JP3054608B2 - Ore supply method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for reducing granular ore using a pre-reduction furnace and a smelting reduction furnace, in which powder is poured from a pre-reduction furnace or the like into a metal bath of the smelting reduction furnace. The present invention relates to a method for supplying granular ore.

[0002]

2. Description of the Related Art Generally, a smelting reduction method is a method for producing a metal by reducing an ore by using a preliminary reduction furnace and a smelting reduction furnace. The ore is preheated or preliminarily reduced in a granular state in the prereduction furnace, and the ore is further put into a metal bath of the smelting reduction furnace to be finally reduced.
Since a reducing gas such as carbon monoxide is generated from the smelting reduction furnace, the gas is generally sent to a preliminary reduction furnace as a reducing gas also serving as a fluidizing gas.

FIG. 5 (a) is a schematic system diagram showing equipment for performing such a general smelting reduction method. The gas generated from the smelting reduction furnace 58 is first sent to the preliminary reduction furnace 56 as a reducing gas through a path 61 and further sent to a path 62 as exhaust gas. Each of the paths 61 and 62 is provided with a cyclone 59 and 57 that is a collecting portion of the fine ore. On the other hand, the ore is supplied to the preliminary reduction furnace 56 as a raw material from the upper hopper 63 via the path 64, and is supplied from the furnace 56 to the smelting reduction furnace 58 via the path 65. The cyclones 59 and 57 provided in the gas paths 61 and 62 also have paths 68 and 66, respectively, and fine ore is supplied to the smelting reduction furnace 58 through these paths. In addition, since scattered dust such as fine ore and coal contained in the gas from the smelting reduction furnace 58 also falls on the bottom of the wind box 56c of the preliminary reduction furnace 56, the dust is directed toward the smelting reduction furnace 58 from the bottom of the wind box 56c. Even there is a supply path 67 for fine ore.

In order to supply the ore quantitatively to the smelting reduction furnace 58, a special supply device indicated by reference numeral 70 in the figure is provided in each of the paths 65 to 68 described above. The device 70 includes a large number of devices and parts as shown in FIG. That is, a distribution valve 71 is provided at the upper part, and two systems are provided below the distribution valve 71. Each system has a weighing tank and a pressure equalizing pipe. Each weighing tank is connected to a tank body 73 connected to open / close valves 72 and 75 at the top and bottom.
It is necessary to connect a bellows or the like (not shown) between the upper and lower pipes so that the weight is entirely applied to the weighing device 76, in addition to providing a cutout valve 74 immediately below the tank body 73. There is also. In addition, the equalizing pipe connects a supply source (not shown) of a high-pressure gas (such as nitrogen) to the tank body 73. One side of the pressure equalizing pipe is a side near the gas supply source and includes a valve 77, and the other side is opened to the atmosphere side via a valve 78. A supply device similar to the above is described in Japanese Utility Model Publication No. 7-340.
No. 23.

As shown in FIG. 5 (a), a supply device 70 including a large number of devices and components is arranged in each of the ore paths 65 to 68 to the smelting reduction furnace 58 as shown in FIG. 5 (b). ,
This is because there is a pressure difference between the fluidized bed 56a and the wind box 56c of the preliminary reduction furnace 56, which is the supply source of the ore, and each of the cyclones 57, 59, and the smelting reduction furnace 58, which is the supply destination of the ore. That is, the inside of the smelting reduction furnace 58 is
6 The gas pressure is significantly higher than in the other parts. Therefore, by merely providing an on-off valve or the like in each of the above-described paths 65 to 68, when the valve is opened to move the granular material, the preliminary reduction furnace 56 from the side of the smelting reduction furnace 58 having a high pressure. The gas is blown up toward the side of the like, and the quantitative supply of the granular material becomes impossible.

In this regard, the supply device 70 shown in FIG. 5B functions as follows. First, the upper open / close valve 72 of one tank body 73 is opened and the lower open / close valve 7 is opened.
5 is closed, the upper vessel (fluidized bed 56a of pre-reduction furnace 56, wind box 56c, or each cyclone 57
The ore sent from (59) is received in the tank body 73. At this time, with respect to the other tank body 73, the ore in the tank body 73 is directed to the smelting reduction furnace 58 by closing the upper open / close valve 72 and opening the lower open / close valve 75 (the cutout valve 74 is also activated). Pay out. In this way, the weighed ore in an accurate amount is supplied to the smelting reduction furnace 58, and the upper and lower on-off valves 72 and 75 of each tank body 73 are closed. No gas is blown up from the side, and the ore is supplied smoothly.

When the ore in the tank body 73 is exhausted, the open / close state of the upper and lower on-off valves 72 and 75 is reversed between the tank body 73 and the former tank body 73.
While the ore is dispensed from 3, the ore is received from the upper container in the latter tank body 73. However, when the tank bodies 73 are switched in this way, the pressure in each tank body 73 is adjusted in advance using a pressure equalizing pipe. That is, as for the tank body 73 on the side where the ore is to be dispensed, the valve 77 on the gas supply source side is opened to increase the internal pressure to the pressure in the smelting reduction furnace 58, but the ore will be accepted. With respect to the tank body 73 on the side to be set, the valve 78 on the atmosphere side is opened to reduce the internal pressure to the pressure in each container above. If the pressure is not adjusted in advance in this way, gas is blown up inside or above the tank body 73 at the moment when the on-off valves 72 and 75 are switched, and stable ore dispensing becomes impossible.

