US20140208896A1 - Slag ladle for separation and recovery of molten iron from slag - Google Patents

Slag ladle for separation and recovery of molten iron from slag Download PDF

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Publication number
US20140208896A1
US20140208896A1 US14/125,092 US201214125092A US2014208896A1 US 20140208896 A1 US20140208896 A1 US 20140208896A1 US 201214125092 A US201214125092 A US 201214125092A US 2014208896 A1 US2014208896 A1 US 2014208896A1
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Prior art keywords
slag
ladle
edge
molten metal
iron
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Abandoned
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US14/125,092
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English (en)
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Ramchandra Harisa Tupkary
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Individual
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/50—Pouring-nozzles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/04—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like tiltable
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B3/00—General features in the manufacture of pig-iron
    • C21B3/04—Recovery of by-products, e.g. slag
    • C21B3/06—Treatment of liquid slag
    • C21B3/10—Slag pots; Slag cars
    • 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
    • F27B14/08—Details peculiar to crucible or pot furnaces
    • F27B14/0806—Charging or discharging devices
    • 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
    • F27D3/159—Equipment for removing or retaining slag for retaining slag during the pouring of the metal or retaining metal during the pouring of the slag
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2400/00—Treatment of slags originating from iron or steel processes
    • C21B2400/02—Physical or chemical treatment of slags
    • C21B2400/022—Methods of cooling or quenching molten slag
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2400/00—Treatment of slags originating from iron or steel processes
    • C21B2400/04—Specific shape of slag after cooling
    • C21B2400/044—Briquettes or moulded bodies other than sheets
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B2400/00—Treatment of slags originating from iron or steel processes
    • C21B2400/05—Apparatus features
    • C21B2400/066—Receptacle features where the slag is treated
    • C21B2400/072—Tanks to collect the slag, e.g. water tank
    • 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
    • Y02P10/20—Recycling

Definitions

  • the present subject matter relates, in general, to the field of steel making and, in particular, to separation of molten metal from slag.
  • Steel is made by purifying metallic iron charge in the form of, individually or in some combination of, molten pig iron, solid sponge iron and iron/steel scrap.
  • Slag is generally produced as a waste by-product during the steel-making process. Slag occurs in a molten state and is essentially a mixture of various oxides of silicon, calcium, iron and other metals.
  • Molten refined steel is obtained by separating the slag from the molten refined steel at the end of the steel-making process. Effective steel-making process requires that at the end of the process, the molten refined steel is separated cleanly from the slag for further processing of molten refined steel either by direct casting or by secondary refining and then casting. The process of separation of slag varies with different steel-making processes.
  • the entrapped iron is recovered from the solidified slag by first crushing the solidified slag to a suitable size to liberate the iron particles from the solidified slag, and by subsequent magnetic separation of the liberated iron from the non-magnetic slag.
  • the magnetically separated iron is invariably contaminated with slag. Equally a part of iron remains attached with the main bulk of the solidified slag and goes finally to waste. Further, during cooling and solidification of the slag, some part of iron is lost due to oxidation.
  • the solidified slag can not be ground to fine particles to better recover the iron particles as there is an economically acceptable limit for grinding the solidified slag so that the separated iron can be reused as a source of iron-metallic in the steel-making furnace.
  • the process of iron separation and recovery by the magnetic separation results in only 60-70 percent recovery of useful iron contained in the solidified slag. The remaining iron is practically lost in the wasteful slag, without any more possibility of its economic recovery.
  • the separation of the iron from the slag in molten conditions is achieved by attaching a device to a slag-ladle and modifying the process of slag pouring in pits.
  • the slag-ladle typically used for separation and recovery of iron is modified. The device takes into consideration the differential forces of surface tensions, densities, viscosities, and fluid flow characteristics of slag and molten iron in the slag.
  • a device is attached on to an edge of the slag-ladle, which is used for separation of molten slag and recovery of molten iron from the molten slag.
  • the device differentiates the momentums of flow of molten slag and molten iron during slag pouring process and prevents the flow of molten iron associated with the molten slag along with the flow of molten slag during the slag pouring process and collection process thereafter.
  • FIG. 1 illustrates a slag ladle containing the slag and the molten iron as known in the prior art.
  • FIG. 2 and FIG. 3 illustrate disposal of the slag and the molten iron from the slag ladle as known in the prior art.
  • FIGS. 4 a, 4 b, and 4 c illustrate a device to be attached to the slag ladle, in accordance with different embodiments of the present subject matter.
