WO2006110949A1

WO2006110949A1 - Hot metal supply apparatus

Info

Publication number: WO2006110949A1
Application number: PCT/AU2006/000518
Authority: WO
Inventors: Trevor Williams; William Edwin John
Original assignee: Technological Resources Pty. Limited
Priority date: 2005-04-18
Filing date: 2006-04-18
Publication date: 2006-10-26
Also published as: UA93373C2; CN101194029A; CN101194029B

Abstract

A hot metal supply apparatus for supplying molten metal from a remote furnace (5) to a direct smelting plant, for example for use in starting up a direct smelting process in the direct smelting vessel (SRV), is disclosed. The apparatus includes a transfer apparatus for transferring molten metal from a furnace (5) that produces the molten me to the direct smelting vessel (SRV), said transfer apparatus includes a hot metal receiving station for receiving molt metal from the furnace (5) and supplying the molten metal into the vessel (SRV), and the hot meatal receiving station includes a runner (37) that extends outwardly from the vessel (SRV).

Description

HOT METAL SUPPLY APPARATUS

The present invention relates to hot metal start- ups of molten bath-based direct smelting processes for producing molten metal in direct smelting vessels .

In particular, the present invention relates to an apparatus for supplying hot metal, ie molten metal, to direct smelting vessels.

The present invention relates particularly, although by no means exclusively, to molten bath-based direct smelting processes for producing molten iron from iron-containing metalliferous feed material, such as iron ores, partly reduced iron ores and iron-containing waste streams (for example, from steelmaking plants) .

A known molten bath-based direct smelting process is generally referred to as the HIsmelt process. In the context of producing molten iron, the HIsmelt process includes the steps of:

(a) forming a bath of molten iron and slag in a direct smelting vessel;

(b) injecting into the bath: (i) a metalliferous feed material, typically iron ore in the form of fines; and (ii) a solid carbonaceous material, typically coal, which acts as a reductant of the iron ores and a source of energy; and

(c) smelting metalliferous feed material to iron in the bath.

The term "smelting" is herein understood to mean thermal processing wherein chemical reactions that reduce metal oxides take place to produce molten metal .

In the HIsmelt process metalliferous feed material and solid carbonaceous material are injected into the molten bath through a number of lances/tuyeres which are inclined to the vertical so as to extend downwardly and inwardly through the side wall of the smelting vessel and into a lower region of the vessel so as to deliver at least part of the solids material into the metal layer in the bottom of the vessel. To promote the post-combustion of reaction gases in an upper part of the vessel, a blast of hot oxygen-containing gas, typically air or oxygen-enriched air, which may be oxygen-enriched, is injected into an upper region of the vessel through a downwardly extending lance. Off-gases resulting from the post-combustion of reaction gases in the vessel are taken away from the upper part of the vessel through an off-gas duct. The vessel includes refractory-lined water cooled panels in the side wall and the roof of the vessel, and water is circulated continuously through the panels in a continuous circuit.

Start-up of molten bath-based direct smelting processes, such as the HIsmelt process, is a critical step because of the potential for causing damage to direct smelting vessels during the course of start-up that could interrupt start-up altogether or shorten the ultimate life of a smelting campaign.

There are a range of options for hot and cold start-ups of molten bath-based direct smelting processes.

Hot start-up options include supplying a required charge of molten metal to a direct smelting vessel at a required charge temperature and thereafter selectively supplying feed materials including carbonaceous material, oxygen-containing gas, fluxes, and metalliferous feed materials to the vessel and operating the vessel under start-up operating conditions until such time as the vessel reaches target steady-state operating conditions.

For commercial reasons it is important that the HIsmelt process, and other molten bath-based direct smelting processes, operate for smelting campaigns of at least 12 months. Hence, start-ups of commercially viable processes should be events that are relatively infrequent.

The term "smelting campaign" is understood herein to mean operation of a molten bath-based direct smelting process, such as the HIsmelt process, without a total shutdown of the process involving end tapping of molten metal and slag from a direct smelting vessel.

There are other situations in which it may be necessary to supply molten metal to a direct smelting vessel. One such situation is where a direct smelting process operating in the vessel has been in a "hold" phase for an extended period of time and the molten metal in the vessel has cooled to an extent that the addition of molten metal is required to increase the temperature of the molten metal as part of a process for re-starting the process.

The present invention is concerned with supplying molten metal to a direct smelting vessel as part of a hot start-up process for a direct smelting process and in other situations in which molten metal is required.

In situations where a direct smelting plant for carrying out a molten bath-based direct smelting process is a stand-alone plant and there are no readily available existing sources of molten metal, the direct smelting plant requires a specific furnace for producing molten metal and an apparatus for transferring the molten metal to a direct smelting vessel of the plant. In these situations, important issues are production and transfer of molten metal to the direct smelting vessel, particularly when the capacity of the furnace or the means for transferring molten metal, such as ladles and torpedo cars, is less than the amount of molten metal required at start up.

In situations where the molten bath-based direct smelting plant forms part of a larger plant, such as a steelmaking plant, where there are readily available existing sources of molten metal, such as from a blast furnace, the production of molten metal is not as serious an issue and the main issue is that of transferring the molten metal to a direct smelting vessel.

