JPH10298670A - Production of sintered ore - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the product yield of sintered ore and to restrain the discharging quantity of NOX by roughly pulverizing powdery coke into a specified grain size, finely pulverizing anthracite to adjust the specific grain size and blending these materials into the sintering raw material. SOLUTION: After blending the powdery coke and the anthracite into the sintering raw material, these raw materials are mixed and granulated and charged into a sintering machine and sintered to produce the sintered ore. At this time, the powdery coke is roughly pulverized into the grain size of >0 to 5.0 mm by >=80 wt.% and the anthracite is finely pulverized and adjusted to the gain size >0 to 2.0 mm by >=80 wt.% and these are blended into the sintering raw material. Then, the grain sizes of the powdery coke of >0 to 1.0 mm by 30-55 wt.%, 1.0-2.0 mm by 10-60 wt.% and 2.0-10.0 mm by >0 to 35 wt.%, are adjusted or granulated and blended into the sintering raw material, Further, the grain size of the anthracite of >0 to 1.0 mm by 55-70 wt.%, 1.0-2.0 mm at >0 to 30 wt.% and 2.0-10 mm at >0 to 30 wt.%, are adjusted or granulated and blended into the sintering raw material. By this method, the production can be increased while fixing the discharging quantity of NOX.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sintered ore in which coke breeze and anthracite are blended into a sintering raw material, the whole blended raw material is mixed and granulated, and then fired by a sintering machine. .

[0002]

2. Description of the Related Art Conventionally, in the production of sintered ore, sintering raw materials are mixed with coke breeze as a heat source, anthracite of low cost and low nitrogen content, mixed, granulated by a granulator, and then sintered. The sintering operation is carried out by igniting coke breeze and anthracite in the surface layer of the sintering bed with an ignition furnace, and sucking from below while maintaining good permeability of the sintering layer. Then, in order to improve the quality of the sinter, the particle size has been adjusted to reduce the coke breeze and the anthracite that have an adverse effect on the air permeability to 0.5 mm or less.

[0003]

However, these means can improve the permeability of the sintered layer, but make the grain size coarser for anthracite with poor flammability, but rather decrease the burning rate of the anthracite. As a result, there is a problem that the temperature in the sintered layer is lowered, the product yield is lowered, and the production rate is lowered as a result. Furthermore, despite the use of anthracite with low N content, the temperature in the sintering layer decreases, so that the NOx conversion rate of coke and anthracite deteriorates, and the suppression of NOx generation by using anthracite with low N content. There is a drawback that the effect cannot be sufficiently exhibited.

Japanese Patent Application Laid-Open No. 62-220590 discloses that 70% of a part having a particle size of 5 mm or less is contained in 100 parts of fine coke containing 50% by weight or more of a part having a particle size of 0.25 mm or less.
The above-mentioned coal is blended in a ratio of 10 to 70 parts, and a hydraulic binder such as cement, granulated blast furnace fine powder and the like is added to the obtained mixture in an amount of 3% or less, and granulated and cured to obtain a desired granular fuel. The method of obtaining is described. Although this method is effective in improving the combustibility of coke breeze, coal with low flammability (anthracite) becomes coarser due to granulation. , Lowering product yield
There is a disadvantage that the effect of suppressing the amount of Ox emission is reduced.

An object of the present invention is to provide a method for producing a sintered ore that improves product yield and significantly reduces NOx emissions when coke breeze and anthracite are simultaneously used as a fuel for a sintering compound. With the goal.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention adjusts or granulates the particle size distribution of coke breeze and anthracite to be blended in a sintering raw material before sintering. The combustion speed is made almost the same, the maximum temperature in the sintered layer is raised, and the product yield is improved, and the NOx emission is largely suppressed. That is, the gist of the present invention is as follows.

[0007] In a method for producing a sintered ore in which coke breeze and anthracite are blended into a sintering raw material, mixed, granulated, charged into a sintering machine and calcined, coke breeze is coarsely pulverized to 0%.
Sinter ore characterized in that super-5.0 mm has a particle size of 80 wt% or more, and anthracite is finely pulverized to adjust the particle size of more than 0 to 2.0 mm to 80 wt% or more and blended into a sintering raw material. Manufacturing method.

