JPH0260609B2 - - Google Patents
Info
- Publication number
- JPH0260609B2 JPH0260609B2 JP1703281A JP1703281A JPH0260609B2 JP H0260609 B2 JPH0260609 B2 JP H0260609B2 JP 1703281 A JP1703281 A JP 1703281A JP 1703281 A JP1703281 A JP 1703281A JP H0260609 B2 JPH0260609 B2 JP H0260609B2
- Authority
- JP
- Japan
- Prior art keywords
- tantalum
- alkali metal
- double salt
- salt
- phosphorus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 35
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 27
- 150000003839 salts Chemical class 0.000 claims description 26
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 24
- 239000011574 phosphorus Substances 0.000 claims description 24
- 229910052698 phosphorus Inorganic materials 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 21
- 239000000843 powder Substances 0.000 claims description 19
- 229910052715 tantalum Inorganic materials 0.000 claims description 18
- 239000003990 capacitor Substances 0.000 claims description 11
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 10
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 8
- 229910052783 alkali metal Inorganic materials 0.000 claims description 7
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 238000002425 crystallisation Methods 0.000 claims description 3
- 230000008025 crystallization Effects 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 3
- 239000010955 niobium Substances 0.000 claims description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 3
- 238000000622 liquid--liquid extraction Methods 0.000 claims description 2
- 238000011084 recovery Methods 0.000 claims description 2
- 238000000638 solvent extraction Methods 0.000 claims description 2
- 239000007858 starting material Substances 0.000 claims description 2
- -1 alkali metal tantalum fluoride complexes Chemical class 0.000 claims 6
- 229910001515 alkali metal fluoride Inorganic materials 0.000 claims 1
- 238000000926 separation method Methods 0.000 claims 1
- APLLYCDGAWQGRK-UHFFFAOYSA-H potassium;hexafluorotantalum(1-) Chemical compound [F-].[F-].[F-].[F-].[F-].[F-].[K+].[Ta+5] APLLYCDGAWQGRK-UHFFFAOYSA-H 0.000 description 14
- 235000011007 phosphoric acid Nutrition 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 10
- 239000000243 solution Substances 0.000 description 9
- 239000000047 product Substances 0.000 description 8
- 239000002994 raw material Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000002940 repellent Effects 0.000 description 3
- 239000005871 repellent Substances 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 150000003018 phosphorus compounds Chemical class 0.000 description 2
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 description 2
- 239000011698 potassium fluoride Substances 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000004438 BET method Methods 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 1
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 1
- 229920000388 Polyphosphate Polymers 0.000 description 1
