JP3167076B2 - Operating method of exhaust gas circulation sintering machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating an exhaust gas circulating sintering machine, and more particularly, to preventing mixing of powdery coke into quasi-granulated raw material particles. The present invention relates to an operation method of an exhaust gas circulating sintering machine capable of reducing the amount of coke per unit weight, improving product yield, and realizing stable segregation of the amount of coke over the entire raw material layer.

[0002]

2. Description of the Related Art As one type of operation method for continuously sintering sintering raw materials, air is sucked downward from a sintering bed while moving a large number of sintering beds in a sintering machine in a daisy chain. There are known a Dwyroid type in which sintering is performed, and an exhaust gas circulation sintering method in which exhaust gas discharged from a sintering machine is returned to a sintering bed and reused as a heat source for sintering a sintering raw material.

In each operation method, a sintering material containing coke is charged on a sintering bed from a charging hopper, and then ignited in the upper part of the material layer in an ignition furnace of a sintering machine, and a heat-retaining furnace is set up. During the passage, the hot red tropics having a temperature of about 1100 degrees gradually descend to the lower layer, and the combustion is completed before being discharged from the sintering machine. The ideal sintering (appropriate sintering) by the Dwyroid method is shown by the broken line in the graph of FIG.

Meanwhile, in the exhaust gas circulation system, high-temperature exhaust gas is sucked into the raw material layer from above the bed, so that the preheating of the sintering raw material after passing through the red tropics becomes excessive as compared with the Dwyroid system in which air is sucked. The red tropical zone having a large pressure loss becomes thicker toward the lower layer of the raw material layer (see the solid line in FIG. 6). As a result, the air permeability deteriorates, and the sintering temperature becomes higher from the upper layer to the lower layer, and the strength of the sintered ore, which is a major determinant of the temperature, varies, thereby lowering the product yield.

[0005] In order to solve these problems, the amount of coke blended in the sintering raw material, for example, as described in "Method of sintering iron ore" in JP-A-53-125904, is disclosed. Is increased toward the upper layer side of the raw material layer so that an appropriate heat balance can be obtained over the entire layer on the sintering bed.
According to this method, the sintering temperature of the raw material layer is made as uniform as possible by obtaining an appropriate heat balance, sinter having a stable strength is produced, and the product yield is improved.

As a method of increasing the coke amount toward the upper layer side of the raw material layer, for example, as shown in FIG.
A method using a sizing / dispersion type charging apparatus (Japanese Utility Model Laid-Open No. 1-66599) having a number of bear-shaped bars shown in FIG. As shown in FIG. 7, the sizing / dispersion type charging device 10
0 indicates that the pseudo-granulated large-sized sintering raw material F is dropped from the wide end between the bars 102 onto the moving empty sintering bed 101, and then the sintering material having the gradually reduced particle size is obtained. The raw material F falls from the center and the vicinity of the base of the bar 102, and finally, the sintering raw material F having the smallest particle size falls from the end of the base of the bar 102.

As shown in FIG. 8, powdery coke C is adhered to the particle surface of the sintering raw material F in the granulation step. As the surface area of the coke increases, the overall coke amount increases. Therefore, this sizing / dispersion type charging device 100
When the raw material is charged into the sintering bed 101, the amount of coke in the upper layer of the raw material layer on which the fine sintering raw material F is laminated is larger than that in the lower layer.

However, in a usual granulation method, a sintering raw material F is added while adding a predetermined amount of water in a mixer.
And the powdered coke C are stirred to form pseudo-granules, so that the powdered coke C is wrapped inside the particles of the sintering raw material F. The powdered coke C that has been mixed into the sintering raw material F
Unlike powdered coke C on the surface of particles directly exposed to a flame during sintering of a raw material, it merely increases the usage of powdered coke C and lowers the product yield irrespective of combustion.

In order to solve this problem, the applicant of the present invention has developed a "preliminary treatment method for sintering raw materials" in Japanese Patent Application Laid-Open No. 54-4809 prior to the present application.
According to this method, a predetermined amount of moisture is impregnated in advance into powdered coke C, and the resulting mixture is mixed with a sintering raw material F and pseudo-granulated by adding a smaller amount of water than usual in a mixer. Thus, raw material particles having a large ratio of powdered coke C adhered to the particle surface can be obtained.