[0008]

Since it is necessary to arrange a supply device 70 as shown in FIG. 5 (b) in each supply path of ore, when producing a metal by the smelting reduction method, conventionally, the following method is used. Such a problem was accompanied. That is, a) the supply device 70 becomes considerably large. Therefore, as a facility for smelting reduction, a considerable space is occupied in the ore supply system, and high production costs are required.

(B) Since the procedure for supplying ore, particularly the procedure for switching the weighing tank body 73, is complicated, precise operating devices for operating the on-off valves 72 and 75 and the valves 77 and 78 are installed. There is a need to. If their operations are not accurate, the supply of ore with high quantitative accuracy becomes difficult.

(C) It is necessary to use expensive on-off valves 72 and 75 and valves 78, and to perform frequent maintenance on them. The on-off valves 72 and the like must be specially designed to pass not only fluids (gases) but also high-temperature powders (ores).
Failure to perform frequent maintenance is likely to cause problems. This is because there is a high possibility that gas will leak due to the progress of abrasion or operation will be disabled due to bite of ore.

The present invention provides a method capable of smoothly and accurately supplying a quantitative ore to a smelting reduction furnace without using a special supply device as shown in FIG. It is intended to facilitate smelting reduction.

[0012]

According to a first aspect of the present invention, there is provided a method for supplying ore, comprising the steps of: a) reducing a granular ore using a preliminary reduction furnace and a smelting reduction furnace; The ore was supplied into the metal bath of the smelting reduction furnace, which is also the gas supply source, and connected to the pre-reduction furnace or the smelting reduction furnace.
From the fine ore collection part to the metal bath of the smelting reduction furnace
A method for supplying fine ore powder (ie, fine ore), wherein a ') the raw material ore to be charged into the pre-reduction furnace is weighed, and b) the ore is placed in a deposition pipe connected to the fluidized bed of the pre-reduction furnace. Ore is deposited to a height sufficient to withstand the pressure difference between the two furnaces (more precisely, the pressure difference between the lower part of the pre-reduction furnace connected to the deposition pipe and the internal space of the smelting reduction furnace), and the ore deposit canal Kirikuzushi from below by cutout means connected to the lower portion of the deposition tube and poured into the smelting reduction furnace, c) and, the charging amount is a predetermined set value bed height of the fluidized bed in the pre-reduction furnace Automatic control to keep
Without its weighing and control, b ') also connected to the lower portion of the fine ore collecting portion as described above
The pressure between the collecting part and the smelting reduction furnace
High enough to resist the difference (the height at which the ore does not flow)
It is necessary to deposit fine ore to
Inside the sedimentary pipe by cutting means connected to the lower part of the sedimentation pipe
The fine ore is cut down from below and put into the smelting reduction furnace, and c ')
Is automatically controlled (the input amount) to keep the amount of
The weighing is not performed .

The supply method according to the first aspect has the following operation. That is: 1) Gas is not blown up from the smelting reduction furnace side even if a tank as shown in FIG. 5B having on-off valves at the top and bottom is not provided in the path of the ore from the preliminary reduction furnace . B) above
As described above, the ore is deposited in the deposition pipe located between the preliminary reduction furnace and the smelting reduction furnace at a height sufficient to withstand the pressure difference between the two. When the ore is deposited in this manner, the ore seals the gas in the smelting reduction furnace, so that the gas is prevented from being blown up. The pile height of the ore that can withstand the pressure difference between the two reduction furnaces is determined by the pressure difference and the properties of the ore (particle size, density, etc.).
The minimum requirement is that the ore accumulates at such a height that the ore is not fluidized by the pressure difference. 1 ') The same applies to the fine ore path.
Even without providing a tank as shown in FIG.
No gas is blown up from the smelting reduction furnace side. the above
Similar to 1) above, accumulates in the accumulation pipe based on b ') above
This is because the ore seals the gas in the smelting reduction furnace. b ')
Is different from that connected to the fluidized bed as in b) above.
Ore is often not filled inside, but in c ') above
Therefore, the accumulation of ore above a certain height is secured in the sedimentation pipe.
Therefore, gas spouting is stably prevented. What
It should be noted that the gas route from the smelting reduction furnace or
Flour ore is floating and they are installed in each path.
Cyclone or pre-reduction furnace wind box as a collecting part
It generally gathers at the bottom of each. The method of the invention
Is the melting of the fine ore that collects in each collection area in this way.
The supply to the reduction furnace also requires special weighing means as shown in Fig. 5.
This is done smoothly and accurately without the use of.

2) While preventing the gas from being blown up as described in 1 ) above, the ore, which is a granular material, can be gradually supplied from the side of the preliminary reduction furnace to the side of the smelting reduction furnace. B) above
As described in the above, the ore in the sedimentation pipe is cut down from below by the cutting means and is put into the smelting reduction furnace. Since the cutting means cuts down the deposited ore from below and does not drop the entire amount of the deposited ore at once, the ore is kept in the state of being deposited in the sedimentary pipe even during cutting by the same means, and the gas It continuously prevents the blow-up. 2 ') While preventing gas injection as described in 1') above
Also, the fine ore is gradually moved from the collection part to the smelting reduction furnace side.
Can be supplied. As in 2) above, fine
While keeping the fine ore, the ore is cut by the cutting means of b ').
From the bottom and put into the smelting reduction furnace.

