JP3233755B2 - Sinter containing iron scrap - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintered ore used as a raw material when producing hot metal in a blast furnace or the like.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a schematic process diagram of a conventional process for producing a conventional sintered ore. The ore is ore hopper 1,
Limestone, which is an auxiliary material, is cut out from a limestone hopper 3, a coke breeze as fuel is cut out from a coke breeze hopper 2, and a returned ore is cut out from a return hopper (not shown) in a predetermined amount. Addition and humidity control granulation.

[0003] The sintering raw material after humidity conditioning granulation is once charged into a raw material feeder 5, cut out from a drum feeder 6, and cut into a chute 7.
To fill the pallet 8 to form the filling layer 9. The layer thickness of this filling layer is 550 mm. The coke breeze in the surface layer portion of the packed bed 9 is ignited by the ignition furnace 10, and the coke is burned while sucking air downward, and the raw material is sequentially sintered from the upper layer to the lower layer with this combustion heat to form a sintered ore. . Japanese Patent Application Laid-Open No. 63-274723 discloses a sintered ore obtained by sintering by a method utilizing the heat generated by pre-reduced iron having a high metallization rate. On the other hand, in recent years, a large number of iron scrap pieces (hereinafter simply referred to as scraps) called light-weight scraps derived from automobiles, home appliances, containers, Dalai powder, and the like have been generated, and their effective use has been demanded.

[0004]

The Fe content of sintered ore tends to decrease due to the increase of inferior iron ore powder in recent years. As a method for increasing the content of sinter ore Fe, there is sinter ore produced by utilizing the heat generated by the pre-reduced iron of the method described in the above-mentioned JP-A-63-274723, and the Fe content of the sinter is reduced. Can be somewhat enhanced. However, this method is difficult to handle due to oxidative heat generated in the air during the transportation time and becomes high temperature before it can be used for sintering, leaving problems in the transportation method. There is.

[0005] On the other hand, scraps called light-weight scraps derived from automobiles, home appliances, containers, Dalai powder, and the like are generated as shredders or shreds by a shredder or as cutting chips generated in a machining process. Because of its small size, its use in electric furnaces and converters is not welcomed, and there is a need for a way to effectively use lightweight scrap. An object of the present invention is to provide a sintered ore containing a lightweight scrap inside.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a sinter produced by blending iron scrap with a sintering raw material and producing the same using a downward suction type sintering machine. An iron scrap-containing sintered ore comprising an undissolved portion of iron scrap remaining in an amount of 1 % by mass or more and 70% by mass or less based on the total amount of the sintering raw material and the iron scrap. In the following description, all unit display% is mass%.
And simply expressed as% hereinafter.

[0007]

When a sinter having a high Fe content according to the present invention is charged into a blast furnace to produce hot metal, coke required to reduce iron oxide and produce Fe is reduced, so that the cost of coke per hot metal is reduced. And the increase in tapping volume,
The production cost of hot metal decreases. As for the size of scrap, iron scrap having a thickness of 5 mm or less and a longest side of 50 mm or less (hereinafter referred to as flake iron scrap), iron scrap of a thickness of 10 mm or less and a longest side of 150 mm or less (hereinafter referred to as lump iron scrap) Call).

The mixing ratio of scrap [scrap / (scrap + sintering raw material)] varies depending on the size of the scrap. This is because the amount of scrap dissolved changes depending on the size of the scrap. The larger the scrap, the more the heat transfer to the inside is insufficient and it is difficult to melt, and the smaller the scrap, the better the heat transfer and the better the melting property. Therefore, the lower limit size is not preferably limited. The scrap may be compressed into a spherical shape or a square shape.

[0009] The upper limit of the mixing ratio of the scrap varies depending on the size of the scrap. As shown in FIG. 2, the upper limit of the sinterable compounding ratio of flake iron scrap is 100%. This is because the packing density of the raw material packed layer is increased due to the small size of the scrap, heat is sufficiently transferred between the scraps, and the flake iron scrap is sufficiently melted. The upper limit of the sinterable compounding ratio of lump iron scrap is 70%. This is because the scrap is large, the packing density of the raw material packed layer is low, and the heat transfer of the scrap is insufficient, so that the lump scrap is difficult to melt.

As shown in FIG. 3, the melting amount of flake iron scrap is about 30% at a blending ratio of 100%. In this case, the content of the undissolved flake iron scrap in the sintered ore (that is, the ratio based on the total amount of the sintering raw material and the iron scrap) is 70.
%, And is sintered integrally with the melt of the sintering raw material, so that the strength of the sintered ore is maintained. Therefore, the upper limit of the sinterable compounding ratio of flake iron scrap is 100%. As shown in FIG. 3, the molten amount of the lump scrap becomes a value close to 0% at the blending ratio of 70%. In this case, the content of the undissolved scrap in the sintered ore (that is, the ratio based on the total amount of the sintering raw material and the iron scrap) is such that 100% of the scrap with the blending ratio of 70% remains, and the undissolved scrap is 70%. Becomes Therefore, the scrap is in a form of being physically bitten by the melt of the sintering raw material, which is a limit at which the strength of the sintered ore is maintained. Therefore, the upper limit of the sinterable compounding ratio of the lump iron scrap is 70%. This
Thus, in the present invention, the inclusion of undissolved scrap in the sintered ore
Prevailing rate (that is, a percentage of the total
) Is set to 70%. In addition, undissolved metal in sinter
Scrap content (ie total sintering material and iron scrap)
The lower limit of the ratio to the amount
Minimum amount of undissolved scrap (scrap mix ratio =
10%, undissolved scrap content of iron scrap = 10
%) To 1%.

