Title of Invention	A DIRECT SMELTING PROCESS AND APPARATUS
Abstract	A molten-bath based direct smelting process and apparatus is disclosed. The process comprises injecting feed materials into a molten bath at a velocity of at least 40m/s through at least one solids injection lance (27) having a delivery tube of internal diameter of 40-200mm that is located so that a central axis of an outlet end of the lance is at an angle of 20 to 90 degrees to a horizontal axis. The feed materials injection generates a superficial gas flow of at least 0.04 Nm3/s/m2 within the molten bath. The gas flow causes molten material to be projected upwardly as splashes, droplets and streams and form an expanded molten bath zone, with the gas flow and the upwardly projected molten material causing strong mixing of the molten bath. The process also comprises injecting an oxygen-containing gas into an upper region of the vessel to post-combust gases released from the molten bath.

Title of Invention

A DIRECT SMELTING PROCESS AND APPARATUS

Abstract

A molten-bath based direct smelting process and apparatus is disclosed. The process comprises injecting feed materials into a molten bath at a velocity of at least 40m/s through at least one solids injection lance (27) having a delivery tube of internal diameter of 40-200mm that is located so that a central axis of an outlet end of the lance is at an angle of 20 to 90 degrees to a horizontal axis. The feed materials injection generates a superficial gas flow of at least 0.04 Nm3/s/m2 within the molten bath. The gas flow causes molten material to be projected upwardly as splashes, droplets and streams and form an expanded molten bath zone, with the gas flow and the upwardly projected molten material causing strong mixing of the molten bath. The process also comprises injecting an oxygen-containing gas into an upper region of the vessel to post-combust gases released from the molten bath.

