Claims
- 1. Agglomerated iron ores produced by the method comprising the steps of
- adding a flux containing lime substance to iron ore comprising more than 80% hematite and less than 20% magnetite, said iron ore having a grain size 5 mm or less, to form a mixture consisting of flux and iron ore;
- primarily pelletizing the mixture of flux and iron ore to form first pellets;
- adding flux containing lime substance and solid fuel selected from the group consisting of grain coke, grain cha, dust coal and grain charcoal, having more than 50% of grain size of -125 .mu.m, and in an an amount of 2.5 to 3.5 weight percent based on the amount of iron ore to the first pellets obtained from the primary pelletizing;
- secondarily pelletizing the first pellets to coat the first pellets with said lime substance and solid fuel and to form minipellets from the first pellets having grain size ranging from 3 to 9 mm and having their surfaces coated with said solid fuel to effect diffusion bonding; and
- processing the mini-pellets on a travelling grate sintering furnance by subjecting the mini-pellets first to drying, then subsequently to firing at a temperature of a maximum of 1270.degree. C. for about 1 minute, then thereafter indurating and cooling, and then finally to crushing and filtering, thereby to produce agglomerated iron ores of said mini-pellets having a diameter of more than 3 mm,
- wherein the total amount of flux is sufficient to produce basicicity of the agglomerated ores to be in the range of 1.8 to 2.0 and wherein more than 50% of the total flux added in both the parimary and secondary pelletizing steps is added in the primary pelletizing step,
- so that the agglomerated iron ores comprise a plurality of substantially completely spherical pellets having a surface and consisting of a core consisting of iron ores and flux and a coated layer of said solid fuel on sasid surface of said core.
- 2. Agglomerated ores of claim 1, wherein said mini-pellets have diameters of 5 to 8 mm.
- 3. Agglomerated ores of claim 1, wherein said grain size is not more than 1 mm.
- 4. Agglomerated ores of claim 1, wherein said mini-pellets are bonded with calcium ferrite on their surfaces.
- 5. Agglomerated ores, comprising a plurality of substantially completely spherical pellets, said pellets consisting of a core having a surface and consisting of iron ores and fluxes and a coated layer of a solid fuel on said surface of said core and combined with the surface thereof by a diffusion bond, said pellets being 3 to 9 mm in diameter, and said solid fuel layer being -125 .mu.m, and said iron ores of not more than 5 mm grain size comprising more than 80% hematite and less than 20% magnetite, wherein said solid fuel is selected from the group consisting of grain coke, grain char, dust coal, grain petroleum coke and grain charcoal.
- 6. Agglomerated ores of claim 1, wherein said solid fuel is added in an amount of more than 50% of total addition amount in a primary pelletization.
- 7. Agglomerated ores of claim 1, wherein said solid fuel is added in an amount of 2.5 to 3.5% in a secondary pelletization.
- 8. Agglomerated ores of claim 7, wherein said solid fuel is added in an amount of 2.7 to 3.0% in a secondary pelletization.
- 9. Agglomerated ores of claim 1, wherein said fluxes are lime substances, and are added such that basicicity in products is determined to be 1.8 to 2.0.
- 10. Agglomerated ores of claim 1, wherein the products by said diffusion bond have fine fabrications comprising the hematite and calcium ferrite.
- 11. Agglomerated ores of claim 1, wherein said pellets are 5 to 8 mm in grain diameter.
- 12. Agglomerated ores of claim 1, wherein SiO.sub.2, as a bond strengthening agent, is added in an amount of 3.5 to 4.5%.
- 13. Agglomerated ores of claim 1, wherein ordinary sintered raw materials of -125 .mu.m are not more than 10%, and ordinary pellets of -44 .mu.mm are more than 60% in the grain iron ores as raw materials.
Priority Claims (1)
Number |
Date |
Country |
Kind |
59-227944 |
Oct 1984 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 871,305 filed 6-6-86 now abandoned which is a division of application Ser. No. 769,624 filed 8-15-85 filed as PCT JP85/00192 on Apr. 12, 1985, published as WO86/02668 on May 6, 1986, now U.S. Pat. No. 4,722,750.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4082540 |
Sasaki et al. |
Apr 1978 |
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4129437 |
Taguchi et al. |
Dec 1978 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
769624 |
Aug 1985 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
871305 |
Jun 1986 |
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