JPS6156300B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing sintered ore that is excellent in normal temperature and reduced pulverization strength, and an apparatus used in the method.

The conventional method for producing sintered ore will be explained with reference to Figs. 1 to 4. What is shown in Fig. 1 is a mixture of iron ore, limestone, gangue, coke, etc. granulated from the feed hopper a. The sintering raw material consisting of is supplied to the upper part of the pallet conveyor type sintering machine b,
The coke in the sintering raw material is ignited and burned to sinter the raw material, and the coke combustion is sustained by the air f sucked in by the blower e connected from the upper part of the sintering machine b to the lower window box d. When the belt reaches the bottom, the sintered cake g is discharged from the sintering machine b, crushed by a crusher h, and then put into a cooler i, where it is crushed by air supplied by a blower j and the resulting sintered cake is crushed. The method for cooling the granules, as shown in Fig. 2, is that a heat insulating cover k is provided on the downstream side of the ignition furnace c, and high-temperature air that has cooled the sintered granules after crushing is passed from the cooler i to the heat insulating cover k. A third method of supplying the sintered cake to the inside of the sintering machine B to slowly cool the sintered cake on the sintering machine B to prevent thermal distortion caused by rapid cooling with air and vitrification of the sintered slag phase caused by rapid cooling with air. The one shown in the figure has a heavy oil supply device l, a coke feed device m, a re-ignition device n, etc. installed on the downstream side of the ignition furnace c, and the re-ignition device is generated by the air sucked by a blower connected to the lower wind box d. In the method shown in Figure 4, which reburns coke to create reduced sintered ore in order to prevent harmful effects such as oxidation, the sintered cake discharged from sintering machine b is fed into a conveyor-type cooler o. In this method, the blast furnace gas heated by the blast furnace gas heating device p is put into the cooler o, and the sintered cake is slowly cooled. Note that in FIGS. 2 to 4, the same reference numerals as those shown in FIG. 1 indicate the same components.

However, the above-mentioned conventional example has various problems as described below.

(i) Since air for cooling the sintered cake is sucked in from above the sintering machine, the sintered cake is reoxidized and reduced to powder, although the degree differs depending on the case.

(ii) Rapid cooling with air causes thermal distortion and the sintered cake tends to turn into powder.

(iii) Due to air quenching, the sintered slag phase is not sufficiently crystallized and a brittle glass phase remains, so the strength of the sintered ore as a product is weak.

(iv) Avoiding rapid cooling with air and performing slow cooling will result in a decrease in productivity.

(v) When performing slow cooling, a new heat source is required, but the heat is directly released into the atmosphere after slow cooling of the sintered cake, which is not desirable in terms of energy conservation.

The present invention was made for the purpose of eliminating the above-mentioned drawbacks of the conventional means, and its gist is that the sintered ore is heated and sintered in a sintering machine, and after being discharged, the sintered ore is crushed to the required size. The condensation forms a countercurrent vertical moving bed having a reheating layer of sintered ore at the top and a cooling layer of sintered ore at the bottom, and a cooling layer at the bottom of the countercurrent vertical moving bed. Then, a blast furnace gas having a temperature lower than that of the cooling layer is supplied to cool the sintered ore that has been reheated in the reheating layer and descended to the cooling layer, and the sintered ore in the cooling layer is cooled. The high-temperature blast furnace gas is discharged to the outside of the cooling layer, the heat is recovered from the high-temperature blast furnace gas discharged from the cooling layer, and the blast furnace gas whose temperature has decreased due to heat recovery is cooled by sinter. A part of the blast furnace gas discharged from the cooling layer that did not circulate to the cooling layer is combusted, and the combusted blast furnace gas has a higher content than the blast furnace gas. A low-temperature gas is mixed and heated to a temperature higher than the temperature of the reheating layer above the countercurrent type vertical moving bed to a degree that does not cause the sintered ore to melt, and the high-temperature gas is made into a high-temperature gas. The sintered ore is supplied to the reheating layer to reheat the sintered ore.

