Elements. It is one or more metal elements selected from the group, and each of the substitution amounts x and y is a number of 0 ≦ x and y ≦ 0.05, and n is the average valence of Mb as f , N = f−2. In particular, the Ma is selected from the group consisting of cadmium (Cd), magnesium (Mg), cobalt (Co), nickel (Ni), strontium (Sr), calcium (Ca), copper (Cu), and zinc (Zn). One or more metal elements, and the Mb is niobium (Nb), tungsten (W), manganese (Mn), scandium (Sc), yttrium (Y), titanium (Ti), vanadium (V), chromium ( One or more metal elements selected from the group consisting of Cr), molybdenum (Mo), aluminum (Al), indium (In), and tin (Sn).

ｘ、ｙが０でない時、この正極材料中において、異種金属元素Ｍａ、ＭｂはＦｅの一部を置換した形で入っている。Ｍａは価数が２であり、このＭａのＦｅに対する置換量ｘの置換導入によって、充電（酸化）状態においてＬｉがｘだけ残存するオリビン型結晶構造を実現する。Ｍａは２＋の酸化状態だけを安定してとるものがよい。また、Ｍｂは価数が３以上であり、このＭｂのＦｅに対する置換量ｙの置換導入によって、Ｍｂの価数をｆとして、放電（還元）状態においてＬｉがＦｅに対してｎｙ（ただし、ｎ＝ｆ−２）だけ欠損になるオリビン型結晶構造を実現する。   When x and y are not 0, different metal elements Ma and Mb are contained in the positive electrode material in a form in which a part of Fe is substituted. Ma has a valence of 2, and by introducing substitution of this substitution amount x of Ma with Fe, an olivine-type crystal structure in which only Li remains in the charged (oxidized) state is realized. It is preferable that Ma takes only the 2+ oxidation state stably. In addition, Mb has a valence of 3 or more. By introducing substitution of the substitution amount y of Mb to Fe, the valence of Mb is set to f, and Li is ny (but n = F-2) to realize an olivine type crystal structure that is deficient.

＜リン酸鉄リチウム系正極材料の製造方法の概要＞
リン酸鉄リチウム系正極材料は、当該正極材料の原型となる正極活物質ＬｉＦｅＰＯ４の原料となる物質のみ、または正極活物質の原料となる物質と、前記式中のＦｅを置換しうる価数が２の元素であり且つ元素周期表において２族、１１族、１２族に属する金属元素の群から選ばれる１種以上の金属元素Ｍａを含む化合物と、前記式中のＦｅを置換しうる価数が３以上の元素であり且つ元素周期表において３族、４族、５族、６族、１３族、１４族に属する金属元素の群から選ばれる１種以上の金属元素Ｍｂを含む化合物と、を混合して得られる焼成前駆体を、所定温度、所定時間、所定雰囲気で焼成することにより、一般式Ｌｉ１−ｎｙ（ＭａｘＭｂｙＦｅ１−ｘ−ｙ）ＰＯ４で表され、オリビン型結晶構造を有し、各置換量である前記ｘとｙは、０≦ｘ、ｙ≦０．０５の数であり、前記ｎは前記Ｍｂの平均価数をｆとして、ｎ＝ｆ−２である結晶１次粒子として得ることができる。 <Outline of manufacturing method of lithium iron phosphate positive electrode material>
The lithium iron phosphate-based positive electrode material is a valence that can replace only the substance that is a raw material of the positive electrode active material LiFePO 4 that is the prototype of the positive electrode material, or the substance that is the raw material of the positive electrode active material, and Fe in the above formula And a compound containing one or more metal elements Ma selected from the group of metal elements belonging to Groups 2, 11, and 12 in the Periodic Table of Elements and a value capable of substituting Fe in the above formula A compound containing at least one metal element Mb selected from the group of metal elements which are elements having a number of 3 or more and belonging to Group 3, 4, 5, 6, 13, 13 in the periodic table , By firing in a predetermined atmosphere at a predetermined temperature for a predetermined time, and expressed by a general formula Li 1-ny (Max x M y Fe 1-xy ) PO 4 , It has an olivine type crystal structure and each substitution amount The x and y are numbers of 0 ≦ x and y ≦ 0.05, and the n can be obtained as crystalline primary particles where n = f−2, where f is the average valence of the Mb. .

