US3536309A - Apparatus for the manufacture of chrome powder - Google Patents

Apparatus for the manufacture of chrome powder Download PDF

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Publication number
US3536309A
US3536309A US715114*A US3536309DA US3536309A US 3536309 A US3536309 A US 3536309A US 3536309D A US3536309D A US 3536309DA US 3536309 A US3536309 A US 3536309A
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US
United States
Prior art keywords
powder
crucibles
chromium oxide
magnesium
chromium
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Expired - Lifetime
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US715114*A
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English (en)
Inventor
Gilles M Gohin
Andre R Hivert
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Office National dEtudes et de Recherches Aerospatiales ONERA
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Office National dEtudes et de Recherches Aerospatiales ONERA
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/30—Obtaining chromium, molybdenum or tungsten
    • C22B34/32—Obtaining chromium
    • 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
    • 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
    • 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
    • Y10S266/00—Metallurgical apparatus
    • Y10S266/905—Refractory metal-extracting means

Definitions

  • the object of this invention is to extend the process on an industrial scale, i.e. to make it possible to treat in a single operation masses of chromium oxide of suflicient bulkiness for the cost to permit numerous and wide applications.
  • a particular object of the invention is to provide a process and an apparatus for obtaining in a single operation chromium powder in several dozen kilograms or even more in spite of the highly exothermic character of the reaction.
  • Another object of the invention is to provide a process and an apparatus whereby an exothermic reaction can be controlled satisfactorily without prolonging excessively the reaction time.
  • a general object of the invention is to provide a process and an apparatus for obtaining chromium powder of a much greater degree of fineness than that of ordinary industrial powder and at a competitive cost.
  • the process involves using magnesium in the most available form, i.e. in the form of ingots, and disposing the powder to be treated in the same receptacle as the ingot or ingots, so that the working of the process is particularly simple.
  • the invention comprises steps that enable violence of the reaction to be effectively counteracted. This violence is liable to occur because of the exothermic character of the reaction. By these steps the temperature of the whole is limited to the desired value so that the vaporisation of the magnesium is not acceleratedbeyond what is necessary.
  • an industrial quantity of chromium oxide powder is divided into masses between one and about 10 kilograms, magnesium in in- Unitcd States Patent 3,536,309 Patented Oct. 27, 1970 got form is embedded in each of these masses, which are thermally insulated from each other, and the industrial quantity is heated in the same enclosure and in a single treatment phase.
  • each portion of the mass is brought into the optimum reaction conditions without being subjected excessively to the influence of the heat liberated by the other portions simultaneously undergoing the reaction.
  • the process resulting in the production of chromium oxide powder is influenced by dividing the treated mass.
  • the invention makes it possible to take advantage simultaneously of the bulk of the mass treated in one operation, with the resulting economic advantages, and also the strictness of the control to which each of the portions can be subjected so that the reaction may proceed under optimum conditions, with, as a result, a complete or practically complete conversion of the chromium oxide into chromium of exceptionally fine particle size.
  • the invention avoids the formation, in spite of the bulk of the total mass treated, of conglomerates of various compositions resulting from excessive local raising of the temperature. These conglomerates otherwise appear inevitably when chromium oxide in a large mass is heat-treated with magnesium vapour.
  • the invention therefore provides a means for extending the industrial use of magnesium as a reducing agent for oxides, such as Cr O whose formation heat is not so great as that of the oxides usually reduced by magnesium, while keeping the reduced metal in the state of a very fine powder.
  • the mass of chromium oxide to be treated is distributed in crucibles or pots piled one on top of each other, means being provided for the provision of thermal insulation between the successive crucibles.
  • the invention proposes the application of an insulating layer as a heat barrier between the portions contained in two successive crucibles.
  • an insulating layer for this purpose it proposes, for example, divided magnesia or alumina in the form of a powder of sulficiently porous agglomerate.
  • the invention is also characterised by the use of graphite as material to make the crucibles intended to be superimposed on each other, which retain their form in spite of the mechanical stresses and thermal influences to which they are subjected, so that they can be disposed in a column for the treatment of large masses.
  • the invention also relates to an arrangement whereby the graphite crucibles are disposed in several columns; the high conductivity of the graphite ensures a good distribution in the reaction masses of the thermal flux coming from one or several peripheral resistors.
  • the invention also proposes placing the reaction mass in iron or mild-steel dishes because of their resistance to corrosion by magnesium, each of the dishes being placed in a graphite crucible.
  • the crucibles are in an inert atmosphere, for example of argon, leak-proofness being ensured by a cooled seal remote from the treatment crucibles.
  • FIG. 1 is a diagrammatic vertical section through an apparatus according to the invention in one embodiment
  • FIG. 2 is a diagrammatic section through a crucible according to the invention in one embodiment
  • FIG. 3 is a view similar to FIG. 2 but for another embodiment.
  • FIG. 4 is a diagrammatic horizontal section through another embodiment of the apparatus according to the invention.