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 150000001447 alkali salts Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012043 crude product Substances 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 238000005323 electroforming Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910001512 metal fluoride Inorganic materials 0.000 description 1
- 125000005341 metaphosphate group Chemical group 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000001205 polyphosphate Substances 0.000 description 1
- 235000011176 polyphosphates Nutrition 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 235000003270 potassium fluoride Nutrition 0.000 description 1
- 229910001414 potassium ion Inorganic materials 0.000 description 1
- 159000000001 potassium salts Chemical class 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 150000003481 tantalum Chemical class 0.000 description 1
- 238000009997 thermal pre-treatment Methods 0.000 description 1
- 238000013519 translation Methods 0.000 description 1
- STCOOQWBFONSKY-UHFFFAOYSA-N tributyl phosphate Chemical compound CCCCOP(=O)(OCCCC)OCCCC STCOOQWBFONSKY-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
- H01G9/048—Electrodes or formation of dielectric layers thereon characterised by their structure
- H01G9/052—Sintered electrodes
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G31/00—Compounds of vanadium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G35/00—Compounds of tantalum
Description
本発明は特殊なアルカリ金属タンタル弗化物複
塩（alkali“earth acid”metal fluoride）の製造
法、並びにこれを電解コンデンサーの電極の製造
に特に適したタンタル金属粉末の回収の原料とし
て用いる方法に関する。
公知の如く、電解コンデンサーの電極として用
いられるタンタル金属粉末から焼結体を製造する
場合、該タンタル金属粉末に含リン化合物をドー
ピングする、即ち意図的にこれを汚染することが
有利である。この方法でつくられたタンタルの陽
極とこれを「フオーミング（forming）」するこ
とにより得られた誘電体との電気的性質は含リン
化合物をドーピングすることにより非常に優れた
ものになる。これはコンデンサーの特殊の充電に
特に利用されている。例えばDE−OS2616367号
のような文献にこれまで知られている限りにおい
ては、タンタル陽極を加工する前に、即ちこれを
凝集させ、プレスし、焼結する前に含リン化合物
をタンタル金属を混合することが普通であつた。
この目的は焼結工程中拡散により金属の中にドー
ピング剤を混入することであつた。しかしDE−
OS2616367号の第３頁、第２節においては、偶然
的な鉱石又は原料に不純物として、或いは意図的
ドーピングによつて導入されるリン化合物は、最
終金属粉末のドーピングに対し好結果を与えない
ということが特に指摘されている。
しかし、上述のこととは対照的に、本発明にお
いては、通常タンタル粉末の出発原料である弗化
タンタルカリウムの製造中に含リン化合物を混入
するとそれからつくられたタンタル金属粉末の性
質に非常に有利な効果を与えることが見出され
た。
上記複塩にリンをドーピングすることの特殊な
効果は、DE−PS2517180号の方法によるアルカ
リ金属を用いた実際の還元を行うための弗化タン
タルカリウムの熱的前処理中に、所謂「撥散段階
（decrepitation stage）」において、特に細かい
粉末に砕け散り（fall apart）そのBET法によつ
て測定された比表面積はドーピングしない
K2TaF7よりも著しく増加している。弗化カリウ
ム（原料）の比表面積とタンタル粉末又はそれか
らつくられたタンタル陽極（最終製品）の性質と
の間の関係は上記DE−PS2517180号に詳細に説
明されている。
弗化タンタルカリウムのドーピング工程を行な
う場合、タンタル塩の弗化水素酸溶液から公知方
法で出発し、これからカリウムイオンを加えて比
較的難溶性のK2TaF7を晶出させる。本発明に例
えば、弗化水素酸中にタンタルを含む溶液に一定
量のリン酸を加えた後、複塩を晶出させる。リン
酸の添加量は得られた生成物を晶出、過、乾燥
させた後、50〜500ppmの所望のリン含量が得ら
れるような量である。リン酸の使用量は生成物を
分析し、初期溶液に対するリン酸の必要添加量を
外挿することにより経験的に決定することができ
る。ドーピングした複塩の以後の処理はDE−
PS2517180号に従つて主として不活性雰囲気中で
乾燥した複塩を加熱する際に起る所謂「撥散工
程」によつて公知方法で行なわれる。この加熱
中、複塩の元の結晶は分解して細かい粉末にな
る。これは表面活性が大きいために液体の金属ナ
トリウムでうまくぬらすことができる。上記特許
に対応する次の工程においては、仕上タンタル金
属粉末をつくり、これをプレスし、高真空下で焼
結し、最後に電流を用いてフオーミングし、再び
公知方法を用いてコンデンサーの電極（タンタル
陽極）をつくる。
本発明に従うドーピングした弗化タンタルカリ
ウムからつくられた金属粉未を用いるとそれから
つくられたコンデンサーの電気的性質が著しく改
善される。特に比電荷（μmC／ｇ）が著しく改