[0010]

However, in this conventional method, the adhering ratio of the powdery coke C to the particle surface increases, but on the other hand, some powdery coke C In spite of causing pseudo-granulation of C, and although the amount is not as large as before, some powdered coke C is wrapped in the raw material particles and the set amount of powdered coke C is mixed. However, there is a problem in that the coke amount is increased toward the upper layer described above, that is, the segregation of the coke amount over the entire raw material layer varies, and the segregation of the coke amount cannot be stably performed.

The present invention has been made in view of such circumstances, and it is possible to prevent powdery coke from being mixed into quasi-granulated raw material particles, thereby reducing the amount of coke per unit weight of the quasi-particles and improving product quality. It is an object of the present invention to provide a method of operating an exhaust gas circulating sintering machine capable of improving the yield and realizing stable segregation of the coke amount over the entire raw material layer.

[0012]

According to the present invention, there is provided a semiconductor device comprising:
The operation method of the exhaust gas circulation sintering machine described above is a soaking process before mixing powder coke with the sintering raw material, and the sintering raw material has a soaking water content of 8.5 to 10.0% by mass. A granulation is performed in advance by adding moisture, and then, in a granulation step, the powdery coke is adhered to and mixed with the particle surfaces of the sintering raw material, and then the pseudo-granulated sintering raw material is sintered. It is configured to be charged into.

The method for operating an exhaust gas circulating sintering machine according to claim 2 is a method for operating an exhaust gas circulating sintering machine according to claim 1, wherein the circulating exhaust gas of a sintering machine for circulating exhaust gas is circulated. According to the amount, the amount of coke in the raw material layer is configured to increase in a graded manner toward the upper layer side of the raw material layer.

[0014]

In the method for operating an exhaust gas circulating sintering machine according to the first or second aspect, the sintering raw material has a soaking water content of 8.5 to 8.5 in the soaking process.
Since the powdered coke is attached to the particle surface after preliminarily granulating with water in a range of 10.0% by mass, there is little possibility that the powdered coke is wrapped in the raw material particles,
Dried powdery coke adheres to the surface of the granulated raw material particles, whereby the amount of coke per unit weight of the pseudo particles can be reduced and the product yield can be improved.

In particular, in the method for operating the exhaust gas circulation sintering machine according to the second aspect, the amount of coke in the raw material layer is reduced according to the exhaust gas circulation location and the circulation amount of the sintering machine for performing exhaust gas circulation sintering. Incremental ramping towards the upper side of the layer increases the appropriate thermal balance across the layers on the sintering bed, in line with the sintering of the various exhaust gas recirculations, which allows the lower red tropical It is possible to reduce the thickness, improve air permeability, stabilize good product strength, and improve product yield. In addition, since powdery coke is attached to the surface of the particles after the sintering material is pre-granulated with moisture in the soaking process, there is almost no powdery coke wrapped in the raw material particles, and the preset value is set. The addition amount of the powdery coke is substantially the amount actually added to the surface of the raw material particles, whereby the variation in the segregation of the coke amount over the entire raw material layer can be eliminated.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is a schematic configuration diagram of a sintering machine of an exhaust gas circulation system to an ore mining unit according to an embodiment of the present invention, and FIG. FIG. 3 and FIG. 3 are schematic structural views of a sintering machine of an exhaust gas circulation type to the feed / discharge section,
FIG. 5 is a graph showing the relationship of proper coke segregation in a layer, and FIG. 5 is an enlarged plan view of raw material particles showing a granulation step.

An operation method of an exhaust gas circulating sintering machine according to one embodiment of the present invention is a method of exhaust gas circulating sintering wherein exhaust gas discharged from a sintering machine through a main duct is returned to a sintering bed by a blower and reused. It is an operation method in the conclusion. Figures 1-3
As shown in FIG. 1, in the exhaust gas circulating sintering machine 10 (10A to 10C) adopting this method, an exhaust gas circulating system (see FIG. An exhaust gas circulation system to the ore supply unit 13 (see FIG. 2) and an exhaust gas circulation system to the supply and discharge units 12 and 13 (see FIG. 3)
There are two types.

