EP1749109B1 - Raffinage de metal en fusion - Google Patents

Raffinage de metal en fusion Download PDF

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Publication number
EP1749109B1
EP1749109B1 EP05744383A EP05744383A EP1749109B1 EP 1749109 B1 EP1749109 B1 EP 1749109B1 EP 05744383 A EP05744383 A EP 05744383A EP 05744383 A EP05744383 A EP 05744383A EP 1749109 B1 EP1749109 B1 EP 1749109B1
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EP
European Patent Office
Prior art keywords
oxygen
primary
molten metal
jet
lance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Not-in-force
Application number
EP05744383A
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German (de)
English (en)
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EP1749109A2 (fr
Inventor
Andrew Miller Cameron
Andrew Peter Richardson
John Kelvin Batham
Mark A. Wilkinson
Michael James Strelbisky
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Messer LLC
Original Assignee
Linde Inc
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Filing date
Publication date
Priority claimed from GB0410835A external-priority patent/GB0410835D0/en
Priority claimed from GB0425540A external-priority patent/GB0425540D0/en
Application filed by Linde Inc filed Critical Linde Inc
Publication of EP1749109A2 publication Critical patent/EP1749109A2/fr
Application granted granted Critical
Publication of EP1749109B1 publication Critical patent/EP1749109B1/fr
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/30—Regulating or controlling the blowing
    • C21C5/32—Blowing from above
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C21C5/4606—Lances or injectors

Definitions

  • This invention relates to a method of refining molten metal.
  • BOS Basic Oxygen Steelmaking
  • the oxygen reacts with carbon that is found in dissolved form in the molten metal to form carbon monoxide.
  • the oxygen reacts with impurities or minor components of the molten metal (for example, silicon) so as to form a slag on the surface of the molten metal.
  • the reaction between oxygen and, say, carbon in the molten metal is not rate limited. It is therefore desirable to maximise the rate at which the oxygen is introduced into the molten metal. Practical issues do, however, limit this rate.
  • One of these issues is the degree of turbulence caused by the introduction of the oxygen into the molten metal. If there is excessive splashing of molten metal, it is believed that wear of the lance through which the oxygen is blown may become excessive resulting in a need to replace the head of the lance so frequently that the economical manufacture of the metal is prejudiced. Excessive splashing of the molten metal may also cause it to be ejected from the vessel giving rise to loss of yield and an increased need for maintenance of downstream equipment. On the other hand, in order to facilitate reaction between oxygen and carbon it is desirable that there is a certain amount of turbulence in the molten metal particularly during the latter stages, typically the last 20% of the blow, when mass transfer limitations can be encountered.
  • EP-A-866 138 and EP-A-866 139 propose that a jet of oxygen as it travels through a stationary atmosphere tends to entrain the stationary atmosphere into it. This entrainment has the effect of reducing the velocity and the thrust of the oxygen jet. It is postulated that as a result of the entrainment the lance head has to be positioned closer to the surface of the molten metal than is ideal, therefore making it more vulnerable to damage by the splashing molten metal.
  • EP-A-866 138 and EP-A-866 139 propose that the lance head is in effect converted into a burner.
  • the secondary flame envelope is formed by ejecting a fuel gas (or liquid fuel) and secondary oxygen from the lance head.
  • the fuel gas and secondary oxygen mix to form a flame.
  • the flame envelope is stated to prevent entrainment of stationary atmosphere into the oxygen jet. Therefore, so it is explained, the oxygen jet does not diverge or lose velocity in the way it would were there to be no flame envelope. Accordingly, the oxygen jet is able to penetrate well beneath the surface of the molten metal, thereby facilitating its reaction with carbon dissolved in the molten metal. Further, the lance head can be readily positioned sufficiently above the molten metal that its rate of wear can be kept to acceptable levels.
  • the formation of the flame envelope has one substantial disadvantage, namely the fuel gas or liquid fuel has to be supplied to the overhead lance.
  • the degree of disadvantage may vary from metal melting or refining process to metal melting or refining process.
