US3423202A - Methods for refining pig iron - Google Patents

Methods for refining pig iron Download PDF

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Publication number
US3423202A
US3423202A US570173A US57017366A US3423202A US 3423202 A US3423202 A US 3423202A US 570173 A US570173 A US 570173A US 57017366 A US57017366 A US 57017366A US 3423202 A US3423202 A US 3423202A
Authority
US
United States
Prior art keywords
converter
refining
slag
phase
longitudinal axis
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
US570173A
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English (en)
Inventor
Jacques Ledune
Paul Nilles
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.)
Centre de Recherches Metallurgiques CRM ASBL
Vodafone GmbH
Original Assignee
Centre de Recherches Metallurgiques CRM ASBL
Mannesmann AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Centre de Recherches Metallurgiques CRM ASBL, Mannesmann AG filed Critical Centre de Recherches Metallurgiques CRM ASBL
Application granted granted Critical
Publication of US3423202A publication Critical patent/US3423202A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/30Regulating or controlling the blowing
    • C21C5/32Blowing from above

Definitions

  • a method of refining pig iron comprises the steps of carrying out two refining stages, separated by a, deslagging stage.
  • an oxygen-containing gas is blown into a converter containing metal to be refined initially while the converter is stationary and subsequently while rotating the converter about its longitudinal axis.
  • oxygen-containing gas is blown into the converter while rotating it about its longitudinalaxis.
  • slight additional movement is applied to the converter towards the end of the second refining stage so as to bring about increased contact between slag and metal and thus stiffen the slag.
  • the present invention concerns improvements in methods for the pneumatic refining of pig iron carried out in a symmetrical, solid bottomed converter adapted to rotate about its longitudinal axis, and in particular to the application of such methods to phosphorus-containing pig iron in the manufacture of steels with a low content of phosphorus.
  • the method is well known at the present time of carrying out a pneumatic refining operation of pig iron in two phases -by means of an oxidising gas injected from above the bath into a symmetrical, solid bottomed converter adapted to rotate about its longitudinal axis.
  • the first phase consists in keeping the converter in an upright position without any rotary motion and in blasting-in the oxidising gas onto and/or into the bath by means of a submerged lance, the necessary slagging agents being added in particulate and/or powder form.
  • the second phase is started, during which the converter rotates about its longitudinal axis whilst the oxidising gas is blasted onto and/or into the bath, and the necessary slagging agents are introduced into the said bath in particulate and/ or powder form.
  • the aim of the present invention is a method by which it is possible to overcome these disadvantages and to produce steels which have a very low content of phosphorus.
  • the method of the invention in which pig iron is refined in two phases separated by deslagging, by means of an oxidising gas injected from above the bath into a solid bottomed converter adapted to rotate about its longitudinal axis, has the essential feature that the first phase is begun with the converter fixed in upright position and is terminated with the converter rotating about its longitudinal axis; the second phase, after deslagging being conducted with the converter rotating about its longitudinal axis.
  • the period of rotation preceding the intermediate deslagging makes it possible easily and economically to produce steels with a very low phosphorus content in for instance lower than 0.015%, for low carbon steels (C, 0.15%), and lower than 0.025% for high carbon steels (C, 0.35
  • the slags obtained have an iron content which does not exceed 10%, while maintaining the qualities necessary for their utilisation in agriculture.
  • the foaming of the slag is less than if it had taken place in the upright phase, and it is accordingly possible to keep more slag in the refining vessel, which is obviously an advantage.
  • the intermediate deslagging takes place when the carbon content of the bath is greater by 0.020% to 0.70% than the carbon content that it is desired finally to obtain.
  • the relatively slight movement of the refining vessel can for instance be a rotation about its longitudinal axis inclined with respect to the horizontal, at a speed equal to or less than 10 rotations per minute.
  • the said relatively slight movement of the refining vessel can also be brought about by a periodic oscillation about the pivot axis of the said vessel, the said axis being perpendicular to the longitudinal axis of the vessel.
  • EXAMPLE 1 FOR LOW CARBON STEEL
  • 29 tons of pig iron were introduced, having 3.6% carbon and 1.9% phosphorus, together with 7,000 kgs. of scrap. Refining took place in two phases by means of pure oxygen, using the slag remaining from the preceding refining.
  • the metal contained 0.8% carbon and 0.15% phosphorus.
  • the temperature of the metal was 1590 C. and the metal contained 0.5% carbon and 0.8% phosphorus, the slag containing 9% iron.
  • EXAMPLE 2 (FOR HIGH CARBON STEEL) 30 tons of pig iron of the same analysis as in Example 1 were introduced into the converter, together with 8 tons of scrap. Again, the slag remaining from the preceding refining process was used.
  • the metal contained 1% carbon and 0.08% phosphorus, whereas the slag titrated 10% iron.
  • a method for refining a bath of pig iron contained in a solid-bottomed converter which is rotatable about its longitudinal axis comprising the steps of (a) blowing an oxidising gas into the converter from above the bath of pig iron while maintaining the converter stationary in an upright position, in a first refining phase,