善される。本発明の生成物、即ちドーピングした
弗化タンタルカリウムが中間製品及び最終製品の
性質に与える効果は下記の実験で示される。
良く知られているように、弗化タンタルカリウ
ム（K2TaF7）を製造する場合、液−液抽出によ
りタンタルからニオブを分離した後H2TaF7の形
でタンタルを含む有機相（例えば、メチルイソブ
チルケトン、トリブチルフオスフエート）から出
発する。高温（約90〜100℃）において易溶性の
カリウム塩（例えば、KCl、KOH、KF）の水溶
液でこれらの溶液からタンタルを再抽出する。水
性再抽出液を冷却した後、比較的難溶性の
K2TaF7を沈澱させ、これを過し乾燥する。
実施例 １
上記の弗化タンタルカリウムK2TaF7の製造法
において、これをドーピングするには正リン酸
（H3PO4）を複塩の結晶化前に水性再抽出液1000
当り85％リン酸（ｄ＝1.71ｇ／cm3）３〜５Kgの
好適量で加える。冷却して複塩を沈澱させる。母
液を分離した後、複塩は乾燥状態で約300〜
500ppmのリンを含んでいる。
実施例 ２
リンをドーピングしたK2TaF7の他の好適な製
造法は粗製K2TaF7の再結晶中に行なわれる。こ
の方法は再抽出工程の粗製品がタンタルコンデン
サー製造用のタンタル金属粉末を製造するための
原料として用いる程十分には純粋でない場合に通
常必要である。
この再結晶中、予め約90〜100℃に加熱した2N
の弗化水素酸溶液を用い、これを撹拌しながら粗
製K2TaF7中に加える。次の過工程において未
成熟な晶出が起ることを防ぐために、K2TaF7に
関し完全な溶液の飽和が起らないようにしなけれ
ばならない。
リンでドーピングするためには、例えば上述の
溶液5000に対し85重量％正リン酸溶液17Kgを加
え、この混合物に加熱撹拌しながら300Kgの粗製
K2TaF7を加える。高温の間複塩の溶液を過す
る。冷却すると複塩の室温における飽和濃度に対
応量を除いてK2TaF7は純粋な形で沈澱する。こ
の方法でつくられたリンをドーピングした
K2TaF7は乾燥後リン含量が約600ppmであつた。
リン酸の添加量を減少させるとドーピングした
K2TaF7中のリン濃度を減少させることができ
る。H3PO4の添加量と最終生成物のリン含量と
の間には略々直線関係がある。適当な実験を用い
ると、実施例２の条件下において、もし10Kgの
H3PO4（85重量％）を加えた場合、ドーピングし
たK2TaF7中のリン含量は300ppmであり、５Kg
のH3PO4（85重量％）を加えると、約100ppmの
ドーピング量が得られることが実験的に決定され
た。実施例２の条件下で約２KgのH3PO4を加え
るとK2TaF7中のリン含量は約50ppmである。
実施例２の条件下において、リンと約50、100、
200、500及び600ppmのリンがドーピングした
2300KgロツトのK2TaF7生成物が得られた。
勿論本発明方法によるリンのドーピングは
H3PO4を用いる場合にのみ限定されるものでは
なく、他のリン化合物、例えば正リン酸のアルカ
リ塩、可溶性のポリリン酸塩、メタリン酸塩その
他を用いることもできる。
本発明により得られたリンをドーピングした弗
化タンタルカリウムの結晶の長さ及び断面はドー
ピングしない塩に比べ著しく大きい。このことは
不純物としての望ましくない元素に関する化学的
純度に好結果を与える。
本発明によりつくられた生成物の利点を評価す
る基準はリンをドーピングした弗化タンタルカリ
ウムを前述の如く電解コンデンサー用のタンタル
金属粉末の製造用の原料として用いられるか否か
で決定される。
即ち前述の実施例に従つてつくられたドーピン
グの程度が異つた複塩を、DE−PS2517180号の
方法によりタンタル金属粉末にする。ドーピング
しない（リンを含まない）複塩を対照のため用い
た。ドーピングしない弗化タンタルカリウム及び
本発明方法によりドーピングした弗化タンタルカ
リウムは、DE−PS2517180号記載の「撥散工程」
で処理した場合、異つた挙動を示す。リンをドー
ピングした実験用試料は撥散工程を行なつた後、
ドーピングしない試料に比べ明らかに細かかつ
た。（この効果は著しい。何故ならばリンをドー
ピングした弗化物複塩は通常のK2TaF7に比べ結
晶化させると大きな結晶を与えるからである。
（前記文献第８頁、英訳第５頁参照）〕。撥散した
塩の粒径が小さいことは活性表面が大きいことを
示し、このことはDE−PS2517180号方法により
処理してタンタル金属粉末にする時に特に有利な
効果を与える。夫々の測定の結果を下記表に示
す。
The present invention relates to a process for the production of a special alkali "earth acid" metal fluoride and its use as a raw material for the recovery of tantalum metal powder, which is particularly suitable for the production of electrodes of electrolytic capacitors. As is known, when producing a sintered body from tantalum metal powder used as an electrode of an electrolytic capacitor, it is advantageous to dope the tantalum metal powder with a phosphorus-containing compound, that is, to intentionally contaminate it. The electrical properties of the tantalum anode produced by this method and the dielectric material obtained by "forming" the tantalum anode are improved by doping with a phosphorus-containing compound. This is especially used for special charging of capacitors. As far as is known so far from the literature, for example DE-OS 2616367, phosphorus-containing compounds are mixed with tantalum metal before processing the tantalum anode, i.e. before it is agglomerated, pressed and sintered. It was normal to do that.