Invariably, there is limited space around a direct smelting vessel for a molten bath-based direct smelting process such as the HIsmelt process. The limited space is due to the relatively small size of such vessels compared to other metallurgical vessels such as blast furnaces. The limited space is also due to ancillary structures, such as access towers, molten material containment walls, and desulphurisation apparatus, that are positioned around the vessel, particularly in the vicinity of a molten metal inlet, such as a forehearth, for supplying molten metal to the vessel.

The limited space has an impact on supplying molten metal to the vessel and, more particularly, has an impact on the apparatus for this purpose.

In particular, the applicant has realised that the space constraints make it difficult for overhead cranes to be used to carry ladles containing molten metal to positions at which the ladles can be tilted to pour molten metal directly into a molten metal inlet in the vessel. In broad terms the present invention provides a hot metal supply apparatus for supplying molten metal to a direct smelting vessel of a direct smelting plant, for example for use in starting up a direct smelting process in the vessel, which hot metal supply apparatus includes a transfer apparatus for transferring molten metal from a furnace that produces molten metal into the direct smelting vessel, and the transfer apparatus includes a hot metal receiving station for receiving molten metal from the furnace and supplying the molten metal into the vessel, and the hot metal receiving station including a runner that extends outwardly from the vessel and has (a) an outer end that is sufficiently clear of ancillary structures around the vessel that limit access to the vessel so that the outer end can receive molten metal transferred from the furnace via ladles or other transfer units and (b) an inner end positioned to supply molten metal to a molten metal inlet of the vessel.

In this context, the "furnace" may be a specific furnace for the direct smelting vessel, such as an induction furnace positioned adjacent the vessel, or another furnace, such as a blast furnace, that forms part of an integrated steelmaking plant that includes the direct smelting vessel.

The ancillary structures include, by way of example, any one or more of access towers, molten material containment walls, and desulphurisation apparatus.

The term "access towers" includes, by way of example, towers of the type that include a frame that has an inner perimeter of framework members located adjacent the vessel side wall and an outer perimeter of framework members spaced away from the vessel and a series of cross- members that interconnect inner and outer perimeters . The runner may be a fixed structure or a removable structure.

In a situation in which the runner is a fixed structure, preferably the runner includes an inner end section that can be retracted or otherwise moved away from an operative position in which it is above the molten metal inlet in order to improve access to the inlet.

Preferably the hot metal receiving station includes a pouring pool positioned in close proximity to the outer end of the runner for receiving molten metal from ladles or other transfer units and supplying the molten metal to the outer end of the runner.

Preferably the hot metal receiving station includes a metal containment area, for example defined by a containment wall or a pit, for containing hot metal spills.

Preferably the runner includes a plurality of runner sections arranged in end to end relationship so that an outlet end of an upstream section (in the direction of flow of molten metal along the runner) is positioned above a successive section so that molten metal flowing along the upstream section flows through the outlet at the outlet end onto the successive section.

Preferably the runner sections are coupled together for relative sliding movement between an expanded operative position and a contracted inoperative transport position in which the assembly can be conveniently lifted into and from the direct smelting plant. Thus, for example, the assembly can be brought into position on the plant at the time of a process start-up and removed after start-up has been completed.

Preferably the transfer apparatus includes: (a) a plurality of ladles for containing molten metal;

(b) the above-described hot metal receiving station for transferring molten metal from the ladles into the direct smelting vessel; and

(c) a transfer runner assembly, hereinafter referred to as "the furnace transfer runner assembly", for transferring molten metal from the furnace to the ladles.

Preferably the furnace transfer runner assembly includes a pouring pool for receiving molten metal from the furnace and a runner for receiving molten metal from the pool via an outlet in the pool and supplying molten metal to the ladles when the ladles are positioned in turn at a ladle filling position.

Preferably the transfer apparatus includes another furnace transfer runner assembly for transferring molten metal from the ladles to the induction furnace when the ladles are located in turn at a molten metal return position, as may be required, for example, as part of a start-up process.

Preferably the other furnace transfer runner assembly includes a pouring pool for receiving molten metal from the ladles when the ladles are located in turn at a molten metal return position and a runner for receiving molten metal from the pool via an outlet in the pool and supplying the molten metal to the furnace.

Preferably the other furnace transfer runner assembly is positioned generally above the furnace transfer runner assembly. Preferably the other furnace transfer runner assembly is positioned for sliding movement inwardly and outwardly in relation to the induction furnace to provide clearance for upward lifting and tilting movement of the furnace to pour molten metal from the furnace into the transfer runner assembly.

Preferably the transfer apparatus further includes an overhead gantry crane assembly for transporting the ladles.

Preferably the overhead gantry crane assembly is adapted to tilt the ladles so that molten metal can be poured from the ladles .

In situations in which the direct smelting vessel includes a forehearth for discharging molten metal from the vessel, preferably the forehearth forms the molten metal inlet of the vessel for supplying molten metal to the vessel.