In each type, a sintering raw material mixed with coke is charged from a charging hopper 15 onto a sintering bed 14 and ignited above a raw material layer 16 in an ignition furnace of a sintering machine 10. While the exhaust gas 11 is being sucked while passing through the heat retention furnace, the hot red tropical zone 17 gradually descends to the lower layer, and the combustion is completed before being discharged from the sintering machine 10. Then, the sintered ore of the produced sintered layer 18 is crushed by the primary crusher,
Cooled in cooler.

As shown in FIG. 5, the method of operating the exhaust gas circulating sintering machine according to the present invention is characterized in that in the soaking process before the powdery coke C is mixed with the sintering raw material F, as shown in FIG. , Granulate in advance with water, and then add powdered coke C
Then, the quasi-granulated sintering raw material F is charged into the sintering bed 14. The soaking process is a process of sintering raw materials F of different brands stored in a plurality of relay tanks, respectively.
This is the process of blending (iron ore) and stacking it in a pile called soaking.

Before being piled up in the soaking material, water is sprayed on the surface of the sintering raw material F so that the soaking water becomes 7.0 to 10.0% by mass, particularly 8.5 to 10.0% by mass. Is done. If the soaking water content is less than 7.0% by mass, the quasi-granulation strength becomes the same as the conventional one, and the effect of the present invention is not obtained. 10.0 mass%
Exceeding the range causes excessive moisture, and conversely causes deterioration of the ventilation of the sintered bed. In addition, it caused a landslide when handling,
Work becomes difficult. For example, when the soaking water is 8.5% by mass, (+0.25 mm% after drying) 乾燥 (+
The pseudo-granulation index GI ₂ obtained by the formula of (0.25 mm%) × 100 was as high as 90%.

Also in the conventional method, the soaking water is as small as about 6.5% by mass due to the water carried in the sintering raw material F piled up in the soaking, and the pseudo-granulation index GI ₂ is 83%.
% Was small. Thereafter, the sintering raw material F is cut out from the ore, and then sent to the granulation process together with the powdery coke C stored in the coke storage section of the ore storage tank, where it is pseudo-granulated by the mixer and granulated. You. The sintering raw material F thus granulated is then sent to the sintering machine 10.

As described above, the sintering raw material F is preliminarily granulated with a predetermined moisture content in the soaking process, and then the powdered coke C is adhered to the particle surfaces. The possibility that the coke C is wrapped is small, and the dry coke C adheres to the surface of the granulated raw particles, so that the coke amount per unit weight of the pseudo particles can be reduced and the product yield can be improved. .

Further, in the present embodiment, the amount of coke in the upper layer of the raw material layer 16 is increased from the lower layer in a graded manner in accordance with the location and the amount of exhaust gas circulation of the sintering machine 10. As a result, an appropriate heat balance can be obtained throughout the layers on the sintering bed 14 in accordance with the sintering of various exhaust gas circulations without forming a grain size fault, and the lower red tropical zone 17a having an optimum thickness is continuously obtained. As a result, the air permeability is improved, good product strength is stabilized, and the product yield is improved. Moreover, as described above, since the sintering raw material F is preliminarily granulated by adding moisture to the sintering raw material F in the ore-sizing process, the powdery coke C is adhered to the particle surface. The binding material F is a pseudo particle having a relatively large bond strength centered on the core particle. Therefore, the powdery coke C wrapped in the raw material particles hardly exists, and the amount of the powdery coke C that is set in advance is substantially the amount added to the actual surface of the raw material particles. Thereby, the variation in the segregation of the coke amount over the entire raw material layer is reduced and the coke amount can be stabilized.

As a means for increasing the amount of coke in the upper layer of the raw material layer 16 in a more inclined manner than in the lower layer, for example, a sizing / dispersion type charging apparatus shown in FIG. When adjusting the segregation index of the coke amount in the upper and lower layers of the raw material layer 16, a simple operation of increasing or decreasing the interval between the bars may be performed.