The purpose was to incorporate the doping agent into the metal by diffusion during the sintering process. But DE−
In OS2616367, page 3, section 2, it is stated that phosphorus compounds introduced as impurities into ores or raw materials by chance or by intentional doping do not have a positive effect on the doping of the final metal powder. This has been particularly pointed out. However, in contrast to the above, in the present invention, the incorporation of a phosphorus-containing compound during the production of potassium tantalum fluoride, which is normally the starting material for tantalum powder, significantly affects the properties of the tantalum metal powder made from it. It has been found that it has a beneficial effect. The special effect of doping the double salt with phosphorus is that during the thermal pretreatment of potassium tantalum fluoride for the actual reduction with alkali metals according to the method of DE-PS2517180, the so-called "repellent" In the "decrepitation stage", the specific surface area measured by the BET method does not fall apart into a particularly fine powder and does not dope.
It is significantly increased compared to K 2 TaF 7 . The relationship between the specific surface area of potassium fluoride (raw material) and the properties of tantalum powder or tantalum anodes made therefrom (finished product) is explained in detail in DE-PS2517180 cited above. When performing the doping step with potassium tantalum fluoride, a known method is used to start from a solution of tantalum salt in hydrofluoric acid, from which potassium ions are added to crystallize relatively sparingly soluble K 2 TaF 7 . For example, in the present invention, a double salt is crystallized after adding a certain amount of phosphoric acid to a solution containing tantalum in hydrofluoric acid. The amount of phosphoric acid added is such that the desired phosphorus content of 50 to 500 ppm is obtained after crystallizing, filtering and drying the product obtained. The amount of phosphoric acid used can be determined empirically by analyzing the product and extrapolating the required amount of phosphoric acid added to the initial solution. The subsequent treatment of the doped double salt is DE−
It is carried out in a known manner according to PS 2,517,180 mainly by a so-called "splatter step" which takes place during heating of the dried double salt in an inert atmosphere. During this heating, the original crystals of the double salt decompose into a fine powder. Due to its high surface activity, it can be successfully wetted with liquid sodium metal. In the next step corresponding to the above patent, a finished tantalum metal powder is prepared, which is pressed, sintered under high vacuum, and finally formed using an electric current, and again using known methods to form the capacitor electrodes. tantalum anode). The use of metal powders made from doped potassium tantalum fluoride according to the present invention significantly improves the electrical properties of capacitors made therefrom. In particular, the specific charge (μmC/g) is significantly improved. The effect of the product of the invention, ie doped potassium tantalum fluoride, on the properties of the intermediate and final products is demonstrated in the following experiments. As is well known, when producing potassium tantalum fluoride (K 2 TaF 7 ), after separating niobium from tantalum by liquid-liquid extraction, an organic phase containing tantalum in the form of H 2 TaF 7 (e.g. Starting from methyl isobutyl ketone, tributyl phosphate). Tantalum is re-extracted from these solutions with aqueous solutions of readily soluble potassium salts (e.g. KCl, KOH, KF) at elevated temperatures (approximately 90-100°C). After cooling the aqueous re-extract, the relatively sparingly soluble
K 2 TaF 7 is precipitated and filtered and dried. Example 1 In the above method for producing potassium tantalum fluoride K 2 TaF 7 , in order to dope it, orthophosphoric acid (H 3 PO 4 ) is added to the aqueous re-extracting solution 1000 ml before crystallization of the double salt.