In situations in which the furnace is a specific furnace positioned adjacent the direct smelting vessel and provided for the purpose of producing molten metal for the direct smelting vessel, such as an induction furnace, preferably the furnace includes a means for lifting and tilting the furnace to facilitate pouring molten metal from the furnace .

In situations in which the furnace is not a specific furnace for the direct smelting vessel and, for example, is a blast furnace that, with the direct smelting vessel, forms part of an integrated steelmaking plant, the above-described furnace transfer runner assembly may be redundant and the apparatus may need only the above- described hot metal receiving station. Moreover, in this situation the furnace transfer runner assembly may not be confined to receiving molten metal from ladles and may receive molten metal from any other suitable molten metal transfer units, such as torpedo cars.

In more general terms, in this situation, the present invention provides a hot metal supply apparatus for supplying molten metal to a direct smelting vessel of a direct smelting plant for use in starting up a direct smelting process in the vessel, which vessel includes a forehearth located at a first level and a runner assembly, as described above, for transferring molten metal from the forehearth to a ladle at a ladle filling station at a second level below the first level, and which hot metal supply apparatus includes the above-described hot metal receiving station.

Preferably the pouring pool of the hot metal receiving station is located at a third level above said second level .

Preferably the plurality of runner sections of the hot metal receiving station extends, in use, between the pouring pool and the forehearth.

Preferably the above-described overhead gantry crane assembly is located at a fourth level above the third level .

According to the present invention there is also provided a direct smelting plant for producing molten metal in a molten bath-based direct smelting process that includes :

(a) a direct smelting apparatus that includes a direct smelting vessel; and

(b) the above-described hot metal supply apparatus for supplying molten metal to a molten metal inlet in the vessel, for example for use in starting up the direct smelting process in the direct smelting vessel .

Preferably the plant includes ancillary apparatus, such as an access tower located around the direct smelting vessel and limiting access to the vessel.

The access tower may include towers of the type that include a frame that has an inner perimeter of framework members located adjacent the vessel side wall and an outer perimeter of framework members spaced away from the vessel and a series of cross-members that interconnect the framework members of the inner and outer perimeters.

Preferably the runner of the transfer apparatus of the hot metal supply apparatus extends through gaps in the access tower.

Preferably the plant includes a desulphurisation apparatus for desulphurising molten metal from the direct smelting vessel .

Preferably the plant includes a casting apparatus for casting desulphurised molten metal into a solid form, such as pigs.

Preferably the plant includes a plurality of ladles for receiving molten metal from the vessel, transferring molten metal through the desulphurisation apparatus, and discharging molten metal into the casting apparatus .

Preferably the desulphurisation apparatus includes a first station for desulphurising molten iron and a second station for de-slagging desulphurised molten iron. Preferably the first desulphurisation station is located at a ladle filling station of the direct smelting vessel and, in use, molten metal supplied from the direct smelting vessel to the ladle filling station is desulphurised at the station.

Preferably the metal containment area of the hot metal receiving station encloses the first desulphurisation station.

Preferably the second desulphurisation station is located away from the first desulphurisation station.

Preferably the second desulphurisation station is located adjacent the casting apparatus at a ladle discharge station of the desulphurisation apparatus.

Preferably the direct smelting plant includes a ladle transfer assembly for carrying the ladles along a pathway between the ladle filling station of the direct smelting vessel and the ladle discharge station of the desulphurisation apparatus.

Preferably the runner of the hot metal receiving station for supplying molten metal to the direct smelting vessel is positioned above the ladle filling station of the direct smelting vessel.

Preferably the direct smelting vessel includes a forehearth for discharging molten metal from the vessel and the forehearth forms the molten metal inlet of the vessel.

According to the present invention there is provided a direct smelting plant that includes a direct smelting vessel having a forehearth, an access tower having an inner periphery adjacent the vessel and an external periphery laterally displaced from the inner periphery, the forehearth extending laterally away from the vessel and located in relation to the external periphery of the tower such that the external periphery prevents direct charging of the forehearth with hot metal, and a hot metal receiving station adapted to receive hot metal from a hot metal supply, such as a furnace, remote from the direct smelting vessel and adapted to supply hot metal to the forehearth, whereby to charge hot metal into the vessel, and the hot metal receiving station including a charging runner extending to the forehearth to supply hot metal to the forehearth.

Preferably the plant includes a metal containment wall located adjacent the forehearth.

Preferably the charging runner is adapted to extend through an opening in the metal containment wall to supply hot metal to the forehearth.

Preferably the opening in the containment wall is closable in a manner to maintain the integrity of the wall when said vessel is producing hot metal.

Preferably at least an end section of the charging runner that extends through the containment wall is moveable whereby the charging runner does not extend through the opening during production thereby enabling the opening to be closed to maintain the integrity of the containment wall.

According to the present invention there is also provides a process for supplying molten metal to a direct smelting vessel of a direct smelting plant, for example for use in starting up a direct smelting process in the vessel, which process includes supplying molten metal from a hot metal supply, such as a furnace, to a hot metal receiving station as described above and supplying the molten metal via the station into the vessel .

