JPS60166211A - Preparation of graphite lamellar compound - Google Patents

Abstract

PURPOSE:To obtain a graphite lamellar compound capable of giving a molded article having a high strength at a low cost with good operability in the titled preparation of dipping graphite in a liquid oxidation medium, by using a mixed solution of a used and recovered oxidation medium and a new oxidation medium. CONSTITUTION:Flake graphite is dipped in a liquid oxidation medium, e.g. a mixed acid of sulfuric acid and nitric acid, and the treated graphite and the residual heating solution are separated in a suitable draining apparatus to give a recovered acid. New flake graphite is then treated with a mixed acid of the above-mentioned mixed acid and the recovered acid to separate the further treated graphite and the residual treating solution by the above-mentioned method. A mixed acid prepared by adding a new acid to the recovered acid is then repeatedly used to continue the treatment for new graphite. Thus, the viscosity of the acid on acid treatment is reduced, and the amount of a neutralizing agent required for discarding of the used acid is reduced. The interlayer residual ratio of the reactant is high, and the expanded graphite obtained by the subsequent expansion treatment has a great expansion. The resultant molded article thereof has a high mechanical strength.

Description

【発明の詳細な説明】 （発明の属する技術分野） 本発明は黒鉛層間化合物の製造方法に関する。[Detailed description of the invention] (Technical field to which the invention pertains) The present invention relates to a method for producing a graphite intercalation compound.

（従来技術とその問題点） 黒鉛は炭素六員環網状平面が積み重なった層状構造をも
ち１層平面内の結合は非常に強く、緻密な網平面を形成
しているが９層平面と直角な方向での結合は弱く１層間
に相対的に広い空間を残している。このため適当な条件
のもとて酸、アルカリ金属、ハロゲン、塩化物等の多種
類の化学種が容易に黒鉛層間内に侵入して炭素原子と結
合し黒鉛眉間化合物を形成する。この黒鉛層間化合物を
適当な温度に加熱すると化合物は瞬間的に分解し。(Prior art and its problems) Graphite has a layered structure in which six-membered carbon ring network planes are piled up, and the bonds within the plane of one layer are very strong, forming a dense network plane, but the planes at right angles to the nine-layer plane The bonding in this direction is weak, leaving a relatively wide space between each layer. Therefore, under appropriate conditions, various chemical species such as acids, alkali metals, halogens, and chlorides easily penetrate into the interlayers of graphite and combine with carbon atoms to form graphite compounds. When this graphite intercalation compound is heated to an appropriate temperature, the compound decomposes instantaneously.

侵入化学種は蒸気となって逸散し、黒鉛は結晶のＣ軸方
向に１０〜４００倍に膨張する。この膨張黒鉛を原料と
して、単独に、または適当な結合材とともに圧縮・成形
すると可撓性に富んだ黒鉛のシート、ペーパー、テープ
等の得られることが知られている。The invading species dissipate as vapor, and the graphite expands 10 to 400 times in the direction of the C-axis of the crystal. It is known that highly flexible graphite sheets, papers, tapes, etc. can be obtained by compressing and molding this expanded graphite alone or together with a suitable binder as a raw material.

黒鉛層間化合物を形成させるだめの液状の酸化媒体とし
ては濃硫酸と硝酸９発煙硝酸、塩素酸カリウム、重クロ
ム酸カリウム、過塩素酸、リン酸。Liquid oxidizing media for forming graphite intercalation compounds include concentrated sulfuric acid, nitric acid, fuming nitric acid, potassium chlorate, potassium dichromate, perchloric acid, and phosphoric acid.

沃素酸、過硫酸及びその化合物など濃硫酸を主体とした
多くの組合せが知られている。Many combinations based on concentrated sulfuric acid are known, such as iodic acid, persulfuric acid, and their compounds.

黒鉛層間化合物の一般的な製造方法としては前記組合せ
の混液中に黒鉛を浸漬して反応させるか。A general method for producing a graphite intercalation compound is to immerse graphite in a mixture of the above combinations and react.

濃硫酸と黒鉛を予めスラリー状にしてこれに硝酸などの
酸化剤を作用させるかして酸処理黒鉛を形成させ、しか
る後、これを水の中に投入して反応を停止させ、その後
脱水、水洗を繰返して所望の黒鉛層間化合物を得名のが
一般的である。Concentrated sulfuric acid and graphite are made into a slurry in advance and treated with an oxidizing agent such as nitric acid to form acid-treated graphite, which is then poured into water to stop the reaction, and then dehydrated. Generally, the desired graphite intercalation compound is obtained by repeating washing with water.

こうした従来法の場合は新規の酸及び酸化剤の混液を用
いるため、酸処理時の粘性が大きくなり作業性が悪くな
る。成形後のシートの強度が小さい、酸処理ごとに新規
な酸を用いるため生産コストがかさむ、一度使用した酸
を廃棄する際、中和のために大量の中和剤を必要とする
など多くの欠点を有していた。In the case of such conventional methods, since a mixture of a new acid and an oxidizing agent is used, the viscosity increases during acid treatment, resulting in poor workability. There are many problems such as the strength of the sheet after forming is low, the production cost increases because a new acid is used for each acid treatment, and a large amount of neutralizing agent is required to neutralize the used acid when discarding it. It had drawbacks.

