Classifications

• • 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
  • F27D27/00—Stirring devices for molten material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
  • B22D1/002—Treatment with gases
  • B22D1/005—Injection assemblies therefor
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
• • 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
  • C22B9/003—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals by induction
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B14/00—Crucible or pot furnaces
  • F27B14/06—Crucible or pot furnaces heated electrically, e.g. induction crucible furnaces with or without any other source of heat
  • F27B14/061—Induction furnaces
  • F27B14/065—Channel type
• • 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
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/18—Charging particulate material using a fluid carrier
• • 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
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/16—Introducing a fluid jet or current into the charge
  • F27D2003/161—Introducing a fluid jet or current into the charge through a porous element
• • 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
  • F27D99/00—Subject matter not provided for in other groups of this subclass
  • F27D99/0001—Heating elements or systems
  • F27D99/0006—Electric heating elements or system
  • F27D2099/0021—Arc heating
• • 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
  • F27D99/00—Subject matter not provided for in other groups of this subclass
  • F27D99/0001—Heating elements or systems
  • F27D99/0006—Electric heating elements or system
  • F27D2099/0031—Plasma-torch heating
• • 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
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/14—Charging or discharging liquid or molten material
• • 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
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/15—Tapping equipment; Equipment for removing or retaining slag
  • F27D3/1545—Equipment for removing or retaining slag
  • F27D3/1554—Equipment for removing or retaining slag for removing the slag from the surface of the melt
  • F27D3/1563—Equipment for removing or retaining slag for removing the slag from the surface of the melt by the use of scrapers
• • 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
  • F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
  • F27D7/02—Supplying steam, vapour, gases, or liquids
• • 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
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/25—Process efficiency