The present invention is described in more detail hereinafter by way of example with reference to the accompanying drawings, of which:

Figure 1 is a top plan view that shows the general layout (with considerable detail removed) of one embodiment of a hot metal supply apparatus in accordance with the present invention and a part of one embodiment of a direct smelting plant in accordance with the present invention that includes a direct smelting vessel, a desulphurisation apparatus, and the hot metal supply apparatus;

Figure 2 is another general layout top plan view (with considerable detail removed) that shows in more detail than Figure 1 the desulphurisation apparatus and the hot metal supply apparatus;

Figures 3 and 4 are perspective views that show in more detail different parts of the hot metal supply apparatus;

Figure 5 is a side elevation that shows the runner of the hot metal supply apparatus for supplying molten metal into the direct smelting vessel;

Figure 6 is an end elevation of the part of the plant shown in Figure 5; and

Figure 7 is a side elevation of the runner shown in Figure 5.

The direct smelting plant shown in the Figures is designed to produce solid pigs of iron and includes: (a) a direct smelting vessel (SRV) for producing molten iron from iron-containing metalliferous feed material, such as iron ores, by a molten bath-based direct smelting process, such as the HIsmelt process,

(b) a desulphurisation apparatus for desulphurising molten iron discharged from the vessel (SRV) that includes a first desulphurisation station 19 (Figures 5 and 6) adjacent the vessel (SRV) and a second desulphurisation station 21 (Figures 2 and 5) adjacent a casting apparatus 23 described herinafter,

(c) a casting apparatus 23 that includes two casters 43 for casting solid pigs of iron from desulphurised molten iron from the desulphurisation apparatus;

(d) a plurality of ladles 7 (Figures 2, 5 and 6) for transferring molten iron discharged from the vessel (SRV) through the desulphurisation apparatus to the casting apparatus 23; and

(e) a hot metal supply apparatus for producing molten iron required for starting up the HIsmelt process in the vessel (SRV) and for transferring the molten iron to the vessel (SRV) as part of the start-up process.

The above-mentioned vessel (SRV) , desulphurisation apparatus, casting apparatus 23, ladles 7, and hot metal supply apparatus are only parts of the direct smelting plant. It is not necessary to mention other parts of the plant in order to describe the invention properly.

The vessel (SRV) may be any suitable vessel for carrying out the HIsmelt process or other molten bath-based direct smelting proces . Australian patent application 27990/01 in the name of the applicant includes a description of the general construction of a HIsmelt vessel. The disclosure in the Australian patent application is incorporated herein by cross-reference.

In basic terms, the HIsmelt vessel (SRV) described in Australian patent application 27990/01 is a vertical vessel that has : a hearth that incudes a base and sides formed from refractory bricks; side walls which form a generally cylindrical barrel extending upwardly from the sides of the hearth and include an upper barrel section and a lower barrel section; a roof; an outlet for offgases; outlets for discharging molten iron continuously and molten slag periodically. The vessel (SRV) is fitted with a downwardly extending gas injection lance (not shown) that delivers a hot air blast into an upper region of the vessel and eight solids injection lances (not shown) extending downwardly and inwardly through a side wall and into the slag layer that inject iron ore, solid carbonaceous material, and fluxes entrained in an oxygen-deficient carrier gas into the metal layer.

In particular, the HIsmelt vessel (SRV) includes a molten metal outlet in the form of a forehearth 13

(Figures 1 and 4) at a first level and a runner assembly for transferring molten iron from the forehearth 13 to a ladle 7 at one of two ladle filling stations adjacent the vessel (SRV) at a second level that is lower than the first level. Figures 5 and 6 show two such ladles 7 at the ladle filling stations.

As can best be seen in Figure 5, the direct smelting plant includes an access tower, generally identified by the numeral 51, that is positioned around the vessel (SRV) and supports (a) access floors for the vessel, such as a cast house floor 53 which provides access to the forehearth 13 and a slag notch (not shown) , and (b) ancillary equipment such as water cooling pipes . In addition, there are floors providing access to solids injection lances (not shown) of the vessel (SRV) and other ancillary equipment. The access tower 51 is made from a plurality of framework members and has an inner perimeter located adjacent the vessel (SRV) and an external perimeter, indicated by the line 57 in Figure 5, laterally displaced from the inner perimeter. The access floors extend between these perimeters.

As indicated above, the desulphurisation apparatus includes a first desulphurisation station 19 for desulphurising molten iron from the vessel (SRV) in ladles 7 at the station and a second desulphurisation station 21 for de-slagging molten iron in the ladles 7 at the station. Figure 5 shows one such ladle 7 at the first desulphurisation station 19. Figure 6 shows another such ladle 7 at the second desulphurisation station 21. Figure 2 shows one such ladle 7 at one of the second desulphurisation station 21.

The first and second desulphurisation stations 19, 21 are spaced apart, with the first desulphurisation station 19 being positioned above the ladle filling station of the vessel (SRV) and the second desulphurisation station 21 being located adjacent the casting apparatus 23.

The ladles 7 are located on ladle transfer cars 29 (Figure 5) that are adapted to move the ladles between the ladle filling station and the second desulphurisation station 21.

