DE19831280A1 - Acidic earth metal, specifically tantalum or niobium, powder for use, e.g., in capacitor production is produced by two-stage reduction of the pentoxide using hydrogen as the first stage reducing agent for initial suboxide formation - Google Patents
Acidic earth metal, specifically tantalum or niobium, powder for use, e.g., in capacitor production is produced by two-stage reduction of the pentoxide using hydrogen as the first stage reducing agent for initial suboxide formationInfo
- Publication number
- DE19831280A1 DE19831280A1 DE19831280A DE19831280A DE19831280A1 DE 19831280 A1 DE19831280 A1 DE 19831280A1 DE 19831280 A DE19831280 A DE 19831280A DE 19831280 A DE19831280 A DE 19831280A DE 19831280 A1 DE19831280 A1 DE 19831280A1
- Authority
- DE
- Germany
- Prior art keywords
- reduction
- stage
- niobium
- ppm
- hydrogen
- 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.)
- Ceased
Links
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 49
- 239000002184 metal Substances 0.000 title claims abstract description 49
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 title claims abstract description 41
- 229910052758 niobium Inorganic materials 0.000 title claims abstract description 32
- 239000010955 niobium Substances 0.000 title claims abstract description 32
- 239000000843 powder Substances 0.000 title claims abstract description 30
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 25
- 239000001257 hydrogen Substances 0.000 title claims abstract description 24
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 22
- 229910052715 tantalum Inorganic materials 0.000 title claims abstract description 16
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 title claims abstract description 16
- 239000003638 chemical reducing agent Substances 0.000 title claims abstract description 9
- 239000003990 capacitor Substances 0.000 title claims description 21
- 230000015572 biosynthetic process Effects 0.000 title claims description 8
- 238000004519 manufacturing process Methods 0.000 title abstract description 8
- 230000002378 acidificating effect Effects 0.000 title abstract 2
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 17
- 239000003054 catalyst Substances 0.000 claims abstract description 16
- 238000005984 hydrogenation reaction Methods 0.000 claims abstract description 14
- 150000002739 metals Chemical class 0.000 claims abstract description 9
- 229910052987 metal hydride Inorganic materials 0.000 claims abstract description 7
- 150000004681 metal hydrides Chemical class 0.000 claims abstract description 7
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 4
- 150000004678 hydrides Chemical class 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 14
- 229910052760 oxygen Inorganic materials 0.000 claims description 14
- 239000001301 oxygen Substances 0.000 claims description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 13
- 239000002253 acid Substances 0.000 claims description 11
- 238000005245 sintering Methods 0.000 claims description 8
- 239000002245 particle Substances 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000011164 primary particle Substances 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- 229910044991 metal oxide Inorganic materials 0.000 claims description 2
- 150000004706 metal oxides Chemical class 0.000 claims description 2
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 claims 1
- 239000007787 solid Substances 0.000 claims 1
- WTKKCYNZRWIVKL-UHFFFAOYSA-N tantalum Chemical compound [Ta+5] WTKKCYNZRWIVKL-UHFFFAOYSA-N 0.000 abstract 1
- 239000011777 magnesium Substances 0.000 description 18
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 14
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 12
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Inorganic materials O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 description 7
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 description 7
- 229910052759 nickel Inorganic materials 0.000 description 6
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 150000001342 alkaline earth metals Chemical class 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910052700 potassium Inorganic materials 0.000 description 3
- 239000002243 precursor Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- CSDQQAQKBAQLLE-UHFFFAOYSA-N 4-(4-chlorophenyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine Chemical compound C1=CC(Cl)=CC=C1C1C(C=CS2)=C2CCN1 CSDQQAQKBAQLLE-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- YZCKVEUIGOORGS-UHFFFAOYSA-N Hydrogen atom Chemical compound [H] YZCKVEUIGOORGS-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- -1 Miller Chemical compound 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 238000011038 discontinuous diafiltration by volume reduction Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 230000009969 flowable effect Effects 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 150000002816 nickel compounds Chemical class 0.000 description 1
- 229910000480 nickel oxide Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-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
- H01G9/0525—Powder therefor
-
- 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
- B22F9/22—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from solid metal compounds using gaseous reductors
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/04—Making non-ferrous alloys by powder metallurgy
- C22C1/045—Alloys based on refractory metals
-
- 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
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
-
- 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
- B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Power Engineering (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
Description
Erdsäuremetallpulver, insbesondere Tantalpulver sind wichtige Ausgangsstoffe der Elektronikindustrie, insbesondere für die Herstellung von Kondensatoren. So hatte nach Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition, Volume A 26, p. 80, 1993, der Verbrauch an Tantal für Kondensatoren bereits mehr als 50% der Weltproduktion an Tantal von ca. 1000 t/a erreicht, wogegen Niob im wesentlichen keinen Eingang in die Kondensatoranwendung gefunden hat, obwohl die Rohstoff basis für Niob erheblich breiter ist als die für Tantal.Earth acid metal powder, especially tantalum powder, are important raw materials for the Electronics industry, especially for the production of capacitors. So had according to Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition, Volume A 26, p. 80, 1993, the consumption of tantalum for capacitors already more than 50% of the World tantalum production of about 1000 t / a reached, whereas niobium essentially has not found its way into the capacitor application, even though the raw material base for niobium is considerably wider than that for tantalum.