（発明の目的） 本発明は、上記した欠点を解消する黒鉛層間化合物の製
造方法を提供することを目的とする。(Objective of the Invention) An object of the present invention is to provide a method for producing a graphite intercalation compound that eliminates the above-described drawbacks.

（発明の構成） 本発明は、黒鉛を液状の酸化媒体に浸漬処理して黒鉛層
間化合物を形成させたのち核酸化媒体を回収し、これに
新しい液状の酸化媒体を加えだ混液により新しい黒鉛を
浸漬処理することを特徴とする黒鉛層間化合物の製造方
法に関する。(Structure of the Invention) The present invention involves immersing graphite in a liquid oxidizing medium to form a graphite intercalation compound, recovering the nucleic oxidizing medium, adding new liquid oxidizing medium to this, and producing new graphite using the mixed liquid. The present invention relates to a method for producing a graphite intercalation compound, which is characterized by immersion treatment.

本発明で用いられる黒鉛は、一般に知られている天然鱗
状黒鉛の他、キッシュ黒鉛、熱分解黒鉛が使用できるが
、入手の容易な点で天然鱗状黒鉛が望ましい。As the graphite used in the present invention, in addition to the generally known natural flaky graphite, quiche graphite and pyrolytic graphite can be used, but natural flaky graphite is preferable because it is easily available.

液状の酸化媒体は濃硫酸を主体とし硝酸をはじめ前記各
種酸化剤を加えたものが好ましい。−例として硫酸及び
硝酸からなる酸化媒体について以下に説明する。Preferably, the liquid oxidizing medium is mainly composed of concentrated sulfuric acid, to which nitric acid and the various oxidizing agents mentioned above are added. - By way of example, oxidizing media consisting of sulfuric acid and nitric acid are described below.

濃硫酸２００〜５００重量部、６２％硫酸５０〜２００
重量部の混酸に鱗状黒鉛１００重量部を浸漬処理したの
ち適当な脱液装置９例えば吸引ろ過機、フィルタープレ
ス、遠心脱水装置により処理黒鉛と残存処理液とを分離
する。なおここで残存処理液を回収酸と命名する。続い
て鱗状黒鉛１００重量部を濃硫酸１００〜２００重量部
、６２チ硝酸２０〜１００重量部９回収酸２００〜４０
０重量部の混酸で処理しこれを上記方法により再度処理
黒鉛と残存処理とを分離する。以後繰返し回収酸に新し
い酸を加えた混液を用いて新しい黒鉛について酸処理を
継続する。Concentrated sulfuric acid 200-500 parts by weight, 62% sulfuric acid 50-200 parts
After immersing 100 parts by weight of flaky graphite in 100 parts by weight of mixed acid, the treated graphite and the remaining treatment liquid are separated by a suitable dewatering device 9, such as a suction filter, a filter press, or a centrifugal dewatering device. Note that the remaining treatment liquid is herein referred to as recovered acid. Subsequently, 100 parts by weight of scaly graphite were mixed with 100 to 200 parts by weight of concentrated sulfuric acid, 20 to 100 parts by weight of 62 nitric acid, and 200 to 40 parts by weight of recovered acid.
After treatment with 0 parts by weight of mixed acid, the treated graphite and the remaining treated graphite are separated again by the above method. Thereafter, the acid treatment of the new graphite is continued using a mixture of the recovered acid and new acid.

処理された黒鉛の反応の程度を示す目安としては、黒鉛
層間に残存した反応物の量を測定した値Ｉｃ（％）を用
いるのが便利でめる。Ｉｃの測定は処理黒鉛を水洗、脱
水した後黒鉛粒子表面に付着しだ水分を１１０℃以下の
温度で除去した重量Ｗ、をめ、このＷｌと次に３５０℃
で１時間処理し黒鉛層間の反応物質を揮発させ、この時
の重量Ｗ２とから下記式でめる。As a measure of the degree of reaction of the treated graphite, it is convenient to use the value Ic (%), which is the amount of the reactant remaining between the graphite layers. To measure Ic, the treated graphite is washed with water and dehydrated, and then the water adhering to the surface of the graphite particles is removed at a temperature of 110°C or lower, which is the weight W.
The reaction material between the graphite layers is volatilized by treatment for 1 hour, and the weight is calculated from the weight W2 at this time using the following formula.

Ｉ　Ｗ２ Ｉ　ｃ　＝　−Ｘ　１００　（％） Ｗｌ Ｉｃ０値が大きいほど理想的な反応状態である。I　W2 Ic = -X 100 (%) Wl The larger the Ic0 value is, the more ideal the reaction state is.