Embodiments of the present invention will be described below with reference to the drawings.

Reference numeral 1 in FIG. 5 is a sintering machine having the same structure as the conventional one, and on the top surface of the sintering machine 1, an ignition furnace 2, a heat retention furnace 3, a heat retention furnace 3, and a heat retention furnace are arranged in order from the upstream side to the downstream side. A cover 4 is provided. A pipe 5 is connected to each of the ignition furnace 2, heat retention furnace 3, and heat retention cover 4, and the pipe 5 is connected to a pipe 8 provided with a blower 6 and a heat exchanger 7.

A front window box 9 is located on the bottom of the sintering machine 1.
and rear window box 10 are installed,
The front windbox 9 is connected to a pipe 14 which is equipped with a dust remover 11 and a blower 12 in the middle and has a chimney 13 at its downstream end. The rear windbox 10 is connected to a pipe 16 equipped with a blower 15 in the middle, and the exhaust gas rich in oxygen gas sucked from above the sintering machine 1 is transferred to a combustor 25 (described later).
It is configured so that it can be delivered to

At the rear of the discharge side of the sintering machine 1, a hopper 18 and a reheater 1 are installed to form a countercurrent vertical moving layer 17.
9. Coolers 20 are arranged sequentially from the top to the bottom, and the reheater 19 has a line for feeding high-temperature gas mixed with blast furnace gas to reheat the sintered ore 21. 20 are respectively attached with lines for cooling the sintered ore 21 that has been reheated in the reheater 19 and descended to the cooler 20 by circulating blast furnace gas.

A reheater 19 is installed in the line that reheats the sintered ore.
Gas supply piping 22 connected to the bottom and gas exhaust piping 23 attached to the top of the reheater 19
A mixer 24 and a combustor 25 are attached to the pipe 22. In addition, the piping 23 is connected to a primary dust remover 37' and a secondary dust remover 38' in the middle, and branches into pipes 26 and 27 on the downstream side, and the heat exchanger 7 is connected to the pipe 26 in the middle, A chimney (not shown) is provided at the downstream end, while a boiler 28 is connected to the pipe 27 at its midpoint, and a chimney 29 is provided at the downstream end.

The piping 27 includes a piping 32 equipped with a blower 30 and a control valve 31 on the downstream side of the boiler 28.
is connected to the mixer 24, and the pipe 32 is connected to the mixer 24.
It is connected to the.

The line for cooling the sintered ore includes a pipe 33 connected to the lower part of the cooler 20 to feed blast furnace gas sent from the blast furnace into the cooler 20, and a pipe 33 connected to the upper part of the cooler 20 for discharging blast furnace gas. A blower 35 and a pipe 36 for supplying blast furnace gas are connected to the pipe 33, and a primary dust remover 37, a secondary dust remover 38, and a boiler 39 are connected to the pipe 34. Furthermore, the pipe 34 is connected to the blower 3 of the pipe 33.
5, and a blast furnace gas circulation line is formed by pipes 33 and 34.

A pipe 41 equipped with a blower 40 is connected to the pipe 34 on the downstream side of the boiler 39.
The pipe 41 is connected to the combustor 25. The piping 16 is also connected to the combustor 25 .

A pipe 43 having a control valve 42 in the middle is connected to a portion of the pipe 41 downstream of the blower 40, and the pipe 43 is connected to the downstream side of the control valve 31 of the pipe 32.

A pipe 44 may be connected to a portion of the pipe 34 between the secondary dust remover 38 and the boiler 39,
In that case, the pipe 44 is connected between the blower 40 of the pipe 41 and the combustor 25.

Next, the operation of the present invention will be explained.