The hot metal supply apparatus is a specific apparatus positioned adjacent the vessel (SRV) for the purpose of supplying molten iron for the vessel, for example at start-up, and the following description is in the context of this type of furnace. It is noted that the present invention also extends to situations in which the hot metal supply apparatus is part of an integrated steelmaking plant, and for example is a blast furnace, and is operable to produce molten iron for other purposes.

The hot metal supply apparatus shown in the Figures includes :

(a) an induction furnace 5 for melting iron prills and producing batches of molten iron in the furnace;

(b) a plurality of ladles 9 (Figures 2, 3 and 5 only) for transferring molten iron from the induction furnace 5 to the vessel (SRV) ;

(c) a furnace transfer runner assembly for transferring molten iron from the furnace 5 to the ladles 9; and

(d) a hot metal receiving station for receiving molten iron from the ladles 9 and for transferring molten iron to the direct smelting vessel (SRV) .

The ladles 9 are standard ladles for transporting molten iron. The ladles 9 are adapted to be lifted and carried by an overhead crane assembly, described hereinafter, between a ladle filling position at the induction furnace 5, a ladle discharge position at an upstream end of the hot metal receiving station, and a molten metal return position at the induction furnace 5, and various holding locations (not shown) .

The induction furnace 5 is a standard induction furnace that is operable to melt iron prills.

The induction furnace 5 is adapted to be lifted and tilted to pour molten iron from the furnace 5 via the furnace transfer runner assembly into the ladles 9 when the ladles are at the ladle filling position. Figures 2 and 3 show one such ladle 9 at the ladle filling position.

The furnace transfer runner assembly includes a pouring pool 29 (Figure 3) for receiving molten metal from the induction furnace 5. The pool 29 is positioned above and to one side of the furnace 5 when the furnace is in a standard heating position as shown in the Figures. As is indicated above, the furnace 5 can be lifted and tilted. The pool 29 is positioned so that molten iron flows into the pool when the furnace 5 is in the raised position and is tilted.

The furnace transfer runner assembly also includes a runner 31 for receiving molten iron from the pool 29 via an outlet in the pool 29 and supplying molten iron to the ladles 9 when the ladles are positioned in turn at the ladle filling position.

The hot metal receiving station includes a pouring pool 35 for receiving molten iron from the ladles 9 when the ladles are located in turn at the ladle discharge position. The pool 35 is in an elevated position that is to one side of the pathway of the ladles 7 between the vessel (SRV) and the desulphurisation apparatus 21. The elevated position of the pouring pool 35 is at a third level that is higher than the above-described first and second levels. In addition, the location of the pouring pool 35 is in a space that is well clear of the access tower 51 and is clearly accessible to the ladles 9.

The hot metal receiving station also includes a runner generally identified by the numeral 37 for receiving molten metal from the pool 35 via an outlet in the pool and supplying molten iron to the forehearth 13 of the vessel (SRV) . The access tower 51 and the runner 37 are constructed and arranged so that the runner 37 can extend to a position above the forehearth 13 to supply molten iron to the vessel (SRV) via the forehearth 13.

The hot metal receiving station also includes a hot metal containment area. The containment area operates to contain any molten iron that may happen to be spilt during transfer of molten iron to the hot metal receiving station. Locating the hot metal receiving station and the containment area remote from the vessel (SRV) means that any spill is contained in an area remote from the vessel (SRV) and the access tower around the vessel. This prevents hot metal damage to the vessel (SRV) and the tower along with plant and equipment located near the vessel.

The above-described combination of a pouring pool 35 and the runner 37 is necessary to supply molten iron to the forehearth 13 because of space constraints around the vessel (SRV) .

Specifically, the framework members that form the access tower 51 are located sufficiently close to the forehearth 13 so that is not possible for a ladle suspended from an overhead gantry crane to be moved to a position adjacent the forehearth 13 for direct charging of the forehearth 13 with molten iron poured from the ladle.

In addition, even if direct overhead crane access to the forehearth 13 was possible, the close proximity of the cast house floor 53 to the forehearth 13 means that there would be significant safety concerns associated with direct positioning a ladle adjacent the forehearth 13 and pouring molten iron into the forehearth 13 via the ladle. In this regard, it is typically desirable that the height difference between the pouring lip of a ladle and the surface onto which the metal is poured is as limited as possible. This restriction on distance provides for greater control over the pour so as to prevent spillage of molten iron and is also to limit cooling of molten iron during the pour. This requirement means that the base of the ladle (which is typically 3 metres or more in height) would extend well below the surface onto which the molten iron would be poured. In the case of the forehearth 13, its upper region projects above the level of the cast house floor 53 by a distance in the order of 1 metre. As such, the cast house floor 53 prevents the pouring lip of a ladle from being brought into sufficient proximity with the forehearth for a direct charge.

Another factor is that the access tower 51 includes a containment wall 59 (Figure 5) adjacent the forehearth. The containment wall 59 prevents hot gas and molten iron that might escape from the forehearth 13 during overpressure situations from entering into the hot metal handling area that contains the ladle filling stations, the first desulphurisation station 19 and other hot metal handling and processing equipment adjacent the vessel (SRV) . This helps to prevent equipment, such as electrical cables, from being damaged by such hot gas and/or metal.