（実施例） 実施例１ 固定炭素分９７チ、灰分２％で４２メツシユにピークを
もつマダガスカル産天然鱗状黒鉛１００９を濃硫酸３０
０９．濃硝酸ｉｏｏｇの混酸中に１時間浸漬処理した。(Example) Example 1 Natural scaly graphite 1009 from Madagascar, which has a fixed carbon content of 97%, an ash content of 2%, and a peak of 42 mesh, was dissolved in concentrated sulfuric acid 30%.
09. It was immersed in a mixed acid of concentrated nitric acid (IOOG) for 1 hour.

このときの混酸の粘度は約１７（ｐｏｊｓｅ）でおった
。その後吸引ろ過機により処理液を分離し、処理黒鉛を
水洗、脱水した。このときのＩｃは約９１であった。以
上を比較例とする。The viscosity of the mixed acid at this time was about 17 (pojse). Thereafter, the treated liquid was separated using a suction filter, and the treated graphite was washed with water and dehydrated. Ic at this time was about 91. The above is a comparative example.

続いてここで分離した回収酸２００９に濃硫酸１５０９
、濃硝酸５０９を加えた混酸中で新しい天然鱗状黒鉛１
００ｇを同様に処理したところ。Subsequently, concentrated sulfuric acid 1509 was added to the recovered acid 2009 separated here.
, new natural flaky graphite 1 in mixed acid with concentrated nitric acid 509
00g was treated in the same way.

回収酸の粘度は約１１［ｐｏｉｓｅ〕に減少し、？＃ら
れた黒鉛層間化合物のＩＣは約１２．２％に増大した。The viscosity of the recovered acid decreases to about 11 [poise], and ? The IC of the mixed graphite intercalation compound increased to about 12.2%.

実施例２ 酸処理を１０回繰返した回収酸２００ｇに濃硫酸１５０
ｇ、濃硝酸５０ｇを加えた混酸中で実施例１の黒鉛１０
０ｇを処理した。この時回収酸の粘度は１２　［ｐｏｉ
ｓｅ　］でおった。実施例１と同様に回収酸を分離した
後、処理黒鉛を水洗、脱水し黒鉛層間化合物を作成した
。このＩｃは１２．４％でめった。Example 2 150 g of concentrated sulfuric acid was added to 200 g of recovered acid after acid treatment was repeated 10 times.
10 g of the graphite of Example 1 in a mixed acid containing 50 g of concentrated nitric acid.
0g was processed. At this time, the viscosity of the recovered acid is 12 [poi
se]. After separating the recovered acid in the same manner as in Example 1, the treated graphite was washed with water and dehydrated to create a graphite intercalation compound. This Ic was rare at 12.4%.

比較例及び実施例で得られた層間化合物を８００℃で３
分間熱処理して膨張黒鉛を得た。この膨張黒鉛を面圧１
００　Ｋｐ／Ｃｍ２で圧縮成形し２ｍｍの厚みのシート
を得た。このシートのカサ比重及び引張強度の値を第１
表妬示す。The intercalation compounds obtained in the comparative examples and examples were heated at 800°C for 3
Expanded graphite was obtained by heat treatment for a minute. The surface pressure of this expanded graphite is 1
Compression molding was performed at 0.00 Kp/Cm2 to obtain a sheet with a thickness of 2 mm. The bulk specific gravity and tensile strength values of this sheet are
Show jealousy.

第１表 第１表から実施例のものは比較例のものよりカサ比重が
小さく（膨張黒鉛の膨張が大きく）、引張強さが小さい
ことが明瞭である。From Table 1, it is clear that the samples of the Examples have smaller bulk specific gravity (larger expansion of expanded graphite) and lower tensile strength than those of the Comparative Examples.

以上の実施例から明らかな様に本発明の方法で得られる
黒鉛層間化合物は、全て新規の酸化媒体から出発する従
来法に比べて低コストな上１反応物質の眉間残存率が極
めて高く、その後の膨張処理で得られる膨張黒鉛は膨張
が大きく、その成形加工品は良い機械的強度を有する。As is clear from the above examples, the graphite intercalation compound obtained by the method of the present invention is lower in cost than the conventional method, which starts from a new oxidation medium, and has an extremely high glabella residual rate of the first reactant. The expanded graphite obtained by the expansion treatment has a large expansion, and the molded products thereof have good mechanical strength.

加えて酸化媒体の粘性も低いので作業性も向上し低コス
トとなる。In addition, since the viscosity of the oxidizing medium is low, workability is improved and costs are reduced.

Claims (1)

【特許請求の範囲】 １、黒鉛を液状の酸化媒体に浸漬処理して黒鉛層間化合
物を形成させたのち核酸化媒体を回収し。 これに新しい液状の酸化媒体を加えた混液により新しい
黒鉛を浸漬処理することを特徴とする黒鉛層間化合物の
製造方法。[Claims] 1. Graphite is immersed in a liquid oxidizing medium to form a graphite intercalation compound, and then the nucleic oxidizing medium is recovered. A method for producing a graphite intercalation compound, which comprises immersing new graphite in a mixed solution in which a new liquid oxidizing medium is added.