Full Text	A DIRECT SMELTING PROCESS AND APPARATUS The present invention relates to a process and an apparatus for producing molten metal (which term includes metal alloys), in particular although by no means exclusively iron, from ferrous material, such as ores, partly reduced ores and metal-containing waste streams. The present invention relates particularly to a molten metal bath-based direct smelting process and an apparatus for producing molten metal from a ferrous material. One known molten bath-based direct smelting process for producing molten ferrous metal is the DIOS process. The DIOS process includes a pre-reduction stage and a smelt reduction stage. In the DIOS process ore (- 8mm) is pre-heated (750°C) and pre-reduced (10 to 30%) in fluidised beds using offgas from a smelt reduction vessel which contains a molten bath of metal and slag, with the slag forming a deep layer on the metal. The fine (-3mm) and coarse (-8mm) components of the ore are separated in the pre-reduction stage of the process. Coal and pre- heated and pre-reduced ore (via two feed lines) are fed continuously into the smelt reduction furnace from the top of the furnace. The ore dissolves and forms FeO in the deep layer of slag and the coal decomposes into char and volatile matter in the slag layer. Oxygen is blown through, a specially designed lance that improves secondary combustion in the foamed slag. Oxygen jets burn carbon monoxide that is generated with the smelting reduction reactions, thereby generating heat that is transferred to the molten slag. The FeO is reduced at the slag/metal and slag/char interfaces. Stirring gas introduced into the hot metal bath from the bottom of the smelt reduction vessel improves heat transfer efficiency and increases the slag/metal interface for reduction. Slag and metal are tapped periodically. Another known direct smelting process for producing molten ferrous metal is the AISI process. The AISI process also includes a pre-reduction stage and a smelt reduction stage. In the AISI process pre-heated and partially pre-reduced iron ore pellets, coal or coke breeze and fluxes are top charged into a pressurised smelt reactor which contains a molten bath of metal and slag. The coal devolatilises in the slag layer and the iron ore pellets dissolve in the slag and then are reduced by carbon (char) in the slag. The process conditions result in slag foaming. Carbon monoxide and hydrogen generated in the process are post combusted in or just above the slag layer to provide the energy required for the endothermic reduction reactions. Oxygen is top blown through a central, water cooled lance and nitrogen is injected through tuyeres at the bottom of the reactor to ensure sufficient stirring to facilitate heat transfer of the post combustion energy to the bath. The process offgas is de- dusted in a hot cyclone before being fed to a shaft type furnace for pre-heating and pre-reduction of the pellets to FeO or wustite. Another known direct smelting process, which relies on a molten metal layer as a reaction medium, and is generally referred to as the HIsmelt process, is described in International application PCT/AU96/00197 (WO 96/31627) in the name of the applicant. The HIsmelt process as described in the International application comprises: (a) forming a bath of molten metal and slag in a vessel; (b) injecting into the bath: (i) metalliferous feed material, typically metal oxides; and (ii) a solid carbonaceous material, typically coal, which acts as a reducfcant of the metal oxides and a source of energy; and (c) smelting the metalliferous feed material to metal in the metal layer. The HIsmelt process also comprises injecting oxygen-containing gas into a space above the bath and post- combusting reaction gases, such as CO and H2, released from the bath and transferring the heat generated to the bath to. contribute to the thermal energy required to smelt the metalliferous feed materials. The HIsmelt process also comprises forming a transition zone in the space above the nominal quiescent surface of the bath in which there is a favourable mass of ascending and thereafter descending droplets or splashes or streams of molten materiel which provide an effective medium to transfer to the bath the thermal energy generated by post-combusting reaction gases above the bath. The HIsmelt process as described in the International application is characterised by forming the transition zone by injecting a carrier gas, metalliferous feed material, and solid carbonaceous material into the bath through a section of the side of the vessel that is in contact with the bath and/or from above the bath so that the carrier gas and the solid material penetrate the bath and cause molten material to be projected into the space above the surface of the bath. The HIsmelt process as described in the International application is an improvement over earlier forms of the HIsmelt process which form the transition zone by bottom injection of gas and/or carbonaceous material into the bath which causes droplets and splashes and streams of molten material to be projected from the bath. The applicant has carried out extensive research and pilot plant work on direct smelting processes and has made a series of significant findings in relation to such processes. Accordingly, the present invention provides a direct smelting process for producing metals (which term includes metal alloys) from a ferrous material said process comprises the steps of : (a) forming a bath of molten metal and molten slag in a metallurgical vessel ; (b) injecting feed materials being solid material and carrier gas into the molten bath at a velocity of at least 40m/s through a downwardly extending solids injection lance having a delivery tube of internal diameter of 40 - 200 mm that is located so that a central axis of an outlet end of the lance is at an angle of 20 to 90 degrees to a horizontal axis and generating a superficial gas flow of at least 0.04 nm3/s/m2 within the molten bath (where m2 relates to the area of a horizontal cross-section through the molten bath) at least in part by reactions of injected material in the bath which causes molten material to be projected upwardly as splashes, droplets and streams and form an expanded molten bath zone, the gas flow and the upwardly projected molten material causing substantial movement of material within the molten bath and strong mixing of the molten bath, the feed materials being selected so that, in an overall sense, the reactions of the feed materials in the molten bath are and strong mixing of the molten bath, the feed materials being selected so that, in an overall sense, the reactions of the feed materials in the molten bath are endothermic; and (c) injecting an oxygen- containing gas into an upper region of the vessel via at least one oxygen gas injection lance and post-combusting combustible gases released from the molten bath, whereby ascending and thereafter descending molten material in the expanded molten bath zone facilitate heat transfer to the molten bath. The expanded molten bath zone is characterised by a high volume fraction of gas voidages throughout the molten material. Preferably the volume fraction of gas voidages is at least 30% by volume of the expanded molten bath zone. The splashes, droplets and streams of molten material are generated by the above-described flow of gas within the molten bath. Whilst the applicant does not wish to be bound by the following comments, the applicant believes that the splashes, droplets and streams are generated by a churn-turbulent regime at lower gas flow rates and by a fountain regime at higher gas flow rates. Preferably the gas flow and the upwardly projected molten material cause substantial movement of material into and from the molten bath. Preferably the solid material includes ferrous material and/or solid carbonaceous material. The above-described expanded molten bath zone is quite different to the layer of foaming slag produced in the above-described AISI process. Preferably step (b) includes injecting feed materials into the molten bath so that the feed materials penetrate a lower region of the molten bath. Preferably the expanded molten bath zone forms on the lower region of the molten bath. Preferably step (b) includes injecting feed materials into the molten bath via the lance at a velocity in the range of 80-100 m/s. Preferably step (b) includes injecting feed materials into the molten bath via the lance at a mass flow- rate of up to 2.0 t/m2/s where m2 relates to the cross- sectional area of the lance delivery tube. Preferably step (b) includes injecting feed materials into the molten bath via the lance at a solids/gas ratio of 10-25 kg solids/Nm3 gas. More preferably the solid gas ratio is 10-18 kg solids/Nm3 gas. Preferably the gas flow within the molten bath generated in step (b) is at least 0.04Nm3/s/m2 at the quiescent surface of the molten bath. More preferably the gas flow within the molten bath is at a flow rate of at least 0.2 Nm3/s/m2. More preferably the gas flow rate is at least 0.3 Nm3/s/m2. Preferably the gas flow rate is less than 2 Nm3/s/m2. The gas flow within the molten bath may be generated in part as a result of bottom and/or side wall injection of a gas into the molten bath, preferably the lower region of the molten bath. Preferably the oxygen-containing gas is air or oxygen-enriched air. Preferably the process includes injecting air or oxygen-enriched air into the vessel at a temperature of 800-1400°C and at a velocity of 200-600 m/s via at least one oxygen gas injection lance and forcing the expanded molten bath zone in the region of the lower end of the lance away from the lance and forming a "free" space around the lower end of the lance that has a concentration of molten material that is lower than the molten material concentration in the expanded molten bath zone; the lance being located so that; (i) a central axis of the lance is at an angle of 20 to 90° relative to a horizontal axis; (ii) the lance extends into the vessel a distance that is at least the outer diameter of the lower end of the lance; and (iii) the lower end of the lance is at least 3 times the outer diameter of the lower end of the lance above the quiescent surface of the molten bath. Preferably the concentration of molten material in the free space around the lower end of the lance is 5% or less by volume of the space. Preferably the free space around the lower end of the lance is a semi-spherical volume that has a diameter that is at least 2 times the outer diameter of the lower end of the lance. Preferably the free space around the lower end of the lance is no more than 4 times the outer diameter of the lower end of the lance. Preferably at least 50%, more preferably at least 60%, by volume of the oxygen in the air or oxygen enriched air is combusted in the free space around the lower end of the lance. Preferably the process includes injecting air or oxygen-enriched air into the vessel in a swirling motion. The term "smelting" is understood herein to mean thermal processing wherein chemical reactions that reduce the ferrous feed material take place to produce liquid metal. The term "quiescent surface" in the context of the molten bath is understood to mean the surface of the molten bath under process conditions in which there is no gas/solids injection and therefore no bath agitation. Preferably the process includes maintaining a high slag inventory in the vessel relative to the molten ferrous metal in the vessel. The amount of slag in the vessel, ie the slag inventory, has a direct impact on the amount of slag that is in the expanded molten bath zone. The relatively low heat transfer characteristics of slag compared to metal is important in the context of minimising heat loss from the expanded molten bath zone to the water cooled side walls and from the vessel via the .. The amount of slag in the vessel, ie the slag inventory, may be controlled by the tapping rates of metal and slag. The production of slag in the vessel may be controlled by varying the feed rates of metalliferous feed material, carbonaceous material, and fluxes to the vessel and operating parameters such as oxygen-containing gas injection rates. Preferably the process includes controlling the level of dissolved carbon in molten iron to be at least 3 wt% and maintaining the slag in a strongly reducing condition leading to FeO levels of less than 6 wt%, more preferably less than 5 wt%, in the slag. Preferably ferrous material is smelted to metal at least predominantly in the lower region of the molten bath. Invariably, this region of the vessel is where there will be a high concentration of metal. In practice, there will be a proportion of the ferrous material that is smelted to metal in other regions of the vessel. However, the objective of the process of the present invention, and an important difference between the process and prior art processes, is to maximise smelting of ferrous material in the lower region of the molten bath. Step (b) of the process may include injecting feed materials through a plurality of solids injection lances and generating the gas flow of at least 0/04 Nm3/s/m2 within the molten bath. The injection of ferrous material and carbonaceous material may be through the same or separate side walls of the vessel. By appropriate process control, slag in the expanded molten bath zone can form a layer or layers on the side walls that adds resistance to heat loss from the side walls. Therefore, by changing the slag inventory it is possible to increase or decrease the amount of slag in the expanded molten bath zone and on the side walls and therefore control the heat loss via the side walls of the vessel. The slag may form a "wet" layer or a "dry" layer on the side walls. A "wet" layer comprises a frozen layer that adheres to the side walls, a semi-sol id (mush) layer, and an outer liquid film. A "dry" layer is one in which substantially all of the slag is frozen. The amount of slag in the vessel also provides a measure of control over the extent of post combustion. Specifically, if the slag inventory is too low there will be increased exposure of metal in the expanded molten bath zone and therefore increased oxidation of metal and dissolved carbon in metal and the potential for reduced' post-combustion and consequential decreased post combustion, notwithstanding the positive effect that metal in the expanded molten bath zone has on heat transfer to the metal layer. In addition, if the slag inventory is too high the one or more than one oxygen-containing gas injection lance/tuyere will be buried in the expanded molten bath zone and this minimises movement of top space reaction gases to the end of the or each lance/tuyere and, as a consequence, reduces potential for post-combustion. lances. Preferably the process includes causing molten material to be projected above the expanded molten bath zone. Preferably the level of post-combust ion is at least 40%/ where post-combustion is defined as: [C02] + [H20] [C02] + [H20] + [CO] + [H2] where; [C02] = volume % of C02 in off-gas o [HaO] = volume % of HaO in off-gas [CO] = volume % of CO in off-gas [H2] = volume % of H2 in off-gas The expanded molten bath zone is important for 2 reasons. , Firstly, the ascending and thereafter descending molten material is an effective means of transferring to the molten bath the heat generated by post-combustion of reaction gases. Secondly, the molten material, and particularly the slag, in the expanded molten bath zone is an effective means of minimising heat loss via the side walls of the vessel. Ra important difference between the preferred embodiment of the process of the present invention and prior art processes is that in the preferred embodiment the main smelting region is the lower region of the molten bath and the main oxidation (ie heat generation) region is above and in an upper region of the expanded molten bath zone and these regions are spatially well separated and heat transfer is via physical movement of molten metal and slag between the two regions. The present invention also provides an apparatus for producing metal from a ferrous material by a direct smelting process, which apparatus apparatus comprises a fixed non-tiltable vessel that contains a molten bath of metal and slag and includes a lower region and an expanded molten bath zone above the lower region, the expanded molten bath zone being formed by gas flow from the lower region which carries molten material upwardly from the lower region, said vessel comprises : a) a health formed of refractory material having a base and sides in contact with the lower region of the molten bath; b) side walls extending upwardly from the sides of the hearth and being in contact with an upper region of the molten bath and the gas continuous space, wherein the side walls that contact the gas continuous space include water cooled panels and a layer of slag on the panels; c) at least one lance extending downwardly into the vessel and injecting oxygen-containing gas into the vessel above the molten bath; d) at least one lance injecting feed materials being ferrous material and/ or carbonaceous material and carrier gas into the molten bath at a velocity of at least 40 m/s, the lance being located so that a central axis of an outlet end of the lance is angled downwardly at an angle of 20 to 90° to a horizontal axis, the lance having a delivery tube for injecting feed materials which has an internal diameter of 40 - 200 mm; and e) a means for tapping molten metal and slag from the vessel. Preferably the feed material injection lance is located so that the outlet end of the lance is 150-1500mm above the nominal quiescent surface of a metal layer of the molten bath. Preferably the feed materials injection lance includes a central core tube through which to pass the ' solid particulate material; an annular cooling jacket surrounding the central core tube throughout a substantial part of its length, which jacket defines an inner elongate annular water flow passage disposed about the core tube, an outer elongate annular water flow passage disposed about the inner water flow passage, and an annular end passage interconnecting the inner and outer water flow passages at a forward end of the cooling jacket; water inlet means for inlet of water into the inner annular water flow passage of the jacket at a rear end region of the jacket; an water outlet means for outlet of water from the outer annular water flow passage at the rear end region of the jacket, whereby to provide for flow of cooling water forwardly along the inner elongate annular - passage to the forward end of the jacket then through the end flow passage means and backwardly through the outer elongate annular water flow passage, wherein the annular end passage curves smoothly outwardly and backwardly from the inner elongate annular passage to the outer elongate annular passage and the effective cross-sectional area for water flow through the end passage is less than the cross-sectional flow areas of both the inner and outer elongate annular water flow passages. The present invention is described further by way of example with reference to the accompanying drawings of which: Figure 1 is a vertical section illustrating in schematic form a preferred embodiment of the process and the apparatus of the present invention; Figures 2A and 2B join on the line A-A to form a longitudinal cross-section through one of the solids injection lances shown in Figure 1; Figure 3 is an enlarged longitudinal cross- section through a rear end of the lance; Figure 4 is an enlarged cross-section through the forward end of the lance; and Figure 5 is a transverse cross-section on the line 5-5 in Figure 4. The following description is in the context of smelting iron ore to produce molten iron and it is understood that the present invention is not limited to this application and is applicable to any suitable ferrous ores and/or concentrates - including partially reduced metallic ores and waste revert materials. The direct smelting apparatus shown in Figure 1 includes a metallurgical vessel denoted generally as 11. The vessel 11 has a hearth that incudes a base 12 and sides 13 formed from refractory bricks; side walls 14 which form a generally cylindrical barrel extending upwardly from the sides 13 of the hearth and which includes an upper barrel section formed from water cooled panels (not shown) and a lower barrel section formed from water cooled panels (not shown) having an inner lining of refractory bricks; a roof 17; an outlet 18 for off-gases; a forehearth 19 for discharging molten metal continuously; and a tap-hole 21 for discharging molten slag. In use, under quiescent conditions, the vessel contains a molten bath of iron and slag which includes a layer 22 of molten metal and a layer 23 of molten slag on the metal layer 22. The term "metal layer" is understood herein to mean that region of the bath that is predominantly metal. The space above the nominal quiescent surface of the molten bath is hereinafter referred to as the "top space". The arrow marked by the numeral 24 indicates the position of the nominal quiescent surface of the metal layer 22 and the arrow marked by the numeral 25 indicates the position of the nominal quiescent surface of the slag layer 23 (ie of the molten bath). The term "quiescent surface" is understood to mean the surface when there is no injection of gas and solids into the vessel. The vessel is fitted with a downwardly extending hot air injection lance 26 for delivering a hot air blast into an upper region of the vessel and post-combusting reaction gases released from the molten bath. The lance 26 has an outer diameter D at a lower end of the lance. The lance 26 is located so that: (i) a central axis of the lance 26 is at an angle of 20 to 90° relative to a horizontal axis (the lance 26 shown in Figure 1 is at an angle of 90°); (ii) the lance 26 extends into the vessel a distance that is at least the outer diameter D of the lower end of the lance; and (iii) the lower end of the lance 26 is at least 3 times the outer diameter D of the lower end of the lance above the quiescent surface 25 of the molten bath. The vessel is also fitted with solids injection lances 27 (two shown) extending downwardly and inwardly through the side walls 14 and into the molten bath with outlet ends 82 of the lances 27 at an angle of 20-70° to the horizontal for injecting iron ore, solid carbonaceous material, and fluxes entrained in an oxygen-deficient carrier gas into the molten bath. The position of the lances 27 is selected so that their outlet ends 82 are above the quiescent surface 24 of the metal layer 22. This position of the lances 27 reduces the risk of damage through contact with molten metal and also makes it possible to cool the lances 27 by forced internal water cooling without significant risk of water coming into contact with the molten metal in the vessel. Specif icallyy the position of the lances 27 is selected so that the outlet ends 82 are in the range of 150-1500mm above the quiescent surface 24 of the metal layer 22. In this connection, it is noted that, whilst the lances 27 are shown in Figure 