前記焼成は一度の焼成によって行うことも可能であるが、焼成工程を２つに分けることによって、より高い２次電池性能が得られるリン酸鉄リチウム系正極材料を得ることができる。例えば、３００℃〜４００℃程度の低温の温度範囲で焼成を行う第１の焼成工程（仮焼成）と、前記第１の焼成よりも高温域（５００℃〜８００℃程度、より好ましくは６００℃〜７００℃程度）で焼成を行う第２の焼成工程（本焼成）とを行うことによって製造される。   The firing can be performed by one firing, but by dividing the firing step into two, a lithium iron phosphate-based positive electrode material capable of obtaining higher secondary battery performance can be obtained. For example, a first baking step (temporary baking) in which baking is performed in a low temperature range of about 300 ° C. to 400 ° C. and a temperature range higher than the first baking (about 500 ° C. to 800 ° C., more preferably 600 ° C. It is manufactured by performing the 2nd baking process (main baking) which bakes by about -700 degreeC.

また、リン酸鉄リチウム系正極材料の表面に、導電性炭素を析出させた炭素析出正極材料は、炭素析出のない場合よりもさらに高い充放電特性を示すことが可能となる。該炭素析出正極材料は、例えば、前記と同様に正極活物質の原料となる物質のみ、または正極活物質の原料となる物質に前記Ｍａおよび／またはＭｂの有機酸塩、ハロゲン化物、硝酸塩、アルコキシド等の化合物を添加し、例えば擂潰混合等して焼成前駆体を得た後、一旦３００〜４５０℃にて数時間（例えば５時間程度）かけて第１の焼成工程（仮焼成）を行った後、炉より取り出し、その焼成処理物に対して、炭素被覆原料、例えば、石炭ピッチなどのビチューメン類、またはデキストリンなどの糖類を所定量添加、擂潰・混合し、さらに数時間乃至１日程度、所定雰囲気で第２の焼成工程（本焼成）を行うことにより製造することができる。   Moreover, the carbon deposition positive electrode material in which conductive carbon is deposited on the surface of the lithium iron phosphate-based positive electrode material can exhibit higher charge / discharge characteristics than the case without carbon deposition. The carbon-deposited positive electrode material may be, for example, the same material as the positive electrode active material as described above, or the organic acid salt, halide, nitrate, alkoxide of Ma and / or Mb as a raw material of the positive electrode active material. Etc., for example, crushed and mixed to obtain a calcined precursor, and then the first calcining step (temporary calcining) is performed at 300 to 450 ° C. for several hours (eg, about 5 hours). After that, it is taken out from the furnace, and a predetermined amount of a carbon coating raw material, for example, bitumens such as coal pitch, or saccharides such as dextrin is added to the fired processed product, crushed and mixed, and then for several hours to one day. It can be manufactured by performing the second baking step (main baking) in a predetermined atmosphere.

仮焼成においては、正極材料の原料が加熱により最終的な正極材料に至る中間的な状態まで反応し、その際、多くの場合は熱分解によるガス発生を伴う。仮焼成の終了温度としては、発生ガスの大部分が放出し終わり、かつ最終生成物の正極材料に至る反応が完全には進行しない温度（すなわち、より高温域での第二段階の本焼成時に正極材料中の構成元素の再拡散・均一化が起こる余地を残した温度）が選択される（ただしこの時、組成の大半は既にリン酸鉄リチウム系正極活物質となっている）。   In the pre-baking, the raw material of the positive electrode material reacts to an intermediate state that reaches the final positive electrode material by heating, and in this case, gas generation is often caused by thermal decomposition. The temperature at which the calcining is finished is a temperature at which most of the generated gas has been released and the reaction leading to the positive electrode material of the final product does not proceed completely (that is, during the second stage of the main calcination at a higher temperature range). The temperature that leaves room for re-diffusion / homogenization of the constituent elements in the positive electrode material is selected (however, most of the composition is already a lithium iron phosphate-based positive electrode active material).