  • the furnace 10 which is raisable and lowerable, has a wall 11 made of refractory material on whose inner face there is a heating resistor 12, which is advantageously divided into sections; the current supply of each section may be controlled independently by means indicated diagrammatically at C.
  • the furnace rests on the bottom 13, thus bounding a cylindrical space 14.
  • the treatment enclosure 15 is bounded by a bell-shaped member 16, made for example of refractory alloy and of a generally cylindrical shape, leak-proofness at the bottom edge of the ball-shaped member being provided by a known seal 17 made of rubher or the like and cooled by water circulation.
  • Crucibles or boxes 18 18 18 etc. are piled one on top of the other, the crucible 18 resting by its bottom 19 on the top edge 20 of the crucible 18 etc.
  • the bottom crucible 18 rests on a base 21, keeping it away from the bottom of the furnace and the seal 17.
  • Each of the crucibles 18 is made of graphite and contains in its interior an iron or mild-steel dish 22.
  • Heat insulation is provided between two adjacent crucibles.
  • heat insulation 24 is provided between the bottom 19 of each crucible, with the exception of the bottom crucible 18 and the bottom 23 of the dish it contains.
  • This insulation may consist of a layer of powdered alumina or magnesia.
  • a disc may be provided that is formed by an agglomerate of a material that is sufiiciently insensitive to magnesium vapours, such as magnesia or alumina, and has 'sufl'icient porosity to ensure good heat insulation.
  • a porous-carbon disc may also be used.
  • a magnesium ingot 25 embedded in chromium oxide powder to be treated 26 is placed in each of the receptacles 22.
  • the chromium oxide powder is commercial powder. Its fineness depends on the fineness of the chromium powder it is desired to obtain.
  • the quantity of chromium oxide powder contained in each crucible may be between 1 and about 10 kilograms, and the magnesium mass accords with the quantity of chromium oxide powder.
  • Argon which forms the protective atmosphere, arrives at the bottom of the furnace through the passage 27.
  • each section of the heating resistor 12 is controlled independently from a thermostatic element that is sensitive to the temperature of the reaction mass of the crucible or crucibles opposite the resistor section and therefore mainly heated by the latter. This being so, provision may be made, for the diiferent crucibles, for the observance of a predetermined law, for example in stages, of the variation of the temperature according to the time to which corresponds the progress desired for the reaction, which starts at about 800 C.
  • a programmer provides in known manner for the control of the electricity supply of the various resistor sections taking account of the control provided by the thermostatic elements.
  • the graphite crucibles maintain their shape without creep in spite of the high temperatures they endure; they may be used for a considerable number of treatments.
  • chromium powder When submicronic chromium oxide powder is used as starting material, chromium powder is obtained whose particles have an average diameter approximately between a fraction of a micron and several microns.
  • an iron or mildsteel dish 40 the bottom of which 41 is convex, for example spherical, contains the reaction mass and rests on a layer 24 of powdered refractory material.
  • the dish 22 which has a substantially plane bottom, rests on a slab 42 made of sintered magnesia and held by an inner rim 43 of a graphite dish 44, the bottom of which thus has a large circular aperture 45.
  • the pots or crucibles may be placed side by side but separated thermally from each other.
  • heating is advantageously effected by the roof, the bottom or the roof and the bottom at the same time.
  • FIG. 4 relates to an apparatus according to the invention having four columns of crucibles 31 -61 each of which is similar to the one described above with reference to FIG. 1.
  • a central post 32 is provided; it may have partitions distributed regularly in the form of a cross with inwardly curved arms.
  • the post and partitions are made of one or several materials adapted to effect good heat insulation.
  • the crucible columns are thus thermally separated from each other.
  • the invention provides for the treatment with magnesium vapours of chromium oxide powders whose various particles are further away from each other than those of an ordinary chromium oxide powder. This promotes the action of the magnesium vapour and makes it more regular.
  • An apparatus for the industrial manufacture of chromium powder by reduction of chromium oxide powder by magnesium in vapor form comprising: a bell-type enclosure, means for heating said enclosure disposed externally thereof, a plurality of superimposed crucibles each adapted to contain a reaction mass of substantially l to 10 kilograms of chromium powder, and an embedded magnesium ingot, and a layer of heat-insulating material interposed between the reaction masses of two adjacent superimposed crucibles.
  • the layer is made of a powder of a refractory heat-insulating material selected from the group comprising alumina and magnesia, said powder layer being interposed between the bottom of a crucible and the receptacle containing the reaction mass placed in the latter.
  • each crucible has a large central aperture, and a disc of heat-insulating material resting upon said aperture.
  • heating means comprises electrical resistors divided into a plurality of groups located one above the other and forming separate heating zones, the apparatus further comprising heat-sensing elements opposite said crucibles, and means connected to said resistors and to said elements for controlling the temperature of said resistors as a function of signals delivered by said sensing elements during the reduction reaction.
  • said post is shaped for partially receiving said crucible columns, and is formed of material which thermally insulates the columns with respect to each other.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
US715114*A 1967-02-28 1968-02-26 Apparatus for the manufacture of chrome powder Expired - Lifetime US3536309A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR96779A FR1520640A (fr) 1967-02-28 1967-02-28 Procédé et appareil pour la fabrication de poudre de chrome