3) FIG. 5 which requires two or more tank bodies
Unlike the case of (b), the necessary function can be provided by arranging only one set of the deposition pipe and the cutting means between the preliminary reduction furnace and the smelting reduction furnace . Even if there is only one set, they can cut out the ore and prevent gas emission as described in 2), and at the same time, can receive the ore sent from the upper preliminary reduction furnace. As long as gas is prevented from being blown up, there is no problem in receiving and depositing the ore from the pre-reduction furnace in the upper part of the deposition pipe.
In order to improve the reliability of the function, two sets (two systems) of the deposition pipes and the cutting means may be arranged in parallel. 3 ') Deposition pipe between each fine ore collection part and smelting reduction furnace
And by arranging only one set of cutting means
Functions are provided. As in 3) above, they are
Prevents gas spouting while cutting ore
Can receive ore sent from above
Because.

4) Since a preferable fluidized bed is always formed in the pre-reduction furnace, the pre-reduction of the ore in the pre-reduction furnace proceeds stably, and the reduction efficiency together with the smelting reduction furnace can be kept high. . Since the ore is supplied from the preliminary reduction furnace to the smelting reduction furnace while controlling such that the bed height of the fluidized bed is maintained at a predetermined set value as in the above c), a flow that is always preferable in the preliminary reduction furnace is performed. A layer is formed. If the ore is charged independently of the pre-reduction furnace, the bed height of the fluidized bed in the pre-reduction furnace will be greatly displaced while continuing the input, and it will be too high to stop or lower the flow. A situation in which much of the ore is scattered due to too much ore can also occur. 5) Almost all ore to be fed into the preliminary reduction furnace as raw material
Can be introduced into the smelting reduction furnace without waste. Reserve
Not only ore from the fluidized bed of the reduction furnace, but also in the gas path, etc.
The fine ore that floats and collects in the fine ore collection area
This is because they are fed into the smelting reduction furnace in parallel. 6) Reduce the amount of ore input in each route to the smelting reduction furnace.
Even without weighing, only the input amount of raw materials to the preliminary reduction furnace is known.
The total amount of ore input to the smelting reduction furnace
You can know. To smelting reduction furnace due to 5) above
Of ore input (total amount)
Because it is almost equal to the quantity. Between the two quantities, the above
Weight fraction of fine ore not collected by the collecting part
(And the weight loss due to the reaction),
Differences are small, and exhaust gas surveys
You can get an overview of the amount (also weight loss due to the reaction)
Can be theoretically grasped), so the amount of
You will know almost exactly.

The supply method according to claim 2, further comprising: d) changing the input amount controlled as in c), changing the set value of the bed height in the pre-reduction furnace, The method is characterized by changing the input amount of raw ore to the furnace.

According to this supply method, 7) not only a preferable fluidized bed is always formed inside the pre-reduction furnace as described in 4), but also the amount of ore charged from the pre-reduction furnace to the smelting reduction furnace is reduced. It can be appropriately changed according to the operation state of the smelting reduction furnace. The amount of ore charged from the pre-reduction furnace to the smelting reduction furnace may be increased or decreased for the purpose of changing the amount of metal production per hour or adjusting the temperature of the metal bath. In such a case, it is possible to smoothly change the input amount. That is,
i) By reducing the set value of the bed height of the fluidized bed as appropriate and increasing the amount of ore charged to the preliminary reduction furnace, the amount of ore input from the furnace to the smelting reduction furnace can be increased. The bed height of the reduction furnace can be kept at the set value (the value lowered as described above). ii) Conversely, increasing the set value of the bed height and then reducing the input amount of raw ore reduces the amount of ore input from the preliminary reduction furnace to the smelting reduction furnace, and also sets the bed height of the preliminary reduction furnace to the set value. (As raised above). Iii) If the set value of the bed height is increased or decreased in accordance with the increase or decrease in the amount of the raw ore charged to the preliminary reduction furnace, the residence time of the raw ore in the fluidized bed is made constant, thereby reducing the ore reduction reaction rate. Can be kept constant.

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] The supply method according to the third aspect is the same as the first aspect.
Other In addition to performing the second supply method, e) in an emergency, supplies the raw material ore toward the source of the ore without passing through a preliminary reducing furnace into the metal bath in the smelting reduction furnace - that said And

According to the method of claim 3 , when the pre-reduction furnace becomes inoperable, or when it becomes necessary to put the raw ore that has not been preheated or pre-reduced into the smelting reduction furnace, etc. In an emergency, the raw ore can be supplied into the smelting reduction furnace without passing through the preliminary reduction furnace.

[0028]

1 and 2 show an embodiment of the present invention. That is, first, FIG.
FIG. 2 is a schematic system diagram of a smelting reduction facility that obtains molten iron by reducing iron ore. Each of FIGS. 2A, 2B, and 2C is a diagram of the facility of FIG. 1 (and FIG. It is a longitudinal cross-sectional view which shows the supply apparatus of the ore used in (equipment).

In FIG. 1, reference numeral 2 denotes a preliminary reduction furnace, and reference numeral 4 denotes a smelting reduction furnace. In the smelting reduction furnace 4, the iron ore preheated and pre-reduced in the pre-reduction furnace 2 is supplied into the iron bath 4a, oxygen is blown into the iron bath from the lance 4b, and coal or the like is charged as a reducing agent. Thereby reducing the iron ore. At that time, since a reducing gas containing carbon monoxide (CO) or the like is generated from the smelting reduction furnace 4, the gas is sent to the preliminary reduction furnace 2 as a reducing gas through the path 11.