第１の焼成工程（仮焼成）に続く第２の焼成工程（本焼成）では、構成元素の再拡散・均一化が起こるとともに、正極材料への反応が完了し、しかも焼結などによる結晶成長を極力防げるような温度域まで昇温および温度保持がなされる。   In the second firing step (main firing) subsequent to the first firing step (preliminary firing), the constituent elements are re-diffusioned and made uniform, the reaction to the positive electrode material is completed, and crystal growth by sintering or the like The temperature is raised and the temperature is maintained so that the temperature can be prevented as much as possible.

尚、前記した炭素析出正極材料を製造する場合は、第１の焼成を行い、該第１の焼成後の焼成処理物に、炭素被覆原料を添加した後、第２の焼成を行うことにより、得られる正極材料の性能をより向上させることができる。炭素被覆原料、特に加熱により融解する石炭ピッチや糖類を用いる場合は、第１の焼成前の原料に添加することも可能であるが（この場合でも相応の正極性能向上効果が得られる）、第１の焼成後の原料（既に原料からのガス発生の大半が終了し、中間生成物となった状態）に添加し、第２の焼成を行うことがより好ましい。つまり、焼成過程における第１の焼成と第２の焼成との間に、原料への炭素被覆原料の添加工程を設けることになる。これにより、加熱により融解・熱分解する石炭ピッチや糖類等の物質が、原料から発生するガスにより発泡することを防ぎ、より均一に正極材料の表面に溶融状態で広がり、より均一に熱分解炭素を析出させることができる。   In addition, when manufacturing the above-described carbon deposition positive electrode material, by performing the first firing, adding the carbon coating raw material to the fired processed material after the first firing, then performing the second firing, The performance of the positive electrode material obtained can be further improved. When using a carbon-coated raw material, particularly coal pitch or saccharide that melts by heating, it can be added to the raw material before the first firing (even in this case, a corresponding positive electrode performance improvement effect can be obtained). More preferably, it is added to the raw material 1 after firing (the state where most of the gas generation from the raw material has already been completed and becomes an intermediate product) and the second firing is performed. That is, a step of adding the carbon-coated raw material to the raw material is provided between the first baking and the second baking in the baking process. This prevents substances such as coal pitch and saccharides that are melted and pyrolyzed by heating from being foamed by the gas generated from the raw material, spread more uniformly in the molten state on the surface of the positive electrode material, and more uniformly pyrolytic carbon. Can be deposited.

また、導電性炭素の析出を行わない場合も、正極材料のより良好な均一性を得るために、第１の焼成と第２の焼成との間に、第１の焼成において得た焼成処理物を十分に粉砕混合した後、所定温度における第２の焼成を行うことが好ましい。   In addition, even when conductive carbon is not deposited, a fired product obtained in the first firing between the first firing and the second firing in order to obtain better uniformity of the positive electrode material. After sufficiently pulverizing and mixing, it is preferable to perform the second baking at a predetermined temperature.

＜正極活物質ＬｉｎＦｅＰＯ４の原料＞
以下では、正極活物質ＬｉＦｅＰＯ４として一般的なオリビン型構造を有するものについて説明する。このオリビン型ＬｉＦｅＰＯ４の原料の中で、リチウム導入用の原料としては、例えばＬｉＯＨ等の水酸化物、Ｌｉ２ＣＯ３等の炭酸塩や炭酸水素塩、ＬｉＣｌ等の塩化物を含むハロゲン化物、ＬｉＮＯ３等の硝酸塩、その他有機酸塩等のＬｉのみ目的の正極材料中に残留するようなＬｉ含有分解揮発性化合物が用いられる。また、Ｌｉ３ＰＯ４、Ｌｉ２ＨＰＯ４、ＬｉＨ２ＰＯ４等のリン酸塩やリン酸水素塩を用いることもできる。 <Raw material of the positive electrode active material Li n FePO 4>
The following describes those having the general olivine structure as a positive electrode active material LiFePO 4. Among the raw materials of this olivine type LiFePO 4, as a raw material for introducing lithium, for example, a hydroxide containing a hydroxide such as LiOH, a carbonate such as Li 2 CO 3, a bicarbonate, a chloride such as LiCl, A Li-containing decomposition volatile compound is used in which only Li such as nitrate such as LiNO 3 or other organic acid salt remains in the target positive electrode material. Moreover, phosphates and hydrogen phosphates such as Li 3 PO 4 , Li 2 HPO 4 , and LiH 2 PO 4 can also be used.