Der Grund hierfür ist darin zu sehen, daß mit dem auf Hellier und Martin (US- A 2,950,185) zurückgehenden Prozeß der Reduktion von Kaliumheptaflorotantalat mittels Natrium in einer Salzschmelze ein Verfahren zur Verfügung steht, sehr reine und feinteilige Tantalpulver zu erzeugen, die die vielfältigen Anforderungen der Kon densatorindustrie erfüllen. Der entsprechende Prozeß über Kaliumheptafloroniobat steht für die Herstellung von hochreinen Niobpulvern nicht zur Verfügung, einerseits wegen der schweren Fällbarkeit und der Aggressivität der entsprechenden Heptaflo roniobatsalze, andererseits fällte das daraus reduzierte Niob sehr unrein an. Demge mäß hat Niob nur in untergeordneten Umfang Eingang in die Kondensatorindustrie gefunden, überwiegend in Bereichen mit geringeren Qualitätsanforderungen. Niob kondensatoren des Standes der Technik zeigen ferner eine auf unzureichende Reinheit zurückzuführende Kristallisationsneigung des isolierenden Oxidfilms, die eine be grenzte Langzeitstabilität bedingt.The reason for this can be seen in the fact that with the Hellier and Martin (US- A 2,950,185) declining process of the reduction of potassium heptaflorotantalate a process is available using sodium in a molten salt, very pure and to produce fine-particle tantalum powder that meets the diverse requirements of the Kon meet the capacitor industry. The corresponding process over potassium heptafloroniobate is not available for the production of high-purity niobium powders, on the one hand because of the difficulty of felling and the aggressiveness of the corresponding heptaflo roniobate salts, on the other hand the resulting niobium was very impure. Demge According to niobium, it only enters the capacitor industry to a minor extent found, mainly in areas with lower quality requirements. Niobium State of the art capacitors also show insufficient purity attributable crystallization tendency of the insulating oxide film, which a be limited long-term stability.
Alternative Herstellungsverfahren für die Metallpulver gehen von den Pentachloriden oder Pentoxiden aus, die mit reduzierenden Alkali- und/oder Erdalkalimetallen, ins besondere Magnesium, thermisch umgesetzt werden (Hurd, US-A 4,687,632). Bei spielsweise beschreiben Dennis und Adamson, U. K. A. E. A. Techn. Note Nr. 92 (154), zitiert in: Miller, Tantalum and Niobium, Miller, Tantalum and Niobium, Lon don 1959, p. 188 einen Prozeß, bei dem Niobpentoxid in eine Magnesiumschmelze eingeleitet wird. Nach Beendigung der Reaktion und Abkühlen wird das Niobmetall- Pulver durch Waschen mit Salzsäure gewonnen. Derartig hergestellte Niobmetall-Pul ver weisen hohe Magnesium- und Sauerstoffgehalte auf, die die Pulver für hochquali tative Kondensator-Anwendungen ungeeignet machen.Alternative manufacturing processes for the metal powder come from the pentachlorides or pentoxides, which with reducing alkali and / or alkaline earth metals, ins special magnesium, can be thermally converted (Hurd, US-A 4,687,632). At for example, Dennis and Adamson, U. K.A.E.A. describe Techn. Note No. 92 (154), cited in: Miller, Tantalum and Niobium, Miller, Tantalum and Niobium, Lon don 1959, p. 188 a process in which niobium pentoxide is melted into a magnesium is initiated. After completion of the reaction and cooling, the niobium metal Powder obtained by washing with hydrochloric acid. Niobium metal pulp produced in this way ver have high magnesium and oxygen levels, which are the powders for high quality Make unsuitable capacitor applications.
Insbesondere wird die für Kondensatoranwendungen erforderliche Agglomeratstruk tur ohne zusätzliche Temperaturbehandlungen nicht erhalten.In particular, the agglomerate structure required for capacitor applications not received without additional temperature treatments.
Die direkte Reduktion von Niobpentoxid mit Wasserstoff erfordert Temperaturen von oberhalb 2 500°C (Miller, Tantalum and Niobium, London 1959, p.188. Die gemein same Reduktion von Niobpentoxid und Nickeloxid im Wasserstoffstrom mit an schließender Entfernung des Nickels als Nickelcarbonyl gelingt bei niedriger Tempe ratur, jedoch weisen auch derartige Niobmetall-Pulver hohe Restgehalte an Nickel auf.The direct reduction of niobium pentoxide with hydrogen requires temperatures of above 2500 ° C (Miller, Tantalum and Niobium, London 1959, p.188) same reduction of niobium pentoxide and nickel oxide in a hydrogen stream the subsequent removal of nickel as nickel carbonyl succeeds at low temperatures rature, however, such niobium metal powders also have high residual nickel contents on.
Die vorliegende Erfindung geht von dem bekannten Verfahren der Reduktion von
Niobpentoxid mit reduzierenden Alkali- und/oder Erdalkalimetallen aus. Dabei ent
stehen Niobmetallpulver mit hohen Sauerstoff und Reduktionsmetallgehalten, die
nicht mehr ausgewaschen werden können. Es wird angenommen, daß es sich hierbei
um in dem Niobmetall gelöste Niobate handelt, die nach folgender Reaktion entste
hen:
The present invention is based on the known method of reducing niobium pentoxide with reducing alkali and / or alkaline earth metals. This creates niobium metal powders with high oxygen and reducing metal contents that can no longer be washed out. It is assumed that these are niobates dissolved in the niobium metal, which arise after the following reaction:
1. Nb2O5 + 5 Mg → 5Nb + 5 MgO
2. Nb2O5 + MgO → MgNb2O6.
1. Nb 2 O 5 + 5 Mg → 5Nb + 5 MgO
2. Nb 2 O 5 + MgO → MgNb 2 O 6 .
Das Niobat, das gegebenenfalls in Form von Clustern in dem Niobmetall vorhanden ist, widersteht dem reduzierenden Angriff des reduzierenden Metalls und läßt sich auch durch Waschen mit Säure aus dem Niobmetall nur unzureichend entfernen.The niobate, which may be present in the form of clusters in the niobium metal resists the reducing attack of the reducing metal and can be also insufficiently remove from the niobium metal by washing with acid.