  • the BOS process the disadvantage is quite substantial because the teachings of EP-A-866 138 and EP-A-866 139 require an overhead fuel supply to be laid on specially for the creation of the flame envelope.
  • the engineering difficulties of doing this are considerable, particularly as the lance normally has to be manipulated between upper and lower positions.
  • the likelihood of hydrogen pick-up by the molten metal is significantly increased and for many grades of steel is unacceptable.
  • US4 396 182 discloses a lance for blowing an oxidising gas onto a bath of molten metal, in which the lance has a set of primary oxygen ports 3 and a set of secondary oxygen ports 6. It is not agreed, however, that entrainment of this secondary jet into the primary jet is disclosed.
  • the main idea on which the invention is based is to create of the outlet of lance a continuous sheet of oxygen [from the secondary jets] which expands in the form of an "umbrella" around the principle jets while being directed toward the bath.
  • JP-A-08-246017 discloses a lance head having an axial oxygen port 1 surrounded by a series of secondary oxygen ports 4.
  • the general arrangement appears to be similar to those of US 4 396 182 , in particular, and there is no disclosure of entraining oxygen from the port 3 into oxygen from the ports 4, or vice versa.
  • US6 432 163 B1 relates to an improvement or modification of the apparatus disclosed in EP-A-866 138 .
  • D5 discloses a lance with central primary oxygen nozzles 5. There is a first ring 8 of secondary nozzles surrounding the primary nozzles 5 and a third ring 9 of tertiary oxygen nozzles outside the ring 8 of secondary nozzles.
  • fuel may be passed through the secondary nozzles. This fuel mixes with the tertiary oxygen and forms a flame shroud or envelope which surrounds the primary oxygen jets.
  • the flame shroud or envelope serves the same purpose as that in EP-A-866138 , namely to prevent entrainment of surrounding atmosphere into the primary jets.
  • the method according to the invention can be operated so as to decrease the time taken to reduce the carbon content of a given volume of molten metal. It is further believed that this result can be achieved without increasing the initial pressure, velocity and flow of the primary oxygen, thereby keeping down the risk of increasing the rate of erosion or damage to the lance head, in comparison with that usually experienced in conventional methods. Increased pressure, velocity and flow of the primary oxygen can also cause ejection of some molten metal and slag from the vessel with attendant loss of yield and maintenance issues.
  • the method and lance head according to the invention also offer the advantage that no fuel is supplied to the lance head, thereby avoiding the need for an overhead fuel supply, such an overhead fuel supply being required for the formation of the shrouded gas jets described in EP-A-866 138 and EP-A-866 139 .
  • the method and lance head according to the invention are particularly intended for use in the Basic Oxygen Steelmaking (BOS) process, but are also applicable to some other steelmaking processes and some processes for refining non-ferrous metals.
  • BOS Basic Oxygen Steelmaking
  • the said primary jet of oxygen is desirably ejected from the lance in both step (a) and step (b) of the method according to the invention at an axial velocity that is supersonic.
  • a supersonic velocity in the range of Mach 1.5 to Mach 3 may be used.
  • each secondary oxygen jet In order to achieve entrainment of each secondary oxygen jet at a suitable intermediate location of its associated primary jet, the longitudinal axis of each secondary jet diverges from the longitudinal axis of its associated primary jet in the direction of travel at an angle of 5° to 25°.
  • each secondary oxygen jet from its associated primary oxygen jet is in the range of 5° to 25° depending on the absolute velocity of the second oxygen jet and its velocity relative to the first oxygen jet. Preferred angles of divergence are in the range of 10° to 20°.
  • secondary oxygen jets typically, from two to eight secondary oxygen jets are used, with from two to six being preferred.
  • the exact number of secondary ports may be selected in accordance with the desired ratio of primary oxygen to secondary oxygen flow.
  • the secondary oxygen flow may be up to 50% of the primary oxygen flow and up to twelve secondary ports may be used. Normally the secondary oxygen flow is from 5 to 50% of the primary oxygen flow.