  • FIGS. 5 a, 5 b, and 5 c illustrate the elevated and plan view of the exemplary device, in accordance with the embodiments of FIGS. 4 a, 4 b, and 4 c of the present subject matter.
  • FIGS. 6 a, 6 b, and 6 c illustrate the elevated and plan view of the exemplary device, in accordance with the embodiments of the present subject matter.
  • FIG. 7 illustrates the operation of the device, in accordance with the embodiments of the present subject matter.
  • FIGS. 8 a, 8 b, 8 c, and 8 d illustrate the device as attached to the slag ladle, in accordance with the embodiments of the present subject matter.
  • FIGS. 9 a, 9 b, and 9 c illustrate a modified slag-ladle, in accordance with yet another embodiment of the present subject matter.
  • FIGS. 10 a, 10 b, and 10 c illustrate a modified device to be attached to the modified slag ladle, in accordance with the embodiments of FIG. 9 a of the present subject matter.
  • FIGS. 11 a, 11 b, and 11 e illustrate the elevated and plan view of the modified device, in accordance with the embodiments of FIGS. 10 a, 10 b, and 10 c of the present subject matter.
  • FIGS. 12 a, 12 b, and 12 c illustrate the elevated and plan view of the modified device, in accordance with another embodiment of the present subject matter.
  • FIGS. 13 a, 13 b, 13 c, and 13 d illustrate the modified device as attached to the modified slag-ladle, in accordance with the embodiments of the present subject matter.
  • BOF Basic Oxygen Furnace
  • EAF Electric Arc Furnace
  • the amount of small amount of molten steel so sacrificed to go with the slag is minimized by the use of floats, which has a density in between that of the slag (2.5 gm/cc) and molten iron (7.5 g/cc).
  • the float settles in between the flowing streams of the slag and the small amount of molten steel at the tap hole and minimizes flowing of slag with the molten steel.
  • the small amount of molten steel so lost in the slag is recovered universally by the magnetic separation process after cooling and solidification of the slag.
  • the slag In EAF process of steelmaking, the slag is allowed to flush out of the furnace during the refining operation itself. However, small amount of molten steel gets mechanically entrapped and entrained with flushing slag. The small amount of molten steel thus ends up with the slag that is collected. Additionally, floats as described above are used to minimize flowing of slag with small amount of molten steel. Alternatively, certain sizable proportion of refined steel is allowed to stay back, along with the leftover slag in the EAF, to act as the heel, for the next heat. But again, some small amount of molten steel always ends up in the flushing slag that is produced.
  • the slag along with small amount of molten iron, in the form of the molten refined steel, is collected in a slag-ladle and transported to a slag pits for subsequent separation and recovery of the small amount of molten iron.
  • the slag-ladle is tilted on one side with the ladle axis in the vertical plane such that the slag flows over the lower edge of the slag-ladle.
  • the slag-ladle is tilted continually till the slag-ladle is turned almost upside down and the slag is completely dumped into the slag pits.
  • the term iron in the slag that is used is to denote essentially the metallic iron of whatever composition as distinct from the slag containing only the oxides.
  • FIG. 1 illustrates a typical slag-ladle 100 in an erect position along with the ladle-axis 102 as vertical and apparent ladle edges 104 a and 104 b.
  • the apparent ladle edges 104 a and 104 b appear as surface 104 in the plan view.
  • the slag-ladle 100 is a massive steel construction. In normal vertical position of the slag-ladle 100 , molten iron 106 , being heavier, settles at the bottom and the slag 108 , being relatively lighter than the molten iron 106 , settles above the molten iron 106 .
  • the molten iron 106 and the slag 108 are immiscible liquids and hence appear as two distinct layers one below the other because of their widely different densities.
  • the molten iron 106 and the slag 108 will always take the shape of the slag-ladle 100 while maintaining a top surface level 110 as always horizontal with respect to their heights in the slag-ladle 100 .
  • FIG. 2 illustrates the tilting of the slag-ladle 100 for pouring of the molten iron 106 and the slag 108 into a slag pit.
  • the tilting of the slag-ladle 100 results in slowly changing the shape taken by the molten iron 106 and the slag 108 in the slag-ladle 100 , while maintaining the top surface level 110 as always horizontal due to basic physical properties of liquids. Due to the difference in densities of the molten iron 106 and slag 108 , the molten iron 106 will always remain at the bottom of the slag-ladle 100 and the slag 108 will remain on top of the molten iron 106 .
  • the continued tilting of the slag-ladle 100 causes the slag 108 to reach the lowermost open top-edge-tip 112 of the slag-ladle 100 first. Further tilting of the slag-ladle 100 results in an outflow of the slag 108 from the slag-ladle 100 .
