US3647420A - Process for producing high-purity niobium and tantalum - Google Patents

Process for producing high-purity niobium and tantalum Download PDF

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Publication number
US3647420A
US3647420A US830542A US3647420DA US3647420A US 3647420 A US3647420 A US 3647420A US 830542 A US830542 A US 830542A US 3647420D A US3647420D A US 3647420DA US 3647420 A US3647420 A US 3647420A
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carbon
tantalum
temperature
oxygen
metal
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US830542A
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Attilio Restelli
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HC Starck GmbH
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HC Starck GmbH
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/20—Obtaining niobium, tantalum or vanadium
    • C22B34/24—Obtaining niobium or tantalum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
    • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
    • B22F9/20—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from solid metal compounds

Definitions

  • the partly reduced product is combined with finely divided carbon pyrolytically precipitated from a hydrocarbon in a retort permeable to hydrogen (at elevated temperature), so that the carbon is uniformly distributed over the surface of the partly reduced product.
  • the mixture of the partially reduced product and the finely divided pyrolytically precipitated carbon is subjected to a temperature below to 2,000 C. and nevertheless sufficient to effect a final reduction.
  • the latter temperature is about l,700 C.
  • the resulting high-purity metal i.e., tantalum or niobium
  • My present invention relates to a process for the production of high-purity metallic tantalum and niobium and, more particularly, to a process for producing tantalum or niobium metal low in oxygen and carbon and particularly suitable for use in electrolytic capacitors.
  • the volatilization step has the additional disadvantage that the vaporized metal suboxides can not be recovered and result in a loss of the starting material. Moreover, there is a tendency, at the elevated temperatures which must be used to vaporize the suboxides, for the metal suboxides to react with the material forming the reaction vessel or crucible and result in a sloughing of crucible material into the reacting mass.
  • the temperature required for volatilizing the superfluous oxygen in the form of suboxides of the metal generally range above 2,000 C., there occurs a sintering or fusing of the reactant material to itself and to the reaction vessel; this makes more difficult the removal of the charge from the reaction vessel.
  • the fused or sintered mass must be broken up or comminuted, thereby giving rise to a comminution step and a formation of fresh surfaces subject to atmospheric oxidation. Such oxidation detrimentally influences the ability to use the metal as sintered anodes in electrolytic capacitors of the type mentioned earlier.
  • Another object of this invention is to provide a process for producing high-purity tantalum and niobium which yields a product low in oxygen and carbon and which does not require mechanical comminution with the disadvantages thus entailed.
  • Yet another object of this invention is to provide a process for the production of high-purity tantalum and niobium which can be operated at temperatures below 2,000 C., thereby avoiding sintering of the mass, consequent difficulty of removing the mass from the reaction vessel, and the necessity of comminuting the mass.
  • Yet a further object of the instant invention is to provide a process for the production of high-purity niobium and tantalum which extends principles set forth in the commonly assigned copending applications Ser. No. 609,00l filed 13 Jan. 1967 (now US. Pat. No. 3,499,753) and Ser. No. 718,929 (now abandoned) and filed 4 Apr. 1968 by myself and Gustav Daedliker.
  • I deposit upon the surfaces of the reduced product of the first stage a finely divided elemental carbon obtained from the pyrolytic decomposition of a hydrocarbon, especially a paraffinic alkane having a carbon number ranging between one and eight.
  • the precipitated pyrolytic carbon is intimately mixed with the reduced product of the initial stage, whereupon the mixture of finely divided carbon and partially reduced oxide, wherein the carbon content now is stoichiometrically equal to the quantity necessary to react all of the oxygen remaining, is reacted at a temperature below to 2000 C. in the second reduction stage and at reduced pressure to yield a final product which may be used in electrolytic capacitors as will be apparent hereinafter.
  • the precipitation of the finely divided carbon film is effected by pyrolysis at or above the pyrolyzing temperature of the gaseous hydrocarbon and especially a hydrocarbon of the paraffin series on a heated metal surface according to the formula:
  • n an integer ranging from one to eight.
  • the reaction vessel. is a material which. at elevated temperatures leg. 700 to l.000 t1). is permeable to hydrogen. for example. a nickel-chromi- .llll-llOn alloy.
  • a nickel-chromi- .llll-llOn alloy By evacuating the furnace containing the sealed retort. I initially am able to effect a hydrogen diffusion from the interior of the vessel and thereby control the amount of precipitated carbon which appears to from in reproducible ratios upon the wall of the vessel and upon the surfaces of the charge.
  • the evacuated hydrogen is burned off. Best results have been found with pyrolysis temperatures ranging between and l.000 C.
  • the intermediate stage wherein a finely divided .iarbon film is precipitated on the surface of the partially reduced metal. permits the second reaction stage to be carried out at temperatures well below l.000 C. preferably at about llS purity and grain structure. most suitable for high quality i imter anodes of niobium and tantalum in high-capacity elecirolytic condensers. Moreover. in the course of the process. the concentrations of nonrefractory impurity metals are reduced to less than five p.p.m.
