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US3525608A - Method for increasing the chromium content of ferrochrome with low chromium content - Google Patents

Method for increasing the chromium content of ferrochrome with low chromium content Download PDF

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Publication number
US3525608A
US3525608A US629890A US3525608DA US3525608A US 3525608 A US3525608 A US 3525608A US 629890 A US629890 A US 629890A US 3525608D A US3525608D A US 3525608DA US 3525608 A US3525608 A US 3525608A
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US
United States
Prior art keywords
ferrochrome
chromium content
chromium
low
content
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
US629890A
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English (en)
Inventor
Petri B Bryk
Jorma B Honkasalo
Rolf Einar Malmstrom
Frans Heikki Tuovinen
Simo Antero Makipirtti
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Outokumpu Oyj
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Outokumpu Oyj
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.)
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Publication date
Application filed by Outokumpu Oyj filed Critical Outokumpu Oyj
Application granted granted Critical
Publication of US3525608A publication Critical patent/US3525608A/en
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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
    • C21C7/00Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00

Definitions

  • Such material is smelted in a conventional manner into ferrochrome, controlling the carbon and silicon content of the charge such that the carbon content of the produced smelt is within the range of 4-8% and silicon content is within the range of 0.2-6.0% and that the molten product is cooled in controlled crystallization conditions, or normally cooled ferrochrome is then heat treated similarly in controlled crystallization conditions, in such a manner that the produced chromium enriched chromiurn-iron-carbide crystals on one hand and crystals containing mainly iron on the other hand exist separate in the solid material in suitable sizes, and that the crystals of the phase containing mainly chromium, after crushing and grinding, are separated by mechanical separation methods, by magnetic or electrostatic means or by means based on differences in specific gravity.
  • the present invention relates to a method for increasing the chromium content of ferrochrome with low chromium content, produced from ores with a low ratio of chromium to iron.
  • One of the principal characteristics of the method according to the present invention is that an ore or concentrate with a low ratio of chromium to iron is smelted in a conventional manner into ferrochrome, controlling the carbon and silicon contents of the smelt, whereupon with utilization of controlled crystallization and afterwards crushing and grinding the product it can be separated into a chromium enriched fraction and another fraction containing a major portion of iron.
  • the resulting fraction containing chromium enriched chromium iron carbides can be used for the production, by suitable conventional methods, of high quality ferrochrome, or it can directly be utilized as alloying element for purposes where the carbon content is not an obstacle.
  • the other fraction containing a major portion of iron can be utilized in steel works and foundries or for other suitable purposes.
  • the method comprises controlling the carbon and silicon contents of the low chromium ferrochrome smelt and controlled cooling of the smelt and/or heat treatment of the cooled product in such a manner that in the low chromium ferrochrome obtained by said method the portion containing metallic iron has a low chromium content and that the crystals of this portion comprise a phase separate from the chromium enriched chromiumiron-carbide crystals.
  • the controlled crystallization is carried out either by controlled cooling of the product or if the cooling has not been controlled then by additional heat treatment of the cooled product or by both of these operations in such a manner that in the obtained ferrochrome with low chromium content the crystals containing iron have a low chromium content and comprise a phase by themselves, separate from the chromium enriched chromiumiron-carbide crystals.
  • These separately crystallized phases can be separated from each other, after crushing and grinding, by magnetic or electrostatic means, means based on difierencs in specific gravity or means based on other mechanical separation methods.
  • the composition of the ferrochrome was:
  • the slag contained 3.7% of Cr O
  • the ferrochrome was cooled as follows:
  • the cooled ferrochrome was crushed, ground to 100 mesh and separated by means of a low-magnetic separator.
  • the non-magnetic portion 381 kg.: Percent Cr 68.8
  • a method for increasing the chromium content of ferrochrome with low chromium content, produced from low chromium-ferro ratio ore by smelting enriched ferrochrome together with coke and flux materials comprising: controlling carbon and silicon content of the smelt during the smelting operation so that smelt produced has a carbon content Within the range of 4% to 8% and has a silicon content within the range of 0.2% to 6%; crystallizing the smelt produced under controlled conditions by rapidly cooling the smelt produced from a temperature near the smelting point of ferrochrome to a temperature of about 1400 C., then slowly cooling the smelt down to a temperature of about 700 C.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US629890A 1966-04-12 1967-04-11 Method for increasing the chromium content of ferrochrome with low chromium content Expired - Lifetime US3525608A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FI0930/66A FI43646B (fi) 1966-04-12 1966-04-12

Publications (1)

Publication Number Publication Date
US3525608A true US3525608A (en) 1970-08-25

Family

ID=8504847

Family Applications (1)

Application Number Title Priority Date Filing Date
US629890A Expired - Lifetime US3525608A (en) 1966-04-12 1967-04-11 Method for increasing the chromium content of ferrochrome with low chromium content

Country Status (3)

Country Link
US (1) US3525608A (fi)
FI (1) FI43646B (fi)
NO (1) NO119951B (fi)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4101310A (en) * 1975-03-20 1978-07-18 Wisconsin Alumni Research Foundation Micron sized spherical droplets of metals and method
US5123957A (en) * 1988-11-11 1992-06-23 Nkk Corporation Method for manufacturing low carbon ferrochrome with high chromium content

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2031947A (en) * 1933-09-20 1936-02-25 Haglund Ture Robert Process for the refining of alloys
US2370608A (en) * 1942-01-08 1945-02-27 Marvin J Udy Metallurgy
US3301669A (en) * 1964-02-27 1967-01-31 Vanadium Corp Of America Production of a high chromium containing ferrochrome

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2031947A (en) * 1933-09-20 1936-02-25 Haglund Ture Robert Process for the refining of alloys
US2370608A (en) * 1942-01-08 1945-02-27 Marvin J Udy Metallurgy
US3301669A (en) * 1964-02-27 1967-01-31 Vanadium Corp Of America Production of a high chromium containing ferrochrome

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4101310A (en) * 1975-03-20 1978-07-18 Wisconsin Alumni Research Foundation Micron sized spherical droplets of metals and method
US5123957A (en) * 1988-11-11 1992-06-23 Nkk Corporation Method for manufacturing low carbon ferrochrome with high chromium content

Also Published As

Publication number Publication date
NO119951B (fi) 1970-08-03
FI43646B (fi) 1971-02-01

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