JPH0141919B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a furnace for heating and reducing iron ore for charging into a metallurgical furnace using gas emitted from the metallurgical furnace.

In the steel industry, iron ore is first reduced with coke in a blast furnace to produce hot metal, which is then injected into a metallurgical furnace.
Steel is made by blowing oxygen into the metallurgical furnace (hereinafter referred to as blowing).

In this steel industry, a large amount of coke is consumed to reduce iron ore (for example, per ton of iron ore,
Consumes 400-500Kg of coke. ), which accounts for most of the energy consumption in the steel industry.

Also, when producing high quality steel by blowing in a metallurgical furnace,
Iron ore is charged into the metallurgical furnace as a coolant for heat balance during smelting.

On the other hand, during blowing, high-temperature reducing gas is generated from the metallurgical furnace, and after this gas is heat recovered in the cooler of the exhaust gas treatment equipment, it is further cooled directly in the wet dust remover, and the gas reaches a temperature of 900 to 1000℃. Generally, the heat retained in the engine is wasted and dissipated.

The inventors of the present invention have comprehensively considered energy conservation in the steel industry, and have made effective use of the retained heat of the gas from the metallurgical furnace, which had been wasted in the past. The idea was to reduce the amount of iron ore processed in the blast furnace by heating and reducing the iron ore that had been previously used in the blast furnace, thereby achieving overall energy savings in the steel industry.

That is, as shown in FIG.
First, heat is recovered from the high-temperature exhaust gas generated in the cooler 2, and the exhaust gas at a temperature of 900 to 1000 degrees Celsius exiting the cooler 2 is directly sprayed with water through the first wet dust collector 3 to lower the temperature. In addition, a heating reduction furnace 8 for iron ore to be charged into a metallurgical furnace has been added to the conventional exhaust gas treatment equipment in which the temperature is lowered and dust removed by a second dust collector, and the iron ore is dissipated from a dispersion tower 6 or collected in a holder 7. A part of the exhaust gas before entering the first wet precipitator 3 is guided to an iron ore heating reduction furnace 8 by a blower 8' to heat and reduce the iron ore and charge it into the metallurgical furnace. It is. It is also possible to connect the outlet side gas duct of the heating reduction furnace 8 to the outlet side of the first dust collector throat portion and omit the blower 8'. That is, in the present invention, iron ore is accommodated in an air-permeable container formed by a louver or the like to form a thick, almost vertical iron ore layer, and a wind box and a Alternatively, a plurality of gas passages are formed using a partition member, and the exhaust gas is introduced from the gas inlet provided at the iron ore outlet side at the lower end of the iron ore layer, and is passed through the gas passages sequentially, and the exhaust gas is introduced from the gas inlet provided at the iron ore outlet side at the lower end of the iron ore layer. Gas is discharged to the outside of the heating reduction furnace 8 from a gas outlet provided on the side, and the temperature of the iron ore is sequentially raised in each of the gas passages from the iron ore inlet side,
As the temperature rises, the reduction reaction is promoted, and at the exit side of the iron ore layer, the iron ore is brought to the highest temperature and the reduction reaction is actively carried out, and after being reduced to almost the required degree, the exhaust gas is passed through each of the passages. The amount of iron ore loaded in the metallurgical furnace is taken out intermittently in accordance with the intermittent operation of the metallurgical furnace, and charged directly into the metallurgical furnace.
The present invention is characterized in that it is adapted to cope with intermittent operation of a metallurgical furnace.