  • each secondary oxygen port from its associated primary oxygen port is typically less than twice the diameter of the primary oxygen port.
  • Each secondary oxygen jet is preferably thinner than the primary oxygen jet.
  • the individual secondary oxygen jets preferably travel separately from one another to their entrainment in the primary jet of oxygen.
  • the head of the lance is typically immersed in the slag layer during the said step (b).
  • each primary oxygen jet and its associated secondary oxygen jets may be such that any or all of the typical or preferred features described above may be employed.
  • a plurality of primary oxygen jets is employed. They typically issue from primary oxygen ports that are arranged generally circumferentially (or on the perimeter of another closed geometric figure).
  • the secondary oxygen ports are typically arranged outside the primary oxygen ports.
  • Each primary oxygen port has a group of secondary oxygen ports associated with it and each group of secondary oxygen ports is arranged on the arc of a circle that is concentric with the primary oxygen port with which said group is associated.
  • the angle subtended by the arc is normally less than 180°.
  • each primary oxygen port is in the form of a convergent-divergent nozzle and each oxygen jet is emitted from the tip of the lance head.
  • Lance heads according to the invention generally have passages for the flow of a coolant, for example, water.
  • all the primary and secondary oxygen ports communicate with a common chamber in the lance head.
  • Such embodiments offer the advantage of mechanical simplicity.
  • the or each primary oxygen port communicates with a chamber in the lance head that does not communicate with the secondary oxygen ports.
  • the primary jet is preferably formed by premixing the stirring gas with the oxygen.
  • the stirring gas is preferably a noble gas, particularly argon.
  • nitrogen may be tolerated as the stirring gas provided it does not have a deleterious effect on the steel.
  • the said primary jet of oxygen may have the same composition throughout a heat. Alternatively its composition can be varied, being increased at one or more instants during a heat. Indeed, there may be during an initial period no deliberate addition of stirring gas. (Some argon will always be present as an impurity in the oxygen.)
  • the need for stirring is usually greatest towards the end of a heat and therefore the mole fraction of stirring gas in the primary jet is preferably greater in the last part (typically the last fifth) of the heat than in the first half of the heat. Indeed, it is possible to continue the supply of stirring gas after the supply of oxygen has been discontinued.
  • BOS Basic Oxygen Steelmaking
  • the vessel 102 has a refractory lining (not shown).
  • the vessel is charged with a batch of molten iron.
  • This volume of molten iron is shown by the reference numeral 106 in Figure 1 .
  • the molten iron is refined by reaction with oxygen.
  • the oxygen is supplied through a vertical lance 110 having a head 112.
  • the lance 110 is typically made of stainless steel and has a plurality of primary ports 114 in its head 112 for the discharge of oxygen.
  • the ports 114 communicate with an oxygen passage 115 through the lance 110.
  • the lance 110 and head 112 are also provided with passages 116 for the flow of a coolant (typically, water) to protect it against catastrophic damage in the hot environment of the BOS vessel 102.
  • the lance 110 is also associated with a lance manipulator (not shown) which is able to raise and lower the lance 110. In typical practice, the lance 110 is operated in two positions.
  • the method according to the invention may equally be used with a lance whose position is controlled dynamically in response to decarburisation rate and other factors. Such dynamic control is well known in the art.
  • the refining of the molten iron commences with the supply of oxygen from the lance head 112 in a soft blowing position.
  • the oxygen is ejected from the head 112 at a supersonic velocity, typically in the range of Mach 1.5 to 3.
  • the oxygen is typically supplied to the lance head at a temperature in the range of 0°C to 50°C. There is no need to preheat the oxygen, but a small amount of incidental preheating may take place as the ambient environmental of a BOS vessel is usually at a substantially higher temperature than normal room temperature.
  • the oxygen is also typically supplied at a pressure in the range of 5 bar to 20 bar so as to enable it to be ejected from the lance head at a supersonic velocity.
  • the primary oxygen penetrates the surface of the molten metal 106 and reacts with carbon and other impurities such as silicon and phosphorus therein.