Next, referring to Table 1, sintering examples (cases 2, 4, and 6) by the operation method of the exhaust gas circulating sintering machine according to one embodiment of the present invention and the conventional exhaust gas circulating sintering machine will be described. The sintering examples (cases 1, 3, and 5) according to the operation method will be specifically compared and described. In addition, the base in Table 1 shows an appropriate sintering operation of the Dwight toroid system as an adjustment target, and 1) to 4) in the same table show four segregation patterns of coke in a layer in FIG. Indicates the segregation index of the coke amount in the upper layer and the lower layer of the raw material layer 16.

[0026]

[Table 1]

As is evident from Table 1, in the soaking step before mixing the powdered coke C with the sintering raw material F, the sintering raw material F was sprinkled with water so as to have a predetermined soaking water content, and was previously granulated. Then, it was sent to the granulation step to attach the powdery coke C to the particle surface, so that the powdery coke C
The amount of coke per unit weight of the pseudo particles was reduced by 0.7 to 3.4 kg / t, and the product yield was improved by 0.8 to 2.9%. Further, the coke amount of the upper layer and the lower layer of the raw material layer 16 is
Depending on the location and amount of exhaust gas circulation of the sintering machine 10, the raw material layer 1
6, because the productivity, product yield, air permeability, cold strength, and the like approach or exceed the values at the time of proper operation of the base, the operation is improved. Coke and recovered steam could be improved.

[0028]

According to the method for operating the exhaust gas circulation sintering machine according to the first and second aspects of the present invention, in the soaking step before mixing the powdery coke with the sintering raw material, the sintering raw material is given a predetermined uniformity. Since water was sprinkled so as to become mineral water and granulated in advance, and then sent to the granulation process to attach powdered coke to the particle surface,
The wrapping of the powdery coke in the raw material particles is reduced, whereby the amount of coke per unit weight of the pseudo particles can be reduced and the product yield can be improved.

In particular, in the operation method of the exhaust gas circulating sintering machine according to the second aspect, the coke amount in the entire raw material layer is increased toward the upper layer side of the raw material layer according to the exhaust gas circulating location and the circulating amount of the sintering machine. As a result, an appropriate heat balance can be obtained over the entire layer on the sintering bed without forming a grain size fault, and a lower red tropical zone of optimal thickness can be continuously formed. As a result, air permeability is improved, good product strength is stabilized, and product yield can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a sintering machine of an exhaust gas circulation system to an ore removal section according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a sintering machine of an exhaust gas circulation type to the ore supplying section.

FIG. 3 is a schematic configuration diagram of a sintering machine of an exhaust gas circulation system to the feed / discharge section.

FIG. 4 is a graph showing the relationship of proper coke segregation in a layer.

FIG. 5 is an enlarged plan view of raw material particles showing a granulation step.

FIG. 6 is a graph showing a holding time at 1000 ° C. in a portion inside a layer.

FIG. 7 is an enlarged side view of a main part showing a use state of the sizing / dispersion type charging device.

FIG. 8 is an enlarged plan view of raw material particles granulated by conventional means.

[Explanation of symbols]

10: Exhaust gas circulation sintering machine, 10A: Exhaust gas circulation sintering machine
10B: Exhaust gas circulating sintering machine, 10C: Exhaust gas circulating sintering machine, 11: Exhaust gas, 12: Mining part, 13: Mining part, 1
4: sintering bed, 15: charging hopper, 16: raw material layer, 1
7: Red tropical, 17a: Lower red tropical, 18: Sintered layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-232935 (JP, A) JP-A-61-153239 (JP, A) JP-A-61-217535 (JP, A) JP-A-53-153 125904 (JP, A) JP-A-63-100137 (JP, A) JP-B-57-45297 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22B 1/00-61 / 00

Claims (2)

(57) [Claims] In a soaking process before mixing powdery coke with a sintering raw material, the sintering raw material has a soaking water content of 8.5 to 10.0.
In the granulation step, the powdered coke is adhered to and mixed with the particle surface of the sintering raw material, and then the pseudo-granulated sintering is performed. A method for operating an exhaust gas circulation sintering machine, comprising charging a sintering material into a sintering bed. 2. The method according to claim 1, wherein the amount of coke in the raw material layer is gradually increased toward the upper layer side of the raw material layer according to an exhaust gas circulating location and a circulating amount of the sintering machine for performing exhaust gas circulating sintering. The method for operating an exhaust gas circulation sintering machine according to claim 1, wherein