A suitable amount of 3 to 5 kg of 85% phosphoric acid (d=1.71 g/cm 3 ) is added per sample. Cool to precipitate the double salt. After separating the mother liquor, the double salt is about 300 ~
Contains 500ppm phosphorus. Example 2 Another preferred method for producing phosphorus-doped K 2 TaF 7 is carried out during recrystallization of crude K 2 TaF 7 . This method is usually necessary when the crude product of the re-extraction step is not pure enough to be used as a raw material for producing tantalum metal powder for tantalum capacitor production. During this recrystallization, 2N preheated to about 90-100℃
of hydrofluoric acid solution, which is added to the crude K 2 TaF 7 with stirring. To prevent premature crystallization from occurring in the next step, complete saturation of the solution with respect to K 2 TaF 7 must not occur. To dope with phosphorus, for example, add 17 kg of 85% by weight orthophosphoric acid solution to 5000 kg of the above solution, and add 300 kg of crude phosphoric acid to this mixture while heating and stirring.
Add K 2 TaF 7 . Strain the double salt solution while hot. Upon cooling, K 2 TaF 7 precipitates in pure form except for an amount corresponding to the saturation concentration at room temperature of the double salt. The phosphorus produced in this way was doped
K 2 TaF 7 had a phosphorus content of about 600 ppm after drying. Doping by reducing the amount of phosphoric acid added
The phosphorus concentration in K 2 TaF 7 can be reduced. There is an approximately linear relationship between the amount of H 3 PO 4 added and the phosphorus content of the final product. Using appropriate experiments, under the conditions of Example 2, if 10Kg.
When H 3 PO 4 (85% by weight) is added, the phosphorus content in the doped K 2 TaF 7 is 300 ppm and 5 Kg
It was experimentally determined that adding 10% of H 3 PO 4 (85% by weight) results in a doping amount of approximately 100 ppm. When about 2 Kg of H 3 PO 4 is added under the conditions of Example 2, the phosphorus content in K 2 TaF 7 is about 50 ppm. Under the conditions of Example 2, phosphorus and about 50, 100,
200, 500 and 600ppm phosphorus doped
A 2300Kg lot of K 2 TaF 7 product was obtained. Of course, phosphorus doping by the method of the present invention is
The use of H 3 PO 4 is not limited, and other phosphorus compounds such as alkali salts of orthophosphoric acid, soluble polyphosphates, metaphosphates, and others can also be used. The crystal length and cross section of the phosphorus-doped potassium tantalum fluoride obtained according to the invention is significantly larger than that of the undoped salt. This favors chemical purity with respect to undesired elements as impurities. The criterion for evaluating the merits of the products made in accordance with the present invention is determined by the use of phosphorus-doped potassium tantalum fluoride as a raw material for the production of tantalum metal powder for electrolytic capacitors, as described above. That is, the double salts with different degrees of doping produced according to the above embodiments are converted into tantalum metal powder by the method of DE-PS2517180. An undoped (phosphorus-free) double salt was used as a control. Undoped potassium tantalum fluoride and potassium tantalum fluoride doped by the method of the present invention can be used in the "repellent process" described in DE-PS2517180.
When treated with , it shows different behavior. After the experimental sample doped with phosphorus was subjected to a repellent process,
It was clearly finer than the undoped sample. (This effect is remarkable because fluoride double salt doped with phosphorus gives larger crystals when crystallized than ordinary K 2 TaF 7 .
(See page 8 of the above document, page 5 of the English translation)]. The small particle size of the atomized salt indicates a large active surface, which has a particularly advantageous effect when processed to tantalum metal powder according to the DE-PS 2517180 process. The results of each measurement are shown in the table below.
【表】
リンをドーピングした弗化タンタルカリウムの
製造に対する本発明方法の効果は対応するタンタ
ル粉末からつくられた電解コンデンサーのタンタ
ル陽極を研究することにより特に明らかである。
DE−PS2517180号記載の方法を再び用い、本発
明方法によりつくられた複塩のK2TaF7からつく
られたタンタル金属粉末を使用し、（これを線に
引いて）円筒形にプレスした試料をつくる。この
プレスした試料を真空炉中で焼結する。誘導体と
して作用する酸化物層を次いで電解フオーミング
により焼結した陽極上に形成した。公知の如く、
この酸化物層の電気的性質は陽極製造用のタンタ
ル粉末の品質として信頼できるものである。これ
らの性質の決定要因を用い本発明（リンをドーピ
ングした弗化タンタルカリウム）とDE−
PS2517180号方法による従来法の製品とを比較し
た。その結果を下記表に示す。
金属粉末を生密度4.0ｇ／cm3までプレスするこ
とによるタンタル陽極の製造
焼結温度 1600℃
フオーミング電圧 100V
フオーミング電流 35ｍＡ／ｇ
フオーミング時間 ２時間
温 度 95±２℃
フオーミング電解質 0.01％H3PO4
測定電解質 10％H3PO4 Table The effectiveness of the process of the invention for the production of phosphorus-doped potassium tantalum fluoride is particularly evident by studying tantalum anodes of electrolytic capacitors made from the corresponding tantalum powder.