  • EXAMPLE Thirty Kilograms (kg) of tantalum pentoxide powder intimately mixed with a fine annealed graphite a 99.6 percent purity in an amount of 4.040 grams lg.) and pressed into tablets weighing two grams ig.) each.
  • the tablets are uniformly heated in a highvacuum furnace to a temperature of l.800 C. to react the graphite with the oxide and form carlhonmonoxide.
  • the reaction temperature is maintained as long .is carbonmonoxide is evolved and the vacuum brought to a iubatmospheric or negative pressure value of about 1 to 5-l0 orr.
  • the resulting partially reduced tantalum. constituting the first-stage product. has an average oxygen content of 1.720 ppm. and a carbon content of 65 p.p.m.
  • lnconel a retort composed of the nickel alloy known as lnconel "r00.
  • ⁇ A suitable lnconel alloy may consist of 77-105 percent iy weight nickel. l4il percent by weight chromium. 0.21-0.05 percent by weight copper. 0.5:1 percent by weight iron. 0.5103 percent by weight manganese. 10.75 percent by weight silicon. 0.08 to 0.2 percent by weight carbon and is permeable by hydrogen at elevated temperatures.
  • the retort is placed bodily in the high-vacuum furnace and heated to a temperature of 900 C. whereupon 38.000 torr X liter (corrected to 0 C.) of methane is added in portions. This .sorresponds approximately to 26.7 g. of carbon. The amount if carbon taken up is determined by the cumulative pressure tlifference. As the methane contacts the interior of the retort and the prereduced metal therein. it pyrolyzes and deposits :1 iinely divided carbon film over these surfaces. The methane pyrolysis results in a gradual reduction of the pressure from the starting level. During pyrolysis. hydrogen lS released and iiiffuses through the wall of the retort. the retort being hermetically sealed except for diffusion through its walls.
  • the retort is then discharged and the mixture of pyrolytically discharged carbon thoroughly mixed with the tantalum pellets.
  • the average carbon content is determined as 690 p.p.m. and 12.0 g. of carbon are calculated as taken up by the metal.
  • the resulting tantalum has an oxygen content of 530 p.p.m. and a carbon content of p.p.m.
  • the tantalum is particularly suited for use in electrolytic capacitors and can be formed into plates as described in US. Pat. No. 3.430.108 or the above-identified application Ser. No. 718.929.
  • EXAMPLE ll As described in Example l. 30 kg. of tantalum pentoxide is ntimately mixed with 4.040 g. of graphite powder. pressed .nto tablets and sintered in vacuo. The resulting first-stage "ECIUCUOH product has an oxygen content of 2.020 p.p.m. and .1 carbon content of 40 p.p.m.
  • the intermediate carbon correction is carried out with 23 xg. of butane whereby l [.700 torr X liters at 800C. is reacted o pyrolytically precipitate the carbon film.
  • the carbon-coated tablets are thoroughly mixed and inalyzed and the average carbon content is found to be about 900 p.p.m.
  • the second-stage reduction is carried out by sintering in iacuum (see Example I) at a temperature of l.850 C. to obam a nigh-purity tantalum product with only [30 p.p.m. of ixvgen.
  • tantalum containing 250 p.p.m. oxygen and tlO-QO p.p.m. carbon.
  • the tantalum is hydrogenated and TllllCd to a fine powder (see applications Ser. No. 609.00l and No. 718.929) by conventional techniques and is thereafter iubiected to dehydrogenation to obtain a metal powder with in average particle size of seven microns.
  • This powder conraining 1.650 p.p.m. oxygen. 50 p.p.m. nitrogen and p.p.m. carbon is characterized by a low content of metallic impurities.
  • the total amount of nickel. chromium. manganese. magriesium. aluminum. silicon. calcium. copper, titanium. zirconium and iron is less than five p.p.m.
  • This powder is formed into sintered anodes for condensers as described generally in the aforementioned application and U.S. patent. More particularly. 1.98 g. of the powder is pressed into an anode. with a diameter of 6.7 mm. and a iDBClfiC gravity of 8.4 g/cm: and sintered for 30 minutes at 950 C. in high vacuum. The resulting anode had an electrical capacity of about 6.240;; FV. The breakdown voltage of the electrode in 0.1 percent H PO is determined to be in excess of 250 volts.
  • the tantalum powders of Example I and ll yield similar results.
  • a process for producing high-purity niobium and tantalum from a corresponding metal oxide comprising the steps .l. reducing the metal oxide by intimately mixing it with eleiiiental carbon and subjecting the resulting mixture to an cievated temperature in vacuo to produce a prereduced iroduct with an oxygen content of about 500 to 10.000 p.p.m.. the elemental carbon mixed with the metal oxide vieing present in an amount less than the quantity "BQUII'Cd to stoichiometrically react all of the oxygen of he oxide to form carbon monoxide and said oxygen is iresent in an excess of at most one percent beyond that stoichiometrically calculated to react with the elemental carbon;
  • reaction vessel is composed of nickel-chromium-iron alloy.
  • hydrocarbon is a paraffinic alkane of the general formula C,,H where n is an integer ranging between l and 8.
  • steps (a) and (c) are each carried out at a temperature below 2,000" C.
  • steps (a) and (c) are each carried out at a pressure ofthe order of 10" torr.
  • step (c) is carried out at a temperature of about 1,700 C.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US830542A 1968-06-06 1969-06-04 Process for producing high-purity niobium and tantalum Expired - Lifetime US3647420A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH838068A CH515996A (de) 1968-06-06 1968-06-06 Verfahren zur Herstellung von hochreinem Niob und/oder Tantal