1 as extending into the vessel, the outlet ends of the lances 27 may be flush with the side wall 14. The lances 27 are described in more detail with reference to Figures 2-5. In use, iron ore, solid carbonaceous material (typically coal), and fluxes (typically lime and magnesia) entrained in a carrier gas (typically N2) are injected into the molten bath via the lances 27 at a velocity of at least 40 m/s, preferably 80-100 m/s. The momentum of the solid material/carrier gas causes the solid material and gas to penetrate to a lower region of the molten bath. The coal is devolatilised and thereby produces gas in the lower bath region. Carbon partially dissolves into the metal and partially remains as solid carbon. The iron ore is smelted to metal and the smelting reaction generates carbon monoxide gas. The gases transported into the lower bath region and generated via devolatilisation and smelting produce significant buoyancy uplift of molten metal, solid carbon, and slag (drawn into the lower bath region as a conse region which generates an upward movement of splashes, droplets and streams of molten metal and slag, and these splashes, and droplets, and streams entrain slag as they move through an upper region of the molten bath. The gas flow generated by the above-described injection of carrier gas and bath reactions is at least 0.04Nm3/s/m2 of the quiescent surface of the molten bath (ie the surface 25) . The buoyancy uplift of molten metal, solid carbon and slag causes substantial agitation in the molten bath, with the result that the molten bath expands in volume and forms an expanded molten bath zone 28 that has a surface indicated by the arrow 30. The extent of agitation is such that there is substantial movement of molten material within the molten bath (including movement of molten material into and from the lower bath region) and strong mixing of the molten bath to the extent that there is reasonably uniform temperature throughout the molten bath - typically, 1450 - 1550°C with a temperature variation of the order of 3 0° in each region. In addition, the upward gas flow projects some molten material (predominantly slag) beyond the expanded molten bath zone 28 and onto the part of the upper barrel section of the side walls 14 that is above the expanded molten bath zone 28 and onto the roof 17. In general terms, the expanded molten bath zone 28 is a liquid continuous volume, with gas bubbles therein.. In addition to the above, in use, hot air at a temperature of 800-1400°C is discharged at a velocity of 200-600 m/s via lance 26 and penetrates the central region of the expanded molten bath zone 28 and causes an essentially metal/slag free space 29 to form around the end of the lance 26. The hot air blast via the lance 26 post-combusts reaction gases CO and H2 in the expanded molten bath zone 28 and in the free space 29 around the end of the lance 26 and generates high temperatures of the order of 2000°C or higher in the gas space. The heat is transferred to the ascending and descending splashes droplets, and streams, of molten material in the region of gas injection and the heat is then partially transferred throughout the molten bath. The free space 29 is important to achieving high levels of post combustion because it enables entrainment of gases in the space above the expanded molten bath zone 28 into the end region of the lance 26 and thereby increases exposure of available reaction gases to post combustion. The combined effect of the position of the lance 26, gas flow rate through the lance 26, and upward movement of splashes, droplets and streams of molten material is to shape the expanded molten bath zone 28 around the lower region of the lance 26. This shaped region provides a partial barrier to heat transfer by radiation to the side walls 14. Moreover, the ascending and descending droplets, splashes and streams of molten material is an effective means of transferring heat from the expanded molten bath zone 28 to the molten bath with the result that the temperature of the zone 28 in the region of the side walls 14 is of the order of 1450°C-1550°C. The construction of the solids injection lances is illustrated in Figures 2 to 5. As shown in these figures, each lance 27 comprises a central core tube 31 through which to deliver the solids material and an annular cooling jacket 32 surrounding the central core tube 31 throughout a substantial part of its length. Central core tube 31 is formed of carbon/alloy steel tubing 33 throughout most of its length, but a stainless steel section 34 at its forward end projects as a nozzle from the forward end of cooling jacket 32. The forward end part 34 of core tube 31 is connected to the carbon/alloy steel section 33 of the core tube through a short steel adaptor section 35 which is welded to the stainless steel section 34 and connected to the carbon/alloy steel section through a screw thread 36. Central core tube 31 is internally lined through to the forward end part 34 with a thin ceramic lining 37 formed by a series of cast ceramic tubes. The rear end of the central core tube 31 is connected through a coupling 38 to a T-piece 39 through which particulate solids material is delivered in a pressurised fluidising gas carrier, for example nitrogen. Annular cooling jacket 32 comprises a long hollow annular structure 41 comprised of outer and inner tubes 42, 43 interconnected by a front end connector piece 44 and an elongate tubular structure 45 which is disposed within the hollow annular structure 41 so as to divide the interior of structure 41 into an inner elongate annular water flow passage 46 and an outer elongate annular water flow passage 47. Elongate tubular structure 45 is formed by a long carbon steel tube 48 welded to a machined carbon steel forward end piece 49 which fits within the front end connector 44 of the hollow tubular structure 41 to form an annular end flow passage 51 which interconnects the forward ends of the inner and outer water flow passages 46, 47. The rear end of annular cooling jacket 32 is provided with a water inlet 52 through which the flow of cooling water can be directed into the inner annular water flow passage 46 and a water outlet 53 from which water is extracted from the outer annular passage 47 at the rear end of the lance. Accordingly, in use of the lance cooling water flows forwardly down the lance through the inner annular water flow passage 46 then outwardly and back around the forward annular end passage 51 into the outer annular passage 47 through which it flows backwardly along the lance and out through the outlet 53. This ensures that the coolest water is in heat transfer relationship with the incoming solids material to ensure that this material does not melt or burn before it discharges from the forward end of the lance and enables effective cooling of both the solids material being injected through the central core of the lance as well as effective cooling of the forward end and outer surfaces of the lance. The outer surfaces of the tube 42 and front end piece 44 of the hollow annular structure 41 are machined with a regular pattern of rectangular projecting bosses 54 each having an undercut or dove tail cross-section so that the bosses are of outwardly diverging formation and serve as keying formations for solidification of slag on the outer surfaces of the lance. Solidification of slag on to the lance assists in minimising the temperatures in the A DIRECT SMELTING PROCESS AND APPARATUS The present invention relates to a process and an apparatus for producing molten metal (which term includes metal alloys), in particular although by no means exclusively iron, from ferrous material, such as ores, partly reduced ores and metal-containing waste streams. The present invention relates particularly to a molten metal bath-based direct smelting process and an apparatus for producing molten metal from a ferrous material. One known molten bath-based direct smelting process for producing molten ferrous metal is the DIOS process. The DIOS process includes a pre-reduction stage and a smelt reduction stage. In the DIOS process ore (- 8mm) is pre-heated (750°C) and pre-reduced (10 to 30%) in fluidised beds using offgas from a smelt reduction vessel which contains a molten bath of metal and slag, with the slag forming a deep layer on the metal. The fine (-3mm) and coarse (-8mm) components of the ore are separated in the pre-reduction stage of the process. Coal and pre- heated and pre-reduced ore (via two feed lines) are fed continuously into the smelt reduction furnace from the top of the furnace. The ore dissolves and forms FeO in the deep layer of slag and the coal decomposes into char and volatile matter in the slag layer. Oxygen is blown through, a specially designed lance that improves secondary combustion in the foamed slag. Oxygen jets burn carbon monoxide that is generated with the smelting reduction reactions, thereby generating heat that is transferred to the molten slag. The FeO is reduced at the slag/metal and slag/char interfaces. Stirring gas introduced into the hot metal bath from the bottom of the smelt reduction vessel improves heat transfer efficiency and increases the slag/metal interface for reduction. Slag and metal are metal components of the lance. It has been found in use that slag freezing on the forward or tip end of the lance serves as a base for formation of an extended pipe of solid material serving as an extension of the lance which further protects exposure of the metal components of the lance to the severe operating conditions within the vessel. It has been found that it is very important to cooling of the tip end of the lance to maintain a high water flow velocity around the annular end flow passage 51. In particular it is most desirable to maintain a water flow velocity in this region of the order of 10 meters per second to obtain maximum heat transfer. In order to maximise the water flow rate in this region, the effective cross-section for water flow through passage 51 is significantly reduced below the effective cross-section of both the inner annular water flow passage 46 and the outer water flow passage 47. Forward end piece 49 of the inner tubular structure 45 is shaped and positioned so that water flowing from the forward end of inner annular passage 46 passes through an inwardly reducing or tapered nozzle flow passage section 61 to minimise eddies and losses before passing into the end flow passage 51. The end flow passage 51 also reduces in effective flow area in the direction of water flow so as to maintain the increased water flow velocity around the bend in the passage and back to the outer annular water flow passage 47. In this manner, it is possible to achieve the necessary high water flow rates in the tip region of the cooling jacket without excessive pressure drops and the risk of blockages in other parts of the lance. In order to maintain the appropriate cooling water velocity around the tip end passage 51 and to minimise heat transfer fluctuations, it is critically important to maintain a constant controlled spacing between. the front end piece 49 tubular structure 45 and the end piece 44 of the hollow annular structure 41. This presents a problem due to differential thermal expansion and contraction in the components of the lance. In particular, the outer tube part 42 of hollow annular structure 41 is exposed to much higher temperatures than the inner tube part 43 of that structure and the forward end of that structure therefore tends to roll forwardly in the manner indicated by the dotted line 62 in Figure 4. This produces a tendency for the gap between components 44, 49 defining the passage 51 to open when the lance is exposed to the operating conditions within the smelting vessel. Conversely, the passage can tend to close if there is a drop in temperature during operation. in order to overcome this problem the rear end of the inner tube 43 of hollow annular structure 41 is supported in a sliding mounting 63 so that it can move axially relative to the outer tube 42 of that structure, the rear end of inner tubular structure 45 is also mounted in a sliding mounting 64 and is connected to the inner tube 43 of structure 41 by a series of circumferentially spaced connector cleats 65 so that the tubes 43 and 45 can move axially together. In addition, the end pieces 44, 49 of the hollow annular structure 41 and tubular structure 45 are positively interconnected by a series of circumf erentially spaced dowels 70 to maintain the appropriate spacing under both thermal expansion and contraction movements of the lance jacket. The sliding mounting 64 for the inner end of tubular structure 45 is provided by a ring 66 attached to a water flow manifold structure 68 which defines the water inlet 52 and outlet 53 and is sealed by an 0-ring seal 69. The sliding mounting 63 for the rear end of the inner tube 43 of structure 41 is similarly provided by a ring flange 71 fastened to the water manifold structure 68 and is sealed by an O-ring seal 72. An annular piston 73 is located within ring flange 71 and connected by a screw thread connection 80 to the back end of the inner tube 43 of structure 41 so as to close a water inlet manifold chamber 74 which receives the incoming flow of cooling from inlet 52. Piston 73 slides within hardened surfaces on ring flange 71 and is fitted with O-rings 81, 82. The sliding seal provided by piston 73 not only allows movements of the inner tube 43 due to differential thermal expansion of structure 41 but it also allows movement of tube 43 to accommodate any movement of structure 41 generated by excessive water pressure in the cooling jacket. If for any reason the pressure of the cooling water flow becomes excessive, the outer tube of structure 41 will be forced outwardly and piston 73 allows the inner tube to move accordingly to relieve the pressure build up. An interior space 75 between the piston 73 and the ring flange 71 is vented through a vent hole 7 6 to allow movement of the piston and escape of water leaking past the piston. The rear part of annular cooling jacket 32 is provided with an outer stiffening pipe 83 part way down the lance and defining an annular cooling water passage 84 through which a separate flow of cooling water is passed via a water inlet 85 and water outlet 86. Typically cooling water will be passed through the cooling jacket at a flow rate of lOOmVhr at a maximum operating pressure of 800kPa to produce water flow velocities of 10 meters/minute in the tip region of the jacket. The inner and outer parts of the cooling jacket can be subjected to temperature differentials of the order of 200°C and the movement of tubes 42 and 45 within the sliding mountings 63, 64 can be considerable during operation of the lance, but the effective cross-sectional flow area of the end passage 51 is maintained substantially constant throughout all operating conditions. It is to be understood that this invention is in no way limited to the details of the illustrated construction and that many modifications and variations will fall within the spirit and scope of the invention. In that regard it is noted that the oxygen gas injection lance can be integral with and form part of the upper body of a solids injections lance. WE CLAIM : 1. A direct smelting process for producing metals (which term includes metal alloys) from a ferrous material said process comprises the steps of : (a) forming a bath of molten metal and molten slag in a metallurgical vessel; (b) injecting feed materials being solid material and carrier gas into the molten bath at a velocity of at least 40m/s through a downwardly extending solids injection lance having a delivery tube of internal diameter of 40-200mm that is located so that a central axis of an outlet end of the lance is at an angle of 20 to 90 degrees to a horizontal axis and generating a superficial gas flow of at least 0.04 Nm3/s/m2 within the molten bath (where m2 relates to the area of a horizontal cross-section through the molten bath) at least in part by reactions of injected material in the bath which causes molten material to be projected upwardly as splashes, droplets and streams and form an expanded molten bath zone, the gas flow and the upwardly projected molten material causing substantial movement of material within the molten bath and strong mixing of the molten bath, the feed materials being selected so that, in an overall sense, the reactions of the feed materials in the molten bath are endothermic; and (c) injecting an oxygen-containing gas into an upper region of the vessel via at least one oxygen gas injection lance and post- combusting combustible gases released from the molten bath, whereby ascending and thereafter descending molten material in the expanded molten bath zone facilitate heat transfer to the molten bath. 2. The process as claimed in claim 1, wherein step (b) comprises injecting feed materials into the molten bath so that the feed materials penetrate a lower region of the molten bath. 3. The process as claimed in claim 1, or claim 2 wherein step (b) comprises injecting feed materials into the molten bath via the lance at a velocity in the range of 80-100 m/s. i i 4. The The process as claimed in claim 3, wherein step (b) comprises injecting feed materials into the molten bath via the lance at a mass flow rate of up to 2.0 t/m3/s where m2 relates to the cross-sectional area of the lance delivery tube. 5. The process as claimed in any one of the preceding claims wherein step (b) comprises injecting feed materials into the molten bath via the lance at a solids/gas ratio of 10-25 kg solids/Nm3 gas. 6. The process as claimed in claim 5, wherein the solids/gas ratio is 10-18 kg solids /Nm3 gas. 7- The process as claimed in any one of the preceding claims wherein step (b) comprises injecting feed materials through a plurality of solids injection lances and generating the gas flow of at least 0.04 Nm3/s/m3 within the molten bath. 8. The process as claimed in any one of the preceding claims wherein the gas flow within the molten bath generated in step (b) is at least 0.04Nm3/s/m2 at the nominal quiescent surface of the molten bath. 9. The process as claimed in claim 8, wherein the gas flow within the molten bath is at a flow rate of at least 0.2 Nm3/s/m2. 10. The process as claimed in claim 9, wherein the gas flow rate is at least 0.3 Nm3/s/m2. 11. The process as claimed in any one of the preceding claims wherein the gas flow within the molten bath generated in step (b) is less than 2 Nm3/s/m2. 12. The process as claimed in any one of the preceding claims wherein the oxygen-containing gas injected into the molten bath in step (c) is air or oxygen-enriched air. 13. The process as claimed in claim 12, wherein step (c) comprises injecting the air or oxygen-enriched air into the vessel at a temperature of 800-1400°C and at a velocity of 200-600 m/s via at least one oxygen gas injection lance and forcing the expanded molten bath zone in the region of the lower end of the lance away from the lance and forming a "free" space around the lower end of the lance that has a concentration of molten material that is lower than the molten material concentration in the expanded molten bath zone; the lance being located so that: (i) a central axis of the lance is at an angle of 20 to 90° relative to a horizontal axis; (ii) the lance extends into the vessel a distance that is at least the outer diameter of the lower end of the lance; and (iii) the lower end of the lance is at least 3 times the outer diameter of the lower end of the lance above the quiescent surface of the molten bath. 14. The process as claimed in any one of the preceding claims wherein step (c) includes injecting oxygen- containing gas into the vessel in a swirling motion. 15. The process as claimed in any one of the preceding claims comprises controlling the level of dissolved carbon in molten iron to be at least 3 wt% and maintaining the slag in a strongly reducing condition leading to FeO levels of less than 6 wt%, more preferably less than 5 wt%, in the slag. 16. The process as claimed in any one of the preceding claims comprises causing molten material to be projected into- a top space above the expanded molten bath zone. 17. The process as claimed in any one of the preceding claims wherein step (c) comprises post-combusting combustible gasses so that the level of post-combustion is at least 40%, where post-combustion is defined as: where: [COa] = volume % of CO2 in off-gas [H2O] = volume % of H2O in off-gas [CO] = volume % of CO in off-gas [H2] = volume % of H2 in off-gas 18. An apparatus for producing metal from a ferrous material by a direct smelting process, which apparatus comprises a fixed non-tiltable vessel that contains a molten bath of metal and slag and includes a lower region and an expanded molten bath zone above the lower region, the expanded molten bath zone being formed by gas flow from the lower region which carries molten material upwardly from the lower region, said vessel comprises : (a) a hearth formed of refractory material having a base and sides in contact with the lower region of the molten bath; (b) side walls extending upwardly from the sides; of the hearth and being in contact with an upper region of the molten bath and the gas continuous space, wherein the side walls that contact the gas continuous space include water cooled panels and a layer of slag on the panels; (c) at least one lance extending downwardly into the vessel and injecting oxygen-containing gas into the vessel above the molten bath; (d) at least one lance injecting feed materials being ferrous material and/or carbonaceous material and carrier gas into the molten bath at a velocity of at least 40 m/s, the : lance being located so that a central axis of an outlet end of the lance is angled downwardly at an angle of 20 to 90° to a horizontal axis, the lance having a delivery tube for injecting feed materials which has an internal diameter of 40-200mm : and (e) a means for tapping molten metal and slag from the vessel. 19. The apparatus as claimed in claim 18, wherein the feed materials injection lance is located so that the outlet end of the lance is 150-1500mm above the nominal quiescent surface of a metal layer of the molten bath. ABSTRACT A DIRECT SMELTING PROCESS AND APPARATUS A molten-bath based direct smelting process and apparatus is disclosed. The process comprises injecting feed materials into a molten bath at a velocity of at least 40m/s through at least one solids injection lance (27) having a delivery tube of internal diameter of 40-200mm that is located so that a central axis of an outlet end of the lance is at an angle of 20 to 90 degrees to a horizontal axis. The feed materials injection generates a superficial gas flow of at least 0.04 Nm3/s/m2 within the molten bath. The gas flow causes molten material to be projected upwardly as splashes, droplets and streams and form an expanded molten bath zone, with the gas flow and the upwardly projected molten material causing strong mixing of the molten bath. The process also comprises injecting an oxygen-containing gas into an upper region of the vessel to post-combust gases released from the molten bath.

