US3313619A - Iron refining processes - Google Patents

Iron refining processes Download PDF

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Publication number
US3313619A
US3313619A US464471A US46447165A US3313619A US 3313619 A US3313619 A US 3313619A US 464471 A US464471 A US 464471A US 46447165 A US46447165 A US 46447165A US 3313619 A US3313619 A US 3313619A
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US
United States
Prior art keywords
furnace
lance
oxygen
bath
inclination
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.)
Expired - Lifetime
Application number
US464471A
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English (en)
Inventor
Decamps Georges
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.)
Sollac SA
Original Assignee
Lorraine de Laminage Continu SA SOLLAC
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Filing date
Publication date
Application filed by Lorraine de Laminage Continu SA SOLLAC filed Critical Lorraine de Laminage Continu SA SOLLAC
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Publication of US3313619A publication Critical patent/US3313619A/en
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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
    • C21C1/00—Refining of pig-iron; Cast iron

Definitions

  • the jet When oxygen is blown into the furnace, the jet intersects with the bath surfaces along an elliptical contour. Part of the gas penetrates the bath and ensures combustion of the impurities, as well as of the carbon, the latter forming carbon monoxide. The remaining oxygen is retained within the furnace to form an atmosphere therein, enabling combustion of the carbon monoxide. According to this method, the lower end of the lance is constantly kept above the surface of the bath and not within the bath.
  • each angle of inclination of the lance corresponds to a well-defined position of the lower end of said lance or tuyere.
  • the process according to the invention for the refining of pig iron in a rotary furnace having its axis inclined, by blowing oxygen at a pressure of the order of 2 kilos per square centimeter into said furnace by means of a movable blast nozzle arranged in the vertical median plane of the furnace above the surface of the metal bath, is characterized in that the position of the blast nozzle is adjusted as a function of the oxygen delivery rate, so that in accordance with the requirements of the various refinice ing steps, each inclination of the lance corresponds to different lengths of penetration of the lance and different oxygen delivery rates, and in that it comprises the following operating steps: at the beginning of the refining operation, when the refining operation is fired and Si and Mn are eliminated from the bath, the lance is disposed to extend a maximum distance into the furnace, so that its front end is positioned just above the bath, substantially at the centre of the surface of the latter, and that the inclination of the said lance is the greatest possible one relative to the horizontal line, and the rate at
  • the oxygen delivery rate is increased to about 2.5 to 3 times its initial value; and subsequently, after the decarbonizing step, and during the following dephosphorization step, the extension of the lance into the furnace is slightly increased, as well as its inclination, and the oxygen delivery rate is decreased, but it still remains about twice as high as its initial value.
  • the oxygen delivery rate is relatively low at the beginning of the refining operation (firing and elimination of Si and Mn), i.e. of the order of conventional oxygen delivery rates of known processes, the lance being sufliciently inclined to the horizontal and a very long portion of its entire length extending into the furnace, so that the distance between the front end of the lance and the bath surface is small and that its axis is situated approximately in the central portion of the bath.
  • the lance is retracted simultaneously, so that its front end is in the vicinity of the aperture of the furnace, but still within said furnace, the elliptical intersection contour increases in area, and the resistance offered by the bath to the penetration of the oxygen is increased as well; moreover the increased length of the path of the jet through the furnace results in an increased retarding action by the fiood of gases issuing from the bath.
  • the ratio of the amount of oxygen penetrating the bath to the amount of oxygen available in the furnace will substantially remain constant.
  • the inclination angle of the lance may also be decreased; in fact, the amount of oxygen penetrating the bath decreases :as the jet axis approaches a condition more nearly tangent to the bath surface.
  • the rotary furnace 6 comprises a metal shell with an internal lining '7 and is supported within a bearing ring 8 formed with axially spaced lateral annular bearing surfaces or ways 5.
  • each bearing surface moves over a set of rollers 10 mounted in bearings 11 formed on a cradle 12 which is supported in bearings 13 by way of journals 14, so that the furnace is adapted to be inclined to different positions depending on the charge, the melt and the heat treatment.
  • One of the rollers 10 is driven from a motor 15 through gearing 16, 17.
  • Thrust bearings 18 pivoted on pivots 19 and engaging the annular ways 9 of the bearing ring 8 serve to prevent lateral shifting of the furnace in inclined condition.
  • the furnace is provided with a single aperture 20 at the centre of an end wall thereof.
  • the gas discharge stack 21 has its inlet spaced by a clearance of about 10 cm. from said aperture when the furnace is positioned in its heat treatment position, at an inclination of say 15 to 20.
  • the stack is provided with a cooling jacket 22 having a water inlet 23 and outlet 24.
  • Mounted across the stack is a lance 25 which is cooled with water delivered at 26 and discharged at 27.
  • a pipe 28 intended for the supply of oxygen and connected to an oxygen source (not shown) through a flexible piping 29.
  • the lance 25 is slidably mounted on a pivotable support by means of a rack-bar mechanism, the rack-bar 36 being secured to the lance 25, and the pinions 37, driven in synchronism, are provided on support 35.
  • the lance 25 is guided on the support 35 by means of two guiding stirrup members 38, secured to the support 35.
  • Said support 35 is pivotably mounted on the discharge stack 21 by means of a horizontal shaft 39 and a forkjoint 40, fastened to the discharge stack 21. Means are provided (not shown), adapted to maintain the support 35 in a predetermined inclined position.
  • the furnace may be inclined to a predetermined position for charging the slagging material as well as the iron ore, through a hopper 30, and to a different position for charging the molten pig iron from a ladle 31, and further, it may be set to a third position for discharging the slag or the refined iron into a movable ladle 32.
  • the molten pig iron is charged into the furnace 6 containing the slag from a previous refining run. Then oxygen is discharged into the furnace in a known manner through lance 25 while the furnace is being rotated.
  • the lance is disposed to extend 2 meters into the furnace and it is provided with a nozzle having a diameter of 140 millimeters.
  • the lance is inclined to the horizontal through an angle of 27.
  • Oxygen is emitted from the lance at a rate of 120 cubic meters per minute.
  • the amount of free oxygen within the furnace 6 is limited, but said amount is sufiicient for burning all of the CO issuing from the bath, without there being any excess of oxygen, for a large proportion of the amount of oxygen entering the bath is absorbed by silicon and manganese, contained in the bath, and only a small proportion combines with the carbon of the metal bath.
  • the lance 25 is raised and retracted, so that its projecting length in the furnace 6 is reduced to 0.75 meter and that its angle of inclination to the horizotnal is 21.
  • said angle of inclination it is still possible to keep the extremity of the intersection contour of the oxygen jet on the metal bath, thus preventing same from impinging upon the bottom of the furnace 6.
  • the rotational speed of furnace 6 is decreased, so as to promote dephosphorization of the metal bath.
  • Part of the oxygen entering the bath is then absorbed by the iron to oxidize the slag, another portion is absorbed by the phosphorous and the remainder is converted into the CO which issues from the bath.
  • oxygen blast periods are reduced from 54 seconds per ton output according to known processes, to about 20 seconds per ton, according to the process of the present invention.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
US464471A 1961-03-24 1965-06-16 Iron refining processes Expired - Lifetime US3313619A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR856679A FR1296596A (fr) 1961-03-24 1961-03-24 Perfectionnements apportés à l'affinage de la fonte