The pre-reduction furnace 2 is a fluidized-bed reactor, and is used to remove powdery ore iron ore (raw iron ore, most of which has a particle size in the range of several tens of μm to 8 mm) supplied from the upper tank 1. As described above, the fluid is fluidized by the reducing gas sent from the smelting reduction furnace 4 and preheated and preliminarily reduced. Raw iron ore is charged from the upper tank 1 to the pre-reduction furnace 2 through the path 14, and the iron ore subjected to the preheating / pre-reduction furnace is supplied into the smelting reduction furnace 4 from the path 15 connected to the lower part of the fluidized bed 2 a. . On the other hand, the gas exiting the fluidized bed 2a is sent to a gas processing facility (not shown) through an exhaust gas path 12. The path 12 is provided with a cyclone 3 which is a collection part of the fine iron ore, and the fine iron ore collected there is supplied to the path 16.
Is also supplied to the smelting reduction furnace 4. In addition, the tank 1 is provided so that the raw iron ore can be directly supplied into the smelting reduction furnace 4 without passing through the preliminary reduction furnace 2.
Between the smelting reduction furnace 4 and the cut-off valve 17a and the on-off valve 1
7b is also connected (in addition, the emergency route 17 including
This path 17 may be provided independently of the tank 1).

The smelting reduction facility shown in the drawing is first characterized by the structure of the preliminary reduction furnace 2 and the layout of the preliminary reduction furnace 2 and the smelting reduction furnace 4. That is, in the pre-reduction furnace 2 shown in the figure,
The horizontal dispersing plate having a vertical through hole and the wind box below the vertical dispersing plate (see FIG. 5A) are eliminated, and instead, a vertical cylinder having a closed upper end and a plurality of horizontal gas blowing nozzles 2c on the peripheral wall is eliminated. The body (vertical cylindrical body 2 b) protrudes inside the pre-reduction furnace 2 (the lower center). The outward opening of the nozzle 2c is located near the bottom in the preliminary reduction furnace 2. The fluidized bed 2a is formed in the furnace 2 by introducing the gas generated in the smelting reduction furnace 4 sent through the path 11 into the cylindrical body 2b and blowing it out of the nozzles 2c into the preliminary reduction furnace 2. The iron ore on the side of the pre-reduction furnace 2 is hard to enter inside because each nozzle 2c is horizontal, and even if it enters, since the nozzle 2c has a certain length or more, the cylindrical body 2b , That is, the inside of the smelting reduction furnace 4. Similarly, when the introduction of the reducing gas is stopped, the iron ore is deposited at an angle of repose in the nozzle 2c and does not fall into the cylinder 2b. Therefore, even if no special means is provided to control the amount of the dropped iron ore to be sent to the smelting reduction furnace 4, the iron bath 4
There is no fear that the temperature of “a” will be disturbed. Since the gas can be blown out at a uniform flow rate from the nozzles 2c evenly arranged on the peripheral wall of the cylindrical body 2b, there is also an advantage that a uniform fluidized bed can be formed in the entire lower part in the preliminary reduction furnace 2.

The layout of the two reduction furnaces 2 and 4 is determined so that the smelting reduction furnace 4 is located immediately below the preliminary reduction furnace 2 as shown in FIG. Ordinary pre-reduction furnace (Fig. 5 (a)) that connects a gas duct from the side into the wind box below the dispersion plate
), The gas is blown into the preliminary reduction furnace 2 by the vertical cylinder 2b as described above.
Such an arrangement is easy. When the two reduction furnaces 2 and 4 are arranged in such a relation directly above and below, the space occupied by them in the steelworks (particularly the space occupied horizontally)
In addition, the gas duct 11 between the two furnaces 2 and 4 and the supply paths 15 and 16 for iron ore can be simplified and made compact.

The supply device including the tank 1 is provided in the supply path 14 of the raw iron ore as described above. This supply device has a configuration similar to that shown in FIG. 5, in which a tank body 1b having open / close valves 1a and 1c and a fixed amount cutoff valve 1e at the top and bottom is installed on a weighing device 1d. . The weighing device 1d is used for measuring the weight of the iron ore supplied to the pre-reduction furnace 2, and the pre-reduction furnace 2 having a high internal pressure is used.
The two on-off valves 1a and 1b are used so that the gas is not blown up from the side such as above. By closing the lower open / close valve 1c and opening the upper open / close valve 1a, the raw iron ore is received from above and weighed, and then the upper open / close valve 1a is weighed.
Is closed and the opening / closing valve 1c is opened and the cut-out valve 1e is driven to supply the raw iron ore to the preliminary reduction furnace 2 at a set input amount (input amount per time). When the supply needs to be performed continuously, it is preferable to provide two tanks 1 and alternately switch the open / close state of the on-off valves 1a and 1c.

The iron ore supply paths 15 and 16 (described above) except for the raw iron ore path 14 described above have an iron ore supply device 20A which can prevent gas spouting even though it does not include a tank or an on-off valve. 20B are provided. Each of the two supply devices 20A and 20B is provided in a vertical deposition pipe 21 and 24 for depositing iron ore therein, cutting means 22 and 25 connected to a lower part thereof, and a pipe below the same. It comprises the shutoff valves 23 and 26 and the like. The iron ore is once deposited inside the deposition pipe, and the deposited iron ore is cut down from below by a cutting means, so that the iron ore is dropped downward (via an open shutoff valve). Since the iron ore is deposited at a height sufficient to withstand the pressure difference between the upper and lower parts in the deposition pipe, the ore serves as a sealing means to prevent gas from being blown up. Since the cutting means gradually cuts down and drops the deposited iron ore from below, the iron ore can always be deposited in the deposition pipe, and the gas spout can be continuously prevented. Details of each of the supply devices 20A and 20B are as follows.