Es wurde nun gefunden, daß sehr reine, sauerstoffarme und lediglich für Konden satoranwendungen tolerierbare Mengen an reduzierendem Metall enthaltende Niob metall-Pulver erhalten werden, wenn das Niobpentoxid mittels Wasserstoff zum Niob suboxid reduziert wird, bevor das Suboxid mittels reduzierend wirkender Metalle zum Niobmetall reduziert wird. Dies schien zunächst deswegen überraschend, weil das Niobsuboxid (NbO2) lediglich 20% weniger Sauerstoff aufweist, als das Niob pentoxid (NbO2,5). Der zunächst überraschende Effekt wird darauf zurückgeführt, daß das Suboxid ein wesentlich dichteres Kristallgitter bildet, als das Pentoxid. Die Dichte von NbO2,5 beträgt 4,47 g/cm3, die von NbO2 dagegen 7,28 g/cm3, d. h. durch Entzug von lediglich 20% des Sauerstoffs wird die Dichte auf das 1,6-fache gestei gert. Unter Berücksichtigung des unterschiedlichen Atomgewichtes von Niob und Sauerstoff ist mit der Reduktion von NbO2,5 zum NbO2 eine Volumenreduktion um 42% verbunden. Der erfindungsgemäße Effekt scheint demgemäß dadurch erklärbar, daß das Magnesium bei Reduktion des Pentoxides relativ leicht in das Gitter einde fundieren kann und dort eine hohe Beweglichkeit besitzt, während die Beweglichkeit des Magnesiums in dem Suboxidgitter erheblich reduziert ist. Demgemäß bleibt das Magnesium bei der Reduktion des Suboxides im wesentlichen auf der Oberfläche und steht für den Angriff der Waschsäuren zur Verfügung.It has now been found that very pure, low-oxygen and only for capacitor applications tolerable amounts of reducing metal containing niobium metal powder can be obtained if the niobium pentoxide is reduced to the niobium suboxide by means of hydrogen before the suboxide is reduced to the niobium metal by means of reducing metals . This initially seemed surprising because the niobium suboxide (NbO 2 ) contains only 20% less oxygen than the niobium pentoxide (NbO 2.5 ). The initially surprising effect is attributed to the fact that the suboxide forms a much denser crystal lattice than the pentoxide. The density of NbO 2.5 is 4.47 g / cm 3 , that of NbO 2, on the other hand, is 7.28 g / cm 3 , ie by removing only 20% of the oxygen, the density is increased 1.6 times . Taking into account the different atomic weights of niobium and oxygen, the reduction of NbO 2.5 to NbO 2 is associated with a volume reduction of 42%. The effect according to the invention accordingly seems to be explained by the fact that the magnesium can be found in the lattice relatively easily when the pentoxide is reduced and has a high mobility there, while the mobility of the magnesium in the suboxide lattice is considerably reduced. Accordingly, the magnesium remains essentially on the surface during the reduction of the suboxide and is available for attacking the washing acids.
Ferner wird durch die Reduktion des Pentoxides mit Wasserstoff ein Suboxid erhal ten, das bereits zu Agglomeraten mit stabilen Sinterbrücken versintert ist, die die für den Einsatz als Kondensatormaterial günstige Struktur aufweisen.Furthermore, a suboxide is obtained by reducing the pentoxide with hydrogen ten, which is already sintered to form agglomerates with stable sintered bridges that are suitable for have a favorable structure as a capacitor material.
Obwohl die Untersuchung zum Gegenstand der vorliegenden Erfindung am Beispiel des Niob durchgeführt wurden, wird angenommen, daß die Herstellung von Tantal pulver in analoger Weise durchgeführt werden kann.Although the investigation of the subject of the present invention using the example of niobium, it is believed that the production of tantalum powder can be carried out in an analogous manner.
Obwohl die Untersuchung zur vorliegenden Erfindung mit Magnesium als Reduk tionsmittel für die Reduktion des Suboxides durchgeführt wurden, wird angenommen, daß als Reduktionsmittel für das Suboxid auch andere Erdalkalimetalle, insbesondere Kalzium und deren Hydride, insbesondere Kalziumhydrid eingesetzt werden können.Although the investigation of the present invention with magnesium as Reduk agents for the reduction of the suboxide are assumed that as a reducing agent for the suboxide also other alkaline earth metals, in particular Calcium and their hydrides, in particular calcium hydride can be used.
Ferner wird angenommen, daß die Reduktion der Suboxide auch mittels Wasserstoff bei Temperaturen von 1100 bis 1300°C durchgeführt werden kann, wenn die Reduk tion in Gegenwart katalytisch wirksamer Substanzen durchgeführt wird. Wesentlich ist lediglich, daß während der Reduktion des Pentoxides zum Suboxid mittels Wasser stoff die Gegenwart von Fremdsubstanzen, die in das Suboxid eindiffundieren und die Ausbildung stabiler Sinterbrücken stören, ausgeschlossen ist. Beispielsweise könnte die Reduktion vom Suboxid zum Metall analog zur Lehre der US-Patentschrift 2,761,776 durchgeführt werden, indem das Suboxid mit reduzierbaren Nickelverbin dungen vermischt wird, und nach Beendigung der Reduktion das Nickel entfernt wird.It is also assumed that the reduction of the suboxides also by means of hydrogen can be carried out at temperatures of 1100 to 1300 ° C if the Reduk tion is carried out in the presence of catalytically active substances. Essential is only that during the reduction of the pentoxide to suboxide using water the presence of foreign substances that diffuse into the suboxide and that Disrupt the formation of stable sinter bridges, is excluded. For example the reduction from suboxide to metal analogous to the teaching of the US patent 2,761,776 can be performed using the suboxide with reducible nickel compound is mixed, and after the reduction, the nickel is removed.
Gegenstand der vorliegenden Erfindung ist demgemäß ein Verfahren zur Herstellung von Erdsäuremetallpulver durch Reduktion der entsprechenden Pentoxide, das da durch gekennzeichnet ist, daß die Reduktion zweistufig durchgeführt wird, wobei in der ersten Stufe als Reduktionsmittel Wasserstoff eingesetzt wird und in der zweiten Stufe als Reduktionsmittel reduzierende Metalle oder Metallhydride oder Wasserstoff in Gegenwart von Hydrierkatalysatoren eingesetzt werden und die erzeugten Erd säuremetallpulver von den entstehenden Metalloxiden bzw. Hydrierkatalysatoren ab getrennt werden.The present invention accordingly relates to a method for the production of earth acid metal powder by reduction of the corresponding pentoxides is characterized in that the reduction is carried out in two stages, wherein in hydrogen is used in the first stage as a reducing agent and in the second Stage as reducing agent reducing metals or metal hydrides or hydrogen be used in the presence of hydrogenation catalysts and the soil produced acid metal powder from the resulting metal oxides or hydrogenation catalysts be separated.