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
US570173A 1965-09-02 1966-08-04 Methods for refining pig iron Expired - Lifetime US3423202A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
BE40624 1965-09-02
BE40698 1965-11-17
LU50148 1965-12-28

Publications (1)

Publication Number Publication Date
US3423202A true US3423202A (en) 1969-01-21

Family

ID=27158413

Family Applications (1)

Application Number Title Priority Date Filing Date
US570173A Expired - Lifetime US3423202A (en) 1965-09-02 1966-08-04 Methods for refining pig iron

Country Status (5)

Country Link
US (1) US3423202A (hu)
BE (3) BE669135A (hu)
GB (1) GB1100577A (hu)
LU (1) LU50148A1 (hu)
NL (1) NL6611214A (hu)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3540879A (en) * 1967-06-27 1970-11-17 Westinghouse Electric Corp Method for controlling phosphorus removal in a basic oxygen furnace
US3844769A (en) * 1972-04-10 1974-10-29 A Calderon Method of controlling emissions from furnaces
US3849117A (en) * 1968-10-07 1974-11-19 Foseco Int Treatment of slags covering molten metals
US4431444A (en) * 1981-07-27 1984-02-14 Skw Trostberg Ag Process for reducing the iron content of cao-rich slags formed during the desulphurization of crude iron

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2853377A (en) * 1954-11-25 1958-09-23 Stora Kopparbergs Bergslags Ab Two step refining process in a tiltable rotary furnace
CA583431A (en) * 1959-09-15 K. E. Johansson Folke Method of refining phosphorus containing pig iron with oxygen into steel in a rotating furnace
GB831251A (en) * 1957-03-12 1960-03-23 Phoenix Rheinrohr Ag Improvements relating to processes for refining phosphorus-containing pig iron
US3136626A (en) * 1960-08-19 1964-06-09 Lorraine Laminage Method of refining cast-iron
US3172756A (en) * 1965-03-09 Process of dephosphorizing pig iron

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA583431A (en) * 1959-09-15 K. E. Johansson Folke Method of refining phosphorus containing pig iron with oxygen into steel in a rotating furnace
US3172756A (en) * 1965-03-09 Process of dephosphorizing pig iron
US2853377A (en) * 1954-11-25 1958-09-23 Stora Kopparbergs Bergslags Ab Two step refining process in a tiltable rotary furnace
GB831251A (en) * 1957-03-12 1960-03-23 Phoenix Rheinrohr Ag Improvements relating to processes for refining phosphorus-containing pig iron
US3136626A (en) * 1960-08-19 1964-06-09 Lorraine Laminage Method of refining cast-iron

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3540879A (en) * 1967-06-27 1970-11-17 Westinghouse Electric Corp Method for controlling phosphorus removal in a basic oxygen furnace
US3849117A (en) * 1968-10-07 1974-11-19 Foseco Int Treatment of slags covering molten metals
US3844769A (en) * 1972-04-10 1974-10-29 A Calderon Method of controlling emissions from furnaces
US4431444A (en) * 1981-07-27 1984-02-14 Skw Trostberg Ag Process for reducing the iron content of cao-rich slags formed during the desulphurization of crude iron

Also Published As

Publication number Publication date
LU50148A1 (hu) 1967-06-28
NL6611214A (hu) 1967-03-03
GB1100577A (en) 1968-01-24
BE683241A (hu) 1966-12-27
BE672473A (hu) 1966-05-17
BE669135A (hu) 1966-03-02

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