JPH07252542A - Exhaust gas circulation sintering method - Google Patents

Abstract

PURPOSE:To provide an exhaust gas circulation sintering method capable of improving the product yield and the productivity of sintered ore by circulating the exhaust gas into the bed in a sintering machine. CONSTITUTION:In this exhaust gas circulation sintering method in which the exhaust gas in the sintering machine is again circulated into the sintering machine bed 2 and reused, the temp. in the part having >=90% vertical cross section of the sintered layer at an ore discharging part 7 for discharging the sintered ore from the sintering machine, or the temp. at least in a part of the sintered layer at the ore discharging part, is restrained to <=1100 deg.C. By this method, the product yield, strength and productivity of the sintered ore are improved, and further, heat source and dusting quantity can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintering operation method, and more specifically, to a product yield of sintered ore in an exhaust gas circulation sintering operation process in which exhaust gas from a sintering machine is recirculated to a bed of the sintering machine for reuse. The present invention relates to a sintering operation method for improving strength and productivity, and further reducing a heat source such as powder coke and a dust generation amount.

[0002]

2. Description of the Related Art In a DL type sintering machine, a sintering raw material composed of powdered ore + powdered coke + limestone has a layer thickness of 400 to 600 m.
m on the sinter machine pallet, and after igniting the powder coke on the surface, air is sucked toward the wind box installed at the bottom of the sintering bed, and the coke powder is burned to solidify and burn. Produce mine.

Therefore, the sintering progresses from the upper layer to the lower layer, and when the combustion of the lowermost layer is completed, the sintering is completed. During this time, the sinter machine pallet moves from the raw material charging side toward the sinter ore discharge side.

The exhaust air temperature in the air box in such a sintering process is low because the heat of combustion is absorbed by the layers in the middle while the layers other than the lower layer are sintered, but the temperature in the lowermost layer burns. When the temperature reaches, the temperature rises rapidly and the exhaust air temperature reaches the highest point. Generally, this highest point is set as a sintering completion point, and when this temperature is confirmed, it is considered that the sintering is completed, and the ore is immediately discharged.

For example, as in the technique disclosed in Japanese Unexamined Patent Publication No. 51-139502, the pallet speed control is performed so that the sintering completion time, that is, the sintering point comes to the point where the ore is just discharged.

[0006]

However, in the conventional exhaust gas circulation sintering operation in which the exhaust gas of the sintering machine is recirculated to the bed of the sintering machine and reused, a high temperature gas is introduced from the upper portion, so that the sintering layer is As a result, the cooling capacity by the gas becomes smaller, and as a result, the thickness of the fusion zone (hereinafter referred to as red tropical zone) in the sintering bed is significantly increased as compared with the normal sintering method.

Therefore, in the exhaust gas circulation sintering method,
For example, if the operation described in JP-A-51-139502 is carried out, the bottom layer is still at a high temperature and is in a molten state at the time of mine removal. When the ore is discharged in such an unsolidified state, it is fragmented by falling impact or crushing by a crusher, and a large amount of fine ore that does not become a sintered mineral product in the finally solidified state is generated.

The present invention is made to solve the above-mentioned drawbacks, and the product yield of the sintered ore is obtained by completely calcination and solidification of the lower part of the sintering bed and then discharging. Provide a sintering operation method that significantly improves strength and productivity and further reduces the heat source such as powder coke and the amount of dust generation.

[0009]

According to the present invention, when a sintered ore is manufactured by a DL type sintering machine, the exhaust gas of the sintering machine is returned to the bed of the sintering machine and reused, and an exhaust gas circulating sintering operation is performed. In the method, an exhaust gas circulation sintering operation method is characterized in that the temperature of 90% or more of the longitudinal section of the sintered layer of the slag discharge part for discharging the sinter from the sintering machine is suppressed to 1100 ° C or less. is there.

Further, according to the present invention, in the exhaust gas circulation sintering operation method in which the exhaust gas of the sintering machine is recirculated to the bed of the sintering machine for reuse, the sintering ore is discharged from the sintering machine. It is an exhaust gas circulation sintering operating method characterized in that the temperature of at least part of the layer is suppressed to 1100 ° C or lower.

In this way, the product yield, strength, and
The productivity is greatly improved, and the heat source such as coke dust and the amount of dust generation are reduced.

[0012]

According to the research conducted by the present inventors, the melting part (hereinafter referred to as red tropical zone) in the sintering bed in the exhaust gas circulation sintering method.
The thickness is thin in the upper layer portion at the initial stage of sintering and becomes thicker as it moves to the lower layer portion, as shown in the schematic side sectional view (a) of the sintering machine in FIG. And in the lowermost layer, the red tropical thickness S grows to about 130 mm. As a result, it was found that the length L of the red tropical zone 4 in the pallet traveling direction was about 10 to 15 m.

