US3184530A - Process for the melting of metals, for example copper, and an electric furnace for the performance of said process - Google Patents

Process for the melting of metals, for example copper, and an electric furnace for the performance of said process Download PDF

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US3184530A
US3184530A US175225A US17522562A US3184530A US 3184530 A US3184530 A US 3184530A US 175225 A US175225 A US 175225A US 17522562 A US17522562 A US 17522562A US 3184530 A US3184530 A US 3184530A
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melting
furnace
electrode
metal
basin
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US175225A
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English (en)
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Properzi Ilario
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    • 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
    • H05B3/00—Ohmic-resistance heating
    • H05B3/60—Heating arrangements wherein the heating current flows through granular powdered or fluid material, e.g. for salt-bath furnace, electrolytic heating
    • 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
    • C22B15/00—Obtaining copper
    • C22B15/0026—Pyrometallurgy
    • C22B15/0028—Smelting or converting
    • C22B15/003—Bath smelting or converting
    • C22B15/0039—Bath smelting or converting in electric furnaces
    • 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
    • C22B4/00—Electrothermal treatment of ores or metallurgical products for obtaining metals or alloys
    • 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
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/04—Dry methods smelting of sulfides or formation of mattes by aluminium, other metals or silicon
    • 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
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/06—Dry methods smelting of sulfides or formation of mattes by carbides or the like
    • 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
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/16—Remelting 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
    • H05B3/00—Ohmic-resistance heating
    • H05B3/02—Details
    • H05B3/03—Electrodes