また、鉄導入用の原料としては、例えば水酸化物、炭酸塩や炭酸水素塩、塩化物等のハロゲン化物、硝酸塩、その他、Ｆｅのみが目的の正極材料中に残留するような分解揮発性化合物（例えば、シュウ酸塩や酢酸塩等の有機酸塩、アセチルアセトン錯体類や、メタロセン錯体等の有機錯体など）のほか、リン酸塩やリン酸水素塩を用いることもできる。また、安価で入手が容易な１次原料である金属鉄、及び酸化鉄（Ｆｅ２Ｏ３、Ｆｅ３Ｏ４等）を用いることもできる。 Examples of the raw material for introducing iron include hydroxides, carbonates, hydrogen carbonates, halides such as chlorides, nitrates, and other decomposition volatile compounds in which only Fe remains in the target positive electrode material. In addition to organic acid salts such as oxalates and acetates, acetylacetone complexes, and organic complexes such as metallocene complexes, phosphates and hydrogen phosphates can also be used. Further, it is also possible to use metallic iron and iron oxide (Fe 2 O 3 , Fe 3 O 4, etc.) that are inexpensive and easily available primary raw materials.

また、リン酸導入用の原料としては、例えば、無水リン酸Ｐ２Ｏ５、リン酸Ｈ３ＰＯ４、およびリン酸イオンのみ正極材料中に残留するような分解揮発性リン酸塩やリン酸水素塩［例えば、（ＮＨ４）２ＨＰＯ４、ＮＨ４Ｈ２ＰＯ４、（ＮＨ４）３ＰＯ４等のアンモニウム塩］を用いることができる。 Moreover, as raw materials for introducing phosphoric acid, for example, anhydrous phosphoric acid P 2 O 5 , phosphoric acid H 3 PO 4 , and decomposed volatile phosphates and phosphoric acid in which only phosphate ions remain in the positive electrode material Hydrogen salts [for example, ammonium salts such as (NH 4 ) 2 HPO 4 , NH 4 H 2 PO 4 , (NH 4 ) 3 PO 4 ] can be used.

これらの原料において、目的の正極材料中に残存した場合に好ましくない元素や物質を含む場合には、これらが焼成中に分解・揮発することが必要である。また、原料にはリン酸イオン以外の不揮発性オキソ酸塩等を用いるべきでないことは言うまでもない。なお、これらにおいては、その水和物を用いる場合もあるが［例えば、ＬｉＯＨ・Ｈ２Ｏ、Ｆｅ３（ＰＯ４）２・８Ｈ２Ｏ等］、上記においては水和物としての表記は全て省略している。 When these raw materials contain elements or substances that are not desirable when remaining in the target positive electrode material, it is necessary that these materials decompose and volatilize during firing. Needless to say, non-volatile oxoacid salts other than phosphate ions should not be used as raw materials. In these cases, hydrates may be used [for example, LiOH.H 2 O, Fe 3 (PO 4 ) 2 · 8H 2 O, etc.]. Omitted.