  • the molten iron 106 shall always remain below the slag 108 while maintaining a top surface of the molten iron 106 and a top surface of the slag 108 as always horizontal.
  • the top surface of the molten iron 106 reaches the lowermost open top-edge-tip 112 of the slag-ladle 100 at a specific angle of tilt depending upon the actual amount of molten iron 106 in the slag-ladle 100 and the design of the slag-ladle 100 .
  • the apparent ladle-wall edges 104 a and 104 b in the vertical plane containing the ladle axis is almost horizontal, as illustrated in FIG. 3 .
  • any further tilt of the slag-ladle 100 results in flowing of the molten iron 106 from the slag-ladle 100 and with a higher momentum of flow than the momentum of flow of slag 108 due to the differences in densities and viscosities.
  • the tilting of the slag-ladle 100 is continued till all the molten iron 106 is poured out, albeit along with some of the slag 108 .
  • a small part of the slag 108 may lag behind and flow out even after the molten iron 106 has fully flown out because of high viscosity of the slag 108 .
  • the pouring of the molten iron 106 and the slag 108 takes place very rapidly and are completed in a very short duration.
  • This process of pouring the slag 108 and the molten iron 106 together results in intermixing of the two immiscible liquids in the slag pit.
  • the extent of intermixing of the molten iron 106 and slag 108 differs from case to case.
  • the extent of intermixing depends upon the process of pouring the slag 108 and various parameters, such as height of the slag-ladle 100 above the ground, rate of tilting, rate of cooling, relative proportion of molten iron 106 and slag 108 , and so on. Water spray is used to cool the slag 108 faster to the extent otherwise possible.
  • the slag 108 is turned upside down several times with a shovel to hasten the cooling and solidification of the slag 108 . All these factors result in development of mechanical and few chemical bonding between the slag 108 and the molten iron 106 , resulting in formation of boulders of the slag 108 with specific gravity in between that of the slag 108 and molten iron 106 . Further, a part of the molten iron 106 gets oxidized on its exposure to atmospheric oxygen and water spray. The semi-hot slag 108 boulders are transported to a slag yard, where the slag 108 is cooled to room temperature and then subjected to further processing, such as magnetic separation of iron from the cooled slag 108 .
  • the cooled slag 108 is crushed to liberate iron particles contained therein and the crushed slag 108 is then subjected to magnetic separation of the iron from the non-magnetic slag 108 .
  • the entire mass of the crushed slag 108 is subjected to magnetic separation.
  • magnetic oxide of iron is formed due to oxidation of molten iron 106 while the slag 108 is being cooled in open atmosphere with water spray.
  • the magnetic oxide of iron thus formed tends to be a part of slag 108 like other oxides in the mass of the slag 108 .
  • Due to the magnetic nature of the magnetic oxide of iron the magnetic oxide of iron picked up along with the iron as a magnetic fraction during the magnetic separation. This magnetic oxide of iron therefore erroneously increases the weight of iron recovered from magnetic separation and subsequently inflates the iron recovery figures and the attendant costs of payment for iron.
  • the process of magnetic separation for the recovery of iron from slag 108 is practiced in a retrograde process, i.e., after cooling and solidification of the molten iron 106 and the slag 108 mixture. Also, some part of iron gets oxidized during cooling and is therefore lost in the slag 108 as its own constituent. Additionally, the formation of magnetic oxide tends to blur the demarcation of magnetic iron and non-magnetic slag 108 , at least to some extent, thereby making clean iron separation more difficult. Moreover, some part of the total iron 106 is left in solid slag 108 and is finally lost with the remaining slag 108 as the iron can not be economically recovered by the magnetic separation process.
  • an apparatus and a method in accordance with the present subject matter is designed to recover the molten iron 106 or any other metal, from the slag 108 in a molten state when both the molten iron 106 and slag 108 exist almost as two distinct phases in the slag-ladle 100 .
  • the apparatus according to the present subject matter, comprises a device fitted over a part of a top-edge of the slag-ladle 100 .
  • the apparatus is designed for separation and recovery of molten iron 106 or any other metal from the slag 108 .
  • the method ensures that the molten iron 106 and slag 108 are separated before they get intermixed during the process of pouring the slag 108 .
  • This method of separation and recovery of the molten iron 106 from the slag 108 in the molten state is based on differential forces of surface tensions, densities, viscosities, and fluid flow characteristics of the molten iron 106 and the slag 108 . Due to these differential forces, relatively different momentums of fluid flow of molten iron 106 and the slag 108 are generated during the process of pouring the slag 108 .