Full Text

A DIRECT SMELTING PROCESS AND APPARATUS
The present invention relates to a process and an
apparatus for producing molten metal (which term includes
metal alloys), in particular although by no means
exclusively iron, from ferrous material, such as ores,
partly reduced ores and metal-containing waste streams.
The present invention relates particularly to a
molten metal bath-based direct smelting process and an
apparatus for producing molten metal from a ferrous
material.
One known molten bath-based direct smelting
process for producing molten ferrous metal is the DIOS
process. The DIOS process includes a pre-reduction stage
and a smelt reduction stage. In the DIOS process ore (-
8mm) is pre-heated (750°C) and pre-reduced (10 to 30%) in
fluidised beds using offgas from a smelt reduction vessel
which contains a molten bath of metal and slag, with the
slag forming a deep layer on the metal. The fine (-3mm)
and coarse (-8mm) components of the ore are separated in
the pre-reduction stage of the process. Coal and pre-
heated and pre-reduced ore (via two feed lines) are fed
continuously into the smelt reduction furnace from the top
of the furnace. The ore dissolves and forms FeO in the
deep layer of slag and the coal decomposes into char and
volatile matter in the slag layer. Oxygen is blown through,
a specially designed lance that improves secondary
combustion in the foamed slag. Oxygen jets burn carbon
monoxide that is generated with the smelting reduction
reactions, thereby generating heat that is transferred to
the molten slag. The FeO is reduced at the slag/metal and
slag/char interfaces. Stirring gas introduced into the hot
metal bath from the bottom of the smelt reduction vessel
improves heat transfer efficiency and increases the
slag/metal interface for reduction. Slag and metal are