Using the method described in DE-PS2517180 again, a sample was pressed into a cylindrical shape (by drawing a line) using tantalum metal powder made from double salt K 2 TaF 7 made by the method of the present invention. Create. This pressed sample is sintered in a vacuum furnace. An oxide layer acting as a dielectric was then formed on the sintered anode by electroforming. As is known,
The electrical properties of this oxide layer are reliable as the quality of tantalum powder for anode production. Using the determinants of these properties, the present invention (phosphorus-doped potassium tantalum fluoride) and DE-
A comparison was made with the conventional product produced by the PS2517180 method. The results are shown in the table below. Manufacture of tantalum anode by pressing metal powder to a green density of 4.0 g/cm 3 Sintering temperature 1600℃ Forming voltage 100V Forming current 35mA/g Forming time 2 hours Temperature 95±2℃ Forming electrolyte 0.01%H 3 PO 4 Measuring electrolyte 10 % H3PO4
【表】
上記実施例に記載されている利点の他に、本発
明でつくられたリンをドーピングしたK2TaF7は
これを処理してタンタル金属粉末にする際及び、
最終的には電解コンデンサー用のタンタル陽極を
つくるためにこの粉末を用いる際に優れた利点を
もつている。ドーピングした複塩中におけるリン
含量の影響は比充電量（μC／ｇ）及び破壊電圧
についての電気的性質に対して特に重要である。
ドーピングしない原料に比べると、ドーピングす
ると比充電量はリン50ppmで約９％、100ppmで
約15％、200ppmで約15％だけ著しく増加する。
しかしリン含量がさらに増加しても僅かしか効果
がない。
リンでドープした弗化タンタルカリウムの他の
重要な性質はそれからつくられたタンタル陽極の
破壊電圧である。これはリンが100ppmの存在下
においてドーピングしない原料に比べ15％増加す
る。このことはそれからつくられた電解コンデン
サーを用いると、高い使用電圧を使用することが
できることを意味する。[Table] In addition to the advantages described in the above examples, the phosphorus-doped K 2 TaF 7 made according to the present invention is useful when processed into tantalum metal powder and
Ultimately, this powder has great advantages when used to make tantalum anodes for electrolytic capacitors. The influence of the phosphorus content in doped double salts is particularly important on the electrical properties in terms of specific charge (μC/g) and breakdown voltage.
Compared to raw materials without doping, doping significantly increases the specific charge by about 9% at 50 ppm phosphorus, about 15% at 100 ppm, and about 15% at 200 ppm.
However, further increases in phosphorus content have little effect. Another important property of phosphorus-doped potassium tantalum fluoride is the breakdown voltage of tantalum anodes made therefrom. This is a 15% increase compared to the undoped raw material in the presence of 100 ppm phosphorus. This means that with electrolytic capacitors made therefrom, high working voltages can be used.