Publications (1)

Publication Number Publication Date
US3536309A true US3536309A (en) 1970-10-27

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Family Applications (1)

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US715114*A Expired - Lifetime US3536309A (en) 1967-02-28 1968-02-26 Apparatus for the manufacture of chrome powder

Country Status (6)

Country Link
US (1) US3536309A (en。)
BE (1) BE711400A (en。)
DE (1) DE1583906A1 (en。)
FR (1) FR1520640A (en。)
GB (1) GB1196092A (en。)
SE (1) SE346333B (en。)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3675910A (en) * 1971-06-25 1972-07-11 Nasa Apparatus for producing metal powders
US5476248A (en) * 1992-08-03 1995-12-19 Japan Metals & Chemicals Co., Ltd. Apparatus for producing high-purity metallic chromium
US5900177A (en) * 1997-06-11 1999-05-04 Eaton Corporation Furnace sidewall temperature control system
US20080056978A1 (en) * 2006-04-29 2008-03-06 Chun-Chieh Chang Method and devices for producing air sensitive electrode materials for lithium ion battery applications

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1829352A (en) * 1928-07-13 1931-10-27 Richard M Heames Heating device
US2282235A (en) * 1940-11-23 1942-05-05 Westinghouse Electric & Mfg Co Hydrocarbon gas treatment for electrographitic material
US2661386A (en) * 1950-10-09 1953-12-01 Lundgren Gosta Theodor Retort type sectional highfrequency furnace
US3227798A (en) * 1962-07-06 1966-01-04 Commissariat Energie Atomique Bell furnace for the preparation of uranium metal by magnesiothermic reduction
US3403213A (en) * 1966-07-20 1968-09-24 Dresser Ind Electric furnace having refractory brick of specific composition in the critical wear areas
US3416779A (en) * 1966-03-15 1968-12-17 Bethlehem Steel Corp Composite refractory lining for basic oxygen furnace

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1829352A (en) * 1928-07-13 1931-10-27 Richard M Heames Heating device
US2282235A (en) * 1940-11-23 1942-05-05 Westinghouse Electric & Mfg Co Hydrocarbon gas treatment for electrographitic material
US2661386A (en) * 1950-10-09 1953-12-01 Lundgren Gosta Theodor Retort type sectional highfrequency furnace
US3227798A (en) * 1962-07-06 1966-01-04 Commissariat Energie Atomique Bell furnace for the preparation of uranium metal by magnesiothermic reduction
US3416779A (en) * 1966-03-15 1968-12-17 Bethlehem Steel Corp Composite refractory lining for basic oxygen furnace
US3403213A (en) * 1966-07-20 1968-09-24 Dresser Ind Electric furnace having refractory brick of specific composition in the critical wear areas

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3675910A (en) * 1971-06-25 1972-07-11 Nasa Apparatus for producing metal powders
US5476248A (en) * 1992-08-03 1995-12-19 Japan Metals & Chemicals Co., Ltd. Apparatus for producing high-purity metallic chromium
US5900177A (en) * 1997-06-11 1999-05-04 Eaton Corporation Furnace sidewall temperature control system
US20080056978A1 (en) * 2006-04-29 2008-03-06 Chun-Chieh Chang Method and devices for producing air sensitive electrode materials for lithium ion battery applications
US8158071B2 (en) * 2006-04-29 2012-04-17 Chun-Chieh Chang Method and devices for producing air sensitive electrode materials for lithium ion battery applications

Also Published As

Publication number Publication date
FR1520640A (fr) 1968-04-12
DE1583906B2 (en。) 1971-01-14
GB1196092A (en) 1970-06-24
DE1583906A1 (en。) 1971-01-14
SE346333B (en。) 1972-07-03
BE711400A (en。) 1968-08-28

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