Definitions

  • One object of the present invention is to be able to provide for the melting of metals, and of copper in particular, in such a manner as to satisfy all the requirements of this operation, by economical means as regards both thermal eciency and low consumption of materials.
  • the process according to the present invention is characterized in that the metal to be melted, for example copper, is completely covered by a layer of graphite or carbon powder, and in that an electric current is passed through the mass consisting of said powder and the metal.
  • Said conducting powder also constitutes a protective coat and, as will appear more clearly-hereinafter, keeps a controlled reducing atmosphere inside the furnace while at the same time insulating said furnace from the outside atmosphere; there is a minimum dispersion of heat and practically no wear on the furnace.
  • FIG. 1 shows a cross-section of the furnace taken along the line I-I of FIG. 3;
  • FIG. 2 shows another cross-section of the same furnace taken along the line II-II of FIG. 4, and in this crosssection, parts of said furnace are seen in a different recip rocal position from that of the foregoing figure;
  • FIG. 3 shows a longitudinal section of the furnace taken along the line III-III of FIG. 1;
  • FIG. 4 shows a plan of the furnace with said parts in said different reciprocal position in relation to FIGURES 1 and 3;
  • FIG. 5 shows a cross-section (like FIG. 1) of another example of a furnace according to the present invention
  • FIGURES 6 and 7 show respectively the axial section and the plan of a variant of the electrode which can be employed in the furnace according to the invention.
  • FIGURES 8 and 9 show, in axial cross-sectional view, two further embodiments of the electrode, on a reduced scale with respect to that of FIGS. 6 and 7.
  • the furnace of the present example is a three-phase in-line furnace composed essentially of two distinct parts, a lower one and an upper one, respectively indicated by the numerals 16 and 4, supported and reciprocally joined by means whereof more will be said hereinafter.
  • the lower part 16 comprises a melting basin 1 on the bottom whereof there can also be provided a pressed down carbon or silicon carbide oor 2.
  • Melting basin 1 is made from a suitable refractory material,
  • Said basin is adapted to receive the metal, which is then melted in the basin itself; in the present example, said metal consists of a bundle of copper cathodes 3; on one side of said basin there is provided a pouring spout 21.
  • the same lower part 16 extends over one side of the furnace into a part 18 on which the upper part 4 can be shifted as will be better disclosed hereinbelow.
  • Said part 4 carries rollers 22 which run on two rails 17; these are integral with supports 23 which are in turn integral with part 16 itself.
  • the upper part 4 is supported by part 16 itself and can perform horizontal movements in relation thereto.
  • the upper part 4 includes generally cylindrical openings or wells bounded by a surface 28 and lined with a refractory material 24.
  • the wells contain the electrodes 5 which, in the present example, are three in number as the furnace is a three-phase one, as can be best seen from FIG. 3.
  • Each electrode 5 is housed in a well bounded by surface 28, and is integral with the current bars 6 embedded in said electrode; the latter is made of carbon or graphite.
  • Electrode 5 is formed with an axial passage 8 bounded by a surface 25, and the outer surface of the electrode, besides having a cylindrical part 26, has a lower frustoconical shape '7.
  • the current bars 6 of the electrodes are integral with the cross-beams 11 which are connected to bars 15 of the transformer supplying the furnace, through electrical conductors 14.
  • Each bar 11 is supported by means of two electrically insulated screws 12 and 13 resting on part 4 itself.
  • Each electrode 5 can therefore be lowered or raised by turning said screws 12 and 13.
  • the furnace is supported by means of columns 29 and a hydraulic piston 19 connected flexibly to part 16: to be precise, said part 16 is pivoted to said column 29 so that it can perform rotations on pins 20.
  • part 16 supports part 4 of the furnace, it follows that the whole furnace can rotate on said pins under the control of the piston 19.
  • the means actuating said piston can be provided in various ways and, for the sake of simplicity, are not shown.
  • axis A on which the furnace rotates is relatively near to the pouring spout 21.
  • All the space above the charge 3 is filled with graphite powder 9, including the space of the wells wherein the electrodes are situated, i.e. said electrodes are completely immersed in said powder.
  • each passage 8 serves to increase the area of contact with the graphite powder and to facilitate the filling and the flowing of said powder which must fill all the empty spaces inside the furnace and close all the cracks communicating with the outside, up to the top 1).
  • the layer of powder besides acting as a resistance, also serves as a useful protective coating.
  • said frusto-conical surfaces 7 serve to reduce the cross-sectional area of the electrode tips in order to reduce the losses due to heat transfer therewithin.
  • FIG- URES 1 to 5 have tapering terminal cross-sections corresponding to the outer frusto-conical surface 7; the type of electrode, also included in the scope of this invention, and illustrated in FIGURES 6 and 7 also has a decreasing cross-section, but has an inner frusto-conical surface 27.
  • Two further electrodes, having a decreasing terminal cross-sectional area, are shown in FIGS. 8 and 9. rI ⁇ he loss of heat which strongly affects the thermal efficiency of electric furnaces with electrodes because of the thermal conductivity of the electrodes themselves, is thus considerably reduced, whilst the resistance to the passage of electric current along the electrodes' remains practically unchanged.
  • the pointed shape of the electrode facilitates the descent thereof.
  • FIG. 2 shows the same section as FIG. 1 but with the upper part i (which runs on said rails 17) in the recharging position, i.e. with said upper part 4 taken to the right (looking at FIG. 2) whilst the graphite powder rests on the bed 1S of refractory material.
  • Suitable means are provided for providing the thrust for this movement. In this position, the operations of controlling, refining, etc., if necessary, take place, and when they have been completed, the liquid metal is taken to be used, whilst the powder in the wells cannot come down into the basin during the discharging phase.
  • the new charge can therefore be introduced into basin 1 after same has been cleaned of residue.
  • Body 4 is taken back to the position shown in FIG. l to start a new heat.
  • the lower part 16, containing the melting basin 1, is manoeuvred, at the moment of pouring, by means of said hydraulic piston 1.9 which obliges the furnace to rotate on said pins 20. Any suitable means can be employed to retain or cover the powder which is thus uncovered.
  • FIG. 5 shows a variant of an embodiment of the furnace described hereinabove.
  • a double basin i.e. besides the above-described part 16
  • a second part 16 at the side of the rst and integral therewith.
  • part 13 is missing and is replaced by the new part 16; the latter is in all respects the same as the first, i.e. it comprises the same basin 1 with conducting floor 2 and pouring spout 21.
  • Part 4 which is in all respects the same as the part 4 described hereinabove. Part 4 in the embodiment under examination can be so shifted as to dispose itself alternately on one and on the other part 16.
  • the whole assembly is actuated by means of two hydraulic pistons 19 and can rotate on pins 20 about its axis A.
  • the electric current can, naturally, have any number of phases; in the case of a single-phase furnace, 'there may be a single electrode immersed in the graphite, the circuit being capable of being closed either through the Hoor or through another electrode.
  • An electrical furnace for melting readily oxidizable metals in a reducing atmosphere including in combination, a furnace body of refractory material, a melting basin recessed in the top surface of said furnace body, said melting basin .adapted to receive a charge of metal to be melted, with said charge covered with an incoherent carbonaceous material, a movable roof of refractory material disposed above said melting basin means for horizontally transporting said roof in a linear path over the top surface of said furnace body, at least two vertical wells extending through said roof, a carbon electrode disposed coaxially in cach said well and extending a substantial distance along the axial length thereof, each said electrode having a bottom portion terminating near the bottom of each said well and positioned over said melting basin, at least one metal member secured to and extending vertically from the top portion of each said electrode for securing said electrodes in place in said wells and providing terminal means for application of an electrical potential thereto, and an incoherent carbonaceous material disposed around each said electrode so as to completely
  • each said electrode has a generally hollow cylindrical configuration with a tapered rbottom portion.
  • An electric furnace according to claim 1 wherein said melting basin is provided with a pouring spout, ⁇ and wherein means are provided for rotating said furnace body in a vertical plane for removal of said melted metal from said melting basin.
  • An electrical furnace for melting -readily Koxidizable metals in a reducing atmosphere including in combination, a furnace body of refractory material, a melting basin recessed in the top surface of said furnace body, said melting basin adapted to receive a charge of metal to be melted, with said charge covered with an incoherent carbonaceous material, a movable roof of refractory material disposed above said melting basin, said roof having three vertical wells extending therethrough, means for horizontally transporting said roof in a linear path over the top surface of said furnace body, a generally cylindrical hollow carbon electrode disposed c0- axially in each said well and extending a substantial distance along the axial length thereof, each said electrode having a tapered bottom portion of reduced cross-section terminating near the bottom of each said well and juxtaposed near the top surface of said melting basin, at least one metal rod secured to each said electrode and extending vertically from the top thereof, means for adjustably holding said rods in place above said wells to thereby position said electrodes and to provide terminal means
  • An electrical furnace for melting copper in a reducing atmosphere including in combination, a furnace body of refractory material, an elongated rectangular melting basin recessed in the -top portion of said furnace body, said melting basin adapted to receive a charge of copper CTI stock to be melted, with said charge completely covered with powdered graphite, a movable roof of refractory material disposed above said inciting basin, means for transporting said roof horizontally over the -top surface of said furnace body in a linear path to thereby make said melting basin accessible for removal of melted copper and to receive additional stoclr to be melted, a plurality of vertical wells extending through said roof, said wells disposed in a row coextensive with Athe elongated length of said melting basin, a generally cylindrical hollow carbon electrode disposed coaxially in each said well ⁇ and extending a substantial distance along the axial length thereof, each Isaid electrode terminating in a bottom portion of reduced cross-section near the bottom of each said well and juxtaposed near the
  • An electrical furnace for melting readily oxidizable metals in a reducing atmosphere including in combination, a furnace body of refractory material, first and second melting basins recessed side by side in the top surface of said furnace body, said melting basins adapted to receive a charge of metal to be melted, with said charge being covered with finely divided carbon powder, a movable roof of refractory material disposed above said furnace body and positioned over one of said melting basins, means to horizontally transport said roof from sai-d position over one said melting basin to a corresponding position over the other said melting basin, a plurality of vertical ⁇ wells extending through said roof, .a generally cylindrical hollow carbon electrode disposed coaxially in each said Well and extending a substantial distance along the axial length thereof, each said electrode having a bottom por-tion of reduced cross-section terminating near the bottom of each said well such that it is positioned above one of said first and second melting basins, at lease one vertically extending metal rod secured to the top portion of each said electrode,

