US3391238A - Preparation for smelting of metals and compounds with high melting points - Google Patents

Preparation for smelting of metals and compounds with high melting points Download PDF

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Publication number
US3391238A
US3391238A US433526A US43352665A US3391238A US 3391238 A US3391238 A US 3391238A US 433526 A US433526 A US 433526A US 43352665 A US43352665 A US 43352665A US 3391238 A US3391238 A US 3391238A
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United States
Prior art keywords
crucible
electrode
smelting
melt
compounds
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Expired - Lifetime
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US433526A
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English (en)
Inventor
Himmelstein Paul
Kuhn Horst
Wille Werner
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US Atomic Energy Commission (AEC)
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Atomic Energy Commission Usa
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • F27D11/08—Heating by electric discharge, e.g. arc discharge
    • 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
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/18—Heating by arc discharge

Definitions

  • This invention relates to the smelting of metals, alloys, and compounds having high melting points. More particularly, this invention discloses an arc furnace in which metals and compounds having a high melting point are smelted by the skull-melting process.
  • furnaces In the metallurgical process of smelting metals, alloys and compounds having high melting points, furnaces are used in which the energy required for smelting is applied in the form of either a concentrated electron beam or an electric arc. Electron beam furnaces can be operated only in a high vacuum or, when using an electron gun, in a medium vacuum. On the other hand, are furnaces can operate either in a vacuum, when the plasma of the arc consists exclusively of the vapor from the melt, or under a inert gas at any desired pressure, when the plasma consists mainly of ionized gas.
  • the second method is particularly suitable when alloys or compounds to be smelted have a component which is slightly volatile at the smelting temperature. The inert gas cannot eliminate their undesired volatility, but it can diminish it.
  • a copper crucible is connected at a suitable point by mechanical fastening to one pole of the power source.
  • the path of the current from the point of contact on the crucible to the point of contact of the are on the melt is then left to chance.
  • the size of the molten pool influences the thickness of the skull, and the force of pressing the skull against the cooled crucible depends upon its temperature and it expansion coefficient. In this way points of contact arise betwen skull and crucible which may be distributed perferentially at the side.
  • the magnetic field accompanying the current is also distorte'd, and this also has adverse effects upon the arc.
  • the contact-points slowly wander, the arc moves about on the molten pool in an uncontrolled way accordingly. The smelting of the material thus occurs very unevenly and the total quantity melted may vary greatly under otherwise identical conditions.
  • the primary objectof this invention is to provide an improved arc furnace for melting metals and compounds having high melting points.
  • Another object of this invention is to provide a stabilized arc for a high temperature are smelting furnace.
  • FIG. 1 illustrates an arc furnace in which the bottom electrode is inserted in the center of the crucible floor and insulated therefrom, and
  • FIG. 2 shows an arc furnace in which the bottom electrode is the crucible floor and is insulated from the sides of the crucible.
  • FIG. 1 shows a copper crucible 1 having a diameter of 180 mm. and a height of mm. [t is cooled by a coil 2 through which water flows.
  • the crucible is surrounded by coil 3 with which a magnetic field of at least 2000 ampere turns can be generated.
  • an electrode 4 which is insulated from the remainder of the crucible by an insulating sheath 5.
  • Above the crucible is a graphite electrode 6 which is secured in a Watercooled holder.
  • the electrode has an axial boring 7 which grows with use into a concave depression 8.
  • the insulated electrode 4 in the crucible is connected to the plus pole of a high-current rectifier and the electrode 6 to the minus pole.
  • the entire smelting apparatus is located in a sealed argon containing vessel which is not illustrated.
  • FIG. 2 shows an alternative design in which the entire floor 9 acts as an electrode and is insulated from the wall 11 by a ring shaped insulating material It The material 12 in the corners of the crucible is part of the unsmelted charge. In this design, too, the entire current flows in an axial direction from the bottom of the crucible through the skull 13 and the melt 14 to the electrode 15.
  • the electrode burns out from the middle.
  • the cathode burning spot stabilizes itself in the middle of the electrode so that there is an appreciable burning away at this point due to the higher temperature.
  • the burn area on the electrode increases and the current load diminishes accordingly, thus the inevitable erosion of the electrode is reduced to a minimum and may be considered to be almost constant. Since the loss of material at the electrode is partly taken up by the melt, it can be seen that as a result of the stabilization of the arc and the increase of the cathode burn area, the impurities in the melt are also reduced.
  • Example Broken pieces of uranium. monocarbide weighing 15 kg. were placed in the crucible.
  • the arc was started by contacting the graphite electrode with the uranium monocarbide.
  • the distance between the melt and the electrode was regulated so that the potential drop is in the order of 35 volts.
  • the melt began to rotate slowly owing to slight asymmetries without diverting the are from the center of the melt.
  • the electrode was drawn up and the molten uranium monocarbide was poured out of the crucible through a spout into a mold and cooled.
  • the arc furnace according to this invention it is possible to carry out a large number of smeltings one after the other in the same vessel. The same amount of material is smelted each time with good reproducibility.
  • the charge material is evenly heated, and the wall of the crucible has no influence on the smelting process.
  • An improved arc furnace for skull melting materials of high melting point comprising:
  • the improved arc furnace of claim 1 wherein the furnace includes means for providing a magnetic field directed axially of the electrodes.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US433526A 1964-04-30 1965-02-17 Preparation for smelting of metals and compounds with high melting points Expired - Lifetime US3391238A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEE0026945 1964-04-30