  • molten iron 106 and slag 108 can be effectively separated as two almost fairly distinct products such that one product consists of essentially most of the slag 108 and other product consists of essentially all the molten iron 106 along with small amount of slag 108 .
  • the device in accordance with the present subject matter is designed to develop differential momentums of the flow of slag 108 and of molten iron 106 by restricting the flow of the molten iron 106 along with the slag 108 during the process of pouring the slag 108 in slag pits for cooling and solidification.
  • the device is designed such that when the device is attached to the slag-ladle 100 , and when in operation, the device suitably and partially closes the circular opening of the slag-ladle 100 , so as to relatively decrease the momentum of flow of molten iron 106 while allowing the slag 108 to gain momentum.
  • the device creates a partial barrier for the molten iron 106 such that the molten iron 106 is retained in the slag-ladle 100 while the slag 108 flows over the barrier. Further, when most of the slag 108 has flown out of the slag-ladle 100 , the device then acts as a chute to allow the flow of molten iron 106 into the required mould for its collection as almost a separate product, fairly free of slag.
  • the device in accordance with one embodiment of the present subject matter, is designed such that the device is defined by two distinct edges, a lower edge and an open edge.
  • the lower edge is designed in a circular profile such that the circular profile conforms to shape, size, and dimensions of a pre-determined segment of an open top-edge of the slag-ladle 100 .
  • the open top-edge of the slag-ladle 100 is circular in shape.
  • the pre-determined segment of the top-edge of the slag-ladle 100 is the place from where the slag 108 flows out of the slag-ladle 100 upon tilting as described earlier.
  • the lower edge of the device is then attached securely at the pre-determined segment of the top-edge of the slag-ladle 100 .
  • the open edge of the device hereinafter referred to as the free edge, may be designed as having one of a straight profile, circular profile, and a profile having a plurality of short edges or a multi-hedral profile.
  • the height of the device is defined as the maximum distance between the free edge and the lower edge in a vertical plane, when attached to the slag-ladle 100 and in operation.
  • the device may be designed such that the lower edge has a flat profile and the free edge has one of the straight profile, the circular profile, and the profile having a plurality of short edges.
  • FIGS. 4 a, 4 b, and 4 c illustrates the isometric view of a device 400 with three probable profiles in accordance with one embodiment of the present subject matter. However, it is to be understood that various other profiles can be used, and that the profile of the device can vary according to the requirements of the slag-ladle 100 used at different plants.
  • FIG. 4 a illustrates the isometric view of the device 400 with a free edge 402 having a straight profile and a lower edge 404 having a circular profile.
  • the area covered by the device 400 is essentially a pre-determined segment of the top-edge of the slag-ladle 100 defined by a certain secant.
  • the straight-line length of the free edge 402 of the device 400 having the straight profile is equal to the size and shape of the secant of the top-edge of the slag-ladle 100 .
  • the circular profile of the lower edge 404 of the device 400 is equal in shape and size to the top-edge of the slag-ladle 100 .
  • the sluice gate 406 is very useful to identify the near-end of only the flow of slag 108 and the beginning of the flow of molten iron 106 from of the slag-ladle 100 during tilting, for preventing the flow of molten iron 106 with the slag 108 into the slag pit.
  • two sluice gates at suitable distance from each other are provided on the free edge 402 of the device 400 in an instance when volume of the molten iron 106 is proportionally higher than volume of the slag 108 .
  • the device 400 is designed without any sluice-gate 406 for smaller sizes of slag-ladle 100 .
  • the free edge 402 is designed having a circular profile in stead of a straight profile for joining smoothly with the top-edge of the slag-ladle 100 and for controlling over-flow of the slag 108 over the free edge 402 .
  • the sluice gate 406 is provided with a small chute 408 conforming to the shape of sluice gate 406 and projecting outwards from the sluice gate 406 .
  • the chute 408 is required for pouring the molten iron 106 in mould to collect the molten iron 106 and cast the molten iron 106 into massive ingots.
  • the chute 408 helps to direct the stream of falling molten iron 106 into the mould where the molten iron 106 will solidify into the shapes and weights of desired iron ingots.
  • the chute 408 is designed such that the molten iron 106 flows out smoothly and in entirety on tilting of the slag-ladle 100 without any hindrance.
  • the mould may be then lifted and inserted for collection of molten iron 106 by the use of a separate carrier designed and operated for the same purpose.
  • the free edge 402 of the device 400 may be designed having a beaker-edge profile to enable pouring of the molten iron 106 into the moulds in a more directed way.
  • a conical portion in the centre of the beaker-edge profile acts as a chute.