First, the route 1 from the fluidized bed of the preliminary reduction furnace 2
The supply device 20 </ b> A provided in 5 includes a deposition pipe 21, a cutting unit 22, and a shutoff valve 23. The device 20
A, the deposition pipe 21 connected to the bottom of the preliminary reduction furnace 2
Means that the pressure difference between the bottom of the furnace 2 and the inside of the smelting reduction furnace 2 is about 8
Considering 40 mmAq, the height is set to about 4 m and the inner diameter (diameter) is set to 200 mm. The iron ore flowing into this route is relatively coarse with an average particle size of about 1.5 mm. According to the investigation by the inventors, if such coarse iron ore is deposited in the pipe by 3 m or more, This is because they resist the above-mentioned pressure difference and prevent the gas from being blown up, and the gas leakage speed becomes very small (less than 0.2 m / s). In such a state, the gas does not fluidize the coarse iron ore deposited in the pipe, and the supply device 20A
Can stably input iron ore. In this example, the cutout means 22 shown in FIG. 2B is used. The cut-out means 22 shown in FIG.
1, a casing 22a is connected under the valve body 22b.
And the angle of the valve body 22b is changed by the hydraulic cylinder 22c. In the state shown in the drawing, the iron ore is deposited on the valve body 22b at an angle of repose, but if the cylinder 22c is contracted and the valve body 22b is tilted, the iron ore falls from above the valve body 22b, and It is put into the smelting reduction furnace 4. In addition, since the casing 22a includes a horizontal portion, the blow-out pipe 22d of the high-pressure inert gas is connected to the bottom of the casing 22a so that the iron ore can be blown off even if it accumulates in that portion. . The maximum speed of the iron ore passing through the inside of the sedimentation pipe 21 at the time of being charged by the cutting means 22 is set to be 0.1 to 0.2 m / s. The shut-off valve 23 shown in FIG. 1 may cause a situation where the iron ore cannot be stopped by a normal method due to an abnormality of the cutting means 22 at the beginning of operation when a sufficient amount of iron ore is not yet deposited in the deposition pipe 21. This is an open / close valve that is normally kept open except when it is closed.

The amount of iron ore fed to the smelting reduction furnace 4 by the cutting means 22 is automatically controlled so that the bed height of the fluidized bed 2a is maintained at a predetermined value. If the opening of the valve body 22b is adjusted irrespective of the bed height, the iron ore in the pre-reduction furnace 2 may be lost or, on the contrary, too much, and an appropriate fluidized bed 2a may not be formed. It is. Specifically, gas pressure sensors (not shown) are arranged at the bottom and the top of the pre-reduction furnace 2, and the valve is set so that the differential pressure that increases according to the bed height becomes a predetermined set value. Body 2
The opening of 2b is adjusted. Therefore, for example, when it is desired to temporarily increase the amount of iron ore supplied to the smelting reduction furnace 4, the set value (target value) of the differential pressure corresponding to the bed height is set slightly lower. When the setting value decreases,
The opening of the valve body 22b is automatically increased in order to increase the amount of iron ore dispensed from the preliminary reduction furnace 2, and this state is maintained until the actual bed height reaches the set value. However, as it is, the opening of the valve body 22b returns to the original position (that is, the input amount also returns to the original value) when the bed height reaches the set value. It is necessary to increase the setting of the input amount of the raw iron ore to the preliminary reduction furnace 2 from the furnace. Conversely, in order to reduce the amount of iron ore charged into the smelting reduction furnace 4, the set value of the bed height (the above differential pressure) is increased, and
In order to continue the state where the input amount is small for a long time, the input amount setting of the raw iron ore from the tank 1 to the preliminary reduction furnace 2 is reduced.

A supply device including a deposition pipe 24, a cutting means 25, and a shutoff valve 26 is provided on a path 16 for supplying the fine iron ore collected at the bottom of the cyclone 3 (collection vessel 3 a) to the smelting reduction furnace 4. 20B are provided. This supply device 20
Of the B, the deposition tube 24 has a height of about 9 m and an inner diameter (diameter) of 200 mm in consideration of a pressure difference between the cyclone 6 and the inside of the smelting reduction furnace 2 of about 2300 mmAq. According to the investigations of the inventors, if fine iron ore, which has a particle size of around 100 μm and easily floats, accumulates 8.5 m or more, they prevent gas blowing up against the above pressure difference. , The gas leak rate is very small (0.0
It is less than 02 m / s). In such a state, the accumulated fine iron ore is not fluidized, and the supply device 20B can stably input the iron ore.
In this example, the cutout means 25 shown in FIG. 2A is used. The cut-out means 25 shown in the figure is connected to a casing 25a below the deposition pipe 24, and has a valve body 25 therein.
b is provided, and the angle of the valve body 25b is supported so as to be changeable by a driving device (not shown) connected to the shaft 25c.
Above the deposition pipe 24, a device (not shown) for detecting the deposition height of iron ore is provided, and the angle of the valve 25b is changed according to the detection result.
That is, in the state shown in the figure, iron ore is deposited on the valve body 25b. However, when the iron ore in the deposition pipe 24 exceeds a predetermined amount, the above-described driving device is activated to tilt the valve body 25b, The iron ore is charged into the lower smelting reduction furnace. The maximum passing speed of the iron ore passing through the sedimentation pipe 24 at the time of its introduction is also 0.1 to
0.2 m / s. The shut-off valve 26 in FIG. 1 is an open / close valve that is normally opened except for the beginning of operation or when an abnormality occurs in the cut-out means 25, similarly to the shut-off valve 23 described above.