Hereinafter, an embodiment of the heating reduction furnace for iron ore for charging into a metallurgical furnace according to the present invention will be described in detail with reference to FIG. 2.
Louvers 9 with an inclination angle of 45° to 60° are arranged at certain intervals to form a breathable container, and iron ore 10 is loaded into the breathable container.
One almost vertical layer of iron ore 10 is formed. By making the width and pitch P of the louver 9 appropriate, the iron ore 10 loaded in this way has an angle of repose between the surface of the iron ore 10 accumulated between the pitch P of the louver 9, and the upper layer The packing density in the lower layer is made uniform, and the louver 9 is housed in a ventilated container without spilling out from the pitch P of the louver 9. A cut-off gate 17 is provided at the outlet 16 of the layer of iron ore 10 and can be opened and closed by a cylinder 18, so that the iron ore 10 can be taken out from within the layer. Reference numeral 11 denotes a gas inlet section, which is provided near the iron ore outlet 16 below the layer, and a gas passage is formed by wind boxes 13 and 14 so as to cross the layer of iron ore 10 at a nearly right angle. On the other hand, the gas outlet 12 is provided near the inlet 15 of the layer of iron ore 10. In this embodiment, there are three gas passages A, B, and C. Note that 19 is a seal gate that prevents air from entering the heating reduction furnace 8 during non-blowing.

FIG. 3 shows another embodiment of the heating reduction furnace of the present invention,
A cylindrical layer of iron ore 10.
3', 14' and the partition members 23, 24 form three gas passages A, B, and C, as in the previous embodiment. In addition, 21 is a gas outlet, and 17' is a cut-off gate.

FIG. 4 shows another embodiment of the thermal reduction furnace of the present invention, showing only the layer of iron ore 10, and in which a cut-off gate 22 is provided for each gas passage. Note that H is the thickness of the layer of iron ore 10.

The operation of the iron ore heating reduction furnace for charging into a metallurgical furnace according to the present invention constructed as described above will be explained.

The thickness H of the layer of iron ore 10 and the number of gas passages passing through the layer of iron ore 10 are determined depending on the refining processing capacity of the metallurgical furnace.

First, with the cutoff gates 17 and 17' closed, the iron ore 10 is transferred from the inlet 15 to the heating reduction furnace 8.
to form a layer of iron ore 10. In this embodiment, the number of gas passages is three, A, B, and C. In this case, the high-temperature gas entering from the gas inlet during blowing first heats the iron ore 10 in the gas passage C section near the outlet 16 of the iron ore 10, and then heats the iron ore 10 in the gas passage B
Then, the iron ore 10 in the gas passage A section is heated, and then the iron ore 10 in the gas passage A section is heated, and the iron ore 10 exits from the gas outlet 12. In this way, the temperature of the iron ore 10 is raised in the order of gas passage C (near the iron ore outlet) to the highest temperature, then gas passage B, and then gas passage A.

These three gas passages are determined according to the refining processing capacity of the metallurgical furnace.In a metallurgical furnace that is operated intermittently, when the metallurgical furnace is started for the third time, the gas passage C is The iron ore 10 in the area is reduced to approximately the required degree at exactly the specified temperature. After this third metallurgical furnace operation, the cut-off gates 17, 17' are opened,
The iron ore 10 that has been heated to a specified temperature and reduced, which is charged in the gas passage C, is taken out, and the cut-off gates 17 and 17' are closed. At this time,
The iron ore 10 located in gas passage B is replaced by the iron ore 1 located in gas passage A in gas passage C.
0 moves to the gas passage B, and the gas passage A is newly loaded with iron ore 10. The iron ore 10 that has been moved to the gas passage C has already been heated to the same temperature and reduced in the second operation of the metallurgical furnace, and is heated to the specified temperature in the fourth operation of the metallurgical furnace. And it will be returned. After the fourth metallurgical furnace operation is completed, the cut-off gates 17, 17' are opened and the iron ore 10 in the gas passage C is similarly taken out. At the same time, the iron ore 10 located in the gas passage B is loaded into the gas passage C, the iron ore 10 located in the gas passage A is loaded into the gas passage B, and a new iron ore 10 is loaded into the gas passage A.

In this way, the iron ore 10 is continuously heated to a specified temperature and reduced, and then introduced into the metallurgical furnace for each operation. In particular, as shown in FIG. 4, by providing a cut-off gate 22 for each gas passage and sequentially opening and closing the cut-off gate 22 from the outlet side, the iron ore 10 is completely separated for each gas passage. It is possible to move in a closed state.