tapped periodically.
Another known direct smelting process for
producing molten ferrous metal is the AISI process. The
AISI process also includes a pre-reduction stage and a
smelt reduction stage. In the AISI process pre-heated and
partially pre-reduced iron ore pellets, coal or coke breeze
and fluxes are top charged into a pressurised smelt reactor
which contains a molten bath of metal and slag. The coal
devolatilises in the slag layer and the iron ore pellets
dissolve in the slag and then are reduced by carbon (char)
in the slag. The process conditions result in slag
foaming. Carbon monoxide and hydrogen generated in the
process are post combusted in or just above the slag layer
to provide the energy required for the endothermic
reduction reactions. Oxygen is top blown through a
central, water cooled lance and nitrogen is injected
through tuyeres at the bottom of the reactor to ensure
sufficient stirring to facilitate heat transfer of the post
combustion energy to the bath. The process offgas is de-
dusted in a hot cyclone before being fed to a shaft type
furnace for pre-heating and pre-reduction of the pellets to
FeO or wustite.
Another known direct smelting process, which
relies on a molten metal layer as a reaction medium, and is
generally referred to as the HIsmelt process, is described
in International application PCT/AU96/00197 (WO 96/31627)
in the name of the applicant.
The HIsmelt process as described in the
International application comprises:
(a) forming a bath of molten metal and slag in a
vessel;
(b) injecting into the bath:

(i) metalliferous feed material, typically
metal oxides; and
(ii) a solid carbonaceous material,
typically coal, which acts as a
reducfcant of the metal oxides and a
source of energy; and
(c) smelting the metalliferous feed material to
metal in the metal layer.
The HIsmelt process also comprises injecting
oxygen-containing gas into a space above the bath and post-
combusting reaction gases, such as CO and H2, released from
the bath and transferring the heat generated to the bath to.
contribute to the thermal energy required to smelt the
metalliferous feed materials.
The HIsmelt process also comprises forming a
transition zone in the space above the nominal quiescent
surface of the bath in which there is a favourable mass of
ascending and thereafter descending droplets or splashes or
streams of molten materiel which provide an effective
medium to transfer to the bath the thermal energy generated
by post-combusting reaction gases above the bath.
The HIsmelt process as described in the
International application is characterised by forming the
transition zone by injecting a carrier gas, metalliferous
feed material, and solid carbonaceous material into the
bath through a section of the side of the vessel that is in
contact with the bath and/or from above the bath so that
the carrier gas and the solid material penetrate the bath
and cause molten material to be projected into the space
above the surface of the bath.

The HIsmelt process as described in the
International application is an improvement over earlier
forms of the HIsmelt process which form the transition zone
by bottom injection of gas and/or carbonaceous material
into the bath which causes droplets and splashes and
streams of molten material to be projected from the bath.
The applicant has carried out extensive research
and pilot plant work on direct smelting processes and has
made a series of significant findings in relation to such
processes.

Accordingly, the present invention provides a direct
smelting process for producing metals (which term
includes metal alloys) from a ferrous material said
process comprises the steps of : (a) forming a bath of
molten metal and molten slag in a metallurgical vessel ;
(b) injecting feed materials being solid material and
carrier gas into the molten bath at a velocity of at
least 40m/s through a downwardly extending solids
injection lance having a delivery tube of internal
diameter of 40 - 200 mm that is located so that a central
axis of an outlet end of the lance is at an angle of 20
to 90 degrees to a horizontal axis and generating a
superficial gas flow of at least 0.04 nm3/s/m2 within the
molten bath (where m2 relates to the area of a horizontal
cross-section through the molten bath) at least in part
by reactions of injected material in the bath which
causes molten material to be projected upwardly as
splashes, droplets and streams and form an expanded
molten bath zone, the gas flow and the upwardly projected
molten material causing substantial movement of material
within the molten bath and strong mixing of the molten
bath, the feed materials being selected so that, in an
overall sense, the reactions of the feed materials in the
molten bath are and strong mixing of the molten bath, the
feed materials being selected so that, in an overall

sense, the reactions of the feed materials in the molten
bath are endothermic; and (c) injecting an oxygen-
containing gas into an upper region of the vessel via at
least one oxygen gas injection lance and post-combusting
combustible gases released from the molten bath, whereby
ascending and thereafter descending molten material in
the expanded molten bath zone facilitate heat transfer to
the molten bath.
The expanded molten bath zone is characterised by
a high volume fraction of gas voidages throughout the
molten material.
Preferably the volume fraction of gas voidages is
at least 30% by volume of the expanded molten bath zone.
The splashes, droplets and streams of molten
material are generated by the above-described flow of gas
within the molten bath. Whilst the applicant does not wish
to be bound by the following comments, the applicant
believes that the splashes, droplets and streams are
generated by a churn-turbulent regime at lower gas flow
rates and by a fountain regime at higher gas flow rates.
Preferably the gas flow and the upwardly
projected molten material cause substantial movement of
material into and from the molten bath.

Preferably the solid material includes ferrous
material and/or solid carbonaceous material.
The above-described expanded molten bath zone is
quite different to the layer of foaming slag produced in
the above-described AISI process.
Preferably step (b) includes injecting feed
materials into the molten bath so that the feed materials
penetrate a lower region of the molten bath.
Preferably the expanded molten bath zone forms on
the lower region of the molten bath.
Preferably step (b) includes injecting feed
materials into the molten bath via the lance at a velocity
in the range of 80-100 m/s.
Preferably step (b) includes injecting feed
materials into the molten bath via the lance at a mass flow-
rate of up to 2.0 t/m2/s where m2 relates to the cross-
sectional area of the lance delivery tube.
Preferably step (b) includes injecting feed
materials into the molten bath via the lance at a
solids/gas ratio of 10-25 kg solids/Nm3 gas.
More preferably the solid gas ratio is 10-18 kg
solids/Nm3 gas.
Preferably the gas flow within the molten bath
generated in step (b) is at least 0.04Nm3/s/m2 at the
quiescent surface of the molten bath.
More preferably the gas flow within the molten
bath is at a flow rate of at least 0.2 Nm3/s/m2.

More preferably the gas flow rate is at least 0.3
Nm3/s/m2.
Preferably the gas flow rate is less than 2
Nm3/s/m2.
The gas flow within the molten bath may be
generated in part as a result of bottom and/or side wall
injection of a gas into the molten bath, preferably the
lower region of the molten bath.
Preferably the oxygen-containing gas is air or
oxygen-enriched air.
Preferably the process includes injecting air or
oxygen-enriched air into the vessel at a temperature of
800-1400°C and at a velocity of 200-600 m/s via at least
one oxygen gas injection lance and forcing the expanded
molten bath zone in the region of the lower end of the
lance away from the lance and forming a "free" space around
the lower end of the lance that has a concentration of
molten material that is lower than the molten material
concentration in the expanded molten bath zone; the lance
being located so that; (i) a central axis of the lance is
at an angle of 20 to 90° relative to a horizontal axis;
(ii) the lance extends into the vessel a distance that is
at least the outer diameter of the lower end of the lance;
and (iii) the lower end of the lance is at least 3 times
the outer diameter of the lower end of the lance above the
quiescent surface of the molten bath.
Preferably the concentration of molten material
in the free space around the lower end of the lance is 5%
or less by volume of the space.
Preferably the free space around the lower end of
the lance is a semi-spherical volume that has a diameter

that is at least 2 times the outer diameter of the lower
end of the lance.
Preferably the free space around the lower end of
the lance is no more than 4 times the outer diameter of the
lower end of the lance.
Preferably at least 50%, more preferably at least
60%, by volume of the oxygen in the air or oxygen enriched
air is combusted in the free space around the lower end of
the lance.
Preferably the process includes injecting air or
oxygen-enriched air into the vessel in a swirling motion.
The term "smelting" is understood herein to mean
thermal processing wherein chemical reactions that reduce
the ferrous feed material take place to produce liquid
metal.
The term "quiescent surface" in the context of
the molten bath is understood to mean the surface of the
molten bath under process conditions in which there is no
gas/solids injection and therefore no bath agitation.
Preferably the process includes maintaining a
high slag inventory in the vessel relative to the molten
ferrous metal in the vessel.
The amount of slag in the vessel, ie the slag
inventory, has a direct impact on the amount of slag that
is in the expanded molten bath zone.
The relatively low heat transfer characteristics
of slag compared to metal is important in the context of
minimising heat loss from the expanded molten bath zone to
the water cooled side walls and from the vessel via the

