JPH0629469B2 - Sintered ore manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a sintered ore.

[Conventional technology]

In the production of sinter, as shown in Fig. 5, iron ore and limestone of 12 mm or less having various miscellaneous properties are mixed with powder coke as a fuel, and granulated raw material 1 is sintered pallet 2
, The ignition furnace 3 ignites the surface of the raw material layer, and the air is sucked through the wind hox 4.
A method of sintering the pallet 2 from the upper layer to the lower layer is used. In this case, in the pallet, the granulation raw material 1 is not directly charged into the grate 5 at the bottom of the pallet 2, but
To prevent the Great 2 and the sintered product from sticking to each other, 5 mm that does not contain powdered coke called the bedding 6
A sinter or lump ore having the above diameter is laid between the great and the sinter granulation raw material 1.

[Problems to be solved by the invention]

However, although the ore used as the raw material for sintering has various properties, the ore with a high content of sintering water (CW) undergoes thermal decomposition of the crystal water during the sintering and firing process, causing an endothermic reaction, which lowers the sintering temperature accordingly. It has a drawback that it is necessary to add a large amount of powdered coke as a fuel. However, on the other hand, an ore with a high CW has a property that after the thermal decomposition of crystal water, the decomposed part has pores and has a porous property and good contact with the melt, and the ore has a good meltability, Except for the endothermic property of hydrothermal decomposition of crystals, it has the advantage that sinter can be produced with less fuel coke. Therefore, as shown in Fig. 4, the ore with a low CW usually enables the production of sinter with a lower unit of coke as shown in Fig. 4, but the raw ore is pre-sintered in advance. When CW is thermally decomposed separately from CW and then used as a sintering raw material, on the contrary, an ore with a high CW can produce a sintered ore with a lower coke unit. Especially, this tendency is observed in ore brands with CW of 2% or more.
Ore with CW of 2% or less has little improvement effect by heat treatment.

Fig. 4 shows the sinter pot test that was prepared with or without the raw material ore of sintering raw material, and with or without heat treatment. Limestone, return ore, and coke powder were added and blended with this. is there. The composition of the sintering raw material is as follows.

Plain ore 57% Limestone 10% Return ore 30% Powder coke 3% Also, it is true that such an ore with a high crystallization water content should be decomposed by some treatment in advance and then sintered. Can reduce fuel (powder coke), but the temperature required for decomposing the water of crystallization in iron ore is industrially required to be 500 ° C or higher, and heat treatment at such high temperature is performed. Energy and equipment are very expensive.

[Means for solving problems]

Therefore, in the present invention, 95% or more has a particle size of 12 mm or less and 5 mm or more, and has a water content of crystallization (CW) of 2.0 wt%.
The present invention provides a method for producing a sintered ore, which comprises using the above iron ore as a bedding ore for producing a sintered ore.

[Specific configuration of the invention]

 The present invention will be described in detail below.

In the present invention, as shown in FIG. 1, iron ore 7 having a CW of 2% or more and a grain size of 12 mm or less is supplied to a bedding hopper 9. In this case, if a large amount of powder of 5 mm or less is mixed in the ore, it is preferable to use a mixer 8 to add water to granulate it to 5 mm or more before supplying it to the bedding hopper 9.
This is because if a large amount of 5 mm or less is mixed, it will be used as a bedding ore and the amount of falling from the pallet floor grate will increase. On the other hand, powdered coke is added to the other ore 10 which is not used in the bedding, and water is added to the ore 10 using the mixer 11 to supply the granulated and calcined raw material 1 to the sintering surge hopper 12.

Thus, on the great of the sintering pallet 2, first the bedding ore 7
Is charged to a thickness of about 10 mm to 200 mm, and firing raw material 1 is charged to a thickness of about 300 mm to 700 mm, and the surface of the raw material layer is ignited by the ignition furnace 3 and air is sucked through the windhox 4. By doing so, the pallet is sintered from the upper layer to the lower layer.

Sinter firing heat is transferred from the upper layer to the lower layer / floor layer in sequence,
In the calcining raw material 1 containing the powdered coke, the temperature is almost 1300 ° C., and the sintering is performed, but in the bed ore 7 containing no powdered coke, the temperature rises to about 1000 ° C. and is subjected to the heat treatment, and the water of crystallization in the ore is removed. It can be disassembled. The thermal energy used here is exhaust gas energy used for sintering on the bed ore, and it is not necessary to newly add coke to the bed ore layer.

In the present invention, the particle size of the iron ore is limited to 12 mm or less, as shown in FIGS. 2 and 3, in the case of an ore having a particle size of 12 mm or more, heat is applied to the center of the ore under the heat treatment heat pattern condition of bedding. This is because the thermal decomposition of water of crystallization does not occur completely.

The calcinated pallet is tilted, the sintered cake and heat-treated bedding are discharged, passed through the crusher 13, and cooled.
Enter 14 and classify with product sieve 15. The product sieving ore is sent to a blast furnace, and the product sieving ore is used as a return ore as a sintering raw material. Thus, the iron ore used for the bedding is heat-treated and then sent to the blast furnace for coarse particles and to the sintering and firing raw material line without CW. The iron ore for bedding with a CW of 2% or more and a particle size of 12 mm or more is sent to the melting furnace in an insufficient state due to the thermal decomposition of CW, that is, in a state where the CW in the product is high. Along with this, heat in the blast furnace is insufficient by the amount required for CW pyrolysis, resulting in an increase in the fuel ratio in the smelting furnace. Therefore, the iron ore used for bedding should be 12 mm or less. Further, in the method of the present invention, the goodness of the bedding may not be used as the iron ore, but may be used as a bedding together with the sinter having a diameter of 5 mm or more which is used in the conventional method.

〔Example〕

 Next, examples of the method of the present invention will be described.

In the flow shown in FIGS. 1 and 5, Table 1 and Table 2
Under the conditions shown in the table, the method of the present invention and the conventional method were compared by changing the bedding floor ore brand and the like.

As a result, as shown in Table 1, it can be seen that the method of the present invention can achieve a significant reduction in the coke unit consumption as compared with the conventional method of using sinter for the bedding. Also, as a bedding floor ore brand
It is also clear that the CW value exceeding 2 wt% significantly reduced the coke unit consumption.

Furthermore, the iron ore (CW 2% or more) used as bedding has a particle size of 12 mm or less, CW has been completely pyrolyzed, and the CW value in the product is 0. On the other hand, those with a diameter of 12 mm or more contain undecomposed CW, and although the CW of the product is high and the unit of sintered powder coke is certainly reduced, it will increase the fuel ratio in the blast furnace.

〔The invention's effect〕

As described above, according to the present invention, the basic unit of coke can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a schematic processing flow chart according to the method of the present invention, and FIGS. 2 and 3 are CW of ore after heat treatment in which lobe river ore (CW = 9%) is simulated in a bedding floor heat pattern. FIG. 4 is an analytical value diagram and an experimental heat pattern diagram at that time, FIG. 4 is a plain ore sintering pot test result diagram, and FIG. 5 is a processing flow diagram of the conventional method. 7 …… bed mat, 8 …… mixer 10 …… sintering raw material

Claims (2)

[Claims] 1. An iron ore containing 95% or more of which has a particle size of 12 mm or less and 5 mm or more and a water content of crystallization (CW) of 2.0 wt% or more is used as a bedding for producing a sintered ore. A method for producing a sintered ore, comprising: 2. The method for producing a sinter according to claim 1, wherein the iron ore obtained by granulating is used as a bed ore for producing a sinter.