  • the beaker-edge profile of the device 400 is useful when the slag 108 has a low viscosity and the volume of the molten iron 106 is relatively smaller than the volume of the slag 108 .
  • FIG. 4 b illustrates the isometric view of the device 400 with the free edge 402 having a circular profile.
  • the free edge 402 of the device 400 is blown up such that the shape of the free edge 402 is changed from a straight edge to a circular edge of appropriate dimensions with appropriate slope of the face of the device 400 for joining smoothly with the top-edge of the slag-ladle 100 .
  • the lower edge 404 of the device 400 is designed having a circular profile conforming to a circular top-edge of the slag-ladle 100 .
  • the sluice gate 406 having the chute 408 is provided at the center of the free edge.
  • FIG. 4 c illustrates the isometric view of the device 400 with the free edge 402 having a multi-hedral profile.
  • the free edge 402 of the device 400 is modified such that the shape of the free edge 402 is changed from circular to a shape having a plurality of straight lines joined together to form a curved length of the free-edge 402 .
  • the free edge 402 may also be made circular at the ends for joining smoothly with the top-edge of the slag-ladle 100 .
  • the lower edge 404 of the device 400 is designed having a circular profile conforming to a circular top-edge of the slag-ladle 100 .
  • the sluice gate 406 having the chute 408 is provided at the center of the free edge.
  • FIG. 5 a illustrates the elevated view 500 and the plan view 502 of the device 400 with the free edge 402 having a straight profile attached to the circular top-edge of the slag-ladle 100 .
  • FIG. 5 b illustrates the elevated view 504 and the plan view 506 of the device 400 with the free edge 402 having a circular profile attached to the circular top-edge of the slag-ladle 100 .
  • FIG. 5 c illustrates the elevated view 508 and the plan view 510 of the device 400 with the free edge 402 having a multi-hedral profile attached to the circular top-edge of the slag-ladle 100 .
  • a collar can be provided on the device 400 .
  • the collar may be useful for better and efficient pouring of the molten iron 106 when the amount of molten iron 106 in the slag 108 is large.
  • the collar can be a segment of a cylindrical shape whose diameter conforms to the circular top-edge of the slag-ladle 100 and to the lower edge 404 of the device 400 having a circular profile.
  • the collar can be of any suitable design according to the shape of the device 400 .
  • the collar can be attached separately to the device 400 using any method known in the art, or the collar can be provided with the device 400 during manufacturing the device 400 .
  • the collar can be designed such that the collar is firmly attached to the top-edge of the slag-ladle 100 at the pre-determined segment from where slag 108 flows out during the pouring of slag 108 .
  • the curved length of the collar should conform to the length of the free edge 402 of the device 400 such that the collar is securely attached to the device 400 .
  • the collar is first securely attached to the slag-ladle 100 and then the device 400 is securely attached to the collar.
  • FIG. 6 a illustrates the elevated view 600 and the plan view 602 of the device 400 with the free edge 402 having a straight profile and a collar 604 attached to the circular top-edge of the slag-ladle 100 .
  • FIG. 6 b illustrates the elevated view 606 and the plan view 608 of the device 400 with the free edge 402 having a circular profile and the collar 604 attached to the circular top-edge of the slag-ladle 100 .
  • FIG. 6 c illustrates the elevated view 610 and plan view 612 of the device 400 with the free edge 402 having a multi-hedral profile and the collar 604 attached to the circular top-edge of the slag-ladle 100 .
  • the device 400 may be securely attached with the slag-ladle 100 by using suitable methods known in the art, such as welding, riveting, bolting, and so on.
  • the device 400 may be replaced as and when the device 400 gets damaged.
  • the device 400 is securely attached with the slag-ladle 100 at the apparent ladle edge 404 b over which the slag 108 flows on tilting. It is symmetrical with respect to the imaginary point, where the vertical plane in which the axis of the slag-ladle 100 rotates, cuts the lower part of the apparent ladle edge 404 b during tilting.
  • the thickness of the device 400 may be equal to or less than the thickness of the wall of the slag-ladle 100 .
  • Height 407 of the device 400 may be conformed to the design and capacity of the slag-ladle 100 and the amount of molten iron 106 to be separated and recovered from the slag 108 . Further, the height 407 of the device 400 should be such that the amount of the molten iron 106 present with the slag 108 is contained in the slag-ladle 100 until the apparent conical edge of the slag-ladle 100 on a lower side in a tilted position is almost horizontal.
  • the volume contained by the slag-ladle 100 and the horizontal plane passing through the bottom edge of the sluice gate 406 of the device 400 shall contain whole of the molten iron 106 inside the ladle, while allowing most of the slag 108 to flow out.