In a method for producing a sintered ore in which coke breeze and anthracite are blended into a sintering raw material, mixed, granulated, charged into a sintering machine and fired, the particle size of the coke breeze is more than 0 to
1.0 mm is 30 to 55 wt%, 1.0 to 2.0 mm is 10 to 60 wt%, and 2.0 to 10.0 mm is more than 0 to 35.
wt% is adjusted or granulated and blended into the raw material for sintering.
0 to 2.0 mm is more than 0 to 30 wt%, 2.0 to 10.0
A method for producing a sintered ore, comprising adjusting or granulating mm to be more than 0 to 30 wt% and blending in a sintering raw material.

[0009] The method for producing a sintered ore as described above, wherein the ratio of anthracite average particle size / coke fine average particle size is adjusted or granulated to 0.45 to 0.90 and blended into a sintering raw material.

[0010] The method for producing a sintered ore described above, wherein the whole compounded raw materials are mixed and granulated, and then charged into a sintering machine via a segregation charging device.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION
While reducing the amount of fine powder of 1.0 mm and increasing the particle size of coarse particles of 1 to 5 mm to improve the combustibility of coke breeze, for anthracite, the amount of fine powder of more than 0 to 1.0 mm is increased, This is a method of improving the flammability by reducing the particle size of coarse particles of 1 to 5 mm.

Table 1 shows an example of the measurement results of the burning rate of coke breeze and anthracite at 1000 ° C., which were subjected to a combustion test by flowing air through a thermobalance. The temperature was raised up to 1000 ° C. by flowing a nitrogen gas (inert gas). As for the coke breeze, it can be seen that the burning speed is higher in the case of 1.0 to 2.0 mm and 2.0 to 5.0 mm than in the case of exceeding 0 to 1.0 mm.
On the other hand, for anthracite, on the other hand, the burning speed of more than 0 to 1.0 mm is the fastest, and 1.0 to 2.0 mm, 2.0 to 5.0 mm.
mm, the burning rate decreased. The porosity of anthracite, a kind of coal, is less than 1/3 of the porosity of coke breeze as shown in Table 2 as measured by a mercury intrusion porosimeter, and the ash content of anthracite is as shown in Table 2. There is more than 1.5 times the ash content of coke.
Since the porosity is small and the ash content is large, it is considered that, unlike coke breeze, the flammability of anthracite is improved as the powder becomes finer.

[0013]

[Table 1]

[0014]

[Table 2]

Combining the reduction of more than 0 to 1.0 mm of the fine coke powder with the increase of more than 0 to 1.0 mm of the anthracite fine powder, unlike the prior art, Since the burning rates of the anthracite coalesce, the maximum temperature in the sintered layer rises. Increasing the maximum temperature in the bed increases the amount of melt generated to improve the product yield of sinter, and furthermore, N contained in coke breeze and anthracite is reduced to FuelNOx (FuelNOx is Th
Unlike thermal NOx, the higher the temperature is, the lower the rate of NOx generation (NOx conversion rate) is reduced.

In the method of the present invention, coke breeze is coarsely pulverized and
Ultra-5.0 mm has a particle size of 80 wt% or more;
Combination of pulverizing anthracite into a particle size of more than 0 to 2.0 mm of 80 wt% or more. When the coke breeze is coarsely pulverized by a pulverizer such as a rod mill so that 5% or less becomes 80% or more, it is generally 1.0 to 1.0 mm.
〜5.0 mm shows a relatively large particle size distribution.
On the other hand, when anthracite is pulverized with a pulverizer such as a rod mill so that 2 mm or less becomes 80% or more, generally, 1.
It shows a particle size distribution in which a value greater than 0 to 1.0 mm relative to 0 to 2.0 mm is relatively large. Therefore, when both are combined, as described above, the combustion speeds of the coke breeze and the anthracite are close to each other, and the effect of improving the product yield and reducing the NOx generation is exhibited.

