EP0041142B1 - Verfahren zur Herstellung von nadelförmigen, im wesentlichen aus Eisen bestehenden, ferromagnetischen Metallteilchen - Google Patents

Verfahren zur Herstellung von nadelförmigen, im wesentlichen aus Eisen bestehenden, ferromagnetischen Metallteilchen Download PDF

Info

Publication number
EP0041142B1
EP0041142B1 EP81103507A EP81103507A EP0041142B1 EP 0041142 B1 EP0041142 B1 EP 0041142B1 EP 81103507 A EP81103507 A EP 81103507A EP 81103507 A EP81103507 A EP 81103507A EP 0041142 B1 EP0041142 B1 EP 0041142B1
Authority
EP
European Patent Office
Prior art keywords
iron
fluidized bed
fluidizing
stirrer
particles
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
Application number
EP81103507A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0041142A1 (de
Inventor
Hansjoerg Dr. Siegle
Hans Heiner Dr. Reich
Horst Dr. Autzen
Werner Dr. Steck
Werner Dr. Loeser
Eckhard Hetzel
Manfred Dr. Ohlinger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Original Assignee
BASF SE
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Publication of EP0041142A1 publication Critical patent/EP0041142A1/de
Application granted granted Critical
Publication of EP0041142B1 publication Critical patent/EP0041142B1/de
Expired legal-status Critical Current

Links

Images

Classifications

    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/06—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/065—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder obtained by a reduction