  • the circular profile of the lower edge 404 of the device 400 is made to conform to the circular top-edge of the slag-ladle 100 .
  • the sluice gate 406 placed at the center of the free edge 402 of the device 400 is designed in relation to the capacity of the slag-ladle 100 and the amount of the molten iron 106 present within the slag-ladle 100 .
  • the molten iron 106 flows out of the sluice gate 406 into the mould meant to collect the separated molten iron 106 .
  • the size of the sluice gate 406 is designed to ensure that all the molten iron 106 flows out into the mould on further tilting without spilling over the molten iron 106 into the already separated slag 108 and in a shortest possible time. This design ensures avoidance of delay fraught with danger of solidification of some of the molten iron 106 in the slag-ladle 100 .
  • the device 400 may be manufactured using the same material as of the slag-ladle 100 such that the service life of the device 400 may be equal to that of the slag-ladle 100 .
  • the device 400 may be manufactured as an assembly of various parts including the slag-ladle 100 or may be manufactured in the form of a modified design as an integral part of the slag-ladle 100 depending upon the various design parameters of slag-ladle 100 . The process of manufacture in either case does not have any influence on the performance of the modified slag-ladle 100 .
  • FIG. 7 illustrates the process of pouring the slag 108 from the apparatus when the device 400 is attached in position with the slag-ladle 100 .
  • the device 400 is symmetrically attached to the slag-ladle 100 at the lowermost tip 112 of the slag-ladle 100 , over which the slag 108 flows out in a tilted position of the slag-ladle 100 .
  • the device 400 is designed to create a critical volume space in the slag-ladle 100 , defined by the lower part of the slag-ladle 100 and the imaginary horizontal plane passing through the bottom of the sluice gate 406 provided in the free-edge 402 of the device 400 , at any position of the slag-ladle 100 .
  • the volume space is critical in separating the slag 108 from the molten iron 106 .
  • the volume space is determined based on the height 407 of the device 400 .
  • the volume space decreases with further tilting of the slag-ladle 100 .
  • the slag 108 in excess of the volume space and placed above the molten iron 106 flows out of, the slag-ladle 100 over the free edge of the device 400 .
  • the slag 108 flows out of the slag-ladle 100 .
  • the molten iron 106 being heavier, remains confined in the volume space generated by the device 400 up to the horizontal level of the bottom of the sluice gate 406 .
  • the tilting of the slag-ladle 100 causes the slag 108 to flow out from over the lower-most tip 112 of the slag-ladle 100 .
  • the excess slag 108 over that occupying the space created by the ladle walls and the horizontal plane passing through the bottom of the sluice gate 406 in the device 400 flows above the device 400 on continuously increasing tilting. With further tilting the above volume space goes on decreasing. Initially, the rate of flow of slag 108 increases on tilting of the slag-ladle 100 but soon the rate of flow of slag 108 begins to decrease.
  • the rate of flow of the slag 108 over the free edge 402 of the device 400 becomes negligible. Then, the slag 108 flows out practically only through the sluice gate 406 in the form of a small pipe-like stream.
  • the instant when the slag 108 flows through the sluice gate 406 is an indication that very little of slag 108 is left in the slag-ladle 100 and that further tilting may result in molten iron 106 flowing out through the sluice gate 406 over the chute 408 .
  • This instant marks the end of selective separation of the slag 108 by pouring out most of the slag 108 while retaining almost all molten iron 106 inside the slag-ladle 100 .
  • the molten iron 106 starts flowing before the remaining slag 108 because of the higher differential momentum of the molten iron 106 than the slag 108 .
  • the device 400 at the time when the molten iron 106 just starts flowing out of the sluice gate 406 , further tilting is immediately stopped.
  • the flow of the molten iron 106 can be visually identified immediately by an operator and the slag-ladle 100 is tilted backwards a little to prevent molten iron 106 from flowing out.
  • the slag-ladle 100 may then be carried to the mould of desired size and shape where the molten iron 106 and the remaining slag 108 are poured into the mould to produce iron ingots.
  • the remaining slag 108 that goes with molten iron 106 gets solidified in the mould along with the molten iron 106 and generally becomes a separate and superficial phase on the iron ingots.
  • the slag 108 may be then chipped off from the iron ingot after their cooling and solidification.
  • the remaining slag 108 can be separated efficiently from the molten iron 106 and the separated slag 108 is not required to be processed further for the recovery of molten iron 106 at any later stage by any other process of recovery.