As described above, according to the present invention, the scrap is mostly or partially melted in the sintered ore,
Alternatively, almost the entire amount is fixed in a form of being physically bitten by a sintered body made of a sintering raw material. FIG. 4 shows an example of a cross-sectional microstructure of the sintered ore according to the present invention. In the sintered ore of FIG. 4A, the content of undissolved scrap at a scrap content of 10% was 9%.
%, And the undissolved scrap content of the sintered ore in FIG. 4 (b) at a scrap content of 80% is 48% scrap. As a comparative example, FIG. 4C shows a sintered ore manufactured by the conventional method using the iron ore of FIG. 5 as a main raw material. The undissolved scrap content is determined by the area ratio of the undissolved scrap from the cross-sectional microstructure of 10 sintered ore having a diameter of 30 mm.

As described above, since the sintered ore according to the present invention contains scrap as compared with the conventional sintered ore, the Fe content in the sintered ore is increased by the Fe of the scrap. When hot metal is manufactured by charging a sintered ore having a high Fe content according to the present invention into a blast furnace, coke required for manufacturing iron by reducing iron oxide is reduced, so that a coke ratio per hot metal amount is reduced, and As the tapping amount increases, the production cost of the hot metal decreases.

[0013]

【Example】

(Embodiment 1) Embodiment 1 of the present invention is shown by the method shown in FIG. The comparison row was implemented by the method of FIG. The ore is cut out from the ore hopper 1, the auxiliary material limestone is cut out from the limestone hopper 3, the coke breeze as fuel is coke breeze hopper 2, and the ore is cut out from the ore hopper (not shown) to carry these sintering raw materials. A scrap having a thickness of 0.1 mm to 2 mm is compressed on a belt conveyor in front of a mixer 4 to be cut into a size having a diameter of 10 mm or less from a scrap hopper 16 so as to have a blending ratio of 10%. Mixer 4 was added with 6.8% of water and subjected to humidity control and granulation.

The scrap and the sintering raw material after the moisture granulation were once charged into a raw material feeder 5, cut out from a drum feeder 6 and charged into a pallet 8 via a chute 7 to form a packed layer 9. The thickness of this filling layer is 600 mm. The coke breeze and the scrap in the surface layer of the packed bed 9 are ignited by the ignition furnace 10 and the coke is burned while sucking air downward. Was manufactured. 9% of undissolved scrap remains in the sintered ore, and Fe of the sintered ore is Fe5 of the conventional sintered ore.
58.32%, which is higher than 6.0%, was high quality.

(Embodiment 2) Embodiment 2 of the present invention is shown by the method shown in FIG. The comparison row was implemented by the method of FIG. Basically, a method similar to that of the first embodiment is used. A scrap iron having a thickness of 3 mm or less and a length of 50 mm or less is cut out from the scrap hopper 16 to a mixing ratio of 80% on a belt conveyor in front of the mixer 4 for transporting the sintering raw material. 6.8% was added and the mixture was subjected to humidity control granulation.

The flake iron scrap and the sintering raw material after the moisture granulation were charged into a pallet 8 to form a packed bed 9. The layer thickness of this filling layer is 550 mm. The coke breeze and flake iron scrap on the surface layer of the packed bed 9 are ignited by the ignition furnace 10 and the coke is burned while sucking air downward, and the raw material is sequentially sintered from the upper layer to the lower layer by the combustion heat. Made ore. 48% of undissolved scrap remained in the sintered ore, and Fe of the sintered ore was 71.0%, which was higher than that of the conventional sintered ore of 56.0%, resulting in high quality.

(Embodiment 3) Embodiment 3 of the present invention will be described by the method shown in FIG. The comparison row was implemented by the method of FIG. Basically, a method similar to that of the first embodiment is used. A lump of scrap having a thickness of 10 mm or less and a length of 150 mm or less was cut out from a scrap hopper 16 at a blending ratio of 30% on a belt conveyor in front of the mixer 4 for transporting the sintering raw material. 6.8%
The mixture was added and subjected to humidity control and granulation.

The lump scrap and the sintering raw material after the moisture granulation were charged into a pallet 8 to form a packed bed 9. The layer thickness of this filling layer is 550 mm. The coke breeze and lump scrap in the surface portion of the packed bed 9 are ignited by the ignition furnace 10 and the coke is burned while sucking air downward, and the combustion heat sinters the raw material sequentially from the upper layer to the lower layer. Made ore. 57% of undissolved scrap remains in the sinter,
Fe of sinter is higher than 56.0% of Fe of conventional sinter6
3.0% and high quality.