According to the cutting means 25, since the valve body 25b opens and closes according to the amount of iron ore deposited in the deposition pipe 24 as described above, the input amount of iron ore to the smelting reduction furnace 4 is:
Control is performed so that the deposition amount (deposition height) is maintained at a predetermined value (9 m described above). Since a predetermined amount of iron ore is constantly deposited in the deposition pipe 24, the supply device 20B
Also, the iron ore can be supplied into the smelting reduction furnace 4 without causing the gas to be blown up from the smelting reduction furnace 4 side. The path 16 is directed from the bottom of the preliminary reduction furnace 2 to the smelting reduction furnace 4 so as to prevent the fine iron ore sent to the smelting reduction furnace 4 through the path 16 from scattering in the smelting reduction furnace 4 as much as possible. It merges with a relatively coarse iron ore path 15. By the merging in this way, the fine powder is introduced into the iron bath 30a of the smelting reduction furnace 30 without scattering as much as the iron ore of coarse particles moves.

The above-described supply devices 20A and 20A
B, or similar devices, can be provided in other parts of the equipment shown in FIG. For example, it is possible to arrange such a device in place of the raw material charging tank 1, and a similar device is provided in the path 17 for directly supplying the raw iron ore into the smelting reduction furnace 4 in an emergency. It is also conceivable to arrange them.

In the smelting reduction equipment as described above, the operation of each of the supply devices 20A and 20B allows the iron ore to be smoothly fed from each of the supply paths 15 and 16 into the smelting reduction furnace 4 without causing gas injection or the like. Feeding takes place. Each route 15
Although no iron ore weighing means is provided in 16, the raw iron ore to be supplied to the preliminary reduction furnace 2 is weighed in the tank 1, so that the total amount of iron ore supplied to the smelting reduction furnace 4 is substantially accurate. You can know. The total amount of iron ore is obtained by subtracting the amount of fine iron ore iron ore that is not collected by cyclone 3 and scatters with exhaust gas from the amount of raw iron ore supplied from tank 1 (weighed in tank 1). However, the amount of fine iron ore that flies off is small.

FIG. 3 is an explanatory diagram showing how the input amount of iron ore is controlled in the smelting reduction facility described above. That is, the diagrams a, b, c, and d in the figure are:
In each case, the horizontal axis represents time, and the vertical axis represents the amount of raw iron ore charged into the pre-reduction furnace 2, the bed height of the fluidized bed in the pre-reduction furnace 2, the supply device 20B to the smelting reduction furnace 4, respectively. Of the fine iron ore and the amount of the coarse iron ore supplied from the supply device 20A to the smelting reduction furnace 4. As can be seen from the figure, for example, from time t ₁ , when only the set value of the bed height is reduced (diagram b) without changing the amount of raw material charged to the preliminary reduction furnace 2 (diagram b), the melting reduction furnace 4 The supply amount of coarse iron ore to steel (diagram d) increases only temporarily (within the time when the bed height changes). Conversely, increasing only the set value of the bed height to the time t _2, the supply amount of the coarse iron ore is reduced only temporarily. As shown at time t _{3, when} the amount of raw material charged to the preliminary reduction furnace 2 (diagram a) is increased and the set value of the bed height is increased (diagram b), the supply amount of fine powder and coarse particles to the smelting reduction furnace 4 is increased. Increase (diagrams c and d). At this time, since the bed height of the preliminary reduction furnace 2 increases along with the input amount of the raw material, the time during which the iron ore stays in the fluidized bed is not shortened, and therefore, the reduction reaction rate of the iron ore is maintained. Conversely, when lowering the bed height settings with raw material input to the pre-reduction furnace 2 as from time t _4, the supply amount of the smelting reduction furnace 4 is reduced to fine-coarse both. Also, as in the time t _5, for example, melt dosage of iron ore to the reducing furnace 4 (diagram d) When only forcibly increased short time, the pre-reduction furnace 2 of the bed height (diagram b) Temporarily falls, then gradually returns.

As shown in FIG. 3, the input amount of fine iron ore (diagram c, in other words, the generated amount) depends on the input amount of raw materials to the preliminary reduction furnace 2. That is, in this method of keeping the deposition amount at the predetermined value, the input amount of fine iron ore (diagram c) is substantially constant unless the input amount of the raw material to the preliminary reduction furnace 2 is changed. In this example, the short-term or minute amount of input to the smelting reduction furnace 4 is adjusted only by the coarse-grained system, and the long-term or large amount of input is adjusted by increasing or decreasing the amount of the raw material. The effectiveness of such control can be explained.

The supply devices 20A and 20B function stably for a long period of time because they do not include a portion that is particularly susceptible to wear and clogging. However, in order to prepare for any trouble, it is preferable to provide another similar path (including the respective supply devices 20A and 20B) in parallel with the illustrated paths 15 and 16 and the like.

