JPH05222422A - Smelting reduction method for ore using coke packing layer type smelting reduction furnace - Google Patents

Abstract

PURPOSE:To omit exhaust gas treating equipment, such as cyclone, venturi scrubber, thickener, or wet type exhaust gas treating equipment, such as venturi scrubber, thickener, and to utilize the exhaust heat to dry raw material. CONSTITUTION:The high temp. exhaust gas discharged from a coke packing layer type smelting reduction furnace 14 is directly supplied into a spray dryer 10, and sensible heat of the exhaust gas is utilized as the heat source for drying slurry-state raw material powder, and the drying of the raw material powder and collection (recovery) of dust in the exhaust gas after recovering the exhaust heat, are executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a smelting reduction method for ores using a coke packed bed type smelting reduction furnace for producing metal by reducing powder containing oxides of effective metals such as iron ore.

[0002]

2. Description of the Related Art In general, a method for smelting and reducing a metal by using a coke packed bed type smelting reduction furnace is performed according to a process flow as shown in FIG. The slurry-like raw material powder generated in other departments is supplied to the honey 23 and settles at the bottom. The concentrated slurry-like raw material powder is sent to a decanter 8 by a pump (P), dehydrated there, further concentrated, and then sprayed into a spray dryer (dryer) 10.

On the other hand, high temperature combustion exhaust gas generated by the hot air generator 11 is blown into the spray dryer 10. In the spray dryer 10, the sprayed slurry-like raw material powder is dried by the high-temperature combustion exhaust gas blown therein, and becomes dry raw material powder and is deposited on the bottom of the spray dryer 10. The combustion exhaust gas that has passed through the spray dryer 10 is further dust-removed by the next dust collector 12, and is discharged from the chimney 6 to the atmosphere.

The dry raw material powder and dust accumulated on the bottoms of the spray dryer 10 and the dust collector 12 are taken out, charged into the storage tank 13, and then passed through the uniform discharge pressure hopper 18 and the injection tank 25, and then vertically from the tuyere 15. It is blown into the mold smelting reduction furnace 14. The raw material powder blown into the smelting reduction furnace 1
It is reduced in 4 and melted to produce metal 21. This smelting reduction furnace 14 is a packed bed type furnace filled with coke 16.

Exhaust gas discharged from the vertical smelting reduction furnace 14 is subjected to primary dust removal by a dry dust remover such as a cyclone 17, and the dry dust is collected there. Next, the exhaust gas is sent to the venturi scrubber 22 as secondary dust removal, and wet dust removal is performed in which water is sprayed and cooled. Then Thickener 5 and Decanter 24
And is collected as wet dust. The above-mentioned dry dust and wet dust are currently used as raw materials for sinter.

The decontaminated clean gas is sent to the gas holder in the gas main pipe 7 and used as a CO-containing gas. Part of it is used for the hot air generator 11.

[0007]

The above conventional process has the following problems. (A) The construction cost of the dust removing equipment for processing the exhaust gas of the vertical smelting reduction furnace is enormous. (B) In addition, operating costs and maintenance costs for the equipment are required. (C) The transportation cost of the collected dust is high. (D) High temperature exhaust gas sensible heat cannot be recovered, resulting in large energy loss.

It is an object of the present invention to provide a technique for solving the above problems and effectively utilizing (recovering) exhaust gas sensible heat and collecting (recovering) dust in exhaust gas at the same time.

[0009]

The present invention has been made to solve the above-mentioned problems, in which exhaust gas discharged from a vertical smelting reduction furnace is directly supplied to a raw material powder dryer (spray dryer), Slurry raw material powder is dried by utilizing sensible heat of exhaust gas, and dust in exhaust gas is adsorbed to the raw material powder and collected, and the collected dust in exhaust gas is returned to the melting reduction furnace together with the raw material powder. Is.

[0010]

In the present invention, the exhaust gas of the vertical smelting reduction furnace is introduced into the raw material powder dryer without passing through the wet dust remover and the raw material is dried by the heat retained therein, while the dust in the gas is removed by the raw material powder. Collect and collect dust. Therefore, a wet dust remover for exhaust gas of the smelting reduction furnace is not required, and a separate heat source for drying the raw material powder is also unnecessary. Further, since the dust in the exhaust gas is adsorbed by the raw material powder and discharged together with it, a system for dust treatment is not required.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the process flow diagram of FIG. It is the same as in FIG. 2 that the slurry-like raw material powder generated in another department is supplied to the shucker 23, sent to the decanter 8, dehydrated and concentrated, and then sprayed in the spray dryer 10.