  • the chemistry of steelmaking is well known and need not be described in detail herein. Suffice it to say that the dissolved carbon in the bath of molten metal has a high affinity for oxygen and reacts rapidly with it to form carbon monoxide, while other impurities react with the oxygen to form a molten slag which, being lighter than the molten ferrous metal, rises to the surface to form a molten slag layer.
  • the velocity of the primary oxygen is such as to cause agitation of the molten metal and there is typically a degree of turbulence at its surface.
  • the slag layer 118 will also be turbulent and will contain a considerable volume of carbon monoxide bubbles as a result of the reaction between the carbon dissolved in the molten ferrous metal and the oxygen.
  • the lance 110 is thus lowered into its hard blowing position with the head 112 immersed in the molten slag 118. (It is this position which is illustrated in Figure 1 .)
  • the primary oxygen is supplied at a supersonic ejection velocity during the hard blowing stage.
  • secondary oxygen is also supplied. If desired, or as an inevitable consequence of the configuration of the lance head, the secondary oxygen may be supplied during the soft blowing phase and may then help to form the slag.
  • the primary oxygen flow rate and velocity may be increased from the soft blowing phase to the hard blowing phase.
  • a plurality of primary oxygen jets is employed and each is associated with a plurality of secondary oxygen jets.
  • One such primary oxygen jet 120 is illustrated schematically in Figure 1 .
  • the primary oxygen jets 120 diverge in the direction of flow of oxygen.
  • Two secondary oxygen jets 122 are shown in Figure 1 .
  • the secondary oxygen jets 122 travel separately from one another. They diverge from the primary oxygen jets 120.
  • the angle of divergence depends on the absolute and relative velocities of the primary and secondary oxygen jets. In general, the lower the absolute and relative velocity of the secondary oxygen jets, the wider can be the angle of divergence.
  • the purpose of the angle of divergence is to ensure that most of the secondary jets are entrained back into the primary jets upstream of the surface of the molten metal.
  • the time taken to reduce the carbon level in the molten metal to a given value is dependent upon the rate at which oxidant molecules are brought into contact with dissolved carbon molecules. Enhancing the rate at which oxidant molecules come into intimate contact with the dissolved carbon reduces the refining time. Accordingly, there are advantages to be had in employing a sizeable quantity of secondary oxidant.
  • the rate of flow of secondary oxidant can be up to 50% of the rate of flow of primary oxidant.
  • the primary oxygen and the secondary oxygen flow via the same chamber in the lance head, there is no freedom in setting the secondary oxygen jet velocity independently of the primary jet velocity; it tends to be a little less than the primary oxygen jet velocity, there being greater "frictional losses" associated with the secondary jets because they are normally generated from thinner passages than the primary jets.
  • the secondary jets would typically exit the secondary passages at sonic velocities but in an underexpanded condition, leading to an immediate strong shock to supersonic flow conditions and a series of shock waves dissipating the kinetic energy of the jets.
  • the secondary oxygen comes from a separate source than the primary oxygen there is a much greater freedom to vary the secondary oxygen velocity.
  • a secondary oxygen velocity substantially less than the primary oxygen velocity facilitates entrainment of the secondary jets into the primary oxygen.
  • argon or other stirring gas may be added to the primary oxygen upstream of the lance 110.
  • the stirring gas is added at a rate up to or equal to that at which secondary oxygen is used.
  • the total flow of gas to the primary jets preferably remains unaltered throughout the hard blowing phase of a heat.
  • the stirring gas may be supplied at constant rate throughout a heat, or may be supplied towards the end of a heat when the level of dissolved carbon is approaching what is desired. Stirring gas may be substituted for some of the primary oxygen and supplied to the primary jets.
  • the supply of oxygen (both primary and secondary) and stirring gas may be stopped and the lance 110 withdrawn from the steelmaking vessel 102.
  • the molten metal may then be tapped off from the vessel 102 in a conventional manner.
