JP7328537B2 - Method for producing sintered ore - Google Patents

Description

The present invention relates to a method for producing sintered ore.

Currently, the main raw material for blast furnace ironmaking is sintered ore. Sintered ore is usually manufactured as follows. First, as raw materials for producing sintered ore, iron raw materials such as iron ore (powder), iron-containing miscellaneous raw materials such as scale and ironmaking dust, MgO-containing auxiliary raw materials such as olivine, CaO-containing auxiliary raw materials such as limestone, return ore , a carbonaceous material (coagulant), etc., which serves as a fuel for sintering (coagulating) the sintered ore by the heat of combustion, is mixed in a predetermined ratio. The blended raw material is granulated to obtain a blended raw material granule. Next, the mixed raw material granules are loaded from the hopper onto a pallet of a downward suction type Dwight Lloyd (DL) type sintering machine to form a raw material packed bed. An ignition furnace (igniter) is used to ignite the carbon material in the raw material packed bed from above (surface) of the formed raw material packed bed. Then, air is sucked from below the pallet while continuously moving the pallet. Oxygen is supplied into the raw material packed bed by suction, and the combustion of the carbonaceous material in the raw material packed bed proceeds from the top to the bottom, and the raw material packed bed is sequentially sintered by the combustion heat of the carbonaceous material. The sintered part (sinter cake) obtained by sintering is pulverized to a predetermined particle size, sieved, etc., and becomes sintered ore, which is a raw material for a blast furnace.

Among methods for producing sintered ore using such a DL type sintering machine, a multistage charging multistage ignition sintering method has been proposed in which the formation of a raw material packed bed and ignition are performed in two or more stages. In the multi-stage charging multi-stage ignition sintering method, the granulated blended raw materials are sequentially charged in the layer height direction of the sintering machine to form multi-stage raw material packed beds, and the surface of each raw material packed bed is ignited, and the bottom In this method, the sintering reaction of each layer proceeds in parallel by sucking air from the layer to sinter the layer.

FIG. 1 is a schematic diagram of a DL sintering machine used for a two-stage charging two-stage ignition sintering method, which is an example of a multi-stage charging multi-stage ignition sintering method. Referring to FIG. 1, granulated mixed raw materials are charged in two stages to form an upper raw material packed layer (hereinafter referred to as upper layer) and a lower raw material packed layer (hereinafter referred to as lower layer). A two-stage charging two-stage ignition sintering method in which sintering is performed by igniting the layer and the lower layer respectively will be described.

In the example shown in FIG. 1, the upper-stage blended raw material that forms the upper layer and the lower-stage blended raw material that forms the lower layer are prepared in separate systems (two systems), and the pallet ( not shown). Specifically, the raw materials for the lower stage are stored in each raw material tank (1D ₁ to 1D _X ) of the lower raw material tank group 1D, and the necessary types and amounts of raw materials are cut out at a predetermined ratio and blended. . The blended raw materials for the lower stage (blended raw materials for the lower stage) are put into the drum mixer 1A for the lower stage, mixed, water is added, and granulated. In addition, raw materials for the upper stage are stored in the raw material tanks (2D ₁ to 2D _X ) of the upper raw material tank group 2D, and the necessary types and amounts of raw materials are cut out at a predetermined ratio and blended. The blended raw materials for the upper stage (blended raw materials for the upper stage) are put into the drum mixer 2A for the upper stage, mixed, water is added, and granulated.

The granulated lower-stage blending raw material (lower-stage blending raw material granules) is charged from the lower-stage surge hopper 1B onto a pallet covered with bedding ore to form a lower layer 10 (lower-stage raw material packed layer). do. The lower layer 10 moves below the lower ignition furnace 1C by moving the pallet in the pallet advancing direction 5, where the carbon material on the surface of the lower layer 10 is ignited by the lower ignition furnace 1C. After ignition, sintering of the lower layer 10 is initiated by a downward suction 6 sucking air from below via a wind box (not shown) under the pallet. Sintering of the lower layer 10 proceeds downward with subsequent downward suction 6 to form the lower layer combustion zone 10A.