The cutting means provided in each of the supply devices 20A and 20B is not limited to the above.
For example, the cutting means 22 provided in the supply device 20A is:
It is also possible to use the one in FIG. 2C instead of the one in FIG. The cut-out means 22 'in FIG.
Iron ore is deposited inside the L-shaped casing 22a 'as shown in the figure, and the nozzle 22d'
It blows high pressure gas into iron ore. For example, by blowing the gas intermittently, the state of accumulation of the iron ore can be broken down and discharged little by little. The cut-out means 25 provided in the supply device 20B is also shown in FIG.
The cutting means 22 or 22 'shown in (b) and (c) can be used instead. Also, in the cutting means 25 as shown in FIG. 2A, the angle of the valve body 25b is adjusted by a spring (or a counter weight 25 indicated by a virtual line in the drawing).
x) or the like. In this case, when the accumulation amount (weight) on the valve body 25b exceeds a certain value, the spring or the like is elastically deformed (or the counterweight is displaced by the balance with the powder weight), and the valve body 25b is automatically moved. If an open configuration is adopted, necessary control can be performed easily and at low cost without using a special sensor or operating means.

FIG. 4 shows a schematic system diagram of a smelting reduction facility different from FIG. 1 as a second embodiment of the invention.
This equipment also reduces iron ore using the preliminary reduction furnace 6 and the smelting reduction furnace 8.

In the smelting reduction facility shown in the figure, a general structure having a dispersion plate 6b and a wind box 6c is used as the preliminary reduction furnace 6. The reducing gas emitted from the smelting reduction furnace 8 is
The fluidized bed 6a is formed inside the pre-reduction furnace 6 by entering the side of the wind box 6c of the pre-reduction furnace 6 through the duct 31 and blowing up through the vertical nozzle of the dispersion plate 6b. And discharged through the duct 32. As for iron ore, first, raw iron ore is weighed by a hopper 33, and
Then, it is supplied to the pre-reduction furnace 6, where it is preheated and pre-reduced, and then supplied mainly through the path 35 into the iron bath 8a of the smelting reduction furnace 8 in the same manner as in the equipment of FIG. Fine iron ore in the exhaust gas passing through the duct 32 is also collected by the cyclone 7 and supplied to the smelting reduction furnace 8 via the path 36 as in the case of FIG.

In the case of the smelting reduction facility shown in FIG.
A cyclone 9 is also provided in the middle of the reducing gas duct 31 from the furnace to the preliminary reducing furnace 6 to collect fine dust such as fine iron ore and coal, and the fine powder is also supplied from the cyclone 9 to the smelting reducing furnace 8. The iron ore supply path 37 is connected. Further, since the iron ore flowing on the dispersion plate tends to fall into the wind box 6c of the preliminary reduction furnace 6, the path 38 is also connected to the bottom of the wind box 6c so that the fine iron ore is further removed. It can be supplied to the smelting reduction furnace 8.

The feature of the smelting reduction method using the equipment shown in FIG.
38, a new supply device 20D, 20E, 20F, 20G that does not include a tank as shown in FIG. 5 is used. Each of these supply devices includes a vertical deposition pipe for depositing iron ore therein, a cutting means connected to a lower portion thereof, and a lower shutoff valve. While preventing gas from being blown up by the ore deposited inside the deposition pipe, the ore is gradually cut down from below by the cutting means and supplied to the smelting reduction furnace 8 below.

The above-described iron ore supply devices 20D and 20E
-Of 20F and 20G, first, the supply device 20D provided in the path 35 from the fluidized bed 6a of the preliminary reduction furnace 6 to the smelting reduction furnace 8 has the same configuration as the supply device 20A in the facility of FIG. It is. In other words, the lower part of the deposition pipe whose length (deposition height of iron ore) and the like are determined in consideration of the pressure difference between the bottom of the preliminary reduction furnace 6 and the inside of the smelting reduction furnace 2 is shown in FIG.
Is connected, and a shut-off valve (not shown) is further arranged below the cut-out means 22. The control of the input amount of iron ore by the cutting means 22 is also performed so that the bed height (gas differential pressure) of the fluidized bed 6a is maintained at a predetermined value, as in the case of FIG. First, the input amount is changed by changing the set value of the bed height, and secondly (that is, as a long-term measure), the input amount of the raw iron ore to the preliminary reduction furnace 6 is changed. This is the same as in the case of FIG.

Each path 36 from the lower part of the cyclone 7.9 and the wind box 6c of the preliminary reduction furnace 6 to the smelting reduction furnace 8
Supply devices 20E and 20F provided in each of 37 and 38
And 20G have the same configuration as the supply device 20B in the facility of FIG. That is, each container (cyclone 7
) And the inside of the smelting reduction furnace 8, the length (deposition height of fine iron ore), etc., is determined in consideration of the
The cut-out means 25 shown in FIG. 2A was connected, and a shut-off valve (not shown) was further arranged below the cut-out means. As described above, the cutting means 25 keeps the amount (deposition height) of the iron ore deposited in the deposition pipe 24 at a predetermined value (a value that does not blow up even when subjected to a differential pressure). Therefore, each supply device 20E / 20
Also in F · 20G, the iron ore can be supplied into the smelting reduction furnace 8 without generating the gas from the smelting reduction furnace 8.

The following points are the same as those in the equipment shown in FIG. 1, although not particularly shown. That is, in order to minimize scattering of the fine iron ore sent to the smelting reduction furnace 8 via the paths 36, 37, and 38, the paths 36, 37, and 38 are connected to the fluidized bed 6 of the pre-reduction furnace 6.
It is good to join with the path 35 of relatively coarse-grained iron ore from a to the smelting reduction furnace 4. B) In order to ensure that the smooth supply of iron ore is not interrupted, a similar route (including each of the supply devices 20D to 20G) is provided in parallel with each of the illustrated routes 35 to 38. It is better to provide another system. C) The cutting means provided in each of the supply devices 20D to 20G is not limited to the above-described means (the cutting means 22 and 25 in FIGS. 2B and 2A).
It is also possible to substitute the cutout means 22 'of (c).