  • the ability to select when and how much stirring gas to supply helps the steelmaker to optimise the steelmaking process.
  • the carbon levels are relatively high and the substitution of stirring gas for oxygen may simply retard the refining.
  • the addition of a stirring gas is believed to be beneficial.
  • first lance head 200 for use in the method according to the invention is illustrated in Figures 2 to 4 .
  • the lance head 200 has a nose 202 at its forward end or tip 204.
  • the nose 202 is surrounded by a sloping annular face 206 which has its inner circumferential edge more forward than its outer circumferential edge.
  • four primary oxygen ports 208 are formed in the annular face 206.
  • Each of the primary oxygen ports 208 has its axis normal to the face.
  • each of the primary oxygen ports 208 has an axis that diverges in the direction of oxygen flow from the longitudinal axis of the lance head 200 itself.
  • the angle of divergence is typically in the order of 5 to 15°.
  • the oxygen ports 208 are arranged circumferentially being equally spaced form one another. As a result of this arrangement the primary oxygen jets penetrate the surface of the molten metal at four different regions, thereby facilitating a good dispersal of the oxygen. If desired, fewer or more primary oxygen ports 208 than the four illustrated may be employed.
  • Each primary oxygen port 208 forms the termination of a convergent-divergent nozzle 210 formed through the lance head 200.
  • the nozzle 210 has an upstream convergent portion 212, an intermediate portion 214 of constant diameter and a divergent potion 216.
  • the convergent portion 212 communicates with an oxygen chamber 218 which is formed as an extension of the head 200.
  • the convergent-divergent nozzles 210 (sometimes referred to as Laval nozzles) are able to eject at supersonic velocity oxygen supplied at elevated pressure to the chamber 218.
  • the design of the convergent-divergent nozzles 210 is preferably such that the oxygen is perfectly expanded on exit from the primary oxygen ports 208.
  • Each primary oxygen port is associated with a plurality of secondary oxygen ports 220. As shown in Figure 2 , each primary oxygen port 208 is associated with two secondary oxygen ports 220. Each port 220 is formed in the annular face 206. The secondary ports 220 are all positioned intermediate the primary oxygen ports 208 and the outer circumferential edge of the annular face 206. Each secondary port 220 is of a considerably smaller diameter than the primary oxygen ports 208. Each secondary port 220 has an axis which in the direction of oxygen flow diverges from the corresponding axis of the primary oxygen port 208 with which it is associated. The angle of divergence may be up to 45° provided that the criteria discussed above with reference to Figure 1 are fulfilled. Typically, however, the angle of divergence is in the range of 5 to 25°, more typically in the range of 10 to 20°.
  • Each secondary oxygen port 220 is at the termination of a secondary oxygen passage 222.
  • the secondary oxygen passages 222 are each formed with an upstream leg 224 and a downstream leg 226.
  • the downstream leg 226 is preferably at an angle to the upstream leg 224.
  • Each upstream leg 224 communicates with the chamber 218.
  • the downstream legs 226 are of smaller diameter than the upstream legs 224. If desired, however, the opposite arrangement can be employed with the upstream legs 224 being of smaller diameter than the downstream legs 226. Such an arrangement may be used if lower secondary oxygen jet velocities are desired.
  • the passages 222 are typically all formed as bore and counterbore.
  • each primary oxygen port 208 is shown as associated with only two secondary oxygen ports 220. Typically, however, each primary oxygen port 208 is associated with a greater number than two of secondary oxygen ports 220. Thus, typically, each primary oxygen port 208 is associated with from two to eight secondary oxygen ports 220.
  • Each group of secondary oxygen ports 220 is preferably arranged on the circumference of a circle that is concentric with the axis of the associated primary oxygen port 208. The spacing of the secondary oxygen ports 220 is such that, in operation, the jets of oxygen that issue therefrom do not merge with one another.
  • Each group of secondary oxygen ports 220 is typically arranged so that the ports 220 do not extend around the entire circumference but instead subtend an arc that is less than 360° and normally less than 180°.