.. The amount of slag in the vessel, ie the slag
inventory, may be controlled by the tapping rates of metal
and slag.
The production of slag in the vessel may be
controlled by varying the feed rates of metalliferous feed
material, carbonaceous material, and fluxes to the vessel
and operating parameters such as oxygen-containing gas
injection rates.
Preferably the process includes controlling the
level of dissolved carbon in molten iron to be at least 3
wt% and maintaining the slag in a strongly reducing
condition leading to FeO levels of less than 6 wt%, more
preferably less than 5 wt%, in the slag.
Preferably ferrous material is smelted to metal
at least predominantly in the lower region of the molten
bath. Invariably, this region of the vessel is where there
will be a high concentration of metal.
In practice, there will be a proportion of the
ferrous material that is smelted to metal in other regions
of the vessel. However, the objective of the process of
the present invention, and an important difference between
the process and prior art processes, is to maximise
smelting of ferrous material in the lower region of the
molten bath.
Step (b) of the process may include injecting
feed materials through a plurality of solids injection
lances and generating the gas flow of at least 0/04
Nm3/s/m2 within the molten bath.
The injection of ferrous material and
carbonaceous material may be through the same or separate

side walls of the vessel.
By appropriate process control, slag in the
expanded molten bath zone can form a layer or layers on the
side walls that adds resistance to heat loss from the side
walls.
Therefore, by changing the slag inventory it is
possible to increase or decrease the amount of slag in the
expanded molten bath zone and on the side walls and
therefore control the heat loss via the side walls of the
vessel.
The slag may form a "wet" layer or a "dry" layer
on the side walls. A "wet" layer comprises a frozen layer
that adheres to the side walls, a semi-sol id (mush) layer,
and an outer liquid film. A "dry" layer is one in which
substantially all of the slag is frozen.
The amount of slag in the vessel also provides a
measure of control over the extent of post combustion.
Specifically, if the slag inventory is too low
there will be increased exposure of metal in the expanded
molten bath zone and therefore increased oxidation of metal
and dissolved carbon in metal and the potential for reduced'
post-combustion and consequential decreased post
combustion, notwithstanding the positive effect that metal
in the expanded molten bath zone has on heat transfer to
the metal layer.
In addition, if the slag inventory is too high
the one or more than one oxygen-containing gas injection
lance/tuyere will be buried in the expanded molten bath
zone and this minimises movement of top space reaction
gases to the end of the or each lance/tuyere and, as a
consequence, reduces potential for post-combustion.

lances.
Preferably the process includes causing molten
material to be projected above the expanded molten bath
zone.
Preferably the level of post-combust ion is at
least 40%/ where post-combustion is defined as:
[C02] + [H20]
[C02] + [H20] + [CO] + [H2]
where;
[C02] = volume % of C02 in off-gas
o
[HaO] = volume % of HaO in off-gas
[CO] = volume % of CO in off-gas
[H2] = volume % of H2 in off-gas
The expanded molten bath zone is important for 2
reasons. ,
Firstly, the ascending and thereafter descending
molten material is an effective means of transferring to
the molten bath the heat generated by post-combustion of
reaction gases.
Secondly, the molten material, and particularly
the slag, in the expanded molten bath zone is an effective
means of minimising heat loss via the side walls of the
vessel.
Ra important difference between the preferred
embodiment of the process of the present invention and
prior art processes is that in the preferred embodiment the
main smelting region is the lower region of the molten bath
and the main oxidation (ie heat generation) region is above

and in an upper region of the expanded molten bath zone and
these regions are spatially well separated and heat
transfer is via physical movement of molten metal and slag
between the two regions.
The present invention also provides an apparatus for
producing metal from a ferrous material by a direct
smelting process, which apparatus apparatus comprises a
fixed non-tiltable vessel that contains a molten bath of
metal and slag and includes a lower region and an
expanded molten bath zone above the lower region, the
expanded molten bath zone being formed by gas flow from
the lower region which carries molten material upwardly
from the lower region, said vessel comprises : a) a
health formed of refractory material having a base and
sides in contact with the lower region of the molten
bath; b) side walls extending upwardly from the sides of
the hearth and being in contact with an upper region of
the molten bath and the gas continuous space, wherein the
side walls that contact the gas continuous space include
water cooled panels and a layer of slag on the panels; c)
at least one lance extending downwardly into the vessel
and injecting oxygen-containing gas into the vessel above
the molten bath; d) at least one lance injecting feed
materials being ferrous material and/ or carbonaceous
material and carrier gas into the molten bath at a
velocity of at least 40 m/s, the lance being located so
that a central axis of an outlet end of the lance is
angled downwardly at an angle of 20 to 90° to a
horizontal axis, the lance having a delivery tube for
injecting feed materials which has an internal diameter
of 40 - 200 mm; and e) a means for tapping molten metal
and slag from the vessel.

Preferably the feed material injection lance is
located so that the outlet end of the lance is 150-1500mm
above the nominal quiescent surface of a metal layer of the
molten bath.
Preferably the feed materials injection lance
includes a central core tube through which to pass the '
solid particulate material; an annular cooling jacket
surrounding the central core tube throughout a substantial
part of its length, which jacket defines an inner elongate
annular water flow passage disposed about the core tube, an
outer elongate annular water flow passage disposed about
the inner water flow passage, and an annular end passage
interconnecting the inner and outer water flow passages at
a forward end of the cooling jacket; water inlet means for
inlet of water into the inner annular water flow passage of
the jacket at a rear end region of the jacket; an water
outlet means for outlet of water from the outer annular
water flow passage at the rear end region of the jacket,
whereby to provide for flow of cooling water forwardly
along the inner elongate annular - passage to the forward end
of the jacket then through the end flow passage means and
backwardly through the outer elongate annular water flow
passage, wherein the annular end passage curves smoothly
outwardly and backwardly from the inner elongate annular
passage to the outer elongate annular passage and the
effective cross-sectional area for water flow through the
end passage is less than the cross-sectional flow areas of
both the inner and outer elongate annular water flow

passages.
The present invention is described further by way
of example with reference to the accompanying drawings of
which:
Figure 1 is a vertical section illustrating in
schematic form a preferred embodiment of the process and
the apparatus of the present invention;
Figures 2A and 2B join on the line A-A to form a
longitudinal cross-section through one of the solids
injection lances shown in Figure 1;
Figure 3 is an enlarged longitudinal cross-
section through a rear end of the lance;
Figure 4 is an enlarged cross-section through the
forward end of the lance; and
Figure 5 is a transverse cross-section on the
line 5-5 in Figure 4.
The following description is in the context of
smelting iron ore to produce molten iron and it is
understood that the present invention is not limited to
this application and is applicable to any suitable ferrous
ores and/or concentrates - including partially reduced
metallic ores and waste revert materials.
The direct smelting apparatus shown in Figure 1
includes a metallurgical vessel denoted generally as 11.
The vessel 11 has a hearth that incudes a base 12 and sides
13 formed from refractory bricks; side walls 14 which form
a generally cylindrical barrel extending upwardly from the
sides 13 of the hearth and which includes an upper barrel
section formed from water cooled panels (not shown) and a

lower barrel section formed from water cooled panels (not
shown) having an inner lining of refractory bricks; a roof
17; an outlet 18 for off-gases; a forehearth 19 for
discharging molten metal continuously; and a tap-hole 21
for discharging molten slag.
In use, under quiescent conditions, the vessel
contains a molten bath of iron and slag which includes a
layer 22 of molten metal and a layer 23 of molten slag on
the metal layer 22.
The term "metal layer" is understood herein to
mean that region of the bath that is predominantly metal.
The space above the nominal quiescent surface of
the molten bath is hereinafter referred to as the "top
space".
The arrow marked by the numeral 24 indicates the
position of the nominal quiescent surface of the metal
layer 22 and the arrow marked by the numeral 25 indicates
the position of the nominal quiescent surface of the slag
layer 23 (ie of the molten bath).
The term "quiescent surface" is understood to
mean the surface when there is no injection of gas and
solids into the vessel.
The vessel is fitted with a downwardly extending
hot air injection lance 26 for delivering a hot air blast
into an upper region of the vessel and post-combusting
reaction gases released from the molten bath. The lance 26
has an outer diameter D at a lower end of the lance. The
lance 26 is located so that:
(i) a central axis of the lance 26 is at an
angle of 20 to 90° relative to a

horizontal axis (the lance 26 shown in
Figure 1 is at an angle of 90°);
(ii) the lance 26 extends into the vessel a
distance that is at least the outer
diameter D of the lower end of the lance;
and
(iii) the lower end of the lance 26 is at least
3 times the outer diameter D of the lower
end of the lance above the quiescent
surface 25 of the molten bath.
The vessel is also fitted with solids injection
lances 27 (two shown) extending downwardly and inwardly
through the side walls 14 and into the molten bath with
outlet ends 82 of the lances 27 at an angle of 20-70° to
the horizontal for injecting iron ore, solid carbonaceous
material, and fluxes entrained in an oxygen-deficient
carrier gas into the molten bath. The position of the
lances 27 is selected so that their outlet ends 82 are
above the quiescent surface 24 of the metal layer 22. This
position of the lances 27 reduces the risk of damage
through contact with molten metal and also makes it
possible to cool the lances 27 by forced internal water
cooling without significant risk of water coming into
contact with the molten metal in the vessel. Specif icallyy
the position of the lances 27 is selected so that the
outlet ends 82 are in the range of 150-1500mm above the
quiescent surface 24 of the metal layer 22. In this
connection, it is noted that, whilst the lances 27 are
shown in Figure 1 as extending into the vessel, the outlet
ends of the lances 27 may be flush with the side wall 14.
The lances 27 are described in more detail with reference
to Figures 2-5.
In use, iron ore, solid carbonaceous material