Definitions

  • the invention relates to the production of acicular ferromagnetic metal particles consisting essentially of iron by reduction of acicular pure iron oxides or iron oxides or iron oxide hydroxides modified with conventional foreign metal ions by means of gaseous reducing agents in a fluidized bed and their use for the production of magnetic recording media.
  • the use of acicular ferromagnetic metal particles with single-range behavior as a magnetizable material for the production of magnetic recording media has long been known.
  • the high coercive field strengths and high values for the remanent magnetization possible with such materials compared to the ferromagnetic iron oxides usually used were early on to look for ways to produce these substances technically in a simple manner according to the theoretical specifications.
  • the pseudomorphic conversion of pure or modified acicular iron oxides with a reducing gas is used in particular.
  • the particles of the reaction product have essentially the same shape and dimension as those of the starting material. Since iron oxides or iron oxide hydroxides in particular can be easily produced using conventional processes under controllable conditions in the size and needle shape required for the ferromagnetic metal particles with single-range behavior, these corresponding production processes in particular have proven to be suitable.
  • reaction temperature is high enough on the one hand so that the chemical reaction proceeds at a sufficient rate, but on the other hand is not so high that the shape of the particles is caused.
  • the particles should also touch each other as little as possible so that they do not grow together.
  • a so-called fluidized bed furnace has also already been used for the further reduction of the iron oxide or oxide hydroxide particles to corresponding iron particles by a gas consisting essentially of hydrogen (DE-A-20 28 536).
  • DE-C-1458 765 describes a multi-stage fluidized bed reactor for the reduction of iron oxides
  • DE-A-23 61 539 the use of a flap furnace according to GB-A-1 104 852 in particular for the reduction of iron oxide and / or Iron oxide hydroxide powder to ferromagnetic material for magnetic recording media is referred to as advantageous.
  • advantageous the powder layer on the various flaps is only about 2 mm thick, so that a technically complex process only allows low space-time yields.
  • the conventional fluidized bed process which allows larger throughputs, is used to reduce the iron oxide hydroxide that is particularly suitable as a starting material for the production of ferromagnetic iron particles, large scatterings with regard to the magnetic properties of the end product must be accepted due to the poor vortex behavior and the resulting channel formation of the iron oxide hydroxide.
  • the object was therefore to provide a method for producing acicular ferromagnetic metal particles consisting essentially of iron, in which the reduction of iron oxide and in particular of iron oxide hydroxide is to take place using the advantages of the fluidized bed method which are known per se but avoiding the known disadvantages, in order to obtain a uniform end product in a reproducible manner.
  • a fluidized bed furnace suitable for the process according to the invention is known per se. As shown by way of example in FIG. 1, it consists of a vertically arranged tube furnace 1, which is usually expanded at the top. After heating, the fluidizing gas, in this case the reducing medium, is blown through the inlet 2 into the heat exchanger 3 and through the fluidizing gas base 4, usually a sintered frit plate, is uniformly distributed over the entire cross section of the tube. With the help of this gas flow, the material to be reduced which is introduced by the feed is kept in a quasi-liquid suspended state 6. The heating elements 7 serve to maintain the required reaction temperature.
  • the gas outlet 8 with downstream filter units is located at the upper end of the furnace.
  • the stirrer 9 which characterizes the method according to the invention and is located directly above the fluidizing gas base 4 and has at least one stirring arm, ensures a uniform distribution of the fluidized product 6 in the fluidizing space.
  • these are removed from the vortex furnace with the aid of the stirrer 9 via the discharge 10, which can also be located centrally below the vortex bottom.
  • the reduction of needle-shaped iron oxides and / or iron oxide hydroxides to uniform metal particles can be carried out.
  • a uniform distribution of both the material in the reaction zone and the temperature in the reaction material is achieved.
  • caking no longer occurs on the reactor wall and thus this cause for an uncontrolled course of the reaction is also prevented.
  • An equally favorable effect of the method according to the invention is based on the fact that the gas velocity in the fluidized bed can be reduced by the influence of the stirrer mounted in the immediate vicinity above the fluidized bed without inhomogeneous whirling occurring. This also results in a reduction in the dust discharge, so that the required filter units can be reduced.
  • a drag flap is attached to at least one agitator arm in such a way that the distance between the agitator arm and the vertebral base is thereby bridged.
  • the arrangement of the drag flap is chosen so that the drag flap lifts off the swirl floor during the swirling process and only touches the swirl floor due to its own weight when the product is discharged.