  • a separate carrier may be used to insert mould in the falling stream of the slag 108 , at an appropriate time, to collect the molten iron 106 in the mould along with the remaining slag 108 for producing the iron ingots.
  • the remaining slag 108 which gets along with molten iron 106 may be chipped off after solidification of the molten iron 106 , as most of the remaining slag 108 will be present only on the surface of the ingots.
  • the automated process may include the following steps in the same order as in manual process, i.e., tilting of the slag-ladle 100 for pouring the slag 108 , identifying flow of the slag 108 in a pipe-like stream, stopping the tilting of slag-ladle 100 , inserting a mould to collect molten iron 106 in the mould and tilting the slag ladle 100 for collecting the molten iron 106 in the mould.
  • the automated process will ensure an effective and efficient method for separation and recovery of molten iron 106 without any perceptible loss of molten iron 106 in slag 108 . Further, the automate process will avoid any human error, attendant loss of iron, and presence of extra slag 108 with the iron in the mould.
  • FIG. 8 a illustrates the device 400 with the free edge 402 having a straight profile as attached to the slag-ladle 100 .
  • FIG. 8 b illustrates the device 400 with the free edge 402 having a straight profile and a collar as attached to the slag-ladle 100 .
  • FIG. 8 c illustrates the device 400 with the free edge 402 having a circular or multi-hedral profile as attached to the slag-ladle 100 .
  • FIG. 8 d illustrates the device 400 with the free edge 402 having a circular or multi-hedral profile with a collar as attached to the slag-ladle 100 .
  • the slag-ladle 100 can be suitably modified by providing a contour at the pre-determined segment of the top-edge of the slag-ladle.
  • FIG. 9 a illustrate a modified slag-ladle 100 with a contour 901 having a straight profile attached to the slag-ladle 100 in accordance with one another embodiment of the present subject matter.
  • FIG. 9 b illustrate a modified slag-ladle 100 with a contour 911 having a circular profile attached to the slag-ladle 100 in accordance with one another embodiment of the present subject matter.
  • FIG. 9 c illustrate a modified slag-ladle 100 with a contour 921 having a multi-hedral profile attached to the slag-ladle 100 in accordance with one another embodiment of the present subject matter.
  • the device 400 is then attached to the contour.
  • the lower edge 404 of the device 400 is correspondingly modified according to the profile of the contour such that the profile of the lower edge 404 conforms to the ladle edge contours for the secure fitment of the device 404 with the slag-ladle 100 as described above.
  • FIG. 10 a illustrates the isometric view of the device 400 with the free edge 402 having a straight profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 .
  • FIG. 10 b illustrates the isometric view of the device 400 with the free edge 402 having a circular profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 .
  • FIG. 10 c illustrates the isometric view of the device 400 with the free edge 402 having a multi-hedral profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 .
  • FIG. 11 a illustrates the elevated view 500 and the plan view 502 of the device 400 with the free edge 402 having a straight profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 .
  • FIG. 11 b illustrates the elevated view 504 and the plan view 506 of the device 400 with the free edge 402 having a circular profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 .
  • FIG. 11 c illustrates the elevated view 508 and the plan view 510 of the device 400 with the free edge 402 having a multi-hedral profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 .
  • a collar may also be attached to the device 400 with a lower edge 402 having a straight profile.
  • FIG. 12 a illustrates the elevated view 600 and the plan view 602 of the device 400 with the free edge 402 having a straight profile, the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 and the collar 604 attached to the top-edge of the slag-ladle 100 .
  • FIG. 12 b illustrates the elevated view 606 and the plan view 608 of the device 400 with the free edge 402 having a circular profile, the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 and the collar 604 attached to the top-edge of the slag-ladle 100 .
  • FIG. 12 c illustrates the elevated view 610 and the plan view 612 of the device 400 with the free edge 402 having a multi-hedral profile, the tower edge 404 having a straight profile conforming to the straight profile of the contour 901 and the collar 604 attached to the top-edge of the slag-ladle 100 .
  • FIG. 13 a illustrates the device 400 with the free edge 402 having a straight profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 as attached to the slag-ladle 100 .
  • FIG. 13 b illustrates the device 400 with the free edge 402 having a straight profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 , and a collar as attached to the slag-ladle 100 .
  • FIG. 13 c illustrates the device 400 with the free edge 402 having a circular or multi-hedral profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 as attached to the slag-ladle 100 .
  • FIG. 13 c illustrates the device 400 with the free edge 402 having a circular or multi-hedral profile and the lower edge 404 having a straight profile conforming to the straight profile of the contour 901 , and a collar as attached to the slag-ladle 100 .