Claims (1)
粉末並びにそれから製造される電解コンデンサー
のための電極の出発物質として使用するのに特に
有利な性質を備えた特定のアルカリ金属タンタル
弗化物複塩を調製する方法であつて、該アルカリ
金属弗化物複塩を調製する際に、該アルカリ金属
タンタル弗化物複塩60ｇ／に対しリン酸又はそ
の塩をH3PO4として0.3〜３ｇ／の割合で添加
し、しかる後該アルカリ金属タンタル弗化物複塩
を晶出せしめ、その結果として乾操該アルカリ金
属タンタル弗化物複塩に基づいて50〜500ppmの
範囲のリン含量の結晶化した乾操アルカリ金属タ
ンタル弗化物複塩を取得することを特徴とする方
法。 ２ タンタルとニオブの分離工程中及びタンタル
の回収工程中に液−液抽出後に弗化水素酸水性ス
トリツピング溶液として得られるような、タンタ
ルを含む溶液に可溶性のリン酸又はその塩を加え
る特許請求の範囲第１項記載の方法。 ３ リン酸又はその塩が、不純なアルカリ金属タ
ンタル弗化物複塩が晶出の目的で導入された溶液
に対して添加される特許請求の範囲第１項記載の
方法。Claims: 1. Certain alkali metal tantalum fluoride complexes with particularly advantageous properties for use as starting materials for tantalum metal powders or tantalum and niobium metal powders and electrodes for electrolytic capacitors produced therefrom. A method for preparing a salt, wherein when preparing the alkali metal fluoride double salt, 0.3 to 3 g of phosphoric acid or its salt as H 3 PO 4 is added to 60 g of the alkali metal tantalum fluoride double salt. and then crystallize the alkali metal tantalum fluoride double salt, resulting in a dry process with a phosphorus content ranging from 50 to 500 ppm based on the alkali metal tantalum fluoride double salt. A method characterized in that an alkali metal tantalum fluoride double salt is obtained. 2. Addition of soluble phosphoric acid or its salts to a solution containing tantalum, such as obtained as an aqueous hydrofluoric acid stripping solution after liquid-liquid extraction, during the separation process of tantalum and niobium and during the recovery process of tantalum. The method described in Scope 1. 3. The method according to claim 1, wherein phosphoric acid or a salt thereof is added to a solution into which the impure alkali metal tantalum fluoride double salt is introduced for the purpose of crystallization.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19803005207 DE3005207C2 (en) | 1980-02-12 | 1980-02-12 | Process for the production of a phosphorus-doped alkali metal-earth acid metal double fluoride and its use |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56125217A JPS56125217A (en) | 1981-10-01 |
| JPH0260609B2 true JPH0260609B2 (en) | 1990-12-17 |
Family
ID=6094413
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1703281A Granted JPS56125217A (en) | 1980-02-12 | 1981-02-09 | Manufacture of alkali subearth-acid metallic fluoride complex |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS56125217A (en) |
| DE (1) | DE3005207C2 (en) |
| GB (1) | GB2068924B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4356028A (en) * | 1981-08-24 | 1982-10-26 | Fansteel Inc. | In situ phosphorus addition to tantalum |
| DE3140248C2 (en) * | 1981-10-09 | 1986-06-19 | Hermann C. Starck Berlin, 1000 Berlin | Use of doped valve metal powder for the production of electrolytic capacitor anodes |
| DE3330455A1 (en) * | 1983-08-24 | 1985-03-14 | GfE Gesellschaft für Elektrometallurgie mbH, 4000 Düsseldorf | METHOD FOR PRODUCING VALVE METAL POWDER FOR ELECTROLYTE CAPACITORS AND THE LIKE |
| DE3336453C2 (en) * | 1983-10-06 | 1985-11-28 | Hermann C. Starck Berlin, 1000 Berlin | Process for increasing the surface area of niobium and tantalum in the form of agglomerated or non-agglomerated powders |
| JPS60149706A (en) * | 1984-01-18 | 1985-08-07 | Showa Kiyabotsuto Suupaa Metal Kk | Manufacture of tantalum powder |
| JPH0421524A (en) * | 1990-05-15 | 1992-01-24 | Nikko Kyodo Co Ltd | Purification of potassium tantalum fluoride |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2517180C3 (en) * | 1975-04-18 | 1979-04-19 | Fa. Hermann C. Starck Berlin, 1000 Berlin | Process for the continuous production of fine, high-capacity earth acid metal powder for electrolytic capacitors |
| US4009007A (en) * | 1975-07-14 | 1977-02-22 | Fansteel Inc. | Tantalum powder and method of making the same |
-
1980
- 1980-02-12 DE DE19803005207 patent/DE3005207C2/en not_active Expired
-
1981
- 1981-02-05 GB GB8103549A patent/GB2068924B/en not_active Expired
- 1981-02-09 JP JP1703281A patent/JPS56125217A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB2068924A (en) | 1981-08-19 |
| DE3005207A1 (en) | 1981-08-27 |
| GB2068924B (en) | 1983-06-29 |
| DE3005207C2 (en) | 1986-06-12 |
| JPS56125217A (en) | 1981-10-01 |
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