(typically coal), and fluxes (typically lime and magnesia)
entrained in a carrier gas (typically N2) are injected into
the molten bath via the lances 27 at a velocity of at least
40 m/s, preferably 80-100 m/s. The momentum of the solid
material/carrier gas causes the solid material and gas to
penetrate to a lower region of the molten bath. The coal
is devolatilised and thereby produces gas in the lower bath
region. Carbon partially dissolves into the metal and
partially remains as solid carbon. The iron ore is smelted
to metal and the smelting reaction generates carbon
monoxide gas. The gases transported into the lower bath
region and generated via devolatilisation and smelting
produce significant buoyancy uplift of molten metal, solid
carbon, and slag (drawn into the lower bath region as a
conse region which generates an upward movement of splashes,
droplets and streams of molten metal and slag, and these
splashes, and droplets, and streams entrain slag as they
move through an upper region of the molten bath. The gas
flow generated by the above-described injection of carrier
gas and bath reactions is at least 0.04Nm3/s/m2 of the
quiescent surface of the molten bath (ie the surface 25) .
The buoyancy uplift of molten metal, solid carbon
and slag causes substantial agitation in the molten bath,
with the result that the molten bath expands in volume and
forms an expanded molten bath zone 28 that has a surface
indicated by the arrow 30. The extent of agitation is such
that there is substantial movement of molten material
within the molten bath (including movement of molten
material into and from the lower bath region) and strong
mixing of the molten bath to the extent that there is
reasonably uniform temperature throughout the molten bath -
typically, 1450 - 1550°C with a temperature variation of
the order of 3 0° in each region.
In addition, the upward gas flow projects some

molten material (predominantly slag) beyond the expanded
molten bath zone 28 and onto the part of the upper barrel
section of the side walls 14 that is above the expanded
molten bath zone 28 and onto the roof 17.
In general terms, the expanded molten bath zone
28 is a liquid continuous volume, with gas bubbles therein..
In addition to the above, in use, hot air at a
temperature of 800-1400°C is discharged at a velocity of
200-600 m/s via lance 26 and penetrates the central region
of the expanded molten bath zone 28 and causes an
essentially metal/slag free space 29 to form around the end
of the lance 26.
The hot air blast via the lance 26 post-combusts
reaction gases CO and H2 in the expanded molten bath zone
28 and in the free space 29 around the end of the lance 26
and generates high temperatures of the order of 2000°C or
higher in the gas space. The heat is transferred to the
ascending and descending splashes droplets, and streams, of
molten material in the region of gas injection and the heat
is then partially transferred throughout the molten bath.
The free space 29 is important to achieving high
levels of post combustion because it enables entrainment of
gases in the space above the expanded molten bath zone 28
into the end region of the lance 26 and thereby increases
exposure of available reaction gases to post combustion.
The combined effect of the position of the lance
26, gas flow rate through the lance 26, and upward movement
of splashes, droplets and streams of molten material is to
shape the expanded molten bath zone 28 around the lower
region of the lance 26. This shaped region provides a
partial barrier to heat transfer by radiation to the side
walls 14.

Moreover, the ascending and descending droplets,
splashes and streams of molten material is an effective
means of transferring heat from the expanded molten bath
zone 28 to the molten bath with the result that the
temperature of the zone 28 in the region of the side walls
14 is of the order of 1450°C-1550°C.
The construction of the solids injection lances
is illustrated in Figures 2 to 5.
As shown in these figures, each lance 27
comprises a central core tube 31 through which to deliver
the solids material and an annular cooling jacket 32
surrounding the central core tube 31 throughout a
substantial part of its length. Central core tube 31 is
formed of carbon/alloy steel tubing 33 throughout most of
its length, but a stainless steel section 34 at its forward
end projects as a nozzle from the forward end of cooling
jacket 32. The forward end part 34 of core tube 31 is
connected to the carbon/alloy steel section 33 of the core
tube through a short steel adaptor section 35 which is
welded to the stainless steel section 34 and connected to
the carbon/alloy steel section through a screw thread 36.
Central core tube 31 is internally lined through
to the forward end part 34 with a thin ceramic lining 37
formed by a series of cast ceramic tubes. The rear end of
the central core tube 31 is connected through a coupling 38
to a T-piece 39 through which particulate solids material
is delivered in a pressurised fluidising gas carrier, for
example nitrogen.
Annular cooling jacket 32 comprises a long hollow
annular structure 41 comprised of outer and inner tubes 42,
43 interconnected by a front end connector piece 44 and an
elongate tubular structure 45 which is disposed within the

hollow annular structure 41 so as to divide the interior of
structure 41 into an inner elongate annular water flow
passage 46 and an outer elongate annular water flow passage
47. Elongate tubular structure 45 is formed by a long
carbon steel tube 48 welded to a machined carbon steel
forward end piece 49 which fits within the front end
connector 44 of the hollow tubular structure 41 to form an
annular end flow passage 51 which interconnects the forward
ends of the inner and outer water flow passages 46, 47.
The rear end of annular cooling jacket 32 is
provided with a water inlet 52 through which the flow of
cooling water can be directed into the inner annular water
flow passage 46 and a water outlet 53 from which water is
extracted from the outer annular passage 47 at the rear end
of the lance. Accordingly, in use of the lance cooling
water flows forwardly down the lance through the inner
annular water flow passage 46 then outwardly and back
around the forward annular end passage 51 into the outer
annular passage 47 through which it flows backwardly along
the lance and out through the outlet 53. This ensures that
the coolest water is in heat transfer relationship with the
incoming solids material to ensure that this material does
not melt or burn before it discharges from the forward end
of the lance and enables effective cooling of both the
solids material being injected through the central core of
the lance as well as effective cooling of the forward end
and outer surfaces of the lance.
The outer surfaces of the tube 42 and front end
piece 44 of the hollow annular structure 41 are machined
with a regular pattern of rectangular projecting bosses 54
each having an undercut or dove tail cross-section so that
the bosses are of outwardly diverging formation and serve
as keying formations for solidification of slag on the
outer surfaces of the lance. Solidification of slag on to
the lance assists in minimising the temperatures in the

A DIRECT SMELTING PROCESS AND APPARATUS
The present invention relates to a process and an
apparatus for producing molten metal (which term includes
metal alloys), in particular although by no means
exclusively iron, from ferrous material, such as ores,
partly reduced ores and metal-containing waste streams.
The present invention relates particularly to a
molten metal bath-based direct smelting process and an
apparatus for producing molten metal from a ferrous
material.
One known molten bath-based direct smelting
process for producing molten ferrous metal is the DIOS
process. The DIOS process includes a pre-reduction stage
and a smelt reduction stage. In the DIOS process ore (-
8mm) is pre-heated (750°C) and pre-reduced (10 to 30%) in
fluidised beds using offgas from a smelt reduction vessel
which contains a molten bath of metal and slag, with the
slag forming a deep layer on the metal. The fine (-3mm)
and coarse (-8mm) components of the ore are separated in
the pre-reduction stage of the process. Coal and pre-
heated and pre-reduced ore (via two feed lines) are fed
continuously into the smelt reduction furnace from the top
of the furnace. The ore dissolves and forms FeO in the
deep layer of slag and the coal decomposes into char and
volatile matter in the slag layer. Oxygen is blown through,
a specially designed lance that improves secondary
combustion in the foamed slag. Oxygen jets burn carbon
monoxide that is generated with the smelting reduction
reactions, thereby generating heat that is transferred to
the molten slag. The FeO is reduced at the slag/metal and
slag/char interfaces. Stirring gas introduced into the hot
metal bath from the bottom of the smelt reduction vessel
improves heat transfer efficiency and increases the
slag/metal interface for reduction. Slag and metal are

metal components of the lance. It has been found in use
that slag freezing on the forward or tip end of the lance
serves as a base for formation of an extended pipe of solid
material serving as an extension of the lance which further
protects exposure of the metal components of the lance to
the severe operating conditions within the vessel.
It has been found that it is very important to
cooling of the tip end of the lance to maintain a high
water flow velocity around the annular end flow passage 51.
In particular it is most desirable to maintain a water flow
velocity in this region of the order of 10 meters per
second to obtain maximum heat transfer. In order to
maximise the water flow rate in this region, the effective
cross-section for water flow through passage 51 is
significantly reduced below the effective cross-section of
both the inner annular water flow passage 46 and the outer
water flow passage 47. Forward end piece 49 of the inner
tubular structure 45 is shaped and positioned so that water
flowing from the forward end of inner annular passage 46
passes through an inwardly reducing or tapered nozzle flow
passage section 61 to minimise eddies and losses before
passing into the end flow passage 51. The end flow passage
51 also reduces in effective flow area in the direction of
water flow so as to maintain the increased water flow
velocity around the bend in the passage and back to the
outer annular water flow passage 47. In this manner, it is
possible to achieve the necessary high water flow rates in
the tip region of the cooling jacket without excessive
pressure drops and the risk of blockages in other parts of
the lance.
In order to maintain the appropriate cooling
water velocity around the tip end passage 51 and to
minimise heat transfer fluctuations, it is critically
important to maintain a constant controlled spacing between.
the front end piece 49 tubular structure 45 and the end