  • the head 200 is formed with an inner integral sleeve 228 and an outer integral sleeve 230 surrounding the oxygen chamber 218.
  • the sleeves 228 and 230 define passages for the flow of a coolant, normally water, through the lance head in its normal operation. These passages extend into the nose 202 of the lance 200.
  • the lance head 200 may simply be welded or otherwise fixed fluid tight to a lance (not shown in Figures 2 to 4 ) which has three concentric passages, an inner one being for oxygen and the two others for coolant. After use to refine a large number of batches of molten metal, it becomes necessary to replace the lance head 200. This may simply be done by cutting off the used head from the lance and welding on a new lance head.
  • the operation of the lance head shown in Figures 2 to 4 is essentially as described herein with reference to Figure 1 .
  • the secondary oxygen jets are entrained in each primary oxygen jet and, as discussed above, enhance the flow of decarburising agent that comes into intimate contact with the molten metal being refined. As a result, it is believed that the time taken to refine a given volume of molten metal of given composition may be reduced in comparison with conventional practice in which only primary jets of oxygen are used. Any combustion of the secondary oxygen that might take place as a result of entrainment of carbon monoxide into the secondary oxygen jets is incidental to the invention.
  • the secondary oxygen jets typically issue at sonic velocity and expand rapidly to supersonic velocity owing to the pressure of differential between their underexpanded exit condition and the ambient vessel pressure. This supersonic velocity may be less than that at which the primary oxygen jets are ejected as a result of "frictional" interaction between the flowing oxygen and the walls defining the secondary oxygen passages 222.
  • FIG. 5 and 6 An alternative embodiment of the lance head is shown in Figures 5 and 6 . Parts in Figures 5 and 6 that correspond to ones in Figures 2 to 4 are indicated by the same reference numerals as in Figures 2 to 4 .
  • the configuration and operation of the lance head shown in Figures 5 and 6 are very similar to the configuration and operation of that shown in Figures 2 to 4 .
  • the main difference between the two embodiments is that in the lance head shown in Figures 5 and 6 the secondary oxygen passages 222 communicate with an annular secondary oxygen chamber 300 that surrounds the chamber 218 and is coaxial therewith. As a result, the secondary oxygen may be ejected at a velocity independent of that at which the primary oxygen issues from the lance head.
  • the secondary oxygen may be ejected at a supersonic velocity greater than the primary oxygen velocity, a supersonic velocity less than the primary oxygen velocity, sonic velocity, or a subsonic velocity.
  • a subsonic secondary oxygen velocity is that it facilitates entrainment of the secondary oxygen jets into the primary oxygen.
  • the lance head can have at its proximal end apertures formed in the wall of an oxygen chamber so as to allow some of the oxygen to be ejected for the purpose of post-combustion of carbon monoxide at a region of the BOS vessel remote from the surface of the molten metal.
  • the lance head can have at its proximal end apertures formed in the wall of an oxygen chamber so as to allow some of the oxygen to be ejected for the purpose of post-combustion of carbon monoxide at a region of the BOS vessel remote from the surface of the molten metal.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Claims (5)

  1. Procédé de raffinage de métal en fusion dans une cuve par la réaction d'oxygène avec des impuretés dans le métal en fusion, dans lequel la cuve contient un volume du métal en fusion, comprenant les étapes suivantes:
    a) éjecter au moins un jet primaire d'oxygène à partir d'une lance qui est positionnée au-dessus du métal en fusion dans le métal en fusion pour la réaction avec des impuretés dans celui-ci et la formation d'une couche de laitier en fusion;
    b) continuer à éjecter le jet primaire d'oxygène à partir de la lance et entraîner ainsi le jet primaire d'oxygène à passer à travers la couche de laitier dans le métal en fusion;
    c) éjecter une pluralité de jets secondaires d'oxygène à partir de la lance, le jet secondaire d'oxygène parcourant une distance séparément du jet primaire d'oxygène; et
    d) entraîner les jets secondaires d'oxygène dans le jet primaire d'oxygène en amont de l'entrée du jet primaire d'oxygène dans le volume de métal en fusion,
    dans lequel la lance comprend une tête qui présente au moins une sortie d'oxygène primaire et une pluralité de sorties d'oxygène secondaires, chaque sortie d'oxygène secondaire étant associée à la sortie d'oxygène primaire ou à l'une des sorties d'oxygène primaires et présentant un axe qui diverge dans la direction d'écoulement de sa sortie d'oxygène primaire associée d'un angle de 5° à 25°, l'angle de divergence assurant que la plupart des jets secondaires sont entraînés à revenir dans les jets primaires en amont de la surface du métal en fusion, dans lequel il y a une pluralité de sorties d'oxygène primaires et un groupe de deux à huit sorties d'oxygène secondaires associées à chaque sortie d'oxygène primaire, et
    dans lequel chaque groupe de sorties d'oxygène secondaires est agencé sur un arc d'un cercle qui est concentrique à la sortie d'oxygène primaire à laquelle ledit groupe est associé.