  • the rest of the fluidized material which is located between the agitator arm and the fluidized bed, can possibly be included in the subsequent reductions in the fluidizing furnace. delivers less uniform product, easy to dispense.
  • a corresponding arrangement is shown by way of example in FIG. 2.
  • the drag flap 11 is articulated on the agitator arm 9. In the case of centric discharge of the product from the vortex furnace, the agitator arm is curved forward. If the discharge is located on the side of the furnace, as shown in FIG. 1, the stirring arm is expediently curved backwards.
  • Suitable starting materials for the process according to the invention for producing the ferromagnetic metal particles consisting essentially of iron are all acicular iron oxides which are pure or modified with conventional foreign metal ions. These are the known modifications of the iron (III) oxide hydroxides, which are used in particular in the production of magnetic materials for magnetic recording media, the needle-shaped a- or ⁇ -iron (III) oxides derived therefrom and the magnetite and mixtures thereof. These substances can also be used in a form modified with foreign metal ions, usually cobalt, nickel or chromium.
  • acicular goethite, lepidocrocite or mixtures thereof with an average particle length of 0.1 to 2 ⁇ m, preferably 0.2 to 1.2 ⁇ m, a length-to-thickness ratio has proven to be particularly advantageous for the production of the metal particles from 5: 1 to 40: 1 and a BET specific surface area (SN) from 25 to 80m 2 .
  • the annealed products of the iron (III) oxide hydroxides mentioned can also be used in the same way, the annealing expediently taking place at 250 to 700.degree.
  • the iron oxides listed are given shape-stabilizing in a known manner in order to better maintain the particle shape, e.g. DE-A-24 34 058, -24 34 096, -26 46 348, -27 14 588 and -27 43 298. This finishing is preferably carried out on the iron oxide hydroxide stage before the particles are subjected to a tempering or conversion process.
  • the acicular ferromagnetic metal particles which can be obtained by the process according to the invention still largely have the shape derived from the starting materials and, despite the preceding conversion reaction, they are uniform. As a result, they are characterized by high values with regard to their magnetic properties, such as the coercive force and above all the remanence.
  • the high squareness of the hysteresis loop indicates a narrow switching field thickness distribution due to the uniform shape.
  • Such metal particles are outstandingly suitable as magnetic materials for the production of magnetic recording media.
  • these substances are expediently passivated before further processing.
  • the fluidized bed furnace used for the process according to the invention is also particularly suitable here.
  • the present invention is explained by way of example using the following experiments.
  • the magnetic values of the samples were measured with a vibration magnetometer at a magnetic field of 160 kA / m.
  • Specific remanence (M r / e) and saturation (M e) are given in nTm 3 / g.
  • the feed product ⁇ -FeOOH produced according to DE-B-12 04 644 and equipped with phosphoric acid and oxalic acid according to DE-A-26 46 348, is in a fluidized bed with stirrer according to Figure 1 at 350 ° C with hydrogen with a 64-fold excess of hydrogen within 6 hours reduced.
  • the speed of the stirrer was 28 rpm.
  • the magnetic properties of the resulting iron particles are shown in Table 1.
  • the feed product y-FeOOH produced in accordance with DE-B-1061 760 and equipped as in Example 1, is heated in air for one hour at 600 ° C. and then in a vortex furnace according to FIG. 1 at 350 ° C. within 4.5 (Sample a) or 6 hours (sample b) reduced (speed 28 rpm).
  • the magnetic properties of the resulting materials are given in Table 2.
  • 800 parts of the passivated iron particles produced according to Example 4 are in a 600-volume steel cylinder mill, which contains 9000 parts of steel balls with a diameter between 4 and 6 mm, with 456 parts of a 13% solution of a thermoplastic polyester urethane from adipic acid, 1.4 butanediol and 4,4'-diisocyanatodiphenylmethane in a solvent mixture of equal parts of tetrahydrofuran and dioxane, 296 parts of a 10% solution of a polyvinylformal binder, containing 82% vinyl formal, 12% vinyl acetate and 6% vinyl alcohol units, in the solvent mixture mentioned, 20 parts of butyl stearate and others 492 parts of the solvent mixture mentioned and mixed for 4 days.
  • the magnetic dispersion thus prepared on a polyethylene terephthalate carrier film of 11.5 m thickness JL will be - wear and dried after passing through a directional magnetic field within 2 minutes at 80 to 100 ° C.
  • the magnetic layer is smoothed and compacted by pulling over heated and polished rollers at temperatures from 60 to 80 ° C.
  • the finished magnetic layer is 3.5 ⁇ m thick.
  • the coated film is cut into strips 3.8 mm wide.
  • the electroacoustic properties of these tapes are measured based on DIN 45 512 with a tape speed of 4.75 cm / sec, a bias current J HF of 23 mA and an equalization of 70 JL sec.
  • the table below shows the values for the modulation at 333 Hz ( AT ) and at 10 kHz ( AT ).
  • the tape produced in this way had the following tape data:

