US3564082A - Process for producing powdered light metals,particularly aluminum - Google Patents

Process for producing powdered light metals,particularly aluminum Download PDF

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Publication number
US3564082A
US3564082A US745637A US3564082DA US3564082A US 3564082 A US3564082 A US 3564082A US 745637 A US745637 A US 745637A US 3564082D A US3564082D A US 3564082DA US 3564082 A US3564082 A US 3564082A
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US
United States
Prior art keywords
steam
powder
aluminum
air
atomization
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
US745637A
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English (en)
Inventor
Werner Kartenbeck
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.)
Aurubis AG
Original Assignee
Norddeutsche Affinerie AG
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
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    • 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
    • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
    • 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
    • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
    • B22F2009/0824—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid with a specific atomising fluid
    • B22F2009/0828—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid with a specific atomising fluid with water

Definitions

  • This invention relates to the production of powdered metal. It more particularly refers to an improved process for atomizing molten metal into powder with steam.
  • Light metal powder particularly aluminum powder, is usually produced in industry by one of two atomization processes.
  • 'It is therefore an object of this invention to provide an improved process for the production of powdered light metals.
  • FIG. 1 is a plot of hydrogen formation, by reaction of aluminum and water, against temperature
  • FIG. 2 is a schematic view of the powder formation process of this invention.
  • one aspect of this invention resides in improvements in the steam atomization of molten aluminum to form powdered aluminum. These improvements include utilizing steam which is substantially dry and which is super-heated, and providing that all surfaces of the apparatus in which the process is carried out which come into contact with steam are maintained at a temperature such that substantially no steam will condense thereon.
  • the rate of formation is plotted on the ordinate in milliliters H (under standard conditions), per minute, and per square meters of aluminum surface so that the results of the measurement will be independent on the size and shape of the particles.
  • the steep decline of the rate of hydrogen formation with the increase in temperature is particularly beneficial in the atomization process because the steam temperatures are preferably between 200 and 250 C.
  • the powder which has been produced by the atomization of a jet of molten metal with superheated steam is conveyed in known manner, with the aid of the steam used to produce the powder, to a separating means in which the powder is separated from the steam.
  • the mixture of metal powder and steam is separated under dry conditions and the mixture of metal powder and steam as well as all equipment parts contacted by said mixture are maintained at temperatures which preclude a condensation of steam.
  • all portions of the apparatus from the zone in which the metal is atomized to the separating. zone, inclusive are provided with insulation and/or heating means.
  • the insulation and/or any heating of the apparatus is mainly for the purpose of preventing the formation of moisture in the equipment so that the formation of substantial amounts of hydrogen or of an explosive gas mixture is prevented. Since dry aluminum powder is produced by the process and the time-consuming batch drying in a vacuum is eliminated, the residence time as well as the amount of aluminum powder stored in the equipment are reduced by about two powers of ten.
  • the H content of the gas downstream of the condenser may be measured and this information may be used to control the air addition rate so that the formation of an explosive oxygen-hydrogen gas mixture is avoided.
  • the powder-separating unit is so designed that after atomization of aluminum is stopped, steam continues to be fed with the same free oxygen content until all aluminum powder has been discharged from the separating unit.
  • a melting vessel 1 or a tiltable holding furnace for the molten metal issues a jet of molten metal which fiows into a nozzle 3, which nozzle is mounted on a tower 2 and is surrounded by an annular nozzle 4, through which steam for atomizing the metal enters the tower 2, e.g., at 10 kg./ sq. cm. superatmospheric pressure and 200 C.
  • the metal such as aluminum, emerges from the nozzle 3 and is atomized by the steam from nozzle 4 and carried by it through the tower 2 and a pipe 5 to a filter 6, where the aluminum powder is separated from the steam.
  • the filter is an enclosed rotary vacuum filter, which admits the mixture of steam and powder throughout its cylindrical surface 7.
  • the residual gas is drawn off at a control head 8.
  • a peeling device 9 continuously removes the powder from the filter surface and drops the powder into a conveyor screw 10. This screw is designed to discharge at both ends into two powder-receiving vessels 11a and 11b.
  • the powder-receiving vessels can be disconnected from the screw by two valves 12a and 12b and are filled with a dry inert gas before they are filled with powder.
  • a preheated inert gas enters the system and displaces the steam which adhered to the powder so that the powder is perfectly dry as it enters the storage vessel. In this way, the formation of an explosive mixture in the powder storage vessels is reliably prevented.
  • the steam, freed from the powder, is passed in a pipe 13 into a condenser 14 and is condensed therein by cooling water, which is sprayed from a shower head 15.
  • the uncondensed gas consists virtually only of air and is drawn off by a pump 16.
  • the capacity of said pum should be selected in view of the rate at which air may be added.
  • the desired steam-air mixture in the system can be exactly adjusted by a gas fiow meter for the exhausted air.
  • the air rate measured by said meter is combined with the measured rate of steam entering through the nozzle.
  • Heating may be effected, e.g., with dry steam, hot air, electric heating means, or the like. The details of the heating means are not shown because they are conventional and therefore form no part of this invention.
  • the powder separator When the plant is started, the powder separator must be heated above 100 C. by the wall-heating means 17 and must be scavenged by the dry atomizing steam. The atomization must not begin until the desired temperature conditions have been established in the system. On the other hand, when the plant is stopped, the system must be scavenged with steam until all of the atomized powder has been discharged.
  • EXAMPLE Molten aluminum was blown into the enclosed chamber 2 of the plant described hereinbefore.
  • the molten aluminum was discharged in a freely falling jet from a melting furnace 1 into a tundish 3, provided with a metering nozzle, and was atomized by superheated steam supplied through an annular nozzle 4 at 10 kg./ sq. cm. and 200 C. Air was admixed with the steam at such a rate that the content of free oxygen was about 1%.
  • the powder was separated in a dry state as described hereinbefore. At a steam rate of 600 kilograms per hour, 100 kilograms aluminum powder was produced per hour.
  • the recovered powder had such a particle size distribution that had a particle size under 40 microns; it had a surface area of 0.86 square meter per gram.
  • the oxygen content of the screened powder was 0.05% 0 corresponding to about 0.1% A1 0 What is claimed is:
  • Improved process claimed in claim 1 wherein air 8. Improved process claimed in claim 3, including is admixed with said steam. insulating the walls of said apparatus.