  2. Procédé selon la revendication 1, dans lequel, à l'étape (b), ledit jet primaire d'oxygène est éjecté à une vitesse axiale supersonique qui est comprise dans la gamme de Mach 1,5 à Mach 3.
  3. Procédé selon la revendication 1 ou la revendication 2, dans lequel l'axe longitudinal de chaque jet secondaire diverge de l'axe longitudinal de son jet primaire associé dans la direction de déplacement d'un angle de 10° à 20°.
  4. Procédé selon l'une quelconque des revendications précédentes, dans lequel le flux secondaire d'oxygène équivaut à 5 % à 50 % du flux primaire d'oxygène.
  5. Procédé selon l'une quelconque des revendications précédentes, comprenant en outre l'étape consistant à mélanger avec au moins un gaz d'agitation en amont de l'éjection l'oxygène à partir duquel le jet primaire et/ou le jet secondaire sont formés.
EP05744383A 2004-05-14 2005-05-12 Raffinage de metal en fusion Not-in-force EP1749109B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB0410835A GB0410835D0 (en) 2004-05-14 2004-05-14 Refining molten metal
GB0425540A GB0425540D0 (en) 2004-11-19 2004-11-19 Refining molten metal
PCT/GB2005/001857 WO2005111247A2 (fr) 2004-05-14 2005-05-12 Raffinage de metal en fusion

Publications (2)

Publication Number Publication Date
EP1749109A2 EP1749109A2 (fr) 2007-02-07
EP1749109B1 true EP1749109B1 (fr) 2009-07-22

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EP05744383A Not-in-force EP1749109B1 (fr) 2004-05-14 2005-05-12 Raffinage de metal en fusion

Country Status (8)

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US (1) US20090229416A1 (fr)
EP (1) EP1749109B1 (fr)
JP (1) JP2007537355A (fr)
KR (1) KR20070012478A (fr)
AT (1) ATE437245T1 (fr)
BR (1) BRPI0510988A (fr)
DE (1) DE602005015575D1 (fr)
WO (1) WO2005111247A2 (fr)

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AT506984B1 (de) * 2008-06-17 2010-06-15 Siemens Vai Metals Tech Gmbh Sauerstoffblaslanze mit schutzelement
US9863013B2 (en) * 2011-02-22 2018-01-09 Linde Aktiengesellschaft Apparatus and method for heating a blast furnace stove
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US10240218B2 (en) 2015-06-17 2019-03-26 Larry J Epps Coaxial material-stirring lance and method of use
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KR20070012478A (ko) 2007-01-25
WO2005111247A3 (fr) 2006-04-13
US20090229416A1 (en) 2009-09-17
JP2007537355A (ja) 2007-12-20
ATE437245T1 (de) 2009-08-15
BRPI0510988A (pt) 2007-12-04
DE602005015575D1 (de) 2009-09-03
WO2005111247A2 (fr) 2005-11-24
EP1749109A2 (fr) 2007-02-07

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