Classifications

• • 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
• • 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
• • 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
  • C21C5/30—Regulating or controlling the blowing
  • C21C5/35—Blowing from above and through the bath
• • 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
  • C21C2250/00—Specific additives; Means for adding material different from burners or lances
  • C21C2250/04—Liquid gas
  • C21C2250/042—Liquid oxygen

Definitions

• the invention relates to a method and a device for treating
• Molten metals in particular molten steel, containing a fresh medium of oxygen.
• a number of process designations are derived from the nature of the oxygen incorporation, e.g. the LD, LDAC or OBM process.
• inflation methods such as the AOD method used with oxygen and e.g. Work argon.
• the gaseous oxygen is supplied via a lance or a soil purging the pig iron or the base alloy for the reaction.
• the invention has for its object to provide a method and apparatus for increasing the fresh speed.
• liquid and gaseous oxygen are used for the refining of steels, the jet of liquid oxygen guided within the gaseous oxygen jet being applied to a bath surface of the molten metal already freed from the gaseous oxygen jet by the melt slag and / or introduced into the molten metal.
• the oxygen entry according to the invention in steel fresh has - compared to the previous oxygen input - the significant advantage that the liquid oxygen comes into direct contact with the molten metal, whereby the oxygen - due to the prevailing in Bre ⁇ nfleck the molten metal high temperatures - abruptly evaporates, whereby an intensive bath movement is effected and an increased mass transfer in the molten metal - namely the oxidation, eg of the carbon to carbon monoxide, as well as the slagging of the pig iron adjuncts, e.g. Silicon and manganese - takes place.
• the supply of the lance with gaseous oxygen is carried out in the usual way.
• the execution of the lance tip can be designed as single or multi-point.
• the supply of the lance with liquid oxygen takes place according to the state of
• the lines leading the liquid or gaseous oxygen from the oxygen supply to the lance are designed as flexible hoses and the liquid oxygen line / s additionally vacuum-insulated.
• the fresh process can be controlled by influencing the ratio of the entry amounts of gaseous and liquid oxygen and / or by influencing the gaseous or liquid oxygen pressure and the geometry of the blow nozzle used for the gaseous oxygen input with respect to a higher fresh speed.
• the impact energy of the liquid oxygen can be influenced.
• the liquid oxygen is introduced into the molten metal, in accordance with the prevailing flow conditions and the Reynolds number, either as a homogeneous liquid jet or as a droplet jet, or applied thereto.
• the distance between the lance tip and the bath surface can be changed as in conventional lances.
• the ratio of the amount of liquid and gaseous oxygen introduced by means of the blowing device according to the invention into a molten metal bath can be easily adapted to the respective operating conditions. There is a wide range of variation of almost 100% liquid oxygen and very low gaseous content and vice versa available.
• the liquid oxygen jet (LOX) can also be fed intermittently to the bath surface. This can be done with larger diameters of the discharge - at the same mean mass flow -. As a result, a stable jet of liquid oxygen can be supplied to the molten bath.
• a liquid oxygen supply preferably located in the lance axis.
• the supply of liquid oxygen may be split into one or more holes.
• liquid oxygen line other liquefied gases such. B. argon fed to the melt.
• argon fed to the melt.
• further metallurgical effects such as removal of unwanted gases or inclusions in the molten metal or an additional stirring effect for homogenizing the melt can be achieved.
• the invention will be explained in more detail below with reference to an exemplary embodiment shown in the drawing (FIGS. 1 to 3).
• Fig. 1 is a schematic representation of an oxygen blowing lance according to the invention
