JPS6156299B2 - - 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 sintered to sinter the raw material, and the coke combustion is continued by the air f sucked by the blower e connected from the upper part of the sintering machine b to the lower window box d. When the combustion zone has reached the lower part, 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. The method for cooling the sintered grains, shown in Figure 2, is to install a heat insulation cover k on the downstream side of the ignition furnace c, and to pass the high temperature air that has cooled the crushed sintered grains from the cooler i to the heat insulation cover. A method for slowly cooling the sintered cake on the sintering machine B by supplying the sintered cake to the sintering machine B to prevent the thermal distortion caused by the rapid cooling with air, and to prevent the vitrification of the sintered slag phase caused by the rapid cooling with the air. What is shown in Figure 3 is generated by the air sucked by the blower connected to the lower wind box d, which is provided with a heavy oil supply device l, a coke feed device m, a re-ignition device n, etc. on the downstream side of the ignition furnace e. In the method shown in Figure 4, which reburns coke to create reduced sintered ore in order to prevent harmful effects such as reoxidation, 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 temperature raising device p is put into the cooler o to cool the sintered cake. 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 low.

(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 with a reheating layer of sintered ore at the top and a cooling layer of sintered ore at the bottom, and the sintered ore in the cooling layer is transferred to the burned blast furnace gas. A part of the discharged gas is mixed and adjusted to a temperature higher than the temperature of the reheating layer to an extent that the sintered ore does not melt to produce a high temperature gas, and the high temperature gas is mixed with a part of the discharged gas. Supplying the sintered ore to a heating layer to reheat the sintered ore, exhausting the reheated gas out of the reheating layer to cool the sintered ore in the cooling layer and combining it with the remainder of the exhausted gas, The cooling layer is characterized in that heat is recovered from the combined gas, and the gas, which has been reduced in temperature by recovering the heat, is introduced into the cooling layer to cool the cooling layer.

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 that of the conventional example. At the rear of the discharge side of the sintering machine 1, a hopper 3 and a reheater are installed to form a countercurrent vertical moving bed 2. 4. Coolers 5 are sequentially arranged from the top to the bottom.

A high temperature gas mixed with an inert gas such as _N2 gas is circulated through the reheater 4.
A line is attached to the cooler 5 to reheat the sintered ore 6 that has been put into _the cooler 5. A line is installed to circulate and cool gas mixed with inert gas, etc.

The line for reheating the sintered ore includes a gas supply pipe 7 connected to the bottom of the reheater 4 and the reheater 4.
A gas exhaust pipe 8 connected to the upper part is provided, and the pipe 7 contains exhaust gas from combusting blast furnace gas sent from the combustor 9 and gas after cooling sintered ore, which will be described later. A mixer 10 is provided for mixing. Further, a primary dust remover 11 and a secondary dust remover 12 are attached to the pipe 8.

A gas supply pipe 13 connected to the lower part of the cooler 5 and a gas discharge pipe 14 connected to the upper part of the cooler 5 are attached to the line for cooling the sintered ore. A boiler 15 and a blower 16 are attached to the piping 14, as well as a primary dust remover 17 and a secondary dust remover 18, respectively. Further, the pipe 8 through which the gas reheating the sintered ore is discharged is connected to the inlet side of the boiler 15.

The downstream part of the secondary dust remover 18 of the pipe 14 is connected to the downstream part of the secondary dust remover 12 of the pipe 8 on the upstream side of the boiler 15.
Piping 19 connected immediately after the secondary dust remover 18 of No. 4
is connected to the mixer 10.

A pipe 21 having a chimney 20 at the end is connected to the pipe 8 downstream of the secondary dust remover 12 and upstream of the connection part of the pipe 14 to discharge excess gas into the atmosphere. Heat exchangers 22 and 23 and a blower 24 are attached to the middle part of 21.

Blast furnace gas discharged from a blast furnace (not shown) is heated by a heat exchanger 22 while being fed through a pipe 26 by a blower 25, and is configured to be fed to a combustor 9. It is configured to be fed through a pipe 28 by a blower 27, heated by a heat exchanger 23, and then fed to a combustor 9.

Note that 29 in the figure is a pipe for replenishing inert gas.

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

The sintered cake sintered in the sintering machine 1 is discharged from the sintering machine 1, crushed into a predetermined particle size by a crusher, and put into the hopper 3. In the sintering machine 1, the sintered cake is rapidly cooled by air. Therefore, the sintered ore charged into the hopper 3 has vitrification of the slag phase caused by thermal strain. Therefore, in order to eliminate thermal distortion and recrystallize the glass phase, the following operation is performed, for example.