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BE (1) BE734012A (cs)
CH (1) CH515996A (cs)
DE (1) DE1928149A1 (cs)
FR (1) FR2010259A1 (cs)
GB (1) GB1266065A (cs)

Cited By (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4113479A (en) * 1976-02-27 1978-09-12 Amax Inc. Vacuum smelting process for producing ferrotungsten
US4347084A (en) * 1975-04-18 1982-08-31 Hermann C. Starck Berlin Electrodes of sintered tantalum powder of fine grain size and process of production
US6051044A (en) * 1998-05-04 2000-04-18 Cabot Corporation Nitrided niobium powders and niobium electrolytic capacitors
US6051326A (en) * 1997-04-26 2000-04-18 Cabot Corporation Valve metal compositions and method
US6136062A (en) * 1998-10-13 2000-10-24 H. C. Starck Gmbh & Co. Kg Niobium powder and a process for the production of niobium and/or tantalum powders
US6165623A (en) * 1996-11-07 2000-12-26 Cabot Corporation Niobium powders and niobium electrolytic capacitors
US6171363B1 (en) * 1998-05-06 2001-01-09 H. C. Starck, Inc. Method for producing tantallum/niobium metal powders by the reduction of their oxides with gaseous magnesium
US6348113B1 (en) 1998-11-25 2002-02-19 Cabot Corporation High purity tantalum, products containing the same, and methods of making the same
US6373685B1 (en) 1998-09-16 2002-04-16 Cabot Corporation Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides
US6375704B1 (en) 1999-05-12 2002-04-23 Cabot Corporation High capacitance niobium powders and electrolytic capacitor anodes
US6391275B1 (en) * 1998-09-16 2002-05-21 Cabot Corporation Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides
US6402066B1 (en) 1999-03-19 2002-06-11 Cabot Corporation Method of making niobium and other metal powders
US6462934B2 (en) 1998-09-16 2002-10-08 Cabot Corporation Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides
WO2002037513A3 (en) * 2000-11-06 2003-05-30 Cabot Corp Modified oxygen reduced valve metal oxides
US6576099B2 (en) 2000-03-23 2003-06-10 Cabot Corporation Oxygen reduced niobium oxides
US20040163491A1 (en) * 2000-10-10 2004-08-26 Shekhter Leonid N. Metalothermic reduction of refractory metal oxides
US20040226630A1 (en) * 2003-05-16 2004-11-18 Koenitzer John W. Controlled oxygen addition for metal material
US20050008564A1 (en) * 2003-02-26 2005-01-13 Reed David M. Phase formation of oxygen reduced valve metal oxides and granulation methods
US20050025699A1 (en) * 2003-05-19 2005-02-03 Reed David M. Methods of making a niobium metal oxide and oxygen reduced niobium oxides
US6863750B2 (en) 2000-05-22 2005-03-08 Cabot Corporation High purity niobium and products containing the same, and methods of making the same