When the lower layer 10 whose sintering has started moves to the bottom of the upper surge hopper 2B, the upper mixing raw material (upper mixing raw material granules) granulated by the upper drum mixer 2A is discharged from the upper surge hopper 2B. , is charged onto the lower layer 10 after ignition to form the upper layer 20 (upper raw material packed layer). The upper layer 20 moves below the upper ignition furnace 2C by moving the pallet in the pallet advancing direction 5, where the carbon material on the surface of the upper layer 20 is ignited by the upper ignition furnace 2C. After ignition, the lower suction 6 initiates sintering of the upper layer 20 . Sintering of the upper layer 20 proceeds downward with subsequent downward suction 6 to form the upper layer combustion zone 20A.

The lower layer combustion zone 10A of the lower layer 10 and the upper layer combustion zone 20A of the upper layer 20 are simultaneously sintered and descended by the subsequent downward suction 6 . When the lower layer combustion zone 10A and the upper layer combustion zone 20A reach the bottom of each layer, sintering by combustion of the carbonaceous material is completed, and the sintering zone 3 is formed. Finally, the sintered portion 3 that has completed sintering is discharged from the end of the pallet.

In the two-stage charging two-stage ignition sintering method, the raw material packed bed is divided into two stages, and sintering proceeds simultaneously in the two stages, so that the production volume can be almost doubled. Further, since the exhaust gas used for sintering the upper layer 20 is reused for sintering the lower layer 10 by downward suction, the amount of exhaust gas can be reduced.

The multistage charging and multistage ignition sintering method is disclosed in Patent Documents 1 to 3 and the like. In Patent Document 1, since the multi-stage charging multi-stage ignition sintering method can change the supply ratio of the raw materials of each layer, the yield can be improved by adjusting the particle size of the raw materials of the upper layer 20 and the lower layer 10. It is stated that

Patent document 2 and patent document 3 point out that the sintering strength of the sintered ore of the lower layer 10 is lowered as a problem of the two-stage charging and two-stage ignition sintering method. Specifically, in the two-stage charging two-stage ignition sintering method, as described above, the gas (exhaust gas) used for sintering the upper layer 20 and having a reduced oxygen partial pressure is sucked downward 6 into the lower stage. It is supplied to the layer 10 and used for sintering the lower layer 10 . Therefore, since the lower layer 10 is under a low oxygen partial pressure, the carbonaceous material in the lower layer 10 is incompletely burned, and the amount of heat required for sintering is insufficient. Due to the lack of heat, the progress of the sintering reaction of the lower layer 10 is hindered, and the strength of the sintered ore of the lower layer 10 is lowered.

As a solution to this problem, in Patent Document 2, in order to improve the sintering strength of the sintered ore of the lower layer 10, the fixed carbon concentration in the ironmaking raw material to be sintered is 3.3% on average for all layers. It is described that the fixed carbon concentration of the upper layer 20 is low and the fixed carbon concentration of the lower layer 10 is high. Patent Document 3 describes a lower granulation step of granulating a main compounding raw material other than a carbonaceous material among the lower compounding raw materials with a granulator, and granulation of the main compounding raw material from the latter half of the lower granulating step. Before charging the material into the lower stage surge hopper of the sintering machine, a carbon material charging step of charging the carbon material into the main compounding raw material, and charging the granulated material of the main compounding raw material and the carbon material into the sintering machine. A method for producing sintered ore is described.

JP-A-47-26304 JP-A-62-60829 JP 2018-178148 A

In Patent Document 2, the upper limit is set for the average fixed carbon concentration in all layers, and the coke blending ratio of the upper layer 20 is lowered, so that the amount of heat supplied to the upper layer 20 is reduced, and the sintered ore in the upper layer 20 is reduced. will lead to a decrease in cold strength. In Patent Document 3, by post-adding the carbonaceous material to the blended raw material of the lower system, the carbonaceous material is more likely to come into contact with the gas, the combustion of the carbonaceous material is promoted, and the sintered ore of the lower layer 10 is produced. However, it requires equipment for post-addition of carbonaceous material.