The containment wall 59 extends upwardly from the cast house floor 53 to a height adjacent the overhead gantry crane and/or roof of the building in which the vessel (SRV) is located. In order for the runner 37 to reach the forehearth 13, the containment wall 59 includes a closeable aperture 61 (Figure 5) and the runner 37 is arranged to extend through the aperture. The closeable aperture closes in such a manner as to ensure the integrity of the containment wall 59 when the vessel (SRV) is producing molten iron. Typically, that portion of the runner 37 that extends between the containment wall 59 and the forehearth 13 is moveable so as to be clear of the forehearth 13 when the vessel (SRV) is producing metal. This facilitates personnel access to the forehearth 13 and prevents damage to the under side of the runner 37 by hot metal and radiated heat. In addition, this portion of the runner 37 is typically also able to be moved clear of the aperture in the containment wall 59. This facilitates closure of the aperture in a manner sufficient to maintain the integrity of the wall .

As can best be seen in Figures 5 and 7, the runner 37 has three runner sections 39, 41, 43 arranged in end to end relationship so that a molten metal outlet in an upstream runner section is positioned above a successive runner section. Specifically, each runner section has an upstream and a downstream end in the direction of molten iron flow along the section. In addition, each runner section has a molten iron outlet in the downstream end of the section. In addition, the runner sections are coupled together for relative sliding movement between an expanded operative position shown in the Figures and a contracted inoperative transport position in which the runner 37 can be conveniently lifted into and from the direct smelting plant. Alternatively, the runner sections may be discrete sections that interlock or connect together. Either way, the runner 37 can be brought into position on the plant at the time of a process start-up and removed after start-up has been completed.

The hot metal supply apparatus also includes a another furnace transfer runner assembly for transferring molten iron from the ladles 9 to the induction furnace 5, as may be required as part of a start-up process to maintain the molten iron temperature in the ladles above a target charge temperature for a start-up process.

The other furnace transfer runner assembly includes a third pouring pool 45 for receiving molten iron from the ladles 9 when the ladles are located in turn at the molten iron return position and a runner 47 for receiving molten iron from the pool 45 via an outlet in the pool and supplying the molten iron to the induction furnace 5.

As can best be seen in Figure 3, the other furnace transfer runner assembly comprising the pool 45 and the runner 47 is positioned at a higher level than and generally directly above the first-mentioned furnace transfer runner assembly comprising the pool 29 and the runner 31.

In addition, the other furnace transfer runner assembly comprising the pool 45 and the runner 47 is arranged for sliding movement towards and away from the induction furnace 5 to move the assembly into and from an operative position. Figure 3 shows the other furnace transfer runner assembly in an inoperative position in which the outlet end of the runner 47 is spaced outwardly from the furnace 5. In this position the assembly does not obstruct lifting and tilting movement of the furnace 5 to pour molten iron into the runner 31 of the first-mentioned transfer runner assembly. Inward sliding movement of the other furnace transfer runner assembly towards the induction furnace 5 from the position shown in Figure 3 brings the outlet end of the runner 47 into a position overlying the furnace 5 so that molten metal can flow from the runner into the furnace 5.

The direct smelting plant also includes an overhead gantry crane assembly for transporting the ladles 9 to and from the ladle filling position, the ladle discharge position, and the molten metal return position. The overhead gantry crane assembly is located at a fourth level that is higher than the above-described first, second, and third levels. The overhead gantry crane assembly includes a crane unit 61 (Figures 5 and 6) that is adapted to tilt the ladles 9 as required at the ladle discharge position and the molten metal return position to pour molten iron from the ladles 9 into the pouring pools 35, 45 at these positions. Specifically_/ the crane unit 61 includes a pair of side hooks 63 for engaging pins on opposite sides of the ladles 9 and a rear hook 65 for engaging rear pins on the ladles 9. The rear hook 65 can be raised and lowered as required to tilt the ladles 9 forwardly.

In addition to servicing the hot metal supply apparatus, the overhead gantry crane assembly is also arranged for servicing the ladle filling stations adjacent the vessel (SRV) , the desulphurisation apparatus, and the casting apparatus 23.

The direct smelting plant also includes an additional overhead gantry crane assembly located in the desulphurisation area and a slag rabbler machine carried by the additional overhead gantry crane assembly. The purpose of the slag rabbler machine is to de-slag slag from desulphurised molten metal at the second desulphurisation station 21. The additional overhead gantry crane assembly sits below the overhead gantry crane 61 and moves transversely between the desulphurisation stations 61.

The above-described hot metal supply apparatus is an efficient and effective apparatus for producing molten metal required for a hot start-up of a HIsmelt process and for supplying the molten metal to the vessel SRV as required in the start-up process.

A method of hot start-up of a HIsmelt process may include the following sequence of steps: • Producing a 1st batch of molten iron at a required temperature in the induction furnace 5.

• Pouring the batch into a 1^st ladle 9a.

• Producing a 2nd batch of molten iron at a required temperature in the furnace.

• Pouring the batch into a 2^nd ladle 9b.

• Pouring the molten metal in the ladle 9a back into the furnace and reheating the molten iron in the furnace 5 and returning the reheated molten iron to ladle 9a.