Furthermore, the particle size of the coke breeze is more than 0 to 1.0.
mm is 30 to 55 wt%, 1.0 to 2.0 mm is 10
60wt%, 2.0-10.0mm is more than 0-35wt%
The particle size of anthracite is more than 0 ~ 1.0mm is 55 ~ 70w
t%, 1.0 to 2.0 mm is more than 0 to 30 wt%, 2.0
The reason why ｍｍ10.0 mm is more than 0 to 30 wt% is as follows.

First, it was confirmed from the results of a pot test conducted in advance that the above-mentioned particle size range of coke breeze was optimal for improving product yield and reducing NOx generation.

More than 0 to 1.0 mm of coke breeze is 30 to 5
The reason for setting the content to 5 wt% is as follows. In a normal sintering machine, the upper part of the sintering bed tends to have more than 0 to 1.0 mm of coke breeze, and the middle and lower parts of the bed tend to have more than 1.0 mm of coke breeze. If more than 0 to 1.0 mm of coke breeze is less than 30 wt%, the coke blending ratio in the upper layer of the bed tends to decrease, and the product yield in the upper layer tends to deteriorate. On the other hand, when the particle size exceeds 55% by weight, on the contrary, the phenomenon that the permeability of the sintering bed deteriorates and the productivity decreases becomes remarkable.

The coke breeze 1.0 to 2.0 mm
The reason why the content is set to 60 wt% is that the combustion rate of the coke breeze increases remarkably from 10 wt% or more, but when the content exceeds 60 wt%, the effect level out.

The reason why 2.0 to 10.0 mm of the coke breeze is more than 0 to 35 wt% is that when the content exceeds 35 wt%, a decrease in product yield starts to be seen.

Within the above-mentioned optimum range of the coke breeze particle size, the effect starts to be exhibited when the anthracite is more than 0 to 1.0 mm becomes 55 wt% or more, and when it becomes more than 70 wt%, conversely, the product yield due to the deterioration of the permeability of the sintering bed is obtained. The negative effects of the decline and the decrease in production rate begin to be seen.

[0023] Anthracite 1.0 to 2.0 mm exceeds 0 to 30
The reason for setting it to wt% is that if it exceeds 30 wt%, the burning rate of anthracite starts to decrease remarkably.

2.0 to 10.0 mm of anthracite exceeds 0 to 3
The reason for setting it to 0 wt% is that if it exceeds 30 wt%, the burning rate of anthracite starts to decrease remarkably.

The reason why the ratio of the average particle size of anthracite / the average particle size of coke breeze is adjusted to 0.45 to 0.90 is as follows. Every particle size (10mm or more, 10-5mm, 5-2m
m, 2-1 mm, 1-0.5 mm, 0.5-0.25 m
m, 0.25-0.125 mm, 0.125-0.06
2 mm, 0.062 mm or less).
Within the optimum particle size range of anthracite, when the ratio of the anthracite average particle size / the average coke fine particle size is 0.90 or less, the effects of improving product yield and suppressing NOx generation begin to become remarkable, and as this ratio decreases, NOx generation increases. The result that the effect of the amount suppression became larger was obtained. However, when this ratio is less than 0.45, the permeability of the sintering bed decreases, the phenomenon that the product yield deteriorates conspicuously becomes remarkable, and the effect of suppressing the generation amount of NOx also reaches a plateau.

Furthermore, after adjusting the particle size of the coke breeze and anthracite, mixing and granulating the entire blended raw material, and then charging the mixture into a sintering machine via a segregation charging device, the upper layer of the sintering bed is formed. More than 0 of coke breeze ~ 1.0mm plus more than 0 of anthracite ~
Since 1.0 mm is gathered more, under the condition that the permeability of the sintered bed is constant, the temperature in the upper layer of the bed rises, the component yield in the upper layer is further improved, and the NOx emission is also reduced. At the same time, it is particularly preferable because it is more suppressed.

[0027]

EXAMPLES Table 3 shows the mixing ratio of the raw materials used in the pot test, and Table 4 shows the particle size distribution of coke breeze and anthracite used in the pot test. The charging of the sintering raw material into the pan test apparatus in all tests is performed by a charging apparatus that continuously segregates the grain size in the direction of the bed height (Masami Fujimoto et al .: Materials and Processes, 1 (1988), p. 37-39). Various tests have already confirmed that there is a correspondence between the results of the pot test and the results of the actual operation of the machine.