Publications (1)

Publication Number Publication Date
US3313619A true US3313619A (en) 1967-04-11

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ID=8751601

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US464471A Expired - Lifetime US3313619A (en) 1961-03-24 1965-06-16 Iron refining processes

Country Status (6)

Country Link
US (1) US3313619A (es)
AT (1) AT239286B (es)
ES (1) ES276014A1 (es)
FR (1) FR1296596A (es)
GB (1) GB973815A (es)
LU (1) LU41429A1 (es)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3381951A (en) * 1965-10-12 1968-05-07 Combustion Eng Insulating arrangement to protect the trunnion ring and walls of a basic oxygen vessel
US3617897A (en) * 1968-04-25 1971-11-02 Stora Kopparbergs Bergslags Ab Method for the refining of a carbonaceous metal melt
US3793001A (en) * 1970-05-22 1974-02-19 Centro Speriment Metallurg Process for manufacturing steel
US3856510A (en) * 1972-04-14 1974-12-24 Maximilianshuette Eisenwerk Pig iron refining process
US3860418A (en) * 1971-06-16 1975-01-14 Stora Kopparbergs Bergslags Ab Method of refining iron melts containing chromium
US5143683A (en) * 1991-06-18 1992-09-01 Bethlehem Steel Corporation Protective shield having heat conductive properties
US5248330A (en) * 1992-12-24 1993-09-28 Suedala, Inc. Method of pyroprocessing mineral ore material

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2598393A (en) * 1948-10-25 1952-05-27 Kalling Bo Michael Sture Method in carrying out treatment of melted pig iron or other alloyed iron
US3057616A (en) * 1959-03-10 1962-10-09 Stora Kopparbergs Bergslags Ab Device for refining of metals
US3201107A (en) * 1961-05-18 1965-08-17 Pintsch Bamag Ag Apparatus for supporting and movably guiding oxygen lances for rotating barrel converters in production of steel

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2598393A (en) * 1948-10-25 1952-05-27 Kalling Bo Michael Sture Method in carrying out treatment of melted pig iron or other alloyed iron
US3057616A (en) * 1959-03-10 1962-10-09 Stora Kopparbergs Bergslags Ab Device for refining of metals
US3201107A (en) * 1961-05-18 1965-08-17 Pintsch Bamag Ag Apparatus for supporting and movably guiding oxygen lances for rotating barrel converters in production of steel

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3381951A (en) * 1965-10-12 1968-05-07 Combustion Eng Insulating arrangement to protect the trunnion ring and walls of a basic oxygen vessel
US3617897A (en) * 1968-04-25 1971-11-02 Stora Kopparbergs Bergslags Ab Method for the refining of a carbonaceous metal melt
US3793001A (en) * 1970-05-22 1974-02-19 Centro Speriment Metallurg Process for manufacturing steel
US3860418A (en) * 1971-06-16 1975-01-14 Stora Kopparbergs Bergslags Ab Method of refining iron melts containing chromium
US3856510A (en) * 1972-04-14 1974-12-24 Maximilianshuette Eisenwerk Pig iron refining process
US5143683A (en) * 1991-06-18 1992-09-01 Bethlehem Steel Corporation Protective shield having heat conductive properties
US5248330A (en) * 1992-12-24 1993-09-28 Suedala, Inc. Method of pyroprocessing mineral ore material

Also Published As

Publication number Publication date
GB973815A (en) 1964-10-28
AT239286B (de) 1965-03-25
LU41429A1 (es) 1962-05-24
FR1296596A (fr) 1962-06-22
ES276014A1 (es) 1962-07-16

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