The present invention is a method for producing a sintered ore newly invented in view of the above problems. An object of the present invention is to provide a sintering method capable of suppressing a decrease in the strength of sintered ore in the lower raw material packed bed in a two-stage charging two-stage ignition sintering method (hereinafter simply referred to as a two-stage ignition sintering method). To provide a method for producing ore.

The present invention has been made to solve the above problems, and the gist thereof is as follows.

(1) When charging the sintered ore raw material containing the coagulant into the sintering machine, it is charged in two stages in the bed height direction to form a lower raw material packed bed and an upper raw raw material packed bed. and
igniting the lower raw material packed bed and the upper raw material packed bed with a lower ignition furnace and an upper ignition furnace, respectively, and sucking an oxygen-containing gas from below the lower raw material packed bed;
A sintered ore characterized in that, in the lower raw material packed bed, the amount of heat input from the lower ignition furnace is 1.8% or more with respect to the amount of heat input by the coagulant in the lower raw material packed bed. manufacturing method.
(2) In the lower raw material packed bed, the amount of heat input from the lower ignition furnace is 3.7% or less of the amount of heat input by the coagulant in the lower raw material packed bed. The method for producing sintered ore according to (1).

According to the present invention, in the two-stage ignition sintering method, the strength of the sintered ore in the lower raw material packed bed can be improved by increasing the amount of heat input from the ignition furnace to the lower raw material packed bed.

1 is a schematic diagram of a DL type sintering machine used in a two-stage ignition sintering method; FIG. 1 is a schematic diagram of a DL-type sintering machine used for a two-stage ignition sintering method, which is an embodiment of the present invention; FIG.

The amount of input heat used for sintering the lower layer 10 (the amount of heat input to the sintering reaction) is the amount of input heat supplied by the condensate contained in the lower layer 10 as a raw material, and the amount of heat ignited in the lower ignition furnace 1C. There is an input heat supplied by the ignition gas when The present inventors have studied various means for improving the two-stage ignition sintering method in which the strength of the sintered ore in the lower layer 10 is reduced. It has been found that the strength of the sintered ore of the lower layer 10 is improved by increasing the . The amount of heat input to the lower raw material packed bed (lower layer 10) can be increased by extending the ignition time of the lower ignition furnace 1C or by increasing the ignition intensity. A heat amount equal to or greater than the appropriate input heat amount in the sintered ore production process of a general sintering method (one-step charging, one-step ignition) is supplied to the lower layer 10 from the lower ignition furnace 1C of the two-step ignition sintering method of the present invention. do it.

The present inventors conducted sintering pot tests under different conditions such as the ignition time of the lower ignition furnace 1C, and determined an appropriate range for the amount of heat input from the lower ignition furnace 1C. The present invention was invented based on such findings.
In the two-step ignition sintering method, the lower layer 10 is sintered by setting the amount of heat input from the lower ignition furnace 1C to 1.8% or more with respect to the amount of heat input by the coagulant blended in the lower layer 10. It can improve the strength of ore. In addition, it is desirable that the amount of heat input from the lower stage ignition furnace 1</b>C is 3.7% or less of the amount of heat input by the condensing agent blended in the lower layer 10 .

Here, the amount of heat input by the condensate (charcoal material) contained in the raw material packed bed and the amount of heat input from the ignition furnace are calculated by the following equations (1) and (2), respectively.
Heat input by coagulant = Calorific value of carbonaceous material (MJ/kg carbonaceous material) x Concentration of carbonaceous material (kg carbonaceous material/t-mixed raw material) x Density of mixed raw material (t-mixed raw material/m ³ ) (1 )
Amount of heat input from the ignition furnace = ignition intensity (MJ/m ² ) ÷ layer thickness (m) (2)

The ignition intensity of the above formula (2) is calculated by the following formula (3) in the case of a continuous sintering machine (for example, a Dwight Lloyd sintering machine) that fires while continuously charging the blended raw material. . In the case of a batch-type sintering machine (for example, a sintering pot) in which all the raw materials to be mixed are charged in advance and sintered, calculation is performed by the following formula (4).
Ignition intensity (MJ/m ² ) = ignition gas calorific value (MJ/m ³ ) x ignition gas flow rate (m ³ /min)
÷ pallet width (m) ÷ pallet speed (m/min) (3)
Ignition intensity (MJ/m ² ) = ignition gas calorific value (MJ/m ³ ) x ignition gas flow rate (m ³ /min)
× Ignition time (min) ÷ Pot surface area (m ² ) (4)

FIG. 2 is a schematic diagram of a DL type sintering machine used for the two-stage ignition sintering method, which is one embodiment of the present invention. A feature of the present embodiment is that the amount of heat input to the lower layer 10 by the lower ignition furnace 1X is increased by extending the ignition time of the lower ignition furnace 1X more than the ignition time of the lower ignition furnace 1C. is.