• Figure 2 is a schematic representation of an oxygen supply with intercooling and with a for lance of a molten steel in a converter arranged lance with single-hole lance tip.
• FIG. 3 shows a schematic representation of an oxygen lance with multi-hole lance tip according to the invention
• Fig. 4 is a schematic representation of an oxygen supply
• a gas phase separator and a blow lance with a multi-hole lance tip arranged for refining a steel melt in a converter
• FIG. 1 shows a device which can be used to inject gaseous and liquid oxygen into a molten steel (not shown).
• the oxygen blowing device consists of a blowing lance 1, via the supplied with a water cooling 2 inflow channel 3, gaseous oxygen (GOX) is fed through a discharge nozzle 4 as a gaseous oxygen jet 5 of the molten steel.
• gaseous oxygen GOX
• the erfi ⁇ dungssiee oxygen blowing device also has another, in the inflow 3 of the lance 1 ze ⁇ trisch arranged LOX lance 6, on their provided with a thermal insulation 7 inflow channel 8 deep cold liquid oxygen (LOX) through a discharge nozzle 9 as - from the gas jet 5 enveloped - Centric jet 10 liquid oxygen of the molten steel can be supplied.
• the stream 10 of liquid oxygen supplied to the molten steel by the exhaust nozzle 9 of the LOX lance 6 as a centrifuge stream 10 of liquid oxygen strikes the surface of the molten steel freed from the slag by the gas jet 5 and evaporates as it penetrates into its Burn spot high temperatures having melt pool abruptly, whereby an intensive Badbewegu ⁇ g is effected and thus an increased mass transfer in the molten steel - namely the oxidation of the carbon to carbon monoxide, and the slagging of pig iron companion silicon and manganese - takes place.
• the jet of liquid oxygen 10 is adapted to the respective flow conditions and the Reynolds number and can be supplied to the molten bath either as a homogeneous liquid jet or as a droplet jet.
• the formation of the jet of liquid oxygen may be influenced by the degree of its supercooling.
• the thermal insulation 7 preventing the premature evaporation of the liquid oxygen (LOX) flowing through the inflow channel 8 of the lance 6 consists of a conventional insulating material.
• the jet 10 of liquid oxygen may also be fed intermittently to the molten steel.
• a - formed in accordance with FIG. 1 - one-hole lance 11 is shown schematically, from which a - of a jet 5 gaseous oxygen umhüliter, centric jet of liquid oxygen 10 in the region of liberated from slag 12 liquid steel bath 13 of a converter fourteenth incident.
• the feed of the liquid oxygen (LOX) used as a fresh medium from a liquid oxygen supply 15 into the one-hole blow lance 11 equipped with a cooling water connection 16 takes place through a line 17 designed as a flexible hose.
• the supply of the gaseous oxygen (GOX) likewise used as a fresh medium takes place from a usual, unspecified oxygen gas supply in the lance 11 by a, advantageously designed as a flexible hose line 18th
• the known from DE 43 15 342 C1 liquid oxygen supply 5 consists of a, equipped with conventional and therefore unspecified pipes and valves storage tank 19 for liquid oxygen.
• the for the steel bath 13 of the arranged in the converter 14 single-hole lance 1 1 supplied liquid oxygen is removed from the insulated storage tank 19 through a line 20 and - if the pressure of the storage tank 9 is insufficient - after a shut-off valve 21 via a liquid oxygen pump 22 increases the required pressure and then introduced into a heat exchanger 23.
• the conduit 20 may additionally be provided with a jacket (not shown in the drawing) with a cryogenic medium, for example liquid nitrogen, in order to prevent premature evaporation of the oxygen.
• Heat exchanger 23 is passed from the insulated line 20 behind the shut-off valve 21 through an insulated line 24 branched oxygen via a controlled by a sensor 32 level control system 25 in the heat exchanger 23.
• a negative pressure is generated by means of a pump 26, by which the boiling temperature of the liquid oxygen used as a coolant in the heat exchanger 23 is lowered so that it can serve as a coolant for the fresh oxygen.
• the liquid oxygen used for refining the steel bath 13 in the converter 14 is passed through the heat exchanger 23 in copper coils 27 and thereby cooled by the cooling oxygen surrounding it - depending on the prevailing pressure ratio - below its boiling temperature determined by the pressure. Thereafter, the liquid fresh oxygen is supplied through the formed as an insulated tube line 17 of the arranged in the converter 14 one-hole blast nozzle 11 - and together with the supplied via the line 18 of the lance 11 gaseous oxygen - in the manner previously explained in the steel bath 13 of Converter 14 blown.
• FIG. 3 shows a lance 1 with a three-hole lance tip, the embodiment of which basically corresponds to the blow law 1 described in FIG.
• the blowing lance 1 described in FIG. 3 is designed such that both the liquid oxygen (LOX) and the gaseous oxygen (GOX) in the lance tip fall onto a plurality of partial beams - according to FIG - Divided into three sub-beams.
• LOX liquid oxygen
• GOX gaseous oxygen
• the division of the gaseous oxygen is carried out from the inlet channel 3 for gaseous oxygen to the three located in the lance tip exhaust nozzles 4 for gaseous oxygen.
• the division of the liquid oxygen is carried out by dividing the inflow channel 8 for liquid oxygen on three - not shown in Fig. 3 - inflow channels, which are each provided with a discharge nozzle 9 for liquid oxygen.
• the discharge nozzle / n 4 of the lance 1 emanates the stream 10 of liquid oxygen and the jet of gaseous oxygen enveloping the stream 10 of liquid oxygen with a - customary for multi-hole lance tips - Inclination angle to the lance axis for refining the molten steel.
• this angle is 25 °.
• a, with your multi-hole lance tip in a converter 14 arranged multi-hole lance 28 is shown schematically, from which several, each of a beam 5 of gaseous oxygen enveloped, centric beams 10 liquid oxygen in the region of slag 12th liberated liquid steel bath 13 of the converter 14 impact.
• the supply of the liquid oxygen (LOX) from a liquid oxygen supply 29 into the equipped with a cooling water connection 16 and with a multi-hole lance tip, arranged in the converter 14 multi-hole lance 28 takes place through the insulated line 17 in the form of a flexible hose.
• the supply of the gaseous oxygen (GOX) from a customary and therefore unspecified oxygen gas supply into the multi-hole lance 28 takes place through the line 18.
• the liquid oxygen (LOX) is supplied through the withdrawal line 20 via a check valve 21 through an insulated line 30 a gas phase 31.
• a fill level control system 25 automatically keeps the liquid oxygen used in the gas phase separator 31 at the desired level, for which purpose the level of the liquid oxygen in the gas phase separator 31 is detected by means of a sensor 32.
• the gaseous oxygen is separated from the liquid oxygen.
• the liquid oxygen (LOX) is supplied via the formed as an insulated tube line 17 of the arranged in the converter 14 multi-hole lance 28 and by means of this - together with the supplied via line 18 gaseous oxygen - in a manner previously explained for the purpose of refining the steel bath thirteenth used in the converter 14.
• the gaseous oxygen content resulting from the external introduction of heat into the liquid oxygen is separated by the gas phase separator 31 Multi-hole blowing nozzle 28 separated and fed via a - the level control system 25 containing - line 33 other unspecified consumers.

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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)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (2)

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ID=33461880

Family Applications (1)

Country Status (7)

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• 2003
  • 2003-05-23 DE DE10323826A patent/DE10323826A1/de not_active Withdrawn
• 2004
  • 2004-05-13 WO PCT/EP2004/050800 patent/WO2004104231A2/fr not_active Ceased
  • 2004-05-13 ES ES04741571T patent/ES2369362T3/es not_active Expired - Lifetime
  • 2004-05-13 SI SI200431758T patent/SI1636390T1/sl unknown
  • 2004-05-13 AT AT04741571T patent/ATE515581T1/de active
  • 2004-05-13 PL PL04741571T patent/PL1636390T3/pl unknown
  • 2004-05-13 EP EP04741571A patent/EP1636390B1/fr not_active Expired - Lifetime

Non-Patent Citations (1)

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