The sintering raw material is supplied to the upper part of the sintering machine 1 from an ore feed hopper (not shown), the coke in the sintering raw material is ignited and burned in the ignition furnace 2, and the raw material is sintered, and the raw material is sintered in the heat retention furnace 3. To stabilize the combustion of coke during sintering,
When the heat retaining cover 4 is provided, rapid cooling due to air is prevented. The combustion air of the ignition furnace 2, the heat retention furnace 3, and the air supplied to the heat retention cover 4 are supplied to the piping 8,
5 to the sintering machine 1, passes through a front window box 9 and piping 14, removes dust in a dust remover 11, and is discharged into the atmosphere from a chimney 13. The sintered cake is discharged from the sintering machine 1 after being connected to coke combustion by the air sucked in by the blower 15 and the blower 12 in the area after the heat retention furnace 3, and is crushed to a predetermined particle size by a crusher. However, since the sintered cake is rapidly cooled by air in the area after the heat retention furnace 3, the sintered ore charged into the hopper 18 may undergo thermal distortion or become slag. Vitrification of the phase has occurred. Therefore, in order to eliminate thermal distortion and recrystallize the glass phase, the following operation is performed.

In other words, the sintered cake on the sintering machine 1 is cooled down to about
Approximately 180 ℃ of oxygen-rich exhaust gas and blast furnace gas, which have been sent through the pipe 16 at a temperature of 270°C, are sent from the circulating line through the pipe 41 or 44.
℃ or about 800℃ is combusted in the combustor 25 to become a gas of about 1450℃ and sent to the mixer 24.
In the mixer 24, the gas sent from the pipe 32 or, at the beginning of operation, is mixed with the blast furnace gas sent from the pipe 43 and adjusted to a high temperature of about 1100°C, and then passed through the pipe 22 to the reheater. 19 and moves from the top to the bottom in the reheater 19
Direct contact with sintered ore at 750°C to reduce the sintered ore to about 1000℃
℃ to eliminate thermal distortion of the sintered ore, while recrystallizing the glass phase of the slag, it moves from the bottom to the top in the reheater 19, and is discharged into the pipe 23 as exhaust gas at about 800℃. , from piping 23 to boiler 2
Heat is applied to the boiler 28 through 8 to approximately 180℃
A part of the gas returns to the mixer 24 through the pipe 32, and the rest is released into the atmosphere through the chimney 29.
In addition, the gas passing through the pipe 23 may be transferred to the pipe 2 in some cases.
6 to the heat exchanger 7, and the air sent to the ignition furnace 2, heat retention furnace 3, and heat retention cover 4 on the sintering machine 1 is approximately
It may be preheated to 400℃ and released into the atmosphere at a temperature of approximately 150℃.

From the pipe 33, the pipe 3 is connected from the blast furnace (not shown).
The blast furnace gas sent through 6 and the blast furnace gas circulated through piping 34 are mixed to become a gas at a temperature of approximately 120°C, which is then supplied to cooler 20, where it is reheated and cooled by reheater 19. The sintered ore is moved from the bottom to the top in the cooler 20 while gradually cooling the sintered ore by direct contact with the sintered ore moving from the top to the bottom in the container 20.
It is discharged into the pipe 34 at a temperature of 870°C, dust is removed by the primary dust remover 37 and the secondary dust remover 38, and the heat is passed through the boiler 39.
The temperature will be approximately 180℃. A part of the blast furnace gas is sent to the combustor 25 through the pipe 41, and the rest is circulated and sent into the cooler 20 again. The amount of blast furnace gas supplied into the pipe 33 is equal to the amount of blast furnace gas sent to the combustor 25 from the pipe 41.

When saving fuel in the combustor 25,
The gas having more sensible heat after exiting the secondary dust remover 38 may be sent to the combustor 25 from the pipe 44 without being sent to the boiler 39.

The sintered ore slowly cooled in the cooler 20 is transferred to the cooler 2.
The product is taken out from the bottom of 0. In addition, the steam generated in the boilers 28 and 39 rotates a steam turbine to drive a generator, and energy is recovered.

