EP0250813B1 - Verfahren und Vorrichtung zur Herstellung von Verbundpulvern - Google Patents

Verfahren und Vorrichtung zur Herstellung von Verbundpulvern Download PDF

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Publication number
EP0250813B1
EP0250813B1 EP87107065A EP87107065A EP0250813B1 EP 0250813 B1 EP0250813 B1 EP 0250813B1 EP 87107065 A EP87107065 A EP 87107065A EP 87107065 A EP87107065 A EP 87107065A EP 0250813 B1 EP0250813 B1 EP 0250813B1
Authority
EP
European Patent Office
Prior art keywords
gas
reactor
filter
powder
hot
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 - Lifetime
Application number
EP87107065A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0250813A2 (de
EP0250813A3 (en
Inventor
Kock Dr. Dipl.-Chem. Wulf
Laboreur Dipl.-Ing. Michael
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.)
Dornier GmbH
Original Assignee
Dornier GmbH
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 Dornier GmbH filed Critical Dornier GmbH
Publication of EP0250813A2 publication Critical patent/EP0250813A2/de
Publication of EP0250813A3 publication Critical patent/EP0250813A3/de
Application granted granted Critical
Publication of EP0250813B1 publication Critical patent/EP0250813B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • C22C1/10—Alloys containing non-metals
    • C22C1/1026—Alloys containing non-metals starting from a solution or a suspension of (a) compound(s) of at least one of the alloy constituents
    • 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
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/026—Spray drying of solutions or suspensions
    • 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
    • B22F9/30—Making metallic powder or suspensions thereof using chemical processes with decomposition of metal compounds, e.g. by pyrolysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
    • H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
    • H01H11/048—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts by powder-metallurgical processes
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S75/00—Specialized metallurgical processes, compositions for use therein, consolidated metal powder compositions, and loose metal particulate mixtures
    • Y10S75/956—Producing particles containing a dispersed phase