Als Erdsäuremetalle werden Tantal und Niob bezeichnet. Vorzugsweise werden die Pentoxide in Form von feinteiligen Pulvern eingesetzt. Die Primärkorngröße der Pentoxid-Pulver soll etwa dem 2 bis 3-fachen gewünschten Primärkorngröße der zu erzeugenden Metallpulver entsprechen. Vorzugsweise bestehen die Pentoxid-Teilchen aus fließfähigen Agglomeraten mit mittleren Teilchengrößen von 20 bis 1000 µm, vor zugsweise von 50 bis 300 µm.Tantalum and niobium are referred to as earth acid metals. Preferably the Pentoxides used in the form of finely divided powders. The primary grain size of the Pentoxide powder is said to be about 2 to 3 times the desired primary grain size corresponding metal powder. The pentoxide particles preferably consist from flowable agglomerates with average particle sizes of 20 to 1000 microns preferably from 50 to 300 µm.
Die Reduktion zum Suboxid kann im bewegten oder unbewegten Bett, wie Drehrohr, Etagenofen, Wirbelbett, oder im Durchschubofen erfolgen. Wird ein unbewegtes Bett eingesetzt, soll die Bettiefe 5 bis 15 cm nicht übersteigen, damit das reduzierende Gas das Bett durchdringen kann. Größere Bettiefen sind möglich, wenn eine von unten von dem Gas durchströmte Schüttung eingesetzt wird. Die Temperatur während der Reduktion mit Wasserstoff in der ersten Stufe, kann vorteilhaft zwischen 1.000 und 1.500°C gewählt werden. Niedrige Temperaturen verlangen längere Reduktionszeiten. Durch die Wahl der Reduktionstemperatur und Reduktionszeit kann ferner der Ver sinterungsgrad der zu erzeugenden Metallpulver vorwählbar eingestellt werden. Die Reaktoren sind vorzugsweise mit Molybdänblech oder einer durch H2 nicht reduzier baren Keramik ausgekleidet, um eine Kontamination zu vermeiden.The reduction to suboxide can take place in a moving or unmoving bed, such as a rotary kiln, multi-deck oven, fluidized bed, or in a push-through oven. If an unmoving bed is used, the bed depth should not exceed 5 to 15 cm so that the reducing gas can penetrate the bed. Greater bed depths are possible if a bed through which the gas flows is used. The temperature during the reduction with hydrogen in the first stage can advantageously be chosen between 1,000 and 1,500 ° C. Low temperatures require longer reduction times. Through the choice of the reduction temperature and reduction time, the degree of sintering of the metal powder to be produced can also be preset. The reactors are preferably lined with molybdenum sheet or a ceramic which cannot be reduced by H 2 in order to avoid contamination.
Reduktionszeit und Reduktionstemperatur sind ferner so zu wählen, daß mindestens 20% des Sauerstoffs aus dem Pentoxid entfernt werden. Höhere Reduktionsgrade sind nicht schädlich. Doch gelingt es regelmäßig nicht, innerhalb absehbarer Zeiten und bei tolerierbaren Temperaturen mehr als 60% des Sauerstoffs zu reduzieren. Nach Erreichen eines Reduktionsgrades von 20%, d. h. nach Vorliegen des Suboxides NbO2 bzw. TaO/Ta2O5 wird das Reduktionsprodukt vorzugsweise noch einige Zeit, vorzugsweise ca. 60 bis 360 Minuten bei einer Temperatur von oberhalb 1000°C ge halten (getempert), damit sich die neue, dichte Kristallstruktur ausbilden und stabili sieren kann. Da die Reduktionsgeschwindigkeit mit dem Reduktionsgrad sehr stark abnimmt, ist es ausreichend, das Suboxid bei Reduktionstemperatur unter Wasserstoff gegebenenfalls bei leichter Temperaturabsenkung, zu tempern. Typischerweise sind im Temperaturbereich von 1100 bis 1500°C Reduktions- und Temperzeiten von 2 bis 6 Stunden ausreichend. Die Reduktion mit Wasserstoff hat ferner den Vorteil, daß für Kondensatoranwendungen kritische Verunreinigungen wie F, Cl und C auf bis zu un ter 2 ppm abgesenkt werden.The reduction time and the reduction temperature must also be chosen so that at least 20% of the oxygen is removed from the pentoxide. Higher degrees of reduction are not harmful. However, it is usually not possible to reduce more than 60% of the oxygen within the foreseeable future and at tolerable temperatures. After a degree of reduction of 20% has been reached, ie after the suboxide NbO 2 or TaO / Ta 2 O 5 has been present , the reduction product is preferably kept for a while, preferably about 60 to 360 minutes, at a temperature above 1000 ° C. ), so that the new, dense crystal structure can form and stabilize. Since the rate of reduction decreases very sharply with the degree of reduction, it is sufficient to anneal the suboxide at the reduction temperature under hydrogen, if necessary with a slight decrease in temperature. In the temperature range from 1100 to 1500 ° C., reduction and annealing times of 2 to 6 hours are typically sufficient. The reduction with hydrogen also has the advantage that critical contaminants such as F, Cl and C are reduced to up to less than 2 ppm for capacitor applications.