＜金属ハロゲン化物＞
Ｆｅを置換しうる２価の金属元素の原料として、元素周期表において２族、７族、９族、１０族、１１族、１２族に属する金属元素の群から選ばれる１種以上の金属元素のハロゲン化物（金属ハロゲン化物）を用いることが好ましい。金属ハロゲン化物としては、例えば、塩化物、臭化物、ヨウ化物等が挙げられる（これらの水和物の形態のものも含む）。なお、他の化合物であってもよいことは勿論である。 <Metal halide>
As a raw material of a divalent metal element capable of substituting Fe, one or more metal elements selected from the group of metal elements belonging to Group 2, Group 7, Group 9, Group 10, Group 11 and Group 12 in the periodic table It is preferable to use a halide (metal halide). Examples of the metal halide include chloride, bromide, iodide and the like (including those in the form of these hydrates). Of course, other compounds may be used.

Ｆｅを置換しうる３価以上の金属元素の原料としても、且つ元素周期表において３族、４族、５族、６族、７族、１３族、１４族に属する金属元素の群から選ばれる１種以上の金属元素のハロゲン化物（金属ハロゲン化物）を用いることが好ましい。   It is selected from the group of metal elements belonging to Group 3, Group 4, Group 5, Group 6, Group 7, Group 13 and Group 14 as a raw material of a trivalent or higher valent metal element capable of substituting Fe. It is preferable to use a halide of one or more metal elements (metal halide).

正極材料の原料に添加される金属ハロゲン化物の例を以下に示す（これらの中には水和物もあるが、水和物としての標記は省略する）。ここで、金属ハロゲン化物の中では塩化物が比較的安価で入手しやすく有利である。   Examples of metal halides added to the raw material of the positive electrode material are shown below (some of these also include hydrates, but the titles as hydrates are omitted). Here, among metal halides, chloride is relatively inexpensive and easily available, which is advantageous.

これらの金属ハロゲン化物の添加量は、前記各置換量である前記ｘとｙが、０≦ｘ、ｙ≦０．０５の数となり、且つ後述の組成条件を満たすように調整する。また、金属ハロゲン化物を添加した正極材料の焼成前駆体を焼成する際に、該金属ハロゲン化物の種類に応じて、例えば炭素、水素等の還元剤、酸素等の酸化剤、および／または塩素、ホスゲン等の第３成分を共存させることによって、より好適な条件で異種金属元素複合化正極材料を形成できる場合がある。また、焼成前駆体製造または仮焼成の際に、例えば他の物質（炭素被覆原料となるもの）と混合することにより、金属ハロゲン化物を生成するような条件の下では、これらの金属やその酸化物等を複合化の原料として使用することも可能である。
以上のハロゲン化物の他に、上述の金属元素の有機酸塩、硝酸塩、アセチルアセトナト錯体、金属アルコキシド、金属フェノキシド等も用いることが可能である。 The addition amount of these metal halides is adjusted so that the substitution amounts x and y are 0 ≦ x and y ≦ 0.05, and the compositional condition described later is satisfied. Further, when firing the firing precursor of the positive electrode material to which the metal halide is added, depending on the type of the metal halide, for example, a reducing agent such as carbon and hydrogen, an oxidizing agent such as oxygen, and / or chlorine, By allowing the third component such as phosgene to coexist, it may be possible to form the dissimilar metal element composite cathode material under more suitable conditions. Also, during the production of the calcining precursor or pre-firing, for example, these metals and their oxidations may be used under conditions that produce metal halides by mixing with other materials (materials for carbon coating). It is also possible to use a material or the like as a raw material for compounding.
In addition to the above halides, organic acid salts, nitrates, acetylacetonato complexes, metal alkoxides, metal phenoxides, and the like of the above metal elements can be used.