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Hard Magnetic Materials (AREA)
  • Magnetic Record Carriers (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
EP81103507A 1980-06-04 1981-05-08 Verfahren zur Herstellung von nadelförmigen, im wesentlichen aus Eisen bestehenden, ferromagnetischen Metallteilchen Expired EP0041142B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3021111 1980-06-04
DE19803021111 DE3021111A1 (de) 1980-06-04 1980-06-04 Verfahren zur herstellung von nadelfoermigen, im wesentlichen aus eisen bestehenden, ferromagnetischen metallteilchen

Publications (2)

Publication Number Publication Date
EP0041142A1 EP0041142A1 (de) 1981-12-09
EP0041142B1 true EP0041142B1 (de) 1983-06-29

Family

ID=6103916

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81103507A Expired EP0041142B1 (de) 1980-06-04 1981-05-08 Verfahren zur Herstellung von nadelförmigen, im wesentlichen aus Eisen bestehenden, ferromagnetischen Metallteilchen

Country Status (4)

Country Link
US (1) US4378240A (enrdf_load_stackoverflow)
EP (1) EP0041142B1 (enrdf_load_stackoverflow)
JP (2) JPS5723010A (enrdf_load_stackoverflow)
DE (2) DE3021111A1 (enrdf_load_stackoverflow)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3901027A1 (de) * 1989-01-14 1990-07-26 Studiengesellschaft Kohle Mbh Nadelfoermige eisen-magnetpigmente mit einstellbarer koezitivfeldstaerke und verfahren zu deren herstellung
EP0589296B1 (en) * 1992-09-10 1997-12-29 Kao Corporation Method for production of magnetic metal particles and apparatus therefor
US5581998A (en) * 1994-06-22 1996-12-10 Craig; Joe D. Biomass fuel turbine combuster
US5666890A (en) * 1994-06-22 1997-09-16 Craig; Joe D. Biomass gasification system and method
US6443213B1 (en) * 2000-05-11 2002-09-03 Pcc Airfoils, Inc. System for casting a metal article using a fluidized bed
KR100977147B1 (ko) * 2007-12-31 2010-08-23 세메스 주식회사 유동층 탄소나노튜브 생성 장치 및 그것을 사용한탄소나노튜브 생성 설비 및 방법
WO2010016395A1 (ja) * 2008-08-08 2010-02-11 株式会社 東芝 ナノカーボン生成装置
CN117230267A (zh) * 2023-08-31 2023-12-15 安徽工业大学 一种流化床及提高还原过程中流化抑制黏结的方法

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1033814B (de) * 1953-03-17 1958-07-10 Electro Chimie Metal Verfahren zur Herstellung magnetisierbarer Pulver und Dauermagnete aus solchen Pulvern
US2879154A (en) * 1956-10-02 1959-03-24 Franklin Inst Of The State Of Acicular metal particles and method of making the same
US2947620A (en) * 1957-08-06 1960-08-02 Republic Steel Corp Process of preparing iron powder capable of being rolled directly to sheet form
GB1104852A (en) 1964-05-21 1968-03-06 Jiyuichi Nara Powder-drying apparatus and plant including the same
GB1064406A (en) * 1965-10-23 1967-04-05 Hydrocarbon Research Inc Method of reducing iron oxide
NL6909443A (enrdf_load_stackoverflow) * 1969-06-20 1970-12-22
FR2076745A5 (en) * 1970-01-27 1971-10-15 Siderurgie Fse Inst Rech Fluidised bed treatment - of powdered materials in two stages
DE2361539C2 (de) * 1973-12-11 1984-06-20 Philips Patentverwaltung Gmbh, 2000 Hamburg Verfahren zur Herstellung eines ferromagnetischen, überwiegend aus Eisen bestehenden Materials
DE2434096C2 (de) 1974-07-16 1985-10-17 Basf Ag, 6700 Ludwigshafen Nadelförmige, vorwiegend aus Eisen bestehende ferromagnetische Metallteilchen und Verfahren zu ihrer Herstellung
DE2434058C2 (de) 1974-07-16 1985-12-19 Basf Ag, 6700 Ludwigshafen Nadelförmige, vorwiegend aus Eisen bestehende ferromagnetische Metallteilchen und Verfahren zu ihrer Herstellung
US3967986A (en) * 1975-01-27 1976-07-06 U.S. Philips Corporation Method of preparing ferromagnetic material
DE2646348C2 (de) 1976-10-14 1986-08-28 Basf Ag, 6700 Ludwigshafen Verfahren zur Herstellung von nadelförmigen, ferromagnetischen, im wesentlichen aus Eisen bestehenden Metallteilchen und deren Verwendung zur Herstellung von magnetischen Aufzeichnungsträgern
DE2714588C2 (de) 1977-04-01 1986-06-05 Basf Ag, 6700 Ludwigshafen Verfahren zur Herstellung nadelförmiger ferromagnetischer Eisenteilchen
DE2743298A1 (de) 1977-09-27 1979-04-05 Basf Ag Ferromagnetische, im wesentlichen aus eisen bestehende metallteilchen und verfahren zu deren herstellung
JPS55157214A (en) * 1979-05-25 1980-12-06 Mitsui Toatsu Chem Inc Manufacture of magnetic recording powder