• Producing a 3rd batch of molten iron at a required temperature in the furnace 5.

• Pouring the batch into a 3^rd ladle 9c.

• Pouring the molten metal in the ladle 9b into the vessel (SRV) .

• Pouring the molten metal in the ladle 9a into the vessel (SRV) .

• Pouring the molten metal in the ladle 9c into the vessel (SRV) .

The above-described sequence of steps is an effective method of supplying a required charge of molten iron at a required charge target temperature from the induction furnace 5 to the vessel (SRV) .

Many modifications may be made to the embodiment of the apparatus of the present invention described above without departing from the spirit and scope of the invention.

In an integrated steel making plant, that does not make use of an induction furnace 5, the hot metal supply apparatus may include a ladle charging station.

This charging station may be located in a common hot metal handling area that is defined at one end by the hot metal containment wall and that may also contain the hot metal filling station and the hot metal receiving station.

In use, the ladle charging station receives hot metal that is transferred from torpedo cars or the like that transport hot metal to the charging station from other furnaces on site. The ladle charging station typically includes a hot metal containment area to contain any hot metal spilt during a transfer.

The hot metal containment area of the hot metal receiving station may be co-extensive and/or co-located with hot metal containment facilities for the ladle filling stations and / or the ladle charging station.

In a plant of this arrangement, when the vessel (SRV) is being charged with hot metal, the ladles in the charging pit are first charged with molten metal and are then transported to the hot metal receiving station, for example, by the overhead gantry crane or other suitable transport arrangement .

Claims

1. A hot metal supply apparatus for supplying molten metal to a direct smelting vessel of a direct smelting plant, for example for use in starting up a direct smelting process in the vessel, which hot metal supply apparatus includes a transfer apparatus for transferring molten metal from a furnace that produces molten metal to the direct smelting vessel, and the transfer apparatus includes a hot metal receiving station for receiving molten metal from the furnace and supplying the molten metal into the vessel, and the hot metal receiving station includes a runner that extends outwardly from the vessel and has (a) an outer end that is sufficiently clear of ancillary structures around the vessel that limit access to the vessel so that the outer end can receive molten metal transferred from the furnace via ladles or other transfer units and (b) an inner end positioned to supply molten metal to a molten metal inlet of the vessel.

2. The apparatus defined in claim 1 wherein the runner is a fixed structure or a removable structure.

3. The apparatus defined in claim 3 wherein, in a situation in which the runner is a fixed structure, the runner includes an inner end section of the runner that can be retracted or otherwise moved away from an operative position in which it is above the molten metal inlet in order to improve access to the inlet.

4. The apparatus defined in claim 1 or claim 2 wherein the hot metal receiving station further includes a pouring pool positioned in close proximity to the outer end of the runner for receiving molten metal from ladles or other transfer units and supplying the molten metal to the outer end of the runner.

5. The apparatus defined in any one of the preceding claims wherein the hot metal receiving station includes a metal containment area, for example defined by a containment wall, for containing hot metal spills.

6. The apparatus defined in any one of the preceding claims wherein the runner includes a plurality of runner sections arranged in end to end relationship so that an outlet end of an upstream section (in the direction of flow of molten metal along the runner) is positioned above a successive section so that molten metal flowing along the upstream section flows through the outlet at the outlet end onto the successive section.

7. The apparatus defined in claim 6 wherein the runner sections are coupled together for relative sliding movement between an expanded operative position and a contracted inoperative transport position in which the assembly can be conveniently lifted into and from the direct smelting plant.

8. The apparatus defined in any one of the preceding claims wherein the transfer apparatus includes:

(a) a plurality of ladles for containing molten metal;

(c) a furnace transfer runner assembly for transferring molten metal from the furnace to the ladles.

9. The apparatus defined in claim 8 wherein the furnace transfer runner assembly includes a pouring pool for receiving molten metal from the furnace and a runner for receiving molten metal from the pool via an outlet in the pool and supplying molten metal to the ladles when the ladles are positioned in turn at a ladle filling position.

10. The apparatus defined in claim 8 or claim 9 wherein the transfer means includes another furnace transfer runner assembly for transferring molten metal from the ladles to the induction furnace when the ladles are located in turn at a molten metal return position, as may be required as part of a start-up process.

11. The apparatus defined in claim 10 wherein the other furnace transfer runner assembly includes a pouring pool for receiving molten metal from the ladles when the ladles are located in turn at a molten metal return position and a runner for receiving molten metal from the pool via an outlet in the pool and supplying the molten metal to the furnace.

12. The apparatus defined in claim 10 or claim 11 wherein the other furnace transfer runner assembly is positioned generally above the furnace transfer runner assembly.

13. The apparatus defined in any one of claims 10 to

12 wherein the other furnace transfer runner assembly is positioned for sliding movement inwardly and outwardly in relation to the induction furnace to provide clearance for upward lifting and tilting movement of the furnace to pour molten metal from the furnace into the transfer runner assembly.

14. The apparatus defined in any one of claims 8 to

13 wherein the transfer means further includes an overhead gantry crane assembly for transporting the ladles.