In this embodiment shown in FIG. 2, the difference from the conventional example shown in FIG. 1 is the width of the lower ignition furnace 1X and the lower ignition furnace 1C in the pallet advancing direction 5. As shown in FIG. In the lower-stage ignition furnace 1X of the present embodiment, the width in the pallet advancing direction 5 is larger than that of the lower-stage ignition furnace 1C. The width of the lower stage ignition furnace 1C is widened, for example, the conventional lower stage ignition furnace 1C is modified and expanded in the pallet advancing direction 5, or the pallet advance speed during passage through the ignition furnace is reduced. By extending the time to ignite the surface of the lower layer 10 moving in the direction 5, the amount of heat input to the lower layer 10 is increased. The ignition time is adjusted so that the amount of heat input to the lower layer 10 by the lower ignition furnace 1X is 1.8% or more and 3.7% or less with respect to the amount of heat input by the condensate contained in the lower layer 10. . In addition, as shown in the examples described later, this ignition time is 1 of the ignition time and input heat amount by the ignition furnace when performing the sintering method (single-stage charging, single-stage ignition) with a normal continuous sintering machine. 0.5 times or more and less than 3.0 times.

The embodiment shown in FIG. 2 is an example of the present invention, and the means for increasing the amount of heat input to the lower layer 10 is not limited to extending the ignition time as described above, but for example, increasing the ignition intensity. But it can be done. Coke oven gas (COG) is generally used as the ignition gas for igniting the raw material packed bed used in the ignition furnace, but the ignition gas calorific value (MJ/m ³ ) is greater than that of coke oven gas. may be used to enhance the ignition intensity and increase the amount of heat input to the lower layer 10 . It is also preferable to increase the ignition intensity by increasing the ignition gas flow rate (m ³ /min).

In addition, in the present embodiment, sintered ore is produced by a two-stage ignition sintering method in which the mixed raw material for the upper stage and the mixed raw material for the lower stage are prepared in separate systems and charged on a pallet. It is also possible to prepare the blended raw material for the first stage and the blended raw material for the lower stage in one system. This is because the blending and composition of the raw materials for the upper stage and the raw materials for the lower stage may be the same.

Examples for demonstrating the effects of the present invention will be described. In addition, the present invention is not limited to the following examples.

The inventors confirmed the effect of the present invention by a sintering pot test (300 mm in diameter) that can simulate sintering by a DL sintering machine. Unlike the DL sintering machine, the sintering pot test device does not move the raw material packed layer by pallets, but the mixed raw material containing carbonaceous material is charged into a container of a predetermined size that can be sucked downward and ignited from the top. It is a testing device that advances sintering by sucking downward.
Five experiments of Comparative Examples 1 to 3 and Invention Examples 1 and 2 were conducted as shown in Table 2, which will be described later.

(test case)
The test levels are shown below (see upper part of Table 2).
Comparative Example 1 simulates a normal sintering method (single charging, single ignition), and the ignition time is 1 minute. Comparative Example 2 is a two-stage ignition, and the ignition time of the upper stage and the lower stage was set to 1 minute each. A conventional method with two-stage ignition was modeled. Comparative Example 3, Inventive Example 1 , and Inventive Example 2 employ two-stage ignition, and compared to Comparative Example 2, the ignition time of the upper or lower layer was increased to increase the amount of heat input by ignition.
Comparative Example 1 (single-stage charging, single-stage ignition)
Amount of heat input by ignition (ignition time): 1 minute Comparative Example 2 (two-stage charging, two-stage ignition)
Heat input by ignition (ignition time): 1 minute for upper stage, 1 minute for lower stage Comparative Example 3 (two-stage charging, two-stage ignition)
Input heat amount by ignition (ignition time): 1.5 minutes in the upper stage, 1 minute in the lower stage
Invention Example 1 (Two-stage charging, two-stage ignition)
Amount of heat input by ignition (ignition time): 1 minute in the upper stage, 1.5 minutes in the lower stage Invention Example 2 (Two-stage charging, two-stage ignition)
Amount of heat input by ignition (ignition time): 1 minute on the upper stage, 3 minutes on the lower stage