US20050279187A1 (en) * 2004-06-21 2005-12-22 Shekhter Leonid N Metalothermic reduction of refractory metal oxides
US20060065073A1 (en) * 2004-09-29 2006-03-30 Shekhter Leonid N Magnesium removal from magnesium reduced metal powders
EP1093137A4 (en) * 1999-02-16 2006-07-26 Showa Denko Kk NIOBIUM POWDER, SINTERED ELEMENT BASED ON NIOBIUM, CAPACITOR COMPRISING THIS ELEMENT AND METHOD FOR MANUFACTURING THE CAPACITOR
US7099143B1 (en) 2005-05-24 2006-08-29 Avx Corporation Wet electrolytic capacitors
US20070211413A1 (en) * 2006-03-09 2007-09-13 Avx Corporation Wet electrolytic capacitor containing a cathode coating
US20070211412A1 (en) * 2006-03-09 2007-09-13 Avx Corporation Wet electrolytic capacitor
US20080106852A1 (en) * 2004-11-29 2008-05-08 Showa Denko K.K. Porous Anode Body For Solid Electrolytic Capacitor, Production Method Thereof and Solid Electrolytic Capacitor
US20080105082A1 (en) * 2004-09-29 2008-05-08 Shekhter Leonid N Magnesium Removal From Magnesium Reduced Metal Powders
US20080232030A1 (en) * 2007-03-20 2008-09-25 Avx Corporation Wet electrolytic capacitor containing a plurality of thin powder-formed anodes
US20080232031A1 (en) * 2007-03-20 2008-09-25 Avx Corporation Cathode coating for a wet electrolytic capacitor
US20080232029A1 (en) * 2007-03-20 2008-09-25 Avx Corporation Neutral electrolyte for a wet electrolytic capacitor
WO2010030543A1 (en) * 2008-09-09 2010-03-18 H.C. Starck Inc. Dynamic dehydriding of refractory metal powders
RU2465097C1 (ru) * 2011-05-04 2012-10-27 Федеральное государственное бюджетное учреждение науки Институт химии и технологии редких элементов и минерального сырья им. И.В. Тананаева Кольского научного центра Российской академии наук (ИХТРЭМС КНЦ РАН) Способ получения порошка тантала
US20130014611A1 (en) * 2010-04-01 2013-01-17 Mami Yoshida Method for recovering tantalum
CZ303684B6 (cs) * 1998-05-06 2013-03-06 H. C. Starck Inc. Slitinový prásek, zpusob jeho výroby, anoda kondenzátoru z tohoto slitinového prásku a kondenzátor, a prásek slitiny niobu a tantalu
CN104439264A (zh) * 2014-12-19 2015-03-25 九江有色金属冶炼有限公司 一种铌条的制备方法及其制备的铌条

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ES2020131A6 (es) * 1989-06-26 1991-07-16 Cabot Corp Procedimiento para la produccion de polvos de tantalo, niobio y sus aleaciones.
US5242481A (en) * 1989-06-26 1993-09-07 Cabot Corporation Method of making powders and products of tantalum and niobium
DE19831280A1 (de) * 1998-07-13 2000-01-20 Starck H C Gmbh Co Kg Verfahren zur Herstellung von Erdsäuremetallpulvern, insbesondere Niobpulvern
RU2245384C1 (ru) * 2003-05-20 2005-01-27 Открытое акционерное общество "Чепецкий механический завод" (ОАО ЧМЗ) Способ получения чистого ниобия

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Cited By (88)