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  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
US745637A 1967-07-18 1968-07-17 Process for producing powdered light metals,particularly aluminum Expired - Lifetime US3564082A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEN0030922 1967-07-18

Publications (1)

Publication Number Publication Date
US3564082A true US3564082A (en) 1971-02-16

Family

ID=7345746

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Application Number Title Priority Date Filing Date
US745637A Expired - Lifetime US3564082A (en) 1967-07-18 1968-07-17 Process for producing powdered light metals,particularly aluminum

Country Status (7)

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US (1) US3564082A (xx)
AT (1) AT280621B (xx)
BE (1) BE718110A (xx)
CH (1) CH477932A (xx)
DE (1) DE1583676B1 (xx)
GB (1) GB1163878A (xx)
SE (1) SE318976B (xx)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4449902A (en) * 1982-11-12 1984-05-22 Aluminum Company Of America Apparatus for control of particle size in the production of atomized metal
US4457881A (en) * 1982-09-10 1984-07-03 Aluminum Company Of America Method for collection of atomized metal particles
US4464103A (en) * 1982-08-31 1984-08-07 Aluminum Company Of America Apparatus for the production of atomized metal particles
US4466786A (en) * 1982-08-31 1984-08-21 Aluminum Company Of America Apparatus for production of atomized powder
US4468183A (en) * 1982-08-31 1984-08-28 Aluminum Company Of America Apparatus for the production of particulate metal
US4468182A (en) * 1982-08-31 1984-08-28 Aluminum Company Of America Apparatus for control of powder production
CN103551560A (zh) * 2013-09-29 2014-02-05 鞍钢实业微细铝粉有限公司 一种改性铝粉的制造方法

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4464103A (en) * 1982-08-31 1984-08-07 Aluminum Company Of America Apparatus for the production of atomized metal particles
US4466786A (en) * 1982-08-31 1984-08-21 Aluminum Company Of America Apparatus for production of atomized powder
US4468183A (en) * 1982-08-31 1984-08-28 Aluminum Company Of America Apparatus for the production of particulate metal
US4468182A (en) * 1982-08-31 1984-08-28 Aluminum Company Of America Apparatus for control of powder production
US4457881A (en) * 1982-09-10 1984-07-03 Aluminum Company Of America Method for collection of atomized metal particles
US4449902A (en) * 1982-11-12 1984-05-22 Aluminum Company Of America Apparatus for control of particle size in the production of atomized metal
CN103551560A (zh) * 2013-09-29 2014-02-05 鞍钢实业微细铝粉有限公司 一种改性铝粉的制造方法
CN103551560B (zh) * 2013-09-29 2015-07-01 鞍钢实业微细铝粉有限公司 一种改性铝粉的制造方法

Also Published As

Publication number Publication date
GB1163878A (en) 1969-09-10
DE1583676B1 (de) 1970-12-17
BE718110A (xx) 1968-12-16
SE318976B (xx) 1969-12-22
CH477932A (de) 1969-09-15
AT280621B (de) 1970-04-27

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