In the embodiments of the present invention, the case where the temperature of the gas for reheating the sintered ore is set to about 1100°C is explained, but the temperature is such that the sintered ore does not stick to each other due to melting etc. The present invention may be modified any number of times as long as the temperature is higher than the temperature when the sintered ore is put into the reheater, it can be carried out without a heat insulating cover, and various other changes may be made without departing from the gist of the present invention. Of course, there are other things that can be added.

Since the sintered ore manufacturing method of the present invention and the manufacturing equipment used in the method have the above-described configuration, the room temperature strength and reduction powder strength of the sintered ore can be improved by reheating and cooling with blast furnace gas. Moreover, since the temperature of the gas supplied to the reheating layer can be easily adjusted, the sintered ore does not melt even when reheated, improving the product quality of the sintered ore. Since the process is performed using a counter-current vertical moving bed, the time for gas to pass through is longer than that of a horizontal type, and the sensible heat in the system is efficiently used, and a heat recovery device is used for sintering. Since heat is recovered from the blast furnace gas after the ore has been cooled, it can contribute to energy savings, and the sintered ore that forms the reheating layer and cooling layer is crushed, so compared to when the sintered ore is in the form of a cake. Heat exchange can be performed effectively, and since it is a vertical countercurrent moving bed, there is no restriction on layer thickness, and various excellent effects can be achieved, such as good productivity.

[Brief explanation of the drawing]

1 to 4 are explanatory diagrams of a conventional sintered ore manufacturing method, and FIG. 5 is an explanatory diagram of a sintered ore manufacturing method of the present invention and a manufacturing apparatus used in the method. In the figure, 1 is a sintering machine, 17 is a countercurrent vertical moving bed, 1
8 is a hopper, 19 is a reheater, 20 is a cooler,
24 is a mixer, 25 is a combustor, 28, 39 are boilers, 31, 42 are control valves, 37 is a primary dust remover,
38 is a secondary dust remover.

Claims (1)

[Scope of Claims] 1. Made of sintered ore that has been heated and sintered in a sintering machine, discharged, and then crushed to a required size, the sintered ore has a reheated layer in the upper part and the sintered ore in the lower part. A counter-current vertical moving bed having a cooling layer of The sintered ore that has been reheated in the heating layer and has descended to the cooling layer is cooled, and the blast furnace gas that has become high temperature by cooling the sintered ore in the cooling layer is discharged to the outside of the cooling layer. Heat is recovered from the high-temperature blast furnace gas discharged from the furnace, and the blast furnace gas whose temperature has been lowered due to the heat recovery is circulated to the cooling layer as a gas for cooling the sintered ore, and the blast furnace gas discharged from the cooling layer is A part of the blast furnace gas that did not circulate to the cooling layer is combusted, and a gas lower in temperature than the blast furnace gas is mixed with the combusted blast furnace gas to create a reheating layer above the countercurrent vertical moving bed. The sintering method is characterized in that the temperature is adjusted to a temperature higher than the temperature of the sintered ore so that the sintered ore does not melt to produce a high-temperature gas, and the high-temperature gas is supplied to the reheating layer to reheat the sintered ore. Method for producing concretions. 2. A reheater and a cooler are arranged behind the sintering machine so that the sintered ore moves from above to below, and the blast furnace gas is supplied to the cooler after cooling the sintered ore in the cooler. A circulation line that circulates the blast furnace gas and introduces it to the lower part of the cooler is connected, a heat recovery device is provided at a required position of the circulation line, and a combustor that combusts blast furnace gas and a combustor that burns the blast furnace gas are installed below the reheater. Connect a line equipped with a mixer that mixes the blast furnace gas with gas at a lower temperature than the blast furnace gas, and discharge the gas after reheating the sintered ore in the reheater to the top of the reheater. between the downstream side of the heat recovery device of the circulation line and a required position upstream of the combustor of the line equipped with the combustor and the mixer,
1. A sintered ore manufacturing apparatus, comprising a line for sending a part of blast furnace gas discharged from a cooler to the combustor.