[0052]

The ore supply method according to the first aspect has the following effects. A) The quantitative ore supply from the fluidized bed of the preliminary reduction furnace to the smelting reduction furnace can be performed smoothly and accurately by using a simple and small-sized supply device. Therefore, it is necessary to reduce the space and equipment costs occupied by the ore supply system, to reduce the cost (operational equipment, etc.) required for operating the supply system, and to use valves that are subject to wear or bite by the ore. Since there is no supply system, expensive parts are not required and the maintenance burden is light.

B) Since ore is supplied while controlling the bed height of the fluidized bed to a predetermined set value, a preferable fluidized bed is always formed in the prereduction furnace, and the ore is preliminarily reduced in the prereduction furnace. Progresses stably, and the reduction efficiency together with the smelting reduction furnace can be kept high. c) Supply fine ore floating in gas path to smelting reduction furnace
Can also be achieved by using simple, compact feeders.
Can be performed smoothly and accurately,
The same effect as above a) is obtained for ore supply. d) Almost all ore input to the preliminary reduction furnace
It can be put into a smelting reduction furnace. Also for that,
Weigh ore input in each route to smelting reduction furnace
Without knowing the amount of ore to be put into the preliminary reduction furnace
Nearly accurate total ore input to smelting reduction furnace
You can know.

In the supply method according to the second aspect, further, e) charging ore from the preliminary reduction furnace to the smelting reduction furnace while always forming a preferable fluidized bed inside the preliminary reduction furnace as described in b) above. The amount can be appropriately changed according to the operation state of the smelting reduction furnace. Therefore, it is possible to easily and smoothly change the amount of metal produced per hour in the smelting reduction furnace and adjust the temperature of the metal bath.

[0055]

[0056]

In addition to the above, the supply method according to the third aspect of the present invention can be applied to an emergency such as f) when the pre-reduction furnace is inoperable or when it becomes necessary to put the raw ore into the smelting reduction furnace.
The raw ore can be supplied to the smelting reduction furnace without passing through the preliminary reduction furnace.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, and is a schematic system diagram of a smelting reduction facility.

2 (a), 2 (b) and 2 (c) are longitudinal sectional views showing an ore supply device which can be used in the equipment of FIGS. 1 and 4. FIG.

FIG. 3 is an explanatory diagram showing how the input amount of iron ore is controlled in the smelting reduction facility of FIG.

FIG. 4 shows a schematic system diagram of a smelting reduction facility different from the facility of FIG. 1 as a second embodiment of the invention.

FIG. 5 (a) is a schematic system diagram of a conventional general smelting reduction facility. (B) is the same as (a)
FIG. 4 is a detailed view of an ore supply device 70 used in the facility of FIG.

[Explanation of symbols]

 2.6 Preliminary reduction furnace 2a ・ 6a Fluidized bed 4.8 Smelting reduction furnace 4a ・ 8a Iron bath (metal bath) 20A ・ 20B ・ 20D ~ 20G Supply device 21 ・ 24 Deposition tube 22 ・ 25 ・ 28 Cutting means 23 ・ 26・ 29 Shutoff valve 22b ・ 25b Valve 25c Spring (elastic support member)

(56) References JP-A-3-274211 (JP, A) JP-A-4-325613 (JP, A) JP-A-5-171233 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) C21B 11/00-13/14

Claims (3)

(57) [Claims] In reducing a granular ore using a preliminary reduction furnace and a smelting reduction furnace, a fluidized bed of the preliminary reduction furnace
Toward smelting reduction furnace of the metal bath which is also a gas supply to it to supply granular material ores, pre-reducing furnace or a smelting reduction furnace
Bath in the smelting reduction furnace from the fine ore collection part connected to the
This is a method of supplying fine ore toward the inside, while weighing the raw ore to be put into the pre-reduction furnace, only resisting the pressure difference between the two furnaces in the deposition pipe connected to the fluidized bed of the pre-reduction furnace The ore is deposited up to the height of the ore, and the ore in the deposition pipe is cut down from below by cutting means connected to the lower part of the deposition pipe and put into the smelting reduction furnace,
In addition, the input amount is automatically controlled so that the bed height of the fluidized bed in the preliminary reduction furnace is maintained at a predetermined set value, and the weighed amount is adjusted.
Not performed, and the sediment connected to the lower part of the fine ore collection part described above
In the pipe, resist the pressure difference between the collecting part and the smelting reduction furnace.
While accumulating fine ore to the height required
By a cutting means connected to the lower part of the deposition pipe
The fine ore inside is cut down from below and put into the smelting reduction furnace,
And the input amount is the accumulation of fine ore in the sedimentation pipe.
A method for supplying ore, characterized in that the amount is automatically controlled so as to keep the amount at a predetermined value and the weighing is not performed . 2. The change of the input amount controlled as described above is performed by changing the set value of the bed height in the pre-reduction furnace, and changing the input amount of the raw material ore to the pre-reduction furnace. The method for supplying an ore according to claim 1, wherein the ore is supplied. 3. The method according to claim 1 or 2 is performed.
In addition, in an emergency, without going through the preliminary reduction furnace
From the source of raw ore into the metal bath of the smelting reduction furnace
A method for supplying ore, characterized by supplying a mineral ore.