piece 44 of the hollow annular structure 41. This presents
a problem due to differential thermal expansion and
contraction in the components of the lance. In particular,
the outer tube part 42 of hollow annular structure 41 is
exposed to much higher temperatures than the inner tube
part 43 of that structure and the forward end of that
structure therefore tends to roll forwardly in the manner
indicated by the dotted line 62 in Figure 4. This produces
a tendency for the gap between components 44, 49 defining
the passage 51 to open when the lance is exposed to the
operating conditions within the smelting vessel.
Conversely, the passage can tend to close if there is a
drop in temperature during operation. in order to overcome
this problem the rear end of the inner tube 43 of hollow
annular structure 41 is supported in a sliding mounting 63
so that it can move axially relative to the outer tube 42
of that structure, the rear end of inner tubular structure
45 is also mounted in a sliding mounting 64 and is
connected to the inner tube 43 of structure 41 by a series
of circumferentially spaced connector cleats 65 so that the
tubes 43 and 45 can move axially together. In addition,
the end pieces 44, 49 of the hollow annular structure 41
and tubular structure 45 are positively interconnected by a
series of circumf erentially spaced dowels 70 to maintain
the appropriate spacing under both thermal expansion and
contraction movements of the lance jacket.
The sliding mounting 64 for the inner end of
tubular structure 45 is provided by a ring 66 attached to a
water flow manifold structure 68 which defines the water
inlet 52 and outlet 53 and is sealed by an 0-ring seal 69.
The sliding mounting 63 for the rear end of the inner tube
43 of structure 41 is similarly provided by a ring flange
71 fastened to the water manifold structure 68 and is
sealed by an O-ring seal 72. An annular piston 73 is
located within ring flange 71 and connected by a screw
thread connection 80 to the back end of the inner tube 43

of structure 41 so as to close a water inlet manifold
chamber 74 which receives the incoming flow of cooling from
inlet 52. Piston 73 slides within hardened surfaces on
ring flange 71 and is fitted with O-rings 81, 82. The
sliding seal provided by piston 73 not only allows
movements of the inner tube 43 due to differential thermal
expansion of structure 41 but it also allows movement of
tube 43 to accommodate any movement of structure 41
generated by excessive water pressure in the cooling
jacket. If for any reason the pressure of the cooling
water flow becomes excessive, the outer tube of structure
41 will be forced outwardly and piston 73 allows the inner
tube to move accordingly to relieve the pressure build up.
An interior space 75 between the piston 73 and the ring
flange 71 is vented through a vent hole 7 6 to allow
movement of the piston and escape of water leaking past the
piston.
The rear part of annular cooling jacket 32 is
provided with an outer stiffening pipe 83 part way down the
lance and defining an annular cooling water passage 84
through which a separate flow of cooling water is passed
via a water inlet 85 and water outlet 86.
Typically cooling water will be passed through
the cooling jacket at a flow rate of lOOmVhr at a maximum
operating pressure of 800kPa to produce water flow
velocities of 10 meters/minute in the tip region of the
jacket. The inner and outer parts of the cooling jacket
can be subjected to temperature differentials of the order
of 200°C and the movement of tubes 42 and 45 within the
sliding mountings 63, 64 can be considerable during
operation of the lance, but the effective cross-sectional
flow area of the end passage 51 is maintained substantially
constant throughout all operating conditions.
It is to be understood that this invention is in

no way limited to the details of the illustrated
construction and that many modifications and variations
will fall within the spirit and scope of the invention.
In that regard it is noted that the oxygen gas
injection lance can be integral with and form part of the
upper body of a solids injections lance.

WE CLAIM :
1. A direct smelting process for producing metals
(which term includes metal alloys) from a ferrous material
said process comprises the steps of :
(a) forming a bath of molten metal and molten
slag in a metallurgical vessel;
(b) injecting feed materials being solid
material and carrier gas into the molten
bath at a velocity of at least 40m/s through
a downwardly extending solids injection
lance having a delivery tube of internal
diameter of 40-200mm that is located so that
a central axis of an outlet end of the lance
is at an angle of 20 to 90 degrees to a
horizontal axis and generating a superficial
gas flow of at least 0.04 Nm3/s/m2 within
the molten bath (where m2 relates to the
area of a horizontal cross-section through
the molten bath) at least in part by
reactions of injected material in the bath
which causes molten material to be projected
upwardly as splashes, droplets and streams
and form an expanded molten bath zone, the
gas flow and the upwardly projected molten
material causing substantial movement of
material within the molten bath and strong
mixing of the molten bath, the feed
materials being selected so that, in an
overall sense, the reactions of the feed
materials in the molten bath are
endothermic; and
(c) injecting an oxygen-containing gas into an
upper region of the vessel via at least one

oxygen gas injection lance and post-
combusting combustible gases released from
the molten bath, whereby ascending and
thereafter descending molten material in the
expanded molten bath zone facilitate heat
transfer to the molten bath.
2. The process as claimed in claim 1, wherein step (b)
comprises injecting feed materials into the molten bath so
that the feed materials penetrate a lower region of the
molten bath.
3. The process as claimed in claim 1, or claim 2 wherein
step (b) comprises injecting feed materials into the molten
bath via the lance at a velocity in the range of 80-100 m/s.
i i
4. The The process as claimed in claim 3, wherein step (b)
comprises injecting feed materials into the molten bath via
the lance at a mass flow rate of up to 2.0 t/m3/s where m2
relates to the cross-sectional area of the lance delivery
tube.
5. The process as claimed in any one of the preceding
claims wherein step (b) comprises injecting feed materials
into the molten bath via the lance at a solids/gas ratio of
10-25 kg solids/Nm3 gas.
6. The process as claimed in claim 5, wherein the
solids/gas ratio is 10-18 kg solids /Nm3 gas.
7- The process as claimed in any one of the preceding
claims wherein step (b) comprises injecting feed materials
through a plurality of solids injection lances and
generating the gas flow of at least 0.04 Nm3/s/m3 within
the molten bath.

8. The process as claimed in any one of the preceding
claims wherein the gas flow within the molten bath
generated in step (b) is at least 0.04Nm3/s/m2 at the
nominal quiescent surface of the molten bath.
9. The process as claimed in claim 8, wherein the gas
flow within the molten bath is at a flow rate of at least
0.2 Nm3/s/m2.
10. The process as claimed in claim 9, wherein the gas
flow rate is at least 0.3 Nm3/s/m2.

11. The process as claimed in any one of the preceding
claims wherein the gas flow within the molten bath
generated in step (b) is less than 2 Nm3/s/m2.
12. The process as claimed in any one of the preceding
claims wherein the oxygen-containing gas injected into the
molten bath in step (c) is air or oxygen-enriched air.
13. The process as claimed in claim 12, wherein step (c)
comprises injecting the air or oxygen-enriched air into the
vessel at a temperature of 800-1400°C and at a velocity of
200-600 m/s via at least one oxygen gas injection lance and
forcing the expanded molten bath zone in the region of the
lower end of the lance away from the lance and forming a
"free" space around the lower end of the lance that has a
concentration of molten material that is lower than the
molten material concentration in the expanded molten bath
zone; the lance being located so that: (i) a central axis
of the lance is at an angle of 20 to 90° relative to a
horizontal axis; (ii) the lance extends into the vessel a
distance that is at least the outer diameter of the lower
end of the lance; and (iii) the lower end of the lance is
at least 3 times the outer diameter of the lower end of the
lance above the quiescent surface of the molten bath.

14. The process as claimed in any one of the preceding
claims wherein step (c) includes injecting oxygen-
containing gas into the vessel in a swirling motion.
15. The process as claimed in any one of the preceding
claims comprises controlling the level of dissolved carbon
in molten iron to be at least 3 wt% and maintaining the
slag in a strongly reducing condition leading to FeO levels
of less than 6 wt%, more preferably less than 5 wt%, in the
slag.
16. The process as claimed in any one of the preceding
claims comprises causing molten material to be projected
into- a top space above the expanded molten bath zone.
17. The process as claimed in any one of the preceding
claims wherein step (c) comprises post-combusting
combustible gasses so that the level of post-combustion is
at least 40%, where post-combustion is defined as:

where:
[COa] = volume % of CO2 in off-gas
[H2O] = volume % of H2O in off-gas
[CO] = volume % of CO in off-gas
[H2] = volume % of H2 in off-gas
18. An apparatus for producing metal from a ferrous
material by a direct smelting process, which apparatus
comprises a fixed non-tiltable vessel that contains a molten
bath of metal and slag and includes a lower region and an
expanded molten bath zone above the lower region, the
expanded molten bath zone being formed by gas flow from the
lower region which carries molten material upwardly from

the lower region, said vessel comprises :
(a) a hearth formed of refractory material
having a base and sides in contact with the
lower region of the molten bath;
(b) side walls extending upwardly from the sides;
of the hearth and being in contact with an
upper region of the molten bath and the gas
continuous space, wherein the side walls
that contact the gas continuous space
include water cooled panels and a layer of
slag on the panels;
(c) at least one lance extending downwardly into
the vessel and injecting oxygen-containing
gas into the vessel above the molten bath;
(d) at least one lance injecting feed materials
being ferrous material and/or carbonaceous
material and carrier gas into the molten
bath at a velocity of at least 40 m/s, the :
lance being located so that a central axis
of an outlet end of the lance is angled
downwardly at an angle of 20 to 90° to a
horizontal axis, the lance having a delivery
tube for injecting feed materials which has
an internal diameter of 40-200mm : and
(e) a means for tapping molten metal and slag
from the vessel.
19. The apparatus as claimed in claim 18, wherein the
feed materials injection lance is located so that the
outlet end of the lance is 150-1500mm above the nominal
quiescent surface of a metal layer of the molten bath.

ABSTRACT

A DIRECT SMELTING PROCESS AND APPARATUS
A molten-bath based direct smelting process and apparatus is disclosed.
The process comprises injecting feed materials into a molten bath at a velocity of
at least 40m/s through at least one solids injection lance (27) having a delivery
tube of internal diameter of 40-200mm that is located so that a central axis of an
outlet end of the lance is at an angle of 20 to 90 degrees to a horizontal axis.
The feed materials injection generates a superficial gas flow of at least 0.04
Nm3/s/m2 within the molten bath. The gas flow causes molten material to be
projected upwardly as splashes, droplets and streams and form an expanded
molten bath zone, with the gas flow and the upwardly projected molten material
causing strong mixing of the molten bath. The process also comprises injecting
an oxygen-containing gas into an upper region of the vessel to post-combust
gases released from the molten bath.

A DIRECT SMELTING PROCESS AND APPARATUS

Documents:

Inventors:

PCT Conventions: