Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D19/00—Arrangements of controlling devices
• • 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
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
• • 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
  • C21C5/42—Constructional features of converters
  • C21C5/46—Details or accessories
  • C21C5/4673—Measuring and sampling devices
• • 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
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
  • C21C7/04—Removing impurities by adding a treating agent
  • C21C7/072—Treatment with gases
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
  • F27D21/0014—Devices for monitoring temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
  • F27D21/02—Observation or illuminating devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/16—Introducing a fluid jet or current into the charge
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/16—Introducing a fluid jet or current into the charge
  • F27D2003/162—Introducing a fluid jet or current into the charge the fluid being an oxidant or a fuel
  • F27D2003/163—Introducing a fluid jet or current into the charge the fluid being an oxidant or a fuel the fluid being an oxidant
  • F27D2003/164—Oxygen
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/16—Introducing a fluid jet or current into the charge
  • F27D2003/166—Introducing a fluid jet or current into the charge the fluid being a treatment gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D19/00—Arrangements of controlling devices
  • F27D2019/0003—Monitoring the temperature or a characteristic of the charge and using it as a controlling value
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D19/00—Arrangements of controlling devices
  • F27D2019/0006—Monitoring the characteristics (composition, quantities, temperature, pressure) of at least one of the gases of the kiln atmosphere and using it as a controlling value

Definitions

• This invention relates generally to refining molten metal, e.g. steel, and, more particularly, to analyzing the molten metal bath during the refining.
• Metals such as steel are typically produced and refined in a refractory lined vessel by heating charge materials such as metal bearing scrap, pig iron, ore, limestone, dolomite, etc. to a molten state and blowing oxygen into the resulting molten metal bath in order to oxidize impurities. It is not always possible to know the precise chemical composition of the charge materials prior to the start of processing. Therefore, the composition must be determined after the charge materials have become molten and thoroughly mixed. Moreover, the changing composition of the molten metal bath must be at least periodically determined so as to know the timing and quantity of additives made to the refining vessel contents.
• the standard method for determining the composition of a molten metal bath is to stop the production process, withdrawn a small sample of material, and analyze this sample using a mass spectrometer.
• a method for optically analyzing a molten metal bath comprising:
• flame envelope means a combusting stream around at least one other non-combusting gas stream.
• coalescent gas stream means a gas stream whose diameter remains substantially constant.
• molten metal bath means the contents of a metal refining furnace comprising molten metal and which also may comprise slag.
• optical data means a value describing a characteristic of a molten metal bath which can be sensed by a receiver spaced from the molten metal bath.
• the term "sight glass” means an optically transparent material, such as sapphire or quartz, capable of providing a seal between a pressurized stream of argon gas in a lance and the fiber optic cable or other optical components.
• a light source such as a laser, may be fitted to the sight glass to increase the energy of the molten metal bath observed through the coherent argon gas jet so as to improve the effectiveness of the analysis.
• molten metal furnace 10 which contains a molten metal bath comprising molten metal 4 and a slag layer 5, which may be molten and/or solid, above the pool of molten metal.
• molten metal will comprise iron or steel.
• the slag layer generally comprises one or more of calcium oxide, silicon dioxide, magnesium oxide, aluminum oxide and iron oxide.
• Lance 1 is positioned so as to provide argon gas to the molten metal bath.
• the embodiment illustrated in the Figure is a preferred embodiment wherein the lance is positioned so as to provide the argon gas to the molten metal bath in a direction perpendicular to the surface of the molten metal bath.
• the lance could be positioned through a sidewall of furnace 10 so as to provide the argon gas angularly to the surface of the bath.
• argon is used as the gas through which an optical sighting is made.
• argon due to its inertness relative to the molten metal, provides for a much clearer optical view of the molten metal from the remote sight position.
• the heaviness of the argon gas makes for a better defined impact site at the molten metal than the conventional more lighter gases employed with conventional systems .
• the combination of reduced splashing and other visual impediments at the gas-metal impact site due to the non-reactivity of the argon gas, coupled with the better defined impact site due to the density of the argon gas, enables a much clearer optical view than is possible with conventional systems. This clearer optical view enables better data acquisition and improved data analysis.
• the argon gas is provided from the lance at a high velocity, preferably at sonic or supersonic velocity.
• the velocity of the argon gas stream 3 provided from the lance has a velocity of at least 1000 feet per second (fps) and preferably at least 1500 fps.
• the argon gas stream has a supersonic velocity upon ejection from the lance and also has a supersonic velocity when it contacts the bath surface.
• Fuel and oxidant are provided out from the lance around the argon gas stream and combust to form a flame envelope 2 around the argon gas stream 3.
• the flame envelope extends for the entire length of the argon gas stream within the furnace from the lance ejection end to the bath.
• the fuel used to form flame envelope 2 is preferably gaseous and may be any fuel such as methane or natural gas.
• the oxidant used to form flame envelope 2 may be air, oxygen-enriched air having an oxygen concentration exceeding that of air, or commercial oxygen having an oxygen concentration of at least 90 mole percent.
• Flame envelope 2 serves to keep ambient gas, e.g. furnace gases, from being drawn into or entrained into argon gas stream 3, thereby keeping the velocity of argon gas stream 3 from significantly decreasing and keeping the diameter of argon gas stream 3 from significantly increasing, generally for a distance of at least 2Od where d is the diameter of the nozzle at the lance ejection end from which gas stream 3 is ejected. That is, flame envelope 2 serves to establish and maintain argon gas stream 3 as a coherent gas stream generally for a distance of at least 2Od.
• argon gas stream 3 is a coherent gas stream from the lance to the bath.
• a spectrometer or other instrument capable of measuring light intensity at several wavelengths is employed. Two separate wavelengths are used for measuring temperature. Other wavelengths are used for measuring the quantity of various elements, such as carbon, silicon, copper, chromium, etc. Yet other wavelengths indicate the presence of oxides such as CaO, MnO, and MgO in the field of view, and can be used to determine whether the slag containing these oxides is being completely penetrated.
• a further indicator of penetration of the slag layer is the conversion of light signals from the combustion of sodium and potassium by the shroud fuel, from emission spectra to absorption spectra. This has been shown to occur when the inert argon gas penetrates completely through the slag layer.
• the argon gas passed to the bath in gas stream 3 serves to help refine the molten metal by mixing the bath.
• the high velocity and coherent nature of argon gas stream 3 serves to drive gas stream 3 through slag layer 5 and deep into molten metal 4 so as to enhance the mixing action of the gas delivered to the bath in argon gas stream 3.
• sight glass 9 is mounted on lance 1 on the end opposite the ejection end to provide a pressure seal to prevent leakage of argon gas from the lance while providing an optically transparent view port. This leakage prevention serves not only to reduce gas losses but also serves to reduce the chance of pressure imbalances which could negatively impact the formation and maintenance of the coherency of the argon gas stream. The formation and the maintenance of a coherent gas stream is not attainable with conventional sensing systems.
• Analyzer 7 may be, for example, an optical spectrometer optical pyrometer, or a combination of these instruments. Analyzer 7 employs the data to provide measurements of temperature and composition of the molten metal bath, thereby enabling the operator to make adjustments to the amounts and timing of additional charge materials, fluxing agents, alloys, electrical energy, and reactive agents such as oxygen, to facilitate arriving at the desired endpoint of the refining process.
• the operator can determine when the processing of the metal has reached the conditions specified for the type of metal being produced. Further, if the quantity of certain trace elements such as copper are observed to be outside the quality limitations for the metal being produced, the operator will be able to make adjustments to bring the product into specification before the completion of processing. By knowing the proportion of scrap melted, the operator will know the appropriate time to add additional scrap to the furnace.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Investigating And Analyzing Materials By Characteristic Methods (AREA)
• Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
• Carbon Steel Or Casting Steel Manufacturing (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Treatment Of Steel In Its Molten State (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2005
  • 2005-02-18 US US11/060,808 patent/US20050145071A1/en not_active Abandoned
• 2006
  • 2006-02-08 KR KR1020077021260A patent/KR20070103076A/ko not_active Application Discontinuation
  • 2006-02-08 MX MX2007010080A patent/MX2007010080A/es not_active Application Discontinuation
  • 2006-02-08 BR BRPI0607616A patent/BRPI0607616A2/pt not_active IP Right Cessation
  • 2006-02-08 CN CNA2006800052103A patent/CN101535507A/zh active Pending
  • 2006-02-08 JP JP2007556179A patent/JP2008537014A/ja not_active Abandoned
  • 2006-02-08 TW TW095104250A patent/TW200636224A/zh unknown
  • 2006-02-08 CA CA002598111A patent/CA2598111A1/en not_active Abandoned
  • 2006-02-08 EP EP06720385A patent/EP1853740A2/en not_active Withdrawn
  • 2006-02-08 WO PCT/US2006/004167 patent/WO2006091362A2/en active Application Filing
  • 2006-02-16 AR ARP060100559A patent/AR052294A1/es unknown
• 2007
  • 2007-08-15 ZA ZA200706792A patent/ZA200706792B/xx unknown

Non-Patent Citations (1)

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