Publications (1)

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US3391238A true US3391238A (en) 1968-07-02

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US433526A Expired - Lifetime US3391238A (en) 1964-04-30 1965-02-17 Preparation for smelting of metals and compounds with high melting points

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US (1) US3391238A (xx)
BE (1) BE663252A (xx)
DE (1) DE1433898A1 (xx)
GB (1) GB1070108A (xx)
LU (1) LU48507A1 (xx)
NL (1) NL6502986A (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0021608A1 (en) * 1979-06-04 1981-01-07 Kennecott Corporation Process and apparatus for casting fused refractory oxides having high melting points
US4349909A (en) * 1979-06-04 1982-09-14 Kennecott Corporation Process for casting fused refractory oxides having high melting points
US20100252411A1 (en) * 2009-04-02 2010-10-07 Toshio Awaji Control method of plasma by magnetic field in an exhaust gas treating apparatus and an exhaust gas treating apparatus using the same

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US871338A (en) * 1906-04-21 1907-11-19 Electro Metallurg Francaise Soc Electric furnace.
US1833347A (en) * 1929-11-02 1931-11-24 Samuel W Avis Method of casting
US2727936A (en) * 1954-11-23 1955-12-20 Westinghouse Electric Corp Titanium furnace
US2789150A (en) * 1955-05-25 1957-04-16 Nat Res Corp Heat reservoir and electrode for production of metals in skull type furnace
US2789152A (en) * 1955-06-01 1957-04-16 Nat Res Corp Electric furnace for production of metals
US3180916A (en) * 1961-04-28 1965-04-27 Pechiney Prod Chimiques Sa Electric arc furnaces and method
US3201560A (en) * 1963-03-12 1965-08-17 Robert F Mayo Electric-arc heater

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US871338A (en) * 1906-04-21 1907-11-19 Electro Metallurg Francaise Soc Electric furnace.
US1833347A (en) * 1929-11-02 1931-11-24 Samuel W Avis Method of casting
US2727936A (en) * 1954-11-23 1955-12-20 Westinghouse Electric Corp Titanium furnace
US2789150A (en) * 1955-05-25 1957-04-16 Nat Res Corp Heat reservoir and electrode for production of metals in skull type furnace
US2789152A (en) * 1955-06-01 1957-04-16 Nat Res Corp Electric furnace for production of metals
US3180916A (en) * 1961-04-28 1965-04-27 Pechiney Prod Chimiques Sa Electric arc furnaces and method
US3201560A (en) * 1963-03-12 1965-08-17 Robert F Mayo Electric-arc heater

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0021608A1 (en) * 1979-06-04 1981-01-07 Kennecott Corporation Process and apparatus for casting fused refractory oxides having high melting points
US4349909A (en) * 1979-06-04 1982-09-14 Kennecott Corporation Process for casting fused refractory oxides having high melting points
US20100252411A1 (en) * 2009-04-02 2010-10-07 Toshio Awaji Control method of plasma by magnetic field in an exhaust gas treating apparatus and an exhaust gas treating apparatus using the same
US9675930B2 (en) * 2009-04-02 2017-06-13 Clean Technology Co., Ltd. Control method of plasma by magnetic field in an exhaust gas treating apparatus and an exhaust gas treating apparatus using the same

Also Published As

Publication number Publication date
GB1070108A (en) 1967-05-24
DE1433898A1 (de) 1970-02-05
NL6502986A (xx) 1965-11-01
LU48507A1 (xx) 1966-10-31
BE663252A (xx) 1965-11-03

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