＜焼成前駆体の調製＞
焼成前駆体は、前記したように、前述の正極材料の原料となる物質のみ、または２価と３価以上の異種金属元素Ｍａ、Ｍｂのハロゲン化物を、正極材料の原料となる物質に添加したものを、例えば、遊星ボールミル、揺動または回転式の粉体混合機等を用いて乾燥状態で１時間〜１日程度混合する方法（以下、「乾式混合」と記す）、または例えばアルコール類、ケトン類、テトラヒドロフランなどの有機溶媒、または水等の溶媒もしくは分散媒とともに正極材料の原料に添加され、湿式で例えば１時間〜１日程度、混合・擂潰後、乾燥する方法(以下、「湿式混合」と記す）によって焼成前駆体となる。尚、混合する原料の種類によっては、乾式混合した場合の焼成前駆体を焼成して得られた正極材と、湿式混合した場合の焼成前駆体を焼成して得られた正極材との性能が異なる場合がある。したがって、混合する原料の組み合わせに応じた焼成前駆体調製方法（乾式混合または湿式混合）を選択することが望ましい。 <Preparation of firing precursor>
As described above, the firing precursor is obtained by adding only the above-described material for the positive electrode material, or the divalent and trivalent or higher dissimilar metal elements Ma and Mb to the material for the positive electrode material. For example, using a planetary ball mill, a rocking or rotating powder mixer, etc., for 1 hour to 1 day in a dry state (hereinafter referred to as “dry mixing”), or for example alcohols, A method of adding to a raw material of the positive electrode material together with an organic solvent such as ketones, tetrahydrofuran, or a solvent or dispersion medium such as water, and mixing, crushing, and drying in a wet process, for example, about 1 hour to 1 day (hereinafter referred to as “wet process”). It becomes a calcined precursor by “mixing”). Depending on the type of raw material to be mixed, the performance of the positive electrode material obtained by firing the firing precursor when dry-mixed and the positive electrode material obtained by firing the firing precursor when wet-mixed may be May be different. Therefore, it is desirable to select a firing precursor preparation method (dry mixing or wet mixing) according to the combination of raw materials to be mixed.

本発明は、原料を焼成して合成を行う二次電池用電極材料の原料焼成方法として利用できる。   INDUSTRIAL APPLICABILITY The present invention can be used as a raw material baking method for a secondary battery electrode material that is synthesized by baking raw materials.

１ 焼成装置、 ２ 焼成炉、 ３ 加熱装置、 ４ パージ部、
５ 冷却部、 ６ 焼成前駆体、 ７ 焼成処理物、
８ 不活性ガス（Ｎ２）、 ９ 不活性ガス（Ｎ２）、 １０ 排気、
２１ 焼成装置、 ２２ 焼成前駆体パージ用ライン、 ２３ バルブ、
３１ 焼成装置、 ４１ 焼成装置、 ４２ 熱交換器 1 firing device, 2 firing furnace, 3 heating device, 4 purge section,
5 Cooling part, 6 Firing precursor, 7 Firing treatment product,
8 inert gas (N 2 ), 9 inert gas (N 2 ), 10 exhaust,
21 firing device, 22 firing precursor purge line, 23 valve,
31 baking apparatus, 41 baking apparatus, 42 heat exchanger

Claims (8)

