JPH07166250A - Production of sintered ore using metallic iron - Google Patents

Abstract

PURPOSE:To reduce NOx and CO2 gas contents in sintering exhaust gas without requiring the fuel of powdery coke, etc., by utilizing the combustion heat of metallic iron as the heat source for sintering, at the time of producing the sintered ore by using the iron ore. CONSTITUTION:At the time of producing the sintered ore as the raw material for blast furnace by sintering the powdery iron ore, lime stone, etc., the powder of the metallic iron is added to the mixed material of the iron ore and the lime stone and laid on a sintering bed in a sintering apparatus, and hot blast is supplied from hoods 5, 7 at the upper part. Then the mixed raw material is sintered by oxidation of the metallic iron in the mixed raw material and the high temp. gas with combustion reaction to produce the sintered ore as the raw material for blast furnace. In this case, the high temp. exhaust gas sucked from the end part 1 of the sintering bed is supplied in the raw material from the first hood 5 through a heat exchanger 4 as the clean high temp. hot blast having small quantity of NOx, CO2, etc., after removing the contained solid material through collector 2, 3. Further, the clean air from a blower 6 is heated in the heat exchanger 4 and supplied to the raw material layer from the second hood 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a production method in the field of sinter ore production, which utilizes the addition of a hot air circulation system to promote the oxidation exothermic reaction of metallic iron.

[0002]

2. Description of the Related Art Conventionally, powder coke has been used as a heat source for the production of sinter, and the combustion heat has been used to cause fusion and sintering.

[0003]

By using hot air generated from a sintering machine or clean hot air that has been heat-exchanged in the sintering reaction using metallic iron as a heat source, fuel cost can be reduced and at the same time low NOx and low exhaust gas can be obtained. The object of the present invention was to achieve CO ₂ conversion.

[0004]

Therefore, the present invention is required for sintering by using metallic iron as a heat source and further blowing hot hot air and clean hot air into the sintering bed to promote the oxidation exothermic reaction of the metallic iron. Supply a certain amount of heat.

[0005]

As described above, by changing the conventional sintering method using the combustion heat of powder coke to a sintering method in which the hot air circulation system according to the present invention is added to promote the oxidation exothermic reaction of metallic iron, the fuel cost can be reduced. Reduction, low NOx, low CO ₂ complete sintering can be performed.

[0006]

EXAMPLES Table 1 shows the raw material compounding ratios used in the present sintering method. FIG. 1 is an example of a hot air circulation system flow in which hot air generated from the sintered ore manufacturing process of the present invention is partially heat-exchanged with clean hot air and sent to the sintering bed. In this example, 1,
The hot air sucked from the end of the sintering bed is 2, 3,
After entering the heat exchanger through the dust collector 4, the No. 5
No. 6, clean hot air blown from the hood 1 into the sintering bed, while being sent from the blower 6 and exchanged heat, was No. 7 It blows into the sintering bed from 2 hoods.

[0007] FIG. 2 shows 25 mass of metallic iron.
An example of the sinter ore chemical analysis value by the sintering method including (%) is shown. According to the component values, there is no significant change from the powder coke sintering method.

FIG. 3 shows an example of comparison of NOx emission amount, reduction pulverization rate, and room temperature strength between the conventional powder coke sintering method and the sintering method containing 25 mass% of metallic iron.
Emissions are reduced by 55.9% compared to conventional sintering. Although the reduction powdering rate is slightly worse, the amount of change is small, and the room temperature strength is almost the same, and the quality required by the blast furnace is sufficiently satisfied.

FIG. 4 shows an example of temperature change in the middle layer of the raw material layer in the sintering method containing 25 mass% of metallic iron during the conventional sintering and the sintering according to the present invention. As shown in the figure, the oxidation reaction of metallic iron is efficiently performed by the system that returns part of the high-temperature hot air or clean hot air to the sintering bed, and the starting point of sintering is faster than in conventional sintering. .

[0010]

EFFECTS OF THE INVENTION In the present invention, as compared with the conventional sintering method using coke powder as a heat source, a hot air circulation system is added, and the sintering method enables large-scale use of metallic iron. The following effects can be obtained. 1) As an alternative to the powder coke as a conventional sintering heat source,
It is possible to replace the entire amount with metallic iron. 2) Therefore, a large amount of NOx and CO ₂ are generated during combustion in the conventional powder coke as a sintering heat source, but in the method according to the present invention, since NO is not contained in the metallic iron, NOx that enters from this is zero, and Since the oxidation exothermic reaction of metallic iron is used, the generation of CO ₂ can be reduced. 3) The hot air circulation system recycles the heat that promotes the oxidation exothermic reaction of metallic iron, thus saving energy.

[Brief description of drawings]

FIG. 1 is a flow schematic diagram of a hot air circulation system of the present invention.

FIG. 2 is a table showing chemical product analysis values of a sintered ore containing 25 mass (%) of metallic iron.

FIG. 3 is a comparison table of NOx emission amount, reduction pulverization rate, and room temperature strength of the conventional sintering method and the sintering method of the present invention.

FIG. 4 is a diagram showing a temperature change in a middle layer portion of a sintering raw material layer.

[Explanation of symbols]

 1. Sintering bed 2. Primary preduster 3. Secondary preduster, multi cyclone 4. Heat exchanger 5. No. 1. Circulating hood 6. Cold air blower 7. No. 2 circulation hood

Claims (2)

[Claims] 1. In a sinter production process in which metallic iron is blended, hot air generated from the process or clean hot air of 100 ° C. or higher heat-exchanged by a heat exchanger is blown into the sintering bed to produce metallic iron. A method for producing sinter that utilizes the fact that the surface activity increases, the oxidation reaction is promoted, and the sintering rate is improved. 2. In addition to circulating high-temperature hot air from the wind box under the sintering bed, heat exchange between high-temperature hot air and clean air, which replaces the conventional boiler, is performed to obtain clean hot air, thereby increasing the amount of hot air. Hot air circulation system.