That is, the preheated blast furnace gas sent through the pipe 26 by the blower 25 and the blower 27
The preheated air sent through piping 28 by
It becomes a high temperature gas of about 1100°C and is sent to the mixer 10, where it is mixed with the gas containing inert gas sent from the pipe 19 to become a gas of about 1100°C, which is then reheated from the pipe 7. The sintered ore is charged into the container 4 and is heated by direct contact with the sintered ore that is fed into the hopper 3 at about 750°C, which moves from above to below in the reheater 4, and the heat of the sintered ore is heated. While eliminating distortion and recrystallizing the glass phase of the slag, the slag moves from the bottom to the top in the reheater 4, becomes exhaust gas at approximately 800°C, is discharged into the pipe 8, and is then passed through the primary dust remover 11 and the secondary dust remover. After the dust is removed at step 12, part of the exhaust gas flows into pipe 21 and the rest flows through pipe 8.

The exhaust gas sent to the pipe 21 preheats the blast furnace gas to about 400°C in the heat exchanger 22, preheats the air to about 400°C in the heat exchanger 23, and is discharged from the chimney 20 into the atmosphere.

The exhaust gas fed through the pipe 8 is mixed with the gas sent from the pipe 14 in a state where the temperature is slightly higher than that of the exhaust gas in the middle of the pipe, and the temperature reaches approximately 850°C.
It passes through the boiler 15, gives heat to the boiler 15, becomes a low-temperature gas of 200°C or less, and pipes an inert gas equivalent to the amount of inert gas in the flue gas discharged from the chimney 20. 29 into the pipe 13, and from the pipe 13 to the cooler 5.
The sintered ore is supplied into the cooler 5, is reheated by the reheater 4, and moves from the upper side to the lower side in the cooler 5. The gas is discharged into the pipe 14 as a gas with a temperature of about 900°C or more, and the dust is removed by the primary dust remover 17 and the secondary dust remover 18, and a part of the gas from which the dust has been removed is discharged from the pipe 19. The remaining high-temperature gas enters the pipe 14 into the pipe 8 and adjusts the temperature of the gas sent to the boiler 15.

The sintered ore slowly cooled in the cooler 5 is discharged as a product from the lower part of the cooler 5. Also boiler 15
The steam generated rotates a steam turbine and drives a generator.

The inert gas used in the present invention is N ₂
It is possible to use any gas other than gas, and the temperature at which the sintered ore is reheated may be a high temperature as long as the sintered ore does not adhere to each other due to melting etc. In reality, the upper limit is about 1100° C.), and it goes without saying that various changes can be made without departing from the gist of the present invention.

Since the sintered ore manufacturing method of the present invention and the manufacturing apparatus used in the method have the above-described configuration, the room temperature strength and reduction powder strength of the sintered ore are improved by reheating and cooling with an inert gas. In addition, since the temperature of the gas supplied to the reheating layer can be easily adjusted, the sintered ore does not melt even during reheating, improving the product quality of the sintered ore, and the gas is circulated. Since a heat recovery device is installed in the line where the system is heated, the sensible heat within the system can be used efficiently, contributing to energy savings.Furthermore, the crushed sintered ore can be used to create a vertical reheating layer and cooling layer. This makes it possible to recover heat more effectively than when recovering heat from cake-shaped sintered ore using horizontal heating and cooling layers. Since there is no limit to the number of times, various excellent effects can be achieved, such as improved production efficiency.

[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, 2 is a countercurrent vertical moving bed, 3 is a hopper, 4 is a reheater, 5 is a cooler, 9 is a combustor, 10 is a mixer, 15 is a boiler, 16, 2
4, 25, and 27 are blowers, and 22, 23 are heat exchangers.

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 countercurrent type vertical moving bed with a cooling layer of The temperature is adjusted to a high temperature that does not cause the sintered ore to melt to produce high-temperature gas, the high-temperature gas is supplied to the reheating layer to reheat the sintered ore, and the reheated gas is reheated. The sintered ore in the cooling layer is discharged to the outside of the layer, and the sintered ore in the cooling layer is combined with the rest of the discharged gas, and the heat is recovered from the combined gas, and the gas is cooled to a low temperature by recovering the heat. A method for producing sintered ore, characterized in that the cooling layer is cooled by introducing into the cooling layer. 2. A reheater and a cooler are arranged behind the sintering machine so that the sintered ore moves from above to below, and a combustor and a mixer for burning blast furnace gas are provided below the reheater. The upper part of the reheater and the lower part of the cooler are connected by a circulation line that reheats the sintered ore and feeds the gas discharged from the reheater to the lower part of the cooler, A heat recovery device is connected to the required position of the circulation line, and a line for feeding the gas discharged from the cooler after cooling the sintered ore in the cooler is connected to the upper part of the cooler. is connected to the upstream side of the heat recovery device of the circulation line, and a mixer provided in a line for feeding gas discharged from the cooler and a line connected to the lower part of the reheater is connected to the cooler. A sintered ore manufacturing device, characterized in that the device is connected to a mixer by a line for sending part of the gas discharged from the device to a mixer.