Anschließend wird das Suboxid im Reduktionsaggregat auf Raumtemperatur (< 100°C) abgekühlt, das Suboxidpulver mit feinteiligen Pulvern der reduzierenden Metalle bzw. Metallhydride oder dem Hydrierkatalysator bzw. dessen Vorläuferver bindung (die unter Wasserstoff zum Hydrierkatalysator reduziert wird) vermischt und die Mischung unter Inertgas bzw. Wasserstoff auf die Reduktionstemperatur der zweiten Stufe erhitzt. Die reduzierenden Metalle oder Metallhydride werden vor zugsweise in stöchiometrischer Menge bezogen auf den Restsauerstoff des Erdsäure metallsuboxids, besonders bevorzugt leicht überstöchiometrisch, eingesetzt.The suboxide is then brought to room temperature in the reduction unit (<100 ° C) cooled, the suboxide powder with finely divided powders of the reducing Metals or metal hydrides or the hydrogenation catalyst or its precursor bond (which is reduced to the hydrogenation catalyst under hydrogen) and the mixture under inert gas or hydrogen to the reduction temperature of second stage heated. The reducing metals or metal hydrides are pre preferably in a stoichiometric amount based on the residual oxygen of the earth acid metal suboxide, particularly preferably slightly overstoichiometric, used.
Die Temperatur während der Reduktion in der zweiten Stufe kann vorteilhaft zwischen 900 und 1200°C gewählt werden. Im Falte der Reduktion mit Wasserstoff in Gegenwart von Hydrierkatalysatoren wird bevorzugt eine Temperatur im oberen Be reich des genannten Temperaturbereichs gewählt.The temperature during the reduction in the second stage can be advantageous can be selected between 900 and 1200 ° C. In the fold of reduction with hydrogen in The presence of hydrogenation catalysts is preferably a temperature in the upper range range of the temperature range selected.
Als Reaktoren können die für die erste Reduktionsstufe genannten Reaktoren ein gesetzt werden.The reactors mentioned for the first reduction stage can be used as reactors be set.
Eine besondere bevorzugte Verfahrensweise besteht darin, in der ersten Stufe ein be wegtes Bett einzusetzen und die zweite Stufe ohne Zwischenabkühlung in dem selben Reaktor unter Einleitung der reduzierenden Metalle oder Metallhydride bzw. des Hydrierkatalysators oder dessen Vorstufe durchzuführen. Wird Magnesium als redu zierendes Metall eingesetzt, erfolgt die Einleitung des Magnesiums vorzugsweise als Magnesiumdampf, da auf diese Weise eine leichte Kontrolle der Umsetzung zum Me tallpulver ermöglicht wird.A particularly preferred procedure is to be a in the first stage insert bed and the second stage without intermediate cooling in the same Reactor with introduction of the reducing metals or metal hydrides or Perform hydrogenation catalyst or its precursor. Is magnesium as redu used decorative metal, the introduction of the magnesium is preferably carried out as Magnesium vapor, because in this way an easy control of the conversion to the Me tall powder is made possible.
Als Hydrierkatalysatoren sind prinzipiell alle Katalysatoren geeignet, die in der Lage sind, atomaren Wasserstoff bereitzustellen. Unter Berücksichtigung des Erfordernis ses der späteren Abtrennung des Katalysators von dem Erdsäuremetall werden bevor zugt weniger edle Metalle als Hydrierkatalysatoren eingesetzt, insbesondere Nickel. Bevorzugt kann ein Nickelhydroxid mit einer BET-Oberfläche von oberhalb 50 m2/g als Vorläuferverbindung für den Hydrierkatalysator eingesetzt werden. Das Nickel hydroxid wird dann bei Reduktionstemperatur durch den Wasserstoff zum Nickel katalysator reduziert.In principle, all catalysts which are capable of providing atomic hydrogen are suitable as hydrogenation catalysts. Taking into account the requirement of later separation of the catalyst from the earth acid metal, less noble metals are preferably used than hydrogenation catalysts, in particular nickel. A nickel hydroxide with a BET surface area of above 50 m 2 / g can preferably be used as a precursor compound for the hydrogenation catalyst. The nickel hydroxide is then reduced to the nickel catalyst by the hydrogen at the reduction temperature.
Nach Beendigung der Reduktion zum Erdsäuremetall wird das Metall abgekühlt, so fern die zweite Reduktionsstufe unter Wasserstoff durchgeführt wurde, der Wasser stoff durch Intergas ersetzt, und anschließend das Intergas mit allmählich steigerndem Sauerstoffgehalt zur Desaktivierung des Metallpulvers durch den Reaktor geleitet. Die Oxide der reduzierenden Metalle werden in an sich bekannter Weise durch Waschung mit Säuren entfernt.After completion of the reduction to the earth acid metal, the metal is cooled, so unless the second reduction stage was carried out under hydrogen, water Substance replaced by intergas, and then the intergas with gradually increasing Oxygen content to deactivate the metal powder passed through the reactor. The oxides of the reducing metals are passed through in a manner known per se Wash with acids removed.
Gegenstand der Erfindung ist auch das nach dem erfindungsgemäßen Verfahren er hältliche Niobpulver, das Sauerstoff in Mengen von 2500 bis 4500 ppm/m2 Ober fläche aufweist und im übrigen sauerstoffarm ist, bis zu 10.000 ppm Stickstoff, bis zu 150 ppm Kohlenstoff und ohne Berücksichtigung eines gegebenenfalls vorhandenen Tantalgehaltes weitere Metallgehalte von maximal 350 ppm aufweist, wobei der Me tallgehalt überwiegend das in der zweiten Reduktionsstufe eingesetzte reduzierende Metall bzw. das Hydrierkatalysatormetall ist. Die weiteren Metallgehalte sind in der Summe mit nicht mehr als 100 ppm vorhanden. Der Gehalt an F, Cl, S beträgt zu sammen weniger als 10 ppm.The invention also relates to the niobium powder obtainable by the process according to the invention, which has oxygen in amounts of 2500 to 4500 ppm / m 2 surface and is also low in oxygen, up to 10,000 ppm nitrogen, up to 150 ppm carbon and without considering one optionally present tantalum content has further metal contents of at most 350 ppm, the metal content predominantly being the reducing metal used in the second reduction stage or the hydrogenation catalyst metal. The other metal contents are not more than 100 ppm in total. The F, Cl, S content together is less than 10 ppm.