Definitions

• This invention relates to an apparatus and a method for the secondary refinement of metals, particularly steel.
• ladle furnaces are used extensively for controlling the temperature of the steel coming from a steel furnace and for refining it prior to casting through continuous casting machines.
• a steel casting ladle is positioned under a hood, and electric arc heating applied to the upper surface of the steel in the ladle while argon gas is bubbled through the steel to distribute the heat throughout the contents of the ladle.
• the aforesaid bubbling of argon gas is usually effected by introducing such gas through one or more porous elements located on the bottom of the ladle.
• Such argon gas bubbling is indispensable for ensuring good mass and heat transfer conditions between the steel and the slag.
• electromagnetic stirring may be used for obtaining additional benefits.
• Steel ladles are vertically disposed cylindrical vessels, of which the depth to diameter ratio is normally larger than 1 , and smaller than 2. It will be appreciated that one of the main reasons for having such vessels so vertically disposed, is to maintain the surface area of the bath as small as possible and hence retain the energy of the metal bath inside it.
• a further disadvantage found with such a vertically disposed vessel is that the surface to volume ratio of the metal bath in the vessel is relatively small.
• the metal-slag surface area is increased, thereby reducing the thickness of the slag layer.
• the substantially circular configuration of the surface of the slag layer puts a restriction on the width of such a paddle in the sense that a paddle which is wide enough to extend over the whole width of the slag layer near such lip, is too narrow in a position further away from such lip, thus allowing slag to escape around its ends.
• apparatus for use in the secondary refinement of a metal, particularly steel includes an elongated vessel of which the length to width ratio is greater than two, the vessel being provided with at least one channel type inductor adapted for heating the vessel, and the vessel being adapted in operation to be located with its long side substantially horizontally disposed.
• the aspect ratio of a metal/slag bath inside the vessel i.e. the ratio of the length of its surface to the width of its surface, will be larger than two. It will further be appreciated that the surface area of such a metal/slag bath will be much larger than what the case is with the conventional vertically disposed vessel so that a much larger contact area is available for reaction with chemicals added to the bath for the secondary refining of the metal and/or for the removal of sulphur from such bath and/or for the interaction between the metal bath and its overlying slag layer.
• the at least one inductor is disposed substantially along the centre of the bottom side of the vessel when it is so horizontally disposed.
• Applicant has found that the fact that the bath in such a vessel is heated from below, coupled to the fact that a relatively low metallo static head is present, together with the resulting convection streams, ensure that a sufficiently strong stirring action is created in the vicinity of the inductor(s) to cause effective slag/metal interaction and homogeneous distribution of the refined metal and impurity saturated slag.
• the fluxes and alloys which are required in the refining process can be added in an at least semi-continuous stream to the surface of the metal bath directly above the inductor(s), i.e. where the most active stirring motion is achieved. It will be appreciated that any such fluxes etc which are required in the metal bath can also in conventional manner be introduced to the bath through one or more lances passing from above into the bath.
• additional stirring of the metal bath may be effected by introducing argon and/or nitrogen gas into the bath by means of one or more lances or porous element stirring devices located in the vessel.
• any additional heating which may be required may be effected in conventional manner by means of one or more plasma torches and/or three phase electric arc electrodes.
• the vessel is of round cylindrical configuration in cross section.
• the vessel is provided towards at least one of its shorter ends with an opening through which a paddle or the like can be inserted for scraping the spent slag layer from the metal bath in the vessel.
• a paddle can be used which substantially spans the whole width of the slag layer over substantially the whole length of the slag layer. By pushing or pulling such a paddle along the slag layer, the spent slag can be removed from the top of the metal bath in a very effective manner.
• At least one of the said shorter ends of the vessel may be provided with a recessed outlet.
• the width of the paddle is slightly less than the width of the vessel, the narrow gaps so left between the ends of the paddle and the walls of the vessel ensuring free movement of the paddle in the vessel.
• air or nitrogen may be blown into such gaps to prevent the slag from escaping through the gaps when the paddle is moved along the slag layer.
• the invention also includes within its scope a method for the secondary refining of a metal using the apparatus disclosed above.
• Figure 1 is a diagrammatic side view of apparatus according to the invention
• Figure 2 is a diagrammatic cross sectional view of the apparatus of figure 2, as seen on line I : I in figure 1 ;
• Figure 3 is a diagrammatic plan view of the apparatus of figure 1 as seen in the direction arrow A in figure 1.
• apparatus for carrying out the secondary refinement of a metal comprises a horizontally disposed refractory lined cylindrical vessel 10 of which the length to diameter ratio is greater than 2.
• the length of vessel 10 may, for example, be in the order of 8m and its diameter in the order of 2m, the intention being that it will be filled with liquid metal 11 to a depth in the order of 1 m.
• vessel 10 is shown in the drawings as being of circular configuration in cross section, it can be of any other suitable configuration in cross section such as, for example, substantially square, triangular, etc.
• Vessel 10 is provided along its upper wall with an inlet 12 through which fluxes or the like may be charged to it. Vessel 10 is also provided along the centre of its bottom wall with at least one channel type inductor 13 of 3MW capacity. The upper wall of vessel 10 is also provided along each of its opposite ends with an opening 14 through which an elongated slag paddle 15 may be inserted which is operated by means of a handle 16, the width of paddle 15 being slightly less than the diameter of vessel 10.
• Openings 14 are provided with lids (not shown).
• Vessel 10 is also provided with a lance 17 which passes from above into metal bath 11 and through which argon and/or nitrogen may be passed into bath 11 for stirring purposes.
• vessel 10 may also be provided with one or more porous stirring elements which can be fed with argon and/or nitrogen in order to assist in the stirring of bath 11. Only one of these is shown in dotted lines at 18 in figure 1 of the drawings.
• the molten metal to be refined is charged to vessel 10 through one of the openings 14 to form a bath with a depth in the order of 1m, and the required fluxes introduced through inlet 12.
• lnductor(s) 13 when switched on, not only serve(s) to heat up bath 11 , but through convection and electromagnetic forces also cause(s) the stirring of bath 11.
• stirring may be supplemented by passing argon and/or nitrogen through lance 17 (or element(s) 18) into bath 11.
• paddle 15 is inserted through one of the openings 14, and the slag in layer 19 raked or pushed out through recessed outlets (not shown) provided in the said outer ends of vessel 10.
• the width of paddle 15 is slightly less than the cross sectional diameter of vessel 10 so that when paddle 15 engages slag layer 19, narrow gaps 20 are left between the outer ends of paddle 15 and the inside wall of vessel 10 to allow paddle 15 relatively free to-and-fro movement in vessel 10.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Treatment Of Steel In Its Molten State (AREA)
• Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
• Manufacture And Refinement Of Metals (AREA)

Priority Applications (8)

Applications Claiming Priority (2)

Publications (1)

Family

ID=25587196

Family Applications (1)

Country Status (12)

Citations (4)

• 1999
  • 1999-07-28 CN CN99801308A patent/CN1274390A/zh active Pending
  • 1999-07-28 PL PL99339670A patent/PL339670A1/xx unknown
  • 1999-07-28 SK SK508-2000A patent/SK5082000A3/sk unknown
  • 1999-07-28 TR TR2000/00919T patent/TR200000919T1/tr unknown
  • 1999-07-28 EP EP99929649A patent/EP1021571A1/en not_active Withdrawn
  • 1999-07-28 JP JP2000563838A patent/JP2002522634A/ja active Pending
  • 1999-07-28 AU AU46426/99A patent/AU4642699A/en not_active Abandoned
  • 1999-07-28 CA CA002305741A patent/CA2305741A1/en not_active Abandoned
  • 1999-07-28 BR BR9906673-4A patent/BR9906673A/pt not_active Application Discontinuation
  • 1999-07-28 WO PCT/IB1999/001334 patent/WO2000008216A1/en not_active Application Discontinuation
  • 1999-08-04 TW TW088113307A patent/TW446753B/zh active
• 2000
  • 2000-04-04 BG BG104298A patent/BG104298A/xx unknown

Patent Citations (4)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events