Definitions

  • the invention relates to a method and a device for producing composite powders from precious metals and base metal oxides by atomizing an aqueous solution consisting of precious and base metal salts into a hot reactor.
  • a process for the production of silver powder is known, in which silver powder of the composition Ag / CdO for electrical contacts is produced by spraying an aqueous solution of silver and cadmium salts into a hot reactor and the resulting powder particles after reaction with the reactor atmosphere in a centrifugal separator from the hot gas stream and collected.
  • the aqueous solution is atomized into the reactor using a two-component nozzle, for example with the aid of compressed air.
  • the disadvantage here is that there is a strong tendency for noble metal powders with low base metal oxide contents to form firmly adhering wall coverings which arise due to the high relative speeds between the powder particles and the centrifuge wall.
  • the object of the invention is to avoid high gas velocities in the powder-laden stream and thereby to exclude an undesirable coating on the walls of the collecting chambers.
  • a device for performing the method is the subject of claims 6-14.
  • the maximum exit velocity of the flow from the nozzle is lower for a two-phase flow than for each of the two phases it contains and because the mass flow represented by the gaseous volume flow of the two-phase flow is by three Orders of magnitude smaller than that of a liquid flow of the same size.
  • Another important requirement for the atomizer part is that all surfaces that come into contact with the reactor atmosphere are kept at temperatures above the dew point (which also applies to the surface of the nozzle), and that all surfaces reached by the spray mist are such a high temperature show that falling drops are immediately thrown off the surface again due to the suffering frost effect (formation of a vapor layer between the liquid and a hot surface, which prevents wetting).
  • Both single-component and dual-component nozzles can be used as atomizing nozzles for atomizing the solution.
  • the advantage of the single-substance nozzles is that no propellant (usually air) increases the flow rate in the reactor tube and thus the time the powder particles stay in the hot zone shortened.
  • no propellant usually air
  • Two-component nozzles have the advantage of finer atomization and thus have a positive effect on the kinetics of particle formation.
  • a typical characteristic of precious metal powder with relatively low levels of base metal oxides is the already mentioned strong tendency to form adherent wall coverings. This disadvantage is avoided by low flow speeds and a reduction in unnecessary changes in direction of the powder-laden stream.
  • the decisive factor is the fulfillment of this requirement in the area of separating the noble metal particles (particles) from the reactor atmosphere.
  • the conventional centrifugal separators mentioned work in favor of a compact design and good separation levels with high gas speeds and high centrifugal accelerations, which leads to inevitable clogging problems in the case of hot precious metal powder.
  • the wall of the reactor chamber is endangered by a deposit or growth of powder.
  • This zone is located approximately where the spray cone of the nozzle cuts the wall.
  • the movement of the powder particles towards the wall is intensified by a convection movement due to the high heat flows in the injection part.
  • the occupancy of the reactor wall at this point can be removed with a mechanical cleaning device.
  • a mechanical cleaning device can be a scraper or the like; Imbalance motors are simpler or electropneumatic knockers. The best effect is achieved with the latter, which work in the axial direction of the reactor tube.
  • the pressure equalization In order not to reduce the effectiveness of the gas scrubbing, the pressure equalization must not take place directly with the outside atmosphere, but the pipe for pressure equalization must be connected to the volume, which is approximately atmospheric pressure, but free of extraneous gas. If a gas scrubber with a low pressure drop is selected, the volume after the differential pressure generator and before the gas scrubber meets these requirements.
  • a gas scrubber is suitable for cleaning the exhaust gases under certain conditions.
  • silver is used as the noble metal component
  • solutions of silver nitrate are practically always used which, owing to the properties of the Ag ion, are completely chloride-free.
  • the scrubber can therefore be made of chromium-nickel steel.
  • NO nitrogen monoxide
  • NO2 Three moles of NO2 are two moles of HNO3 (nitric acid) and one mole of NO, which means the volume flow and thus the flow rate is greatly reduced in each absorption stage. This means that considerably more time is available in the next absorption stage for the reaction of the NO with the remaining O2.
  • the limit value is the flow velocity of the exhaust gases with almost complete absorption towards zero. This means that exhaust gas no longer emerges from the outlet cross section of the gas scrubber. For the traces of NO still present there, the dwell time approaches infinity, so that these traces still have sufficient time for oxidation and absorption.
  • H2O2 hydrogen peroxide
  • the figure shows a reactor with a gas-tight reactor chamber 5, 6 which is arranged in a frame, not shown.
  • the reactor chamber 5, 6 is gas-tightly sealed at the top with a lid 17, in the middle of which a nebulizer nozzle 3 is arranged and which is connected by a line 18 via a pump 2 to a container 1 containing an aqueous solution consisting of precious and base metal salts is.
  • Electromagnetically actuated knockers 14 are arranged on the cover 17, which, when triggered, releases and removes the powder particles deposited on the walls of the reactor chamber 5, 6 and cover 17 by means of the knocking pulses.
  • the reactor chamber 5, 6 with its cover 17 consist of a high-temperature alloy and is provided on the outside with an electric heater 4. Water flows around the atomizing nozzle 3 for cooling (see arrow). To compensate for any differential pressures that may occur between the interior of the reactor chamber 5, 6 and the outside atmosphere, pressure compensation or non-return flaps 13 are provided therein.
  • a hot gas filter 7 is flanged to the bottom of the reactor chamber 5, 6, in the interior of which a sedimentation chamber 15 and filter candles 8 are arranged.
  • the exhaust gas flowing through the annular outlet 16 provided in the collecting part 19 to the filter candles 18 passes through lines 20 provided with non-return flaps 13 and water jet pump 10 into a gas scrubber 12 and is discharged via an exhaust pipe 11 after cleaning.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Treating Waste Gases (AREA)
EP87107065A 1986-07-02 1987-05-15 Verfahren und Vorrichtung zur Herstellung von Verbundpulvern Expired - Lifetime EP0250813B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19863622123 DE3622123A1 (de) 1986-07-02 1986-07-02 Verfahren und vorrichtung zur herstellung von verbundpulvern
DE3622123 1986-07-02

Publications (3)

Publication Number Publication Date
EP0250813A2 EP0250813A2 (de) 1988-01-07
EP0250813A3 EP0250813A3 (en) 1988-06-08
EP0250813B1 true EP0250813B1 (de) 1991-03-13

Family

ID=6304185

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87107065A Expired - Lifetime EP0250813B1 (de) 1986-07-02 1987-05-15 Verfahren und Vorrichtung zur Herstellung von Verbundpulvern

Country Status (4)