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Furnace Details (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
US175225A 1961-03-04 1962-02-23 Process for the melting of metals, for example copper, and an electric furnace for the performance of said process Expired - Lifetime US3184530A (en)

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IT402361 1961-03-04

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4410796A (en) * 1981-11-19 1983-10-18 Ultra Carbon Corporation Segmented heater assembly
US4549345A (en) * 1981-11-19 1985-10-29 Wilsey Harvey J Method of making a graphite zig-zag picket heater
US4755658A (en) * 1985-11-12 1988-07-05 Ultra Carbon Corporation Segmented heater system

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1812357A (en) * 1930-01-21 1931-06-30 Mills Alloys Inc Process of manufacturing tungsten carbide
US1901524A (en) * 1929-09-13 1933-03-14 Magnesium Dev Corp Chlorinating apparatus
US1924201A (en) * 1931-01-31 1933-08-29 Koppers Co Inc Apparatus for smelting aluminium and other light metals
US2290028A (en) * 1940-07-02 1942-07-14 Swindell Dressler Corp Electric furnace structure
US2298055A (en) * 1941-04-05 1942-10-06 Int Smelting & Refining Co Melting copper
US2446637A (en) * 1945-11-08 1948-08-10 Chase Brass & Copper Co Method for melting brass chips
US2448886A (en) * 1945-05-19 1948-09-07 Kellogg M W Co Electric furnace
US3025385A (en) * 1959-04-27 1962-03-13 To A Kako Kabushiki Kaisha Electric heating apparatus of fluidized electro-conductive powder resistance

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1901524A (en) * 1929-09-13 1933-03-14 Magnesium Dev Corp Chlorinating apparatus
US1812357A (en) * 1930-01-21 1931-06-30 Mills Alloys Inc Process of manufacturing tungsten carbide
US1924201A (en) * 1931-01-31 1933-08-29 Koppers Co Inc Apparatus for smelting aluminium and other light metals
US2290028A (en) * 1940-07-02 1942-07-14 Swindell Dressler Corp Electric furnace structure
US2298055A (en) * 1941-04-05 1942-10-06 Int Smelting & Refining Co Melting copper
US2448886A (en) * 1945-05-19 1948-09-07 Kellogg M W Co Electric furnace
US2446637A (en) * 1945-11-08 1948-08-10 Chase Brass & Copper Co Method for melting brass chips
US3025385A (en) * 1959-04-27 1962-03-13 To A Kako Kabushiki Kaisha Electric heating apparatus of fluidized electro-conductive powder resistance

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4410796A (en) * 1981-11-19 1983-10-18 Ultra Carbon Corporation Segmented heater assembly
US4549345A (en) * 1981-11-19 1985-10-29 Wilsey Harvey J Method of making a graphite zig-zag picket heater
US4755658A (en) * 1985-11-12 1988-07-05 Ultra Carbon Corporation Segmented heater system

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BE614609A (fr) 1962-07-02
GB982135A (en) 1965-02-03

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