[0028]

[Table 3]

[0029]

[Table 4]

As compared with the comparative example, the average particle size was reduced by decreasing the anthracite by 2 mm or more and increasing by 1 mm or less from Example 1 to Example 3. The particle size of the coke breeze was adjusted by a sieving method, and for anthracite, the particle size was adjusted by a sieving method after crushing once. The ratio of the average particle size of anthracite / the average particle size of coke breeze was 0.78 in Example 1, 0.57 in Example 2, 0.50 in Example 3, and 1.0 in Comparative Example.

FIG. 1 shows the production rate, product yield,
TI (cold strength, measured according to JIS M8712), RD
I (low-temperature reduction pulverization index, ironmaking subcommittee method), JIS reduction rate (JISM8713), and basic unit of NOx emission are shown.

FIG. 2 shows an example of a heat pattern measurement result in the sintering process. According to the method of the present invention, the maximum temperature from the upper layer to the lower layer of the heat pattern in the sintered layer rises to 90%.
There was also a tendency for the high-temperature holding time at 0 ° C. or higher to be uniform, and it was found that this simultaneously improved the product yield and suppressed the amount of NOx generated.

FIG. 3 shows the proportion of carbon in the height direction of the sintered bed layer. It is considered that the effect of the method of the present invention is that the carbon ratio of the upper layer is increased, and anthracite having a fine particle size segregates in the upper layer more.

In the example, the product yield of the sintering bed was improved, and the production rate was improved. In addition, since the maximum temperature in the sintering layer increases and the amount of the melt increases, the product yield and TI and RDI are improved, and the temperature distribution in the sintering layer is made uniform in the bed, in the middle, and in the lower layer, Furthermore, since the micropores are increased and uniformly dispersed in the sintered ore structure, the JIS reduction rate is also improved. Further, since the maximum temperature in the sintered layer rises, FuelNO
The generation amount of x was suppressed.

[0035]

According to the present invention, the product yield of sintered ore can be improved, and NOx emission can be suppressed. It is also possible to increase the amount of sinter production while keeping the NOx emission of the sintering machine exhaust gas constant. In addition, since the properties of the ore to be reduced are greatly improved, it contributes to the stable operation of the blast furnace.

[Brief description of the drawings]

FIG. 1 is a view showing the results of a pot test of a sintered ore.

FIG. 2 is a diagram showing an example of a heat pattern measurement result in a sintered layer.

FIG. 3 is a view showing a carbon ratio in a sintering bed layer height direction of an actual sintering machine.

Claims (4)

[Claims] 1. A method for producing a sintered ore in which coke breeze and anthracite are blended into a sintering raw material, mixed, granulated, charged into a sintering machine and fired, and the coke breeze is coarsely pulverized. Sinter ore characterized in that super-5.0 mm has a particle size of 80 wt% or more, and anthracite is finely pulverized to adjust the particle size of more than 0 to 2.0 mm to 80 wt% or more and blended into a sintering raw material. Manufacturing method. 2. A method for producing a sintered ore in which coke breeze and anthracite are blended into a sintering raw material, mixed, granulated, charged into a sintering machine and fired, wherein the particle size of the coke breeze is more than 0 to 2.
1.0 mm is 30 to 55 wt%, 1.0 to 2.0 mm is 10 to 60 wt%, and 2.0 to 10.0 mm is more than 0 to 35.
wt% is adjusted or granulated and blended into the raw material for sintering.
0 to 2.0 mm is more than 0 to 30 wt%, 2.0 to 10.0
A method for producing a sintered ore, comprising adjusting or granulating mm to be more than 0 to 30 wt% and blending in a sintering raw material. 3. The sintering material according to claim 1, wherein the ratio of anthracite average particle size / coke powder average particle size is adjusted or granulated to 0.45 to 0.90 and blended into a sintering raw material. The method of producing condensate. 4. The method for producing a sintered ore according to claim 3, wherein the whole raw materials are mixed and granulated, and then charged into a sintering machine via a segregation charging device.