Die erfindungsgemäßen Niobpulver können bis zu 50 Gew.-% Tantal enthalten, wenn entsprechende Mischode (Nb, Ta)2O5 eingesetzt werden.The niobium powders according to the invention can contain up to 50% by weight of tantalum if appropriate mixed modes (Nb, Ta) 2 O 5 are used.
Besonders bevorzugte erfindungsgemäße Niobpulver werden in Form von agglo merierten Primärteilchen einer Primärteilchengröße von 100 bis 1000 nm erhalten, wobei die Agglomerate eine Teilchengrößenverteilung nach Mastersizer (ASTM-B- 822) von D10 = 3 bis 7 µm, D50 = 130 bis 180 µm und D90 = 280 bis 350 µm auf weisen. Die erfindungsgemäßen Pulver weisen hervorragende Fließeigenschaften und Preßfestigkeiten, die ihre Verarbeitbarkeit zu Kondensatoren bestimmen, auf. Die Agglomerate sind durch stabile Sinterbrücken, die nach Verarbeitung zu Kondensato ren günstige Porosität gewährleisten, gekennzeichnet.Particularly preferred niobium powders according to the invention are in the form of agglomerates obtained primary particles with a primary particle size of 100 to 1000 nm, where the agglomerates have a particle size distribution according to Mastersizer (ASTM-B- 822) from D10 = 3 to 7 µm, D50 = 130 to 180 µm and D90 = 280 to 350 µm point. The powders according to the invention have excellent flow properties and Compressive strengths that determine their processability into capacitors. The Agglomerates are characterized by stable sintered bridges, which after processing to condensate ensure favorable porosity.
Aus dem erfindungsgemäß bevorzugten Niobpulvern sind unmittelbar nach der Desaktivierung und Sieben durch ein Sieb der Maschenweite 400 µm Kondensatoren herstellbar, die nach Sinterung bei 1100°C und Formierung bei 40 V eine spezifische Kondensatorkapazität von 80.000 bis 250.000 µFV/g (gemessen in Phosphorsäure) und eine spezifische Reststromdichte von weniger als 2 nA/p.FV aufweisen. Nach Sinterung bei 1150°C und Formierung bei 40 V beträgt die spezifische Kondensator kapazität 40 000 bis 150 000 µFV/g mit einer spezifischen Reststromdichte von weni ger als 1 nA/µFV. Nach Sinterung bei 1250°C und Formierung bei 40 V werden Kondensatoren erhalten mit einer spezifischen Kondensatorkapazität (gemessen in Phosphorsäure) von 30 000 bis 80 000 µFV/g mit einer spezifischen Reststromdichte von weniger als 1 nA/µFV. The niobium powders preferred according to the invention are immediately after the Deactivation and sieving through a sieve with a mesh size of 400 µm capacitors producible, which after sintering at 1100 ° C and formation at 40 V a specific Capacitor capacity from 80,000 to 250,000 µFV / g (measured in phosphoric acid) and have a specific residual current density of less than 2 nA / p.FV. To Sintering at 1150 ° C and formation at 40 V is the specific capacitor capacitance 40,000 to 150,000 µFV / g with a specific residual current density of few less than 1 nA / µFV. After sintering at 1250 ° C and formation at 40 V. Capacitors obtained with a specific capacitor capacity (measured in Phosphoric acid) from 30,000 to 80,000 µFV / g with a specific residual current density less than 1 nA / µFV.
Bevorzugte erfindungsgemäße Niobpulver weisen eine spezifische Oberfläche von 2 bis 10 m2/g nach BET auf.Preferred niobium powders according to the invention have a specific surface area of 2 to 10 m 2 / g according to BET.
Die Erfindung wird anhand der nachfolgenden Beispiele näher erläutert: The invention is illustrated by the following examples:
-
a) Es wurde ein Nb2O5 einer nach FSSS bestimmten Teilchengröße von 1,7 µm
mit folgenden Verunreinigungsgehalten eingesetzt:
Summe (Na, K, Ca, Mg) 11 ppm Summe (Al, Co, Cr, Cu, Fe, Ga, Mn, Mo, Ni, Pb, Sb, Sn, Ti, V, W, Zn, Zr) 19 ppm Ta 8 ppm Si 7 ppm C < 1 ppm Cl <3 ppm F 5 ppm S <1 ppm
Sum (Na, K, Ca, Mg) 11 ppm Sum (Al, Co, Cr, Cu, Fe, Ga, Mn, Mo, Ni, Pb, Sb, Sn, Ti, V, W, Zn, Zr) 19 ppm Ta 8 ppm Si 7 ppm C. <1 ppm Cl <3 ppm F 5 ppm S <1 ppm -
b) Das Nb2O5 wurde in einem Molybdan-Schiffchen im Durchschubofen, unter
langsam strömender Wasserstoffatmosphäre innerhalb von 3,5 Stunden gehal
ten durch die heiße Zone des Ofens gefahren.
Das erhaltene Suboxid hatte die Zusammensetzung NbO2.b) The Nb 2 O 5 was driven through the hot zone of the furnace in a push-through furnace in a molybdenum boat under a slowly flowing hydrogen atmosphere for 3.5 hours.
The suboxide obtained had the composition NbO 2 . -
c) Das Produkt wurde auf einen feinmaschigen Rost gegeben, unter dem ein
Tiegel angeordnet war, der Magnesium in 1,1-fach stöchiometrischer Menge
bezogen auf den Sauerstoffgehalt des Suboxids enthielt.
Die Anordnung aus Rost und Tiegel wurde unter Argon-Schutzgas 6 Stunden lang bei 1000°C behandelt. Dabei verdampfte das Magnesium und reagiert mit dem darüberliegenden Suboxid. Anschließend wurde der Ofen abgekühlt (< 100°C) und zur Passivierung der Metallpulveroberfläche allmählich Luft zugeführt.