一つの焼成炉において、二次電池用電極材料の原料である焼成前駆体を焼成する工程をバッチ処理によって繰り返し行う原料焼成方法であって、
先の焼成工程によって得られる焼成処理物を前記焼成炉の温度を下げる工程を経ずに該焼成炉の外部の冷却部に移して冷却を実行し、且つ前記焼成炉に次の焼成工程用の焼成前駆体を入れて前記冷却部による冷却と並行して焼成を開始することを特徴とする原料焼成方法。 In one firing furnace, a raw material firing method in which a step of firing a firing precursor that is a raw material of an electrode material for a secondary battery is repeatedly performed by batch processing,
The fired product obtained by the previous firing step is transferred to a cooling unit outside the firing furnace without passing through the step of lowering the temperature of the firing furnace, and cooled, and the firing furnace is used for the next firing step. A raw material firing method, wherein a firing precursor is placed and firing is started in parallel with cooling by the cooling section. 一つの焼成炉において、二次電池用電極材料の原料である焼成前駆体を焼成する工程をバッチ処理によって繰り返し行う原料焼成方法であって、
先の焼成工程によって得られる焼成処理物を前記焼成炉の温度を焼成温度以下であって２００℃以上に下げる工程を経て該焼成炉の外部の冷却部に移して冷却を実行し、且つ前記焼成炉に次の焼成工程用の焼成前駆体を入れて前記冷却部による冷却と並行して焼成を開始することを特徴とする原料焼成方法。 In one firing furnace, a raw material firing method in which a step of firing a firing precursor that is a raw material of an electrode material for a secondary battery is repeatedly performed by batch processing,
The fired product obtained by the previous firing step is transferred to a cooling unit outside the firing furnace through a step of lowering the temperature of the firing furnace to 200 ° C. or lower and lowering the temperature of the firing furnace, and cooling is performed. A raw material firing method, wherein a firing precursor for the next firing step is placed in a furnace and firing is started in parallel with cooling by the cooling unit. 請求項２に記載された原料焼成方法において、前記焼成炉の温度を焼成温度以下であって２００℃以上に下げる工程で該焼成炉から放出される熱エネルギーを、次工程以降の焼成前駆体の予熱に利用することを特徴とする原料焼成方法。   3. The raw material firing method according to claim 2, wherein the thermal energy released from the firing furnace in the step of lowering the temperature of the firing furnace to 200 ° C. or lower is lower than the firing temperature, A raw material firing method characterized by being used for preheating. 請求項３に記載された原料焼成方法において、次工程以降の焼成前駆体を前記焼成炉に接触させて前記熱エネルギーを吸収することを特徴とする原料焼成方法。   4. The raw material firing method according to claim 3, wherein the thermal energy is absorbed by bringing a firing precursor in a subsequent step and subsequent steps into contact with the firing furnace. 請求項１または２に記載された原料焼成方法において、前記焼成工程は、前記焼成炉内を不活性雰囲気にする不活性ガスを流しつつ行われ、前記焼成炉内を通過して加熱された前記不活性ガスの熱エネルギーを次工程以降の焼成前駆体の予熱に利用することを特徴とする原料焼成方法。   3. The raw material firing method according to claim 1, wherein the firing step is performed while flowing an inert gas that makes the inside of the firing furnace an inert atmosphere, and is heated through the inside of the firing furnace. A raw material firing method, wherein the thermal energy of an inert gas is used for preheating the firing precursor in the subsequent steps. 請求項１〜５のいずれか一項に記載された原料焼成方法において、前記焼成前駆体は不活性ガスによるパージ部において不活性ガスでパージされて前記焼成炉内に入れられることを特徴とする原料焼成方法。   The raw material firing method according to any one of claims 1 to 5, wherein the firing precursor is purged with an inert gas in a purge portion with an inert gas and placed in the firing furnace. Raw material firing method. 二次電池用電極材料の原料である焼成前駆体を焼成炉に入れてバッチ処理によって繰り返し焼成する構成の原料焼成装置であって、
前記焼成炉と別に冷却部を備え、
先の焼成処理によって得られる焼成処理物を前記焼成炉の温度を下げる工程を経ずに該焼成炉の外部の冷却部に移して冷却を実行し、且つ前記焼成炉に次の焼成工程用の焼成前駆体を入れて前記冷却部による冷却と並行して焼成を開始するように構成されていることを特徴とする原料焼成装置。 A raw material firing apparatus having a configuration in which a firing precursor which is a raw material of an electrode material for a secondary battery is placed in a firing furnace and repeatedly fired by batch processing,
A cooling unit is provided separately from the firing furnace,
The fired product obtained by the previous firing process is transferred to a cooling unit outside the firing furnace without passing through the process of lowering the temperature of the firing furnace, and cooled, and the firing furnace is used for the next firing process. A raw material baking apparatus characterized in that a baking precursor is placed and baking is started in parallel with cooling by the cooling section. 請求項7に記載された原料焼成装置において、前記焼成前駆体を不活性ガスによってパージするパージ部を備え、該パージ部において不活性ガスでパージされた焼成前駆体を前記焼成炉内に入れるように構成されていることを特徴とする原料焼成装置。   8. The raw material firing apparatus according to claim 7, further comprising a purge unit that purges the firing precursor with an inert gas, and the firing precursor purged with the inert gas in the purge unit is placed in the firing furnace. The raw material baking apparatus characterized by being comprised in this.
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