15. The apparatus defined in claim 14 wherein the overhead gantry crane assembly is adapted to tilt the ladles so that molten metal can be poured from the ladles.

16. The apparatus defined in any one of the preceding claims wherein, in situations in which the direct smelting vessel includes a forehearth for discharging molten metal from the vessel, the forehearth forms the molten metal inlet of the vessel for supplying molten metal to the vessel .

17. A hot metal supply apparatus for supplying molten metal to a direct smelting vessel of a direct smelting plant, for example for use in starting up a direct smelting process in the vessel, which vessel includes a forehearth located at a first level and a runner assembly for transferring molten metal from the forehearth to a ladle at a ladle filling station at a second level below the first level, and which hot metal supply apparatus includes the hot metal receiving station defined in any one of the preceding claims.

18. The apparatus defined in claim 15 wherein the pouring pool of the hot metal receiving station is located at a third level above said second level .

19. The apparatus defined in claim 17 or claim 18 wherein the plurality of runner sections of the hot metal receiving station extends, in use, between the pouring pool and the forehearth.

20. The apparatus defined in claim claim 18 or claim 19 when dependent on claim 16 wherein the overhead gantry crane assembly is located at a fourth level above the third level .

21 A direct smelting plant for producing molten metal in a molten bath-based direct smelting process that includes :

(a) a direct smelting apparatus that includes a direct smelting vessel having an inlet for molten metal; and

(b) the hot metal supply apparatus defined in any one of the preceding claims for supplying molten metal to a molten metal inlet in the vessel for use in starting up the direct smelting process in the direct smelting vessel.

22. The plant defined in claim 21 includes ancillary apparatus, such as an access tower located around the direct smelting vessel and limiting access to the vessel.

23. The plant defined in claim 22 wherein the access tower includes a frame that has an inner perimeter of framework members located adjacent the vessel side wall and an outer perimeter of framework members spaced away from the vessel and a series of cross-members that interconnect the framework members of the inner and outer perimeters.

24. The plant defined in claim 22 or claim 23 wherein the runner of the vessel runner assembly of the transfer apparatus of the hot metal supply apparatus extends through gaps in the access tower.

25. The plant defined in any one of claims 21 to 24 includes a desulphurisation apparatus for desulphurising molten metal from the direct smelting vessel.

26. The plant defined in claim 25 includes a casting apparatus for casting desulphurised molten metal into a solid form, such as pigs.

27. The plant defined in claim 26 includes a plurality of ladles for receiving molten metal from the vessel, transferring molten metal through the desulphurisation apparatus, and discharging molten metal into the casting apparatus.

28. The plant defined in any one of claims 25 to 27 wherein the desulphurisation apparatus includes a first station for desulphurising molten iron and a second station for de-slagging desulphurised molten iron.

29. The plant defined in claim 28 wherein the first desulphurisation station is located at a ladle filling station of the direct smelting vessel and, in use, molten metal supplied from the direct smelting vessel to the ladle filling station is desulphurised at the station.

30. The plant defined in claim 29 wherein the metal containment area of the hot metal receiving station encloses the first desulphurisation station.

31. The plant defined in claim 29 or claim 30 wherein the second desulphurisation station is located away from the first desulphurisation station.

32. The plant defined in claim 31 wherein the second desulphurisation station is located adjacent the casting apparatus at a ladle discharge station of the desulphurisation apparatus.

33. The plant defined in any one of claims 25 to 32 wherein the direct smelting plant includes a ladle transfer assembly for carrying the ladles along a pathway between the ladle filling station of the direct smelting vessel and the ladle discharge station of the desulphurisation apparatus .

34. The plant defined in claim 33 wherein the runner of the hot metal receiving station for supplying molten metal to the direct smelting vessel is positioned above the ladle filling station of the direct smelting vessel.

35. The plant defined in any one of claims 21 to 34 wherein the direct smelting vessel includes a forehearth for discharging molten metal from the vessel and the forehearth forms the molten metal inlet of the vessel.

36. A direct smelting plant that includes a direct smelting vessel having a forehearth, an access tower having an inner periphery adjacent the vessel and an external periphery laterally displaced from the inner periphery, the forehearth extending laterally away from the vessel and located in relation to the external periphery of the tower such that the external periphery prevents direct charging of the forehearth with hot metal, and a hot metal receiving station adapted to receive hot metal from a hot metal supply, such as a furnace, remote from the direct smelting vessel and adapted to supply hot metal to the forehearth, whereby to charge hot metal into the vessel, and the hot metal receiving station including a charging runner extending to the forehearth to supply hot metal to the forehearth.

37. The plant defined in claim 36 includes a metal containment wall located adjacent the forehearth.

38. The plant defined in claim 37 wherein the charging runner is adapted to extend through an opening in the metal containment wall to supply hot metal to the forehearth.

39. The plant defined in claim 38 wherein the opening in the containment wall is closable in a manner to maintain the integrity of the wall when said vessel is producing hot metal .

40. The plant defined in claim 39 wherein at least an end section of the charging runner that extends through the containment wall is moveable whereby the charging runner does not extend through the opening during production thereby enabling the opening to be closed to maintain the integrity of the containment wall.