Also Published As

Publication number Publication date
DE3021111A1 (de) 1981-12-17
DE3160523D1 (en) 1983-08-04
JPH0431234Y2 (enrdf_load_stackoverflow) 1992-07-28
US4378240A (en) 1983-03-29
JPS5723010A (en) 1982-02-06
JPH0269938U (enrdf_load_stackoverflow) 1990-05-28
EP0041142A1 (de) 1981-12-09

Similar Documents

Publication Publication Date Title
DE3700943C2 (de) Verfahren zur Herstellung von Lepidokrokit
DE2130921B2 (de) Verfahren zur Herstellung von Pulver aus Eisen und/oder Kobalt und/oder
DE69321531T2 (de) Granulierte Teilchen für magnetische Teilchen für magnetische Aufzeichnung und Verfahren für ihre Herstellung
EP0014902B1 (de) Verfahren zur Herstellung von nadelförmigem kobalthaltigem magnetischem Eisenoxid
EP0041142B1 (de) Verfahren zur Herstellung von nadelförmigen, im wesentlichen aus Eisen bestehenden, ferromagnetischen Metallteilchen
DE2252564A1 (de) Kobaltdotierte magnetische eisenoxidteilchen
EP0237944B1 (de) Verfahren zur Herstellung von nadelförmigem alpha-Eisen-III-Oxid
DE2705967C2 (de) Verfahren zur Herstellung von nadelförmigem kobalthaltigem magnetischem Eisenoxid
DE3409164C2 (enrdf_load_stackoverflow)
DE2235383B2 (de) Ferromagnetische nadeiförmige Teilchen für ein Aufzeichnungssystem
EP0063730A2 (de) Verfahren zur Stabilisierung pyrophorer, im wesentlichen aus Eisen bestehender ferromagnetischer nadelförmiger Metallteilchen
EP0024694B1 (de) Verfahren zur Herstellung nadelförmiger ferromagnetischer Eisenteilchen und deren Verwendung
EP0105110B1 (de) Verfahren zur Herstellung nadelförmiger, im wesentlichen aus Eisen bestehender ferromagnetischer Metallteilchen
EP0024692B1 (de) Verfahren zur Herstellung nadelförmiger ferromagnetischer Eisenteilchen und deren Verwendung
DE69315935T2 (de) Verfahren und Vorrichtung zur Herstellung von magnetischen metallischen Teilchen
DE2022013A1 (de) Verfahren zur Herstellung eines nadelfoermigen,mit Kobalt dotierten gamma-Eisenoxyds
DE3028556C2 (de) Verfahren zur Herstellung eines magnetisch stabilen Eisenpulvers
EP0087578B1 (de) Nadelförmiges ferrimagnetisches Eisenoxid und Verfahren zu seiner Herstellung
DE2650890C2 (de) Verfahren zur Herstellung von nadelförmigem, kobaltdotiertem, magnetischem Eisenoxid
EP0078950B1 (de) Verfahren zur Herstellung von nadelförmigen, ferrimagnetischen Eisenoxiden
DE1533368B1 (de) Feines niclelpulver mit daran haftenden kleinen teilchen schwer schmelzbarer oxide und verfahren zur herstellung des pulvers
DE3743039A1 (de) Nadelfoermige, im wesentlichen aus eisen bestehende, ferromagnetische metallteilchen und verfahren zu deren herstellung
DE1250803B (de) Verfahren zur Herstellung von y-FeaOs
DE3520762C2 (enrdf_load_stackoverflow)
DE2261183A1 (de) Polykristallines, ferromagnetisches material und verfahren zu seiner herstellung

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR GB NL

17P Request for examination filed

Effective date: 19811021

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): DE FR GB NL

REF Corresponds to:

Ref document number: 3160523

Country of ref document: DE

Date of ref document: 19830804

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19940422

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19940505

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19940531

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19950508

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19951201

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19950508

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 19951201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19960229

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20000718

Year of fee payment: 20