Das Produkt wurde mit Schwefelsäure so lange gewaschen, bis im Filtrat kein Magnesium mehr nachweisbar war und danach mit VE-Wasser neutralge waschen und getrocknet.
Die Analyse des Niob-Pulvers ergab einen Gehalt an
O von 20.000 ppm (3300 ppm/m2)
Mg von 200 ppm
Fe von 8 ppm
Cr von 13 ppm
Ni von 3 ppm
Ta von 110 ppm
C von 19 ppm
N von 4150 ppm
Die Teilchengrößenbestimmung nach Mastersizer ergab
D10 4,27 µm
D50 160,90 µm
D90 318,33 µm
Die Primärkorngröße wurde visuell zu ca. 500 nm bestimmt. Die Schüttdichte nach Scott betrug 15,5 g/inch3. Die spezifische Oberfläche nach BET 6,08 m2/g. Die als Hall Flow bestimmte Fließfähigkeit betrug 38 s.c) The product was placed on a fine-meshed grate, under which a crucible was arranged, which contained magnesium in a 1.1-fold stoichiometric amount based on the oxygen content of the suboxide.
The rust and crucible assembly was treated under argon protective gas at 1000 ° C. for 6 hours. The magnesium evaporated and reacted with the suboxide above. The furnace was then cooled (<100 ° C.) and air was gradually added to passivate the metal powder surface.
The product was washed with sulfuric acid until magnesium was no longer detectable in the filtrate and then washed with demineralized water and dried.
Analysis of the niobium powder revealed a content of
O of 20,000 ppm (3300 ppm / m 2 )
Mg of 200 ppm
Fe of 8 ppm
Cr of 13 ppm
Ni of 3 ppm
Ta of 110 ppm
C of 19 ppm
N of 4150 ppm
The particle size determination according to Mastersizer showed
D10 4.27 µm
D50 160.90 µm
D90 318.33 µm
The primary grain size was visually determined to be approximately 500 nm. The bulk density according to Scott was 15.5 g / inch 3 . The specific surface area according to BET 6.08 m 2 / g. The fluidity determined as Hall Flow was 38 s. -
d) Aus dem Niobpulver wurden Anoden mit einem Durchmesser von 3 mm und
einer Länge von 5,66 mm und einer Anodenmasse von 0,14 g mit einer Preß
dichte von 3,5 g/cm3 auf einem Niobdraht durch Sintern bei den in Tabelle 1
angegebenen Zeiten und Temperaturen hergestellt.
Die Preßfestigkeit der Anode gemessen nach Chatillon betrug 6,37 kg. Die Anoden wurden bei 80°C in einem Elektrolyten mit 0,1 Vol % H3PO4 bei einer Stromdichte von 100/150 mA bei der in Tabelle 1 angegebenen Span nung formiert und die Kondesatorkenndaten bestimmt, siehe Tabelle 1.d) From the niobium powder were anodes with a diameter of 3 mm and a length of 5.66 mm and an anode mass of 0.14 g with a compact density of 3.5 g / cm 3 on a niobium wire by sintering in the table 1 times and temperatures specified.
The compressive strength of the anode measured according to Chatillon was 6.37 kg. The anodes were formed at 80 ° C in an electrolyte with 0.1 vol% H 3 PO 4 at a current density of 100/150 mA at the voltage specified in Table 1 and the capacitor characteristics were determined, see Table 1.
Beispiel 1 wurde wiederholt mit der Abweichung, daß die Temperatur in der ersten Reduktionsstufe 1300°C betrug.Example 1 was repeated with the difference that the temperature in the first Reduction level was 1300 ° C.
Das Metallpulver hatte folgende Eigenschaften:
The metal powder had the following properties:
Mastersizer
D10 69,67 µm
D50 183,57 µm
D90 294,5 µm
Mastersizer
D10 69.67 µm
D50 183.57 µm
D90 294.5 µm
Primärkorngröße (visuell) 300-400 nm
spez. Oberfläche BET 5 m2/g
frei fließend.Primary grain size (visual) 300-400 nm
spec. BET surface area 5 m 2 / g
free flowing.
Die Preßfestigkeit war extrem hoch:
13 kg bei einer Preßdichte von 3,5 g/cm3, und
8 kg bei einer Preßdichte von 3 g /cm3.
The compressive strength was extremely high:
13 kg at a compression density of 3.5 g / cm 3 , and
8 kg with a compression density of 3 g / cm 3 .
Nach Sinterung bei 1100°C während 20 Minuten (Preßdichte 3 g/m3) wurde nach Formierung bei 40 V eine Kapazität von 222.498 µFV/g und ein Reststrom von 0,19 nA/µFV gemessen.After sintering at 1100 ° C. for 20 minutes (press density 3 g / m 3 ), after formation at 40 V, a capacitance of 222,498 μFV / g and a residual current of 0.19 nA / μFV were measured.
Dieses Beispiel zeigt den Einfluß der Reduktionstemperatur in der ersten Stufe auf die Eigenschaften des Niob-Pulvers:This example shows the influence of the reduction temperature in the first stage on the Properties of the niobium powder:
Drei Chargen Niobpentoxid werden unter sonst gleichen Bedingungen 4 Stunden lang unter Wasserstoff bei 1100°C, 1300°C bzw. 1500°C behandelt. Three batches of niobium pentoxide are made for 4 hours under otherwise identical conditions treated under hydrogen at 1100 ° C, 1300 ° C and 1500 ° C.