As described above in detail, the heating reduction furnace for iron ore for metallurgical furnace charging of the present invention loads iron ore for metallurgical furnace charging into an air-permeable container and forms a layer of iron ore for metallurgical furnace charging. A metallurgical furnace charge in which a plurality of gas passages are formed and cross this layer at approximately right angles, and gas is passed from the outlet side of the iron ore for metallurgical furnace charging in the layer, and the metallurgical furnace charge is charged in one gas passage. Since only the amount of iron ore for metallurgical furnace charging is taken out, the temperature of the iron ore for metallurgical furnace charging is raised sequentially from the gas inlet side to the outlet side to promote the reduction reaction, and the metallurgical furnace charged in the gas inlet passage is heated. Iron ore for charging is heated and reduced by contacting with gas for the number of gas passages, and by determining the number of gas passages according to the operation of the metallurgical furnace, it is possible to reduce the intermittent gas, temperature, and CO2. Even if the concentration changes, iron ore for charging into a metallurgical furnace can be heated and reduced almost uniformly.

Furthermore, by obtaining iron ore for charging into a metallurgical furnace at a constant temperature, it is possible to eliminate the effect on the heat balance and reactions within the metallurgical furnace, and to eliminate gases that occur intermittently and whose temperature and CO concentration are not constant. make effective use of
The effects are significant, including the ability to achieve comprehensive energy savings in the steel industry.

In addition, the thermal reduction furnace for iron ore charging in a metallurgical furnace of the present invention is configured so that the exhaust gas is branched in from the upstream side of the dust remover of the exhaust gas treatment device of the metallurgical furnace, so that a dust collection layer is formed in the exhaust gas main passage. Compared to a method that performs thermal reduction using a packed bed of iron ore or pellets for sintering, since the purpose is not to collect dust, there is a wide range of particle sizes to choose from for the iron ore charged in the metallurgical furnace, and the layer thickness is In addition to being freely selectable, it can be installed without requiring large-scale modification of existing exhaust gas treatment equipment, which has the advantage of significantly reducing equipment costs.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram of the heat-reduction furnace for iron ore for metallurgical furnace charging of the present invention applied to a conventional exhaust gas treatment device, and FIGS. 2 to 4 show examples of the heat-reduction furnace of the present invention. Fig. 2 shows the case where the iron ore for charging the metallurgical furnace is in the form of a flat plate, Fig. 3 shows the case in the case where it is cylindrical, and Fig. 4 shows the case where a cut-off gate is provided for each gas flow path. 8, 8'... Heating reduction furnace, 9... Louver, 10
...Iron ore for charging metallurgical furnace, 11 ...Gas inlet, 1
2... Gas outlet, 13, 13', 14, 14'...
Fukan, 15...Iron ore entrance, 16...Iron ore exit, 17, 17', 22...Cut-off gate,
23...Partition member.

Claims (1)

[Claims] 1. A metallurgical furnace that is installed in the middle of an exhaust gas bypass channel that branches from the upstream side of the dust remover of an exhaust gas recovery device that cools and removes dust from the gas emitted from the metallurgical furnace, and then collects or dissipates the gas, and uses the high-temperature reducing gas introduced therein. This is a heating reduction furnace for iron ore for charging, which includes a ventilable container formed of a louver or the like for storing iron ore and forming a nearly vertical layer of iron ore, and a container for storing iron ore to form a nearly vertical layer of iron ore. A wind box and/or partition member for forming a plurality of gas passages orthogonally is provided,
The upper end of the container is equipped with an iron ore inlet, the lower part of the container is equipped with an outlet for charging iron ore into the metallurgical furnace, and the iron ore outlet side is equipped with an iron ore inlet for charging iron ore into the metallurgical furnace. 1. A thermal reduction furnace for iron ore for charging into a metallurgical furnace, characterized in that a gas inlet is provided for introducing the gas in a branched manner, and a gas outlet for discharging the gas is provided on the inlet side of the iron ore.