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US4347084A (en) * 1975-04-18 1982-08-31 Hermann C. Starck Berlin Electrodes of sintered tantalum powder of fine grain size and process of production
US4113479A (en) * 1976-02-27 1978-09-12 Amax Inc. Vacuum smelting process for producing ferrotungsten
US6420043B1 (en) 1996-11-07 2002-07-16 Cabot Corporation Niobium powders and niobium electrolytic capacitors
US6165623A (en) * 1996-11-07 2000-12-26 Cabot Corporation Niobium powders and niobium electrolytic capacitors
US6051326A (en) * 1997-04-26 2000-04-18 Cabot Corporation Valve metal compositions and method
US6231689B1 (en) 1997-04-26 2001-05-15 Cabot Corporation Valve metal compositions and method
US6517645B2 (en) 1997-04-26 2003-02-11 Cabot Corporation Valve metal compositions and method
US6051044A (en) * 1998-05-04 2000-04-18 Cabot Corporation Nitrided niobium powders and niobium electrolytic capacitors
US6338816B1 (en) 1998-05-04 2002-01-15 Cabot Corporation Nitrided niobium powders and niobium electrolytic capacitors
US6896715B2 (en) 1998-05-04 2005-05-24 Cabot Corporation Nitrided niobium powders and niobium electrolytic capacitors
US20040089100A1 (en) * 1998-05-04 2004-05-13 Fife James A. Nitrided niobium powders and niobium electrolytic capacitors
US6616728B2 (en) 1998-05-04 2003-09-09 Cabot Corporation Nitrided niobium powders and niobium electrolytic capacitors
CZ303684B6 (cs) * 1998-05-06 2013-03-06 H. C. Starck Inc. Slitinový prásek, zpusob jeho výroby, anoda kondenzátoru z tohoto slitinového prásku a kondenzátor, a prásek slitiny niobu a tantalu
CZ302249B6 (cs) * 1998-05-06 2011-01-12 H. C. Starck, Inc. Zpusob výroby kovových prášku
US6171363B1 (en) * 1998-05-06 2001-01-09 H. C. Starck, Inc. Method for producing tantallum/niobium metal powders by the reduction of their oxides with gaseous magnesium
US20040033183A1 (en) * 1998-09-16 2004-02-19 Fife James A. Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides
US6391275B1 (en) * 1998-09-16 2002-05-21 Cabot Corporation Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides
US6462934B2 (en) 1998-09-16 2002-10-08 Cabot Corporation Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides
US20050084445A1 (en) * 1998-09-16 2005-04-21 Kimmel Jonathon L. Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides
US6527937B2 (en) 1998-09-16 2003-03-04 Cabot Corporation Method of making a capacitor anode of a pellet of niobium oxide
US7445762B2 (en) 1998-09-16 2008-11-04 Cabot Corporation Method to partially reduce calcined niobium metal oxide and oxygen reduced niobium oxides
US6373685B1 (en) 1998-09-16 2002-04-16 Cabot Corporation Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides
US6592740B2 (en) 1998-09-16 2003-07-15 Cabot Corporation Methods to make capacitors containing a partially reduced niobium metal oxide
US6759026B2 (en) 1998-09-16 2004-07-06 Cabot Corporation Methods to partially reduce a niobium metal oxide and oxygen reduced niobium oxides
US6136062A (en) * 1998-10-13 2000-10-24 H. C. Starck Gmbh & Co. Kg Niobium powder and a process for the production of niobium and/or tantalum powders
US6893513B2 (en) 1998-11-25 2005-05-17 Cabot Corporation High purity tantalum, products containing the same, and methods of making the same
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US20030168131A1 (en) * 1998-11-25 2003-09-11 Michaluk Christopher A. High purity tantalum, products containing the same, and methods of making the same
US6348113B1 (en) 1998-11-25 2002-02-19 Cabot Corporation High purity tantalum, products containing the same, and methods of making the same
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US6402066B1 (en) 1999-03-19 2002-06-11 Cabot Corporation Method of making niobium and other metal powders
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US20050039577A1 (en) * 1999-03-19 2005-02-24 Habecker Kurt A. Method of making niobium and other metal powders
US7749297B2 (en) 1999-05-12 2010-07-06 Cabot Corporation High capacitance niobium powders and electrolytic capacitor anodes
US20040237714A1 (en) * 1999-05-12 2004-12-02 Habecker Kurt A. High capacitance niobium powders and electrolytic capacitor anodes
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US6576099B2 (en) 2000-03-23 2003-06-10 Cabot Corporation Oxygen reduced niobium oxides
US6863750B2 (en) 2000-05-22 2005-03-08 Cabot Corporation High purity niobium and products containing the same, and methods of making the same
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US6849104B2 (en) 2000-10-10 2005-02-01 H. C. Starck Inc. Metalothermic reduction of refractory metal oxides
US7678175B2 (en) 2000-10-10 2010-03-16 H.C. Starck Inc. Metalothermic reduction of refractory metal oxides
US7150776B2 (en) 2000-10-10 2006-12-19 H.C. Starck Inc. Metalothermic reduction of refractory metal oxides
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DE1928149A1 (de) 1969-12-11
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FR2010259A1 (cs) 1970-02-13
BE734012A (cs) 1969-11-17
CH515996A (de) 1971-11-30

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