Anschließend wird mit Mg-Dampf (6 h, 1000°C) zum Niob-Metall reduziert. Dabei
gebildetes MgO und überschüssiges Mg werden mit Schwefelsäure ausgewaschen. Es
ergeben sich folgende Pulvereigenschaften:
The mixture is then reduced to niobium metal using magnesium vapor (6 h, 1000 ° C.). The MgO and excess Mg formed are washed out with sulfuric acid. The powder properties are as follows:
Claims (10)
Kohlenstoff bis 150 ppm und
Metallgehalte (ohne Berücksichtigung von Tantal) von maximal 500 ppm.7. niobium powder containing oxygen in amounts of 2500-4500 ppm / m 2 surface, nitrogen to 10,000 ppm,
Carbon up to 150 ppm and
Metal content (without taking tantalum into account) of a maximum of 500 ppm.
Priority Applications (27)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19831280A DE19831280A1 (en) | 1998-07-13 | 1998-07-13 | Acidic earth metal, specifically tantalum or niobium, powder for use, e.g., in capacitor production is produced by two-stage reduction of the pentoxide using hydrogen as the first stage reducing agent for initial suboxide formation |
CZ20100604A CZ303685B6 (en) | 1998-05-06 | 1999-05-05 | Niobium powder in the form of agglomerated primary particles, capacitor anode made of such niobium powder and capacitor |
CN200610100397.7A CN1919508B (en) | 1998-05-06 | 1999-05-05 | Metal powders produced by the reduction of the oxides with gaseous magnesium |
EP20080169766 EP2055412B1 (en) | 1998-05-06 | 1999-05-05 | Niobium or tantalum based powder produced by the reduction of the oxides with a gaseous metal |
KR1020007012285A KR100583702B1 (en) | 1998-05-06 | 1999-05-05 | Process for production of metal powders by the reduction of the metal oxides with gaseous reducing agent and metal powders produced therefrom |
AU58965/99A AU757790B2 (en) | 1998-05-06 | 1999-05-05 | Metal powders produced by the reduction of the oxides with gaseous magnesium |
CA002525259A CA2525259C (en) | 1998-05-06 | 1999-05-05 | Metal powders produced by the reduction of the oxides with gaseous magnesium |
JP2000616950A JP4202609B2 (en) | 1998-05-06 | 1999-05-05 | Metal powder produced by oxide reduction using gaseous magnesium |
CN2004100787672A CN1607055B (en) | 1998-05-06 | 1999-05-05 | Niobium powder, anode prepared therefore and capacitor including the anode |
BR9911008-3A BR9911008A (en) | 1998-05-06 | 1999-05-05 | Metal powders produced by reducing oxides with magnesium gas |
BRPI9917635A BRPI9917635B1 (en) | 1998-05-06 | 1999-05-05 | niobium powder in the form of primary agglomerated particles and method for obtaining a capacitor anode |
PT08169766T PT2055412E (en) | 1998-05-06 | 1999-05-05 | Niobium or tantalum based powder produced by the reduction of the oxides with a gaseous metal |
DE69940030T DE69940030D1 (en) | 1998-05-06 | 1999-05-05 | PROCESS FOR PREPARING METAL POWDER BY REDUCING OXIDES, Nb AND Nb-Ta POWDER AND CONDENSATE ANODE MADE THEREFOR |
PT99946575T PT1144147E (en) | 1998-05-06 | 1999-05-05 | Method for producing metal powders by reduction of the oxides, nb and nb-ta powders and capacitor anode obtained therewith |
CZ20100603A CZ303684B6 (en) | 1998-05-06 | 1999-05-05 | Alloy powder, process for its preparation, capacitor anode and niobium and tantalum alloy powder |
ID20002238A ID27391A (en) | 1998-05-06 | 1999-05-05 | METAL POWDER PRODUCED BY OXIDE REDUCTION WITH MAGNESIUM GAS |
EP99946575A EP1144147B8 (en) | 1998-05-06 | 1999-05-05 | METHOD FOR PRODUCING METAL POWDERS BY REDUCTION OF THE OXIDES, Nb AND Nb-Ta POWDERS AND CAPACITOR ANODE OBTAINED THEREWITH |
CN201510310262.2A CN105033283A (en) | 1998-05-06 | 1999-05-05 | Niobium or tantalum based powder produced by the reduction of the oxides with a gaseous metal |
CZ20004112A CZ302249B6 (en) | 1998-05-06 | 1999-05-05 | Process for producing metal powders by reduction of oxides with magnesium vapors and metal powder obtained in such a manner |
BRPI9911008A BRPI9911008B1 (en) | 1998-05-06 | 1999-05-05 | process for the production of metal powder capacitor, niobium powder, capacitor anode, alloy powder for use in electrolytic capacitor manufacturing, process for alloy powder manufacturing |
HK02100530.5A HK1039087B (en) | 1998-05-06 | 2002-01-23 | Process for production of metal powder |
HK05107423A HK1075025A1 (en) | 1998-05-06 | 2005-08-24 | Niobium powder, anode produced therewith, and the anode-containing capacitor |
JP2007275178A JP2008094716A (en) | 1998-05-06 | 2007-10-23 | Metal powder produced by reduction of oxide using gaseous magnesium |
JP2007274870A JP5008523B2 (en) | 1998-05-06 | 2007-10-23 | Metal powder produced by reduction of oxides using gaseous magnesium |
JP2007275024A JP5008524B2 (en) | 1998-05-06 | 2007-10-23 | Metal powder produced by reduction of oxides using gaseous magnesium |
JP2008175539A JP5119065B2 (en) | 1998-05-06 | 2008-07-04 | Method for producing metal powder |
HK16100784.2A HK1212950A1 (en) | 1998-05-06 | 2016-01-25 | Metal powders produced by the reduction of the oxides with gaseous magnesium |
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DE19831280A DE19831280A1 (en) | 1998-07-13 | 1998-07-13 | Acidic earth metal, specifically tantalum or niobium, powder for use, e.g., in capacitor production is produced by two-stage reduction of the pentoxide using hydrogen as the first stage reducing agent for initial suboxide formation |
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US6576099B2 (en) | 2000-03-23 | 2003-06-10 | Cabot Corporation | 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 |
US6679934B2 (en) | 2000-03-01 | 2004-01-20 | Cabot Corporation | Nitrided valve metals and processes for making the same |
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