The embodiment differs from FIG. 2 in that the exhaust gas discharged from the vertical smelting reduction furnace 14 is directly supplied to the spray dryer 10. In the spray dryer 10, the slurry-like raw material powder is dried by the high-temperature exhaust gas, becomes dry raw material powder, adsorbs and collects the dust in the exhaust gas, and deposits on the bottom of the spray dryer 10.

The exhaust gas that has passed through the spray dryer 10 is further dust-removed by the next dust collector 12, and then sent to the gas holder by the gas main pipe 7 for use. A part of it is used in the hot air generator 11. Spray dryer 10 and dust collector 1
The dry raw material powder and dust accumulated on the bottom of No. 2 are extracted from the lower part, charged into the storage tank 13, and then passed through the pressure equalizing hopper 18 and the injection tank 25 and blown from the tuyere 15 into the vertical melting and reduction furnace 14. Get caught.

According to the present invention, by adopting the above-described process, the slurry dryer raw material powder is dried by the spray dryer 10 by effectively utilizing the high temperature exhaust gas sensible heat of the smelting reduction furnace, and at the same time, the dust in the exhaust gas is removed. Can be adsorbed and collected (collected). The temperature of the exhaust gas discharged from the vertical smelting reduction furnace 14 is about 750 ° C. (max about 900 ° C.) at the furnace top,
The amount of exhaust gas was about 26000 Nm ³ / H, and the dust concentration was in the range of about 30 to 50 g / Nm ³ . This exhaust gas is sent to the spray dryer 10 and sprayed into the spray dryer 10 at about 2100 kg / H (water content of about 50
%) Slurry raw material powder is dried and the temperature is about 180 ° C.
Fell below. The exhaust gas was satisfactorily removed by the next dust collector 12 to about 0.5 mg / Nm ³ .

On the other hand, the spray dryer 10 and the dust collector 1
The dried raw material powder and dust collected (recovered) in 2 are withdrawn from the lower portion, charged into the storage tank 13, and then passed through the pressure equalizing hopper 18 and the injection tank 25 and blown into the vertical melting and reducing furnace 14 from the tuyere 15. , Operated without problems.

[0016]

INDUSTRIAL APPLICABILITY According to the present invention, the high temperature exhaust gas discharged from the coke packed bed type smelting reduction furnace is directly supplied to the dryer, and the sensible heat of the exhaust gas is used as a heat source for drying the slurry raw material powder. The drying and recovery of waste heat were performed well. Further, the dust in the exhaust gas could be collected (recovered) well.

As a result of the above, by implementing the present invention, exhaust gas treatment equipment such as a cyclone (or dust remover), a venturi scrubber, and a sychna, which is required in the conventional process, is no longer required. In addition, operating costs and maintenance costs for these facilities, transportation costs for collected dust, etc. have become unnecessary. Furthermore, effects such as a reduction in the amount of coke used in the vertical smelting reduction furnace were obtained.

As an application of the present invention, the cyclone (or dust remover) is arranged in the same manner as in the conventional process, and the wet dust collector such as the venturi scrubber and the shredder is not required, and the effect is considerable.

[Brief description of drawings]

FIG. 1 is a flow diagram illustrating a process of an embodiment of the present invention.

FIG. 2 is a flow chart showing a conventional process.

[Explanation of symbols]

5 Thickener 6 Chimney 7 Gas main 8 Decanter 10 Spray dryer (dryer) 11 Hot air generator 12 Dust collector 13 Storage tank 14 Vertical smelting reduction furnace 15 Tuyere 16 Packed layer 17 Cyclone or dust remover 18 Uniform discharge hopper 20 Blower 21 Metal 22 Venturi scrubber 23 Thickener 24 Decanter 25 Injection tank 26 Ring water cooling / circulation equipment 27 Heat exchanger 28 Blower

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuneo Aihara 1 Kawasaki-cho, Chiba City Inside the Chiba Steel Works, Kawasaki Steel Co., Ltd. (72) Tsuneya Hasegawa 1 Kawasaki-cho, Chiba City Inside the Chiba Steel Works, Kawasaki Steel Co., Ltd.

Claims (1)

[Claims] 1. In a reduction method of a coke packed bed type smelting reduction furnace for producing a metal by reducing a powder containing oxides of an effective metal such as iron ore, high temperature exhaust gas discharged from a vertical smelting reduction furnace is used as a raw material powder. Directly supply to the dryer, dry the slurry-like raw material powder by utilizing the sensible heat of the exhaust gas, adsorb the dust in the exhaust gas to the raw material powder and collect it, and melt and reduce the dust in the exhaust gas together with the raw material powder. A method for smelting reduction of ore using a coke packed bed type smelting reduction furnace characterized by returning to the furnace.