Claims
- 1. A method for manufacturing a chromium-bearing pig iron, comprising:
- preparing cold pellets from powdered chromium ore, powdered coke and flux materials;
- introducing a charge of said cold pellets together with iron ore and coke lumps into a blast furnace to form a burden in the blast furnace;
- blowing a preheating gas into said burden at the middle level of said blast furnace to preheat said burden; and
- blowing a gas containing more than 50% oxygen, into the blast furnace, through a tuyere therein thereby manufacturing chromium bearing pig iron from said charge including said cold pellets.
- 2. The method according to claim 1, wherein said gas containing more than 50% oxygen includes 95 to 100% oxygen.
- 3. The method according to claim 2, wherein said gas includes pure oxygen.
- 4. The method according to claim 1, further comprising a step of blowing a temperature control agent at a nose of the tuyere, into the blast furnace, through the tuyere.
- 5. The method according to claim 4, wherein said temperature control agent includes at least one selected from the group consisting of circulated top gas, steam, water, CO.sub.2 and cold air.
- 6. The method according to claim 4, wherein said step of blowing a temperature control agent includes controlling a tuyere nose flame temperature from 2000.degree. to 2900.degree. C.
- 7. The method according to claim 6, wherein said tuyere nose flame temperature is controlled from 2400.degree. to 2800.degree. C.
- 8. The method according to claim 1, wherein said preheating gas is at a temperature of from 1000.degree. to 1600.degree. C.
- 9. The method according to claim 1, further comprising a step of blowing fuel, through the tuyere, into the blast furnace.
- 10. The method according claim 9, wherein said fuel includes at least one selected from the group consisting of powdered coal, powdered coke, heavy oil and tar oil.
- 11. The method according to claim 1, wherein said cold pellets are prepared by the steps of:
- mixing and pelletizing powdered chromium ore and powdered coke to prepare green pellets; and
- curing said green pellets.
- 12. The method according to claim 11, wherein said step of mixing and pelletizing includes mixing and pelletizing, in addition to said powdered chromium ore and powdered coke, a silica source to prepare said green pellets said cured pellets being capable of being reduced 90% at 1350.degree. C. in said furnace.
- 13. The method according to claim 11, wherein said step of curing said green pellets includes allowing said green pellets to be cured in an air atmosphere.
- 14. The method according to claim 11, wherein said step of curing said green pellets includes rapidly curing said green pellets by a pre-drying, steam treating and post-drying process.
- 15. The method according to claim 1, wherein said step of introducing said cold pellets, said iron ore and said coke includes introducing a flux which causes a slag formed in the blast furnace to contain Al.sub.2 O.sub.3 -MgO of 30% or less.
- 16. The method according to claim 1, wherein said gas containing more than 50% of oxygen is blown at ambient temperature.
- 17. The method for producing chromium-bearing pig iron in a blast furnace which comprises:
- preparing bonded pellets from powdered chromium ore, powdered coke and flux materials;
- introducing into a blast furnace a cold charge of said bonded pellets together with iron ore and coke lumps to form a burden in said blast furnace, said charge being proportioned in terms of Cr and Fe to yield a chromium-bearing pig iron;
- blowing a preheating gas at a temperature of from 1000.degree. to 1600.degree. C. into said burden at the middle level of said blast furnace to preheat said burden; and
- blowing a gas containing more than 50% oxygen through the tuyeres of said blast furnace at a controlled flame temperature between 2000.degree. and 2900.degree. C.,
- to produce chromium-bearing pig iron while yielding a furnace top gas low in nitrogen.
Priority Claims (1)
Number |
Date |
Country |
Kind |
61-134622 |
Jun 1986 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/036,565, filed Apr. 9, 1987.
US Referenced Citations (7)
Foreign Referenced Citations (6)
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Non-Patent Literature Citations (2)
Entry |
Dean, Eugene R., "Utilization of Fuel Gas by Injection Through Blast Furnace Tuyeres", Blast Furnace and Steel Plant, May 1961, pp. 417-422. |
Manufacture of Stainless Steel in the Top-Blown Oxygen Converter by F. C. Langenberg, C. W. McCoy & E. L. Kern disclosed in publication, "Blast Furnace and Steel Plant", dated Aug., 1967. |
Continuations (1)
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Number |
Date |
Country |
Parent |
36565 |
Apr 1987 |
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