  • the apparatus having the device 400 attached with the slag-ladle 100 and the modified process of pouring the slag 108 provides an efficient and effective method of separating and recovering almost the entire molten iron 106 present and associated with the slag 108 in the slag-ladle 100 . Further, the need for the costly, cumbersome, and elaborate crushing and magnetic separation of iron from solid slag is thus completely eliminated. Additionally, the dust otherwise generated in magnetic separation process is eliminated thereby preventing any of the attendant problems of dust pollution. Thus, the slag-ladle 100 with the device 400 attached and the modified process of pouring the slag 108 paves the march on the path for development of green steel plants, in its own right.
  • the modified process of pouring the slag 108 does not interfere with the steel-making process in any way. It is thus easier to adopt with the steel making processes minimizing the loss of molten iron 106 going with the final slag 108 to pits. Moreover, the electric-power consumed during crushing and magnetic separation is totally eliminated and which can bring in carbon-credit to steel plant adopting the device 400 and the modified process of pouring the slag 108 for its cooling and disposal. Furthermore, the slag-ladle 100 with device 400 and modified process of pouring the slag 108 transforms the present process of slag cooling, solidification, crushing and magnetic separation into a simple physical process of separation and recovery of molten iron 106 .
  • the device 400 helps in recovering a clean molten iron 106 present with the slag 108 without practically any loss and wastage due to atmospheric oxidation and due to unrecoverable iron in the slag 108 of the magnetic separation process. Moreover, the molten iron 106 recovered through the modified process of pouring of the slag 108 is clean and in massive lump-form without practically any contamination of the slag 108 . Also, even after attaching the device 400 to the slag-ladle 100 , no additional equipments are needed in the modified process of pouring the slag 108 and subsequent disposal of the slag 108 .
  • the use of the device 400 and the modified process of pouring of the slag 108 enable the recovery of that part of the molten iron 106 , which oxidizes on exposure to open atmosphere during cooling and solidification of the slag 108 .
  • that part of molten iron 106 which can not be recovered by magnetic separation owing to the inherent inefficiency of magnetic separation, and as a result goes with the remaining slag 108 as waste, is recovered using the device 400 without any additional input of raw materials, thereby conserving corresponding amount of the raw materials for traditional iron making processes.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
  • Furnace Details (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
US14/125,092 2011-09-29 2012-09-27 Slag ladle for separation and recovery of molten iron from slag Abandoned US20140208896A1 (en)

Applications Claiming Priority (3)

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IN2772MU2011 2011-09-29
IN2772/MUM/2011 2011-09-29
PCT/IN2012/000645 WO2013076732A2 (en) 2011-09-29 2012-09-27 Slag ladle for separation and recovery of molten iron from slag

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EP (1) EP2760610A4 (ko)
JP (1) JP2014533327A (ko)
KR (1) KR20140079435A (ko)
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WO (1) WO2013076732A2 (ko)

Cited By (1)

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Publication number Priority date Publication date Assignee Title
US10845352B2 (en) * 2016-12-06 2020-11-24 Nippon Steel Corpoation Slag volume evaluation method for molten metal surface

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113774173B (zh) * 2021-09-23 2023-01-10 新兴铸管股份有限公司 渣包车

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JPS5549892U (ko) * 1978-09-29 1980-04-01
JPS5849179Y2 (ja) * 1980-09-04 1983-11-10 株式会社 三社電機製作所 融解金属注入装置
JPS5813875U (ja) * 1981-07-15 1983-01-28 川崎製鉄株式会社 復りんを防止する溶鋼取鍋
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US6488886B1 (en) * 2001-03-09 2002-12-03 Daniel F. Davis Casting ladle
KR20040020156A (ko) * 2002-08-29 2004-03-09 주식회사 포스코 용강 장입 레이들
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US2554836A (en) * 1948-05-14 1951-05-29 Pennsylvania Engineering Corp Skimming device for bessemer converters, large ladles, and the like
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Cited By (1)

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Publication number Priority date Publication date Assignee Title
US10845352B2 (en) * 2016-12-06 2020-11-24 Nippon Steel Corpoation Slag volume evaluation method for molten metal surface

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WO2013076732A3 (en) 2013-08-08
WO2013076732A2 (en) 2013-05-30
KR20140079435A (ko) 2014-06-26
JP2014533327A (ja) 2014-12-11
EP2760610A2 (en) 2014-08-06
EP2760610A4 (en) 2015-08-05
GB201404859D0 (en) 2014-04-30
GB2508323A (en) 2014-05-28

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