(Embodiment 4) Embodiment 4 of the present invention will be described by the method shown in FIG. The comparison row was implemented by the method of FIG. Basically, a method similar to that of the first embodiment is used. A lump scrap having a thickness of 10 mm or less and a length of 150 mm or less was cut out from a scrap hopper 16 at a mixing ratio of 70% on a belt conveyor in front of the mixer 4 for transporting the sintering raw material. 6.8%
The mixture was added and subjected to humidity control and granulation.

The lump scrap and the sintering raw material after the moisture granulation were charged into a pallet 8 to form a packed bed 9. The layer thickness of this filling layer is 550 mm. The coke breeze and lump scrap in the surface portion of the packed bed 9 are ignited by the ignition furnace 10 and the coke is burned while sucking air downward, and the combustion heat sinters the raw material sequentially from the upper layer to the lower layer. Made ore. 98% of undissolved scrap remains in the sinter,
Fe in sinter is higher than 56.0% of Fe in conventional sinter.
It was 1.0%, which was high quality.

(Embodiment 5) Embodiment 5 of the present invention is shown by the method shown in FIG. The comparison row was implemented by the method of FIG. Basically, a method similar to that of the first embodiment is used. A flake iron scrap having a thickness of 5 mm or less and a length of 50 mm or less is cut out from a scrap hopper 16 at a mixing ratio of 10% on a belt conveyor in front of the mixer 4 for transporting the sintering raw material, and water is mixed with the sintering raw material in the mixer 4. 6.8% was added and the mixture was subjected to humidity control and granulation.

The flaked iron scrap and the sintering raw material after the moisture granulation were charged into a pallet 8 to form a packed bed 9. The layer thickness of this filling layer is 550 mm. The coke breeze and flake iron scrap on the surface layer of the packed bed 9 are ignited by the ignition furnace 10 and the coke is burned while sucking air downward, and the raw material is sequentially sintered from the upper layer to the lower layer by the combustion heat. Made ore. 12% of undissolved scrap remained in the sintered ore, and Fe of the sintered ore was 58.0%, which was higher than 56.0% of Fe of the conventional sintered ore, and was of high quality.

(Embodiment 6) Embodiment 6 of the present invention will be described by the method shown in FIG. The comparative example was implemented by the method of FIG. Basically, a method similar to that of the first embodiment is used. A flake iron scrap having a thickness of 5 mm or less and a length of 50 mm or less was cut out from a scrap hopper 16 to a mixing ratio of 100% on a belt conveyor in front of the mixer 4 for transporting the sintering raw material, and mixed with the mixer 4.

The mixed flake iron scrap was charged into a pallet 8 to form a packed bed 9. The thickness of this packed bed is 55
0 mm. The flake iron scrap in the surface layer of the packed bed 9 is ignited by the ignition furnace 10 and the flake iron scrap is sequentially sintered from the upper layer to the lower layer by the heat of oxidation of the flake iron scrap while sucking air downward, thereby reducing the sintered ore. Manufactured. 69% of undissolved scrap remains in the sintered ore,
e was 79.3%, which was higher than the conventional sintered ore of 56.0% Fe, and was of high quality.

(Embodiment 7) Embodiments 7 and 5 of the present invention
Table 1 shows an example of using the sintered ore manufactured by the above method in a blast furnace. According to Table 1, as compared with the sinter of the conventional method, the coke ratio was lowered due to the higher Fe content, and the production cost of hot metal was reduced.

[0026]

[Table 1]

[0027]

The sintered ore according to the present invention contains undissolved scrap in the sintered ore, so that the Fe content is increased and the quality is improved.
In producing blast furnace hot metal, the production cost is reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is a table showing a sinterable limit viewed from a relationship between scrap sizes.

FIG. 3 is a chart showing the relationship between the scrap content in the sintered ore, the scrap melting rate, and the amount of scrap mixed by the size of the scrap.

4A is an optical micrograph of a sintered ore structure containing 10% of a scrap of the present invention, and FIG. 4B is a diagram of 80% of a scrap of the present invention.
It is an optical micrograph of a compound sinter structure, and (c) an optical micrograph of a conventional sinter structure.

FIG. 5 is a schematic process diagram of a conventional production process of a sintered ore.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 ore hopper 2 powder coke hopper 3 limestone hopper 4 granulator 5 raw material feeder 6 drum feeder 7 chute 8 pallet 9 filling layer 10 ignition furnace 11 floor hopper 12 floor supply layer 13 discharge unit 14 crusher 15 sieve 16 scrap hopper

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C22B 1/16-1/20

Claims (1)

(57) [Claims] 1. A sintered ore manufactured by blending iron scrap with a sintering raw material and using a downward suction type sintering machine, wherein an undissolved portion of the iron scrap is provided inside the sintering ore with the sintering raw material and the iron scrap. 1 to 70 mass % or less based on the total amount of iron ore.