With respect to this red tropical zone 4, the temperature distribution of the longitudinal section of the sinter layer as seen from the smelting ore side was measured at the smelting ore discharging section for discharging the sinter, and the product yield of the sinter was obtained. As a result of investigating the relationship with
There is a close relationship between the area ratio below ℃ and the product yield.
It was found that the product yield tends to deteriorate when the area of 100 ° C. or less is about 90% or less, and the highest product yield is exhibited when the area is 90% or more.

The reason for this is that when the area below 1100 ° C. is 90% or less, there is a molten portion in the sintering bed layer, and if the molten material is discharged from the sinter machine pallet in this state, the unsolidified sintering layer will fall and drop. Due to the shearing force caused by crushing with a crusher or crusher, fine particles of 5 mm or less that do not become a sintered product are generated.

Further, when the area is 90% or more at 1100 ° C. or less, there is almost no molten portion in the sintering bed layer, and the sintering bed layer is completely solidified. It was found that even if the crusher was crushed, the generation of fine particles of 5 mm or less that did not become a sintered product showed a minimum value.

In this way, in the sinter machine slag discharge section for discharging sinter from the sinter machine, the temperature of the section having a vertical cross section of the sinter layer of 90% or more is set to 1100 ° C. or less. By firing at, it becomes possible to improve the product yield.

[0017]

EXAMPLES The present invention will now be described in detail based on examples.

FIG. 3 shows an example of a sintering machine suitable for carrying out the present invention. In the figure, 1 is an ignition furnace, 2 is a sintering bed, 3 is a pallet, 4 is a red tropics, 5 is a suction air box, 6 is a radiation thermometer for the sintering bed, 7 is a mine ore, 8 is a circulating gas suction A blower, 9 is a circulating gas suction duct, 10 is a calculator, 11 is a pallet speed controller, 12 is an exhaust blower, 13 is a circulating gas blowing hood, and 14 is a wind leg.

In the sintering, the coke in the raw material layer is ignited in the ignition furnace 1, and the sintering progresses toward the lower side of the sintering bed 2. Since the pallet 3 advances toward the mine ore side 7, the mine ore side of the red tropical zone 4 is located in the lowest layer.

In this case, the temperature distribution of the vertical section of the sintered layer is measured from the slag discharge side by the radiation thermometer 6 for the sintered layer, and the area of 1100 ° C. or less of the vertical section of the sintered layer is calculated by the calculator 10. If the calculated value is 90% or less, the pallet speed adjuster 11 reduces the pallet speed.

As a result, the area of the vertical section of the sintered layer at 1100 ° C. or less in the discharged ore portion where the sintering is completely performed on the sintering machine is increased, and the yield of the sintered mineral product is improved.

The sintered ore fired under these conditions was significantly improved in product yield, strength, and productivity, and the heat source such as powder coke and the amount of dust generation could be reduced.

Table 1 shows the results of operation using the sintering machine shown in FIG.

[0024]

[Table 1]

As shown in Table 1, the product yield according to the conventional example was 80%, while the product yield according to the present invention was significantly improved to 84% and the productivity was also improved. There is.

[0026]

As described above, according to the sintering operation method of the present invention, the temperature of 90% or more of the longitudinal section of the sintered layer of the slag ore is suppressed to 1100 ° C. or less, and the sinter of the sinter ore is sintered. By suppressing the temperature of at least a part of the bed to 1100 ° C or less and solidifying the molten portion in the sintered bed layer almost completely, the product yield, strength, and productivity of the sintered ore are greatly improved. In addition to being able to achieve this, it has become possible to further reduce the heat source such as powder coke and the amount of dust generation.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of a sintering bed for explaining the present invention, in which (a) shows the red tropical position in the sintering bed, and (b) shows the exhaust temperature of the bed lower layer. Show.

FIG. 2 is a drawing showing the relationship between the product yield and the area ratio of the vertical cross section of the sintered layer as viewed from the slag discharge side when the present invention is carried out at a temperature of 1100 ° C. or less.

FIG. 3 is a side sectional view showing an example of a sintering machine suitable for carrying out the present invention.

[Explanation of symbols]

 1 Ignition furnace 2 Sintered bed 3 Pallet 4 Red tropical zone 5 Suction air box 6 Sintered layer radiation thermometer 7 Exhaust ore section 8 Circulating gas suction blower 9 Circulating gas suction duct 10 Arithmetic unit 11 Pallet speed regulator 12 Exhaust blower 13 Circulating gas blowing hood 14 Wind leg

Claims (2)

[Claims] 1. In an exhaust gas circulation sintering operation method in which exhaust gas of a sintering machine is recirculated to a bed of a sintering machine and reused, a longitudinal section of a sintering layer of a slag ore portion for discharging sinter from the sintering machine. 90%
An exhaust gas circulation sintering operation method characterized in that the temperature of the above portion is suppressed to 1100 ° C. or lower. 2. In an exhaust gas circulation sintering operation method in which the exhaust gas of the sintering machine is recirculated to the bed of the sintering machine and is reused, at least one of the sintering layers of the slag discharge section for discharging the sintered ore from the sintering machine. An exhaust gas circulation sintering operation method characterized in that the temperature of a part is suppressed to 1100 ° C or lower.