Country Link
US (2) US4804167A (enrdf_load_stackoverflow)
EP (1) EP0250813B1 (enrdf_load_stackoverflow)
JP (1) JPS6369710A (enrdf_load_stackoverflow)
DE (1) DE3622123A1 (enrdf_load_stackoverflow)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4911769A (en) * 1987-03-25 1990-03-27 Matsushita Electric Works, Ltd. Composite conductive material
US6699304B1 (en) * 1997-02-24 2004-03-02 Superior Micropowders, Llc Palladium-containing particles, method and apparatus of manufacture, palladium-containing devices made therefrom
US6316100B1 (en) * 1997-02-24 2001-11-13 Superior Micropowders Llc Nickel powders, methods for producing powders and devices fabricated from same
US6338809B1 (en) * 1997-02-24 2002-01-15 Superior Micropowders Llc Aerosol method and apparatus, particulate products, and electronic devices made therefrom
US6159267A (en) * 1997-02-24 2000-12-12 Superior Micropowders Llc Palladium-containing particles, method and apparatus of manufacture, palladium-containing devices made therefrom
US6830823B1 (en) 1997-02-24 2004-12-14 Superior Micropowders Llc Gold powders, methods for producing powders and devices fabricated from same
US20050097987A1 (en) * 1998-02-24 2005-05-12 Cabot Corporation Coated copper-containing powders, methods and apparatus for producing such powders, and copper-containing devices fabricated from same
WO2002077625A1 (en) 2001-03-22 2002-10-03 University Of Maryland Sensor probe for measuring temperature and liquid volumetric fraction of a liquid droplet laden hot gas and method of using same
JP3812523B2 (ja) * 2002-09-10 2006-08-23 昭栄化学工業株式会社 金属粉末の製造方法
US20090000758A1 (en) 2007-04-06 2009-01-01 Ashley Stone Device for Casting
US8119073B2 (en) * 2007-08-20 2012-02-21 Ashley Stone Method and device for particulate scrubbing and conditioning
CA3118079A1 (en) 2018-10-29 2020-05-07 Stuart Licht Sustainable, facile separation of the molten carbonate electrolysis cathode product
US12286717B2 (en) * 2020-08-06 2025-04-29 C2Cnt Llc Sustainable, facile separation of the molten carbonate electrolysis cathode product
CN113500214B (zh) * 2021-07-06 2022-07-01 西北工业大学 一种模拟微重力下金属微滴追击熔合过程实时捕获系统

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL31231A (en) * 1968-12-06 1972-04-27 Univ Bar Ilan Production of elementary metals from melts or solutions of metal salts
GB1461176A (en) * 1974-04-11 1977-01-13 Plessey Inc Method of producing powdered materials
US3901492A (en) * 1974-04-29 1975-08-26 Carpenter Technology Corp Apparatus for making metal powder
US4072501A (en) * 1977-04-13 1978-02-07 The United States Of America As Represented By The United States Department Of Energy Method of producing homogeneous mixed metal oxides and metal-metal oxide mixtures
DE2853931A1 (de) * 1978-12-14 1980-06-19 Dornier System Gmbh Verfahren zur herstellung metallischer pulver
DE2929630C2 (de) * 1979-07-21 1983-12-15 Dornier System Gmbh, 7990 Friedrichshafen Verfahren zur Herstellung von Silberpulver
FR2537898A1 (fr) * 1982-12-21 1984-06-22 Univ Paris Procede de reduction de composes metalliques par les polyols, et poudres metalliques obtenues par ce procede
JPH0610281B2 (ja) * 1983-05-10 1994-02-09 トヨタ自動車株式会社 セラミツク−金属複合微粉末体
JPS60152605A (ja) * 1984-01-19 1985-08-10 Natl Res Inst For Metals 溶融金属の噴霧微粉化装置
DE3402500C1 (de) * 1984-01-25 1985-08-01 Nyby Uddeholm Powder AB, Torshälla Verfahren und Vorrichtung zur Herstellung von Metallpulver
US4626278A (en) * 1984-07-26 1986-12-02 Kenney George B Tandem atomization method for ultra-fine metal powder
JPS6193828A (ja) * 1984-10-16 1986-05-12 Natl Res Inst For Metals 混合超微粉の製造法
DE3540255A1 (de) * 1985-11-13 1987-07-23 Mtu Muenchen Gmbh Verfahren zur herstellung einer dispersionsgehaerteten metall-legierung
US4731110A (en) * 1987-03-16 1988-03-15 Gte Products Corp. Hydrometallurigcal process for producing finely divided spherical precious metal based powders
US4787935A (en) * 1987-04-24 1988-11-29 United States Of America As Represented By The Secretary Of The Air Force Method for making centrifugally cooled powders

Also Published As

Publication number Publication date
US4897110A (en) 1990-01-30
DE3622123C2 (enrdf_load_stackoverflow) 1988-10-20
US4804167A (en) 1989-02-14
DE3622123A1 (de) 1988-01-21
EP0250813A2 (de) 1988-01-07
JPS6369710A (ja) 1988-03-29
EP0250813A3 (en) 1988-06-08

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