(Raw material composition)
Table 1 shows the raw materials used and their blending ratios. Iron ores A to D, peridotite, limestone, and quicklime were blended in proportions shown in Table 1. In addition, the carbonaceous material was blended in an external number of 4.5% by mass based on 100% by mass of the new raw material. Iron ores A to D in Table 1 were from different production areas. In addition, the carbonaceous material (coke fine) used as a coagulant had a particle size of −5 mm (less than 5 mm) (below a sieve with a sieve mesh of 5 mm).
The composition of raw materials is the same for the upper layer and the lower layer. In addition, the mixing ratio of raw materials in all cases was kept constant.

(Granulation method)
The raw materials to be mixed were granulated together for the upper layer and the lower layer. Granulation was carried out by mixing for 4 minutes with a test drum mixer (600 mm diameter, 25 rpm rotation speed), adding 6.5% by mass of water to 100% by mass of the blended raw materials, and further processing for 4 minutes.

(Charging/ignition method)
Two pans were prepared: a cylindrical lower pan (φ300 mm) with a height of 500 mm and a cylindrical upper pan (φ300 mm) with a height of 300 mm. In the case of single-stage ignition, two pots were stacked, and granulated blended raw materials (granulated blended raw materials) were charged into the pots to a layer height of 800 mm and ignited for 1 minute (min). In the case of two-stage ignition, the granulated raw material mixture for the lower stage is charged into the lower pot to make the layer height of the lower layer 500 mm, and the granulated raw material mixture for the upper stage is charged into the upper pot to form the upper layer. The height was set to 300 mm. First, a pot for the lower layer having a layer height of 500 mm was set, and the surface of the lower layer was ignited for a predetermined time. After the end of the ignition for a predetermined time, the upper pot with a layer height of 300 mm was set on the lower pot, and after confirming the temperature rise at the 150 mm position of the lower layer, the surface of the upper layer was ignited for a predetermined time. . The suction pressure was kept constant at 1500 mmAq (14.7 kPa) from the start of ignition.

(Sintering time)
Sintering time was measured as follows. Thermocouples were set at positions 60 mm, 150 mm, 300 mm, and 450 mm from the upper surface of the pan for the lower stage. In the case of single-stage ignition, the sintering time was defined as the time required until the peak time of the measured value of the thermocouple at the 450 mm position. On the other hand, in the case of two-stage ignition, the later completion of sintering of the upper layer and the completion of sintering of the lower layer is regarded as the completion of sintering of the entire raw material packed layer (upper layer and lower layer). The time required to reach the second peak time of the thermocouple (completion of sintering of the upper layer) and the time required to reach the first peak time of the thermocouple at the 450 mm position (completion of sintering of the lower layer) is the longer of the two. The sintering time for the entire raw material packed bed was taken as the one. After 3 minutes from the time when the sintering was completed, the suction was stopped to complete the sintering.

(Sintered ore strength)
Sintered ore strength was determined by cold strength (rotational strength index TI) based on JIS M8712 (2009). However, the mass of the test sample was 15 kg. The upper sinter strength indicates the rotation strength index TI of the sinter in the upper pot, and the lower sinter strength indicates the rotation strength index TI of the sinter in the lower pot.

(production rate)
The production rate was obtained by the following formula (5) based on the sintering time measured as described above.
Production rate = product amount (t)/sintered area (0.07 m ² )/sintered time (days) (5)
After sintering, the resulting sintered cake was dropped four times from a height of 2 m, and the weight of the sintered product having a particle size of +5 mm (more than 5 mm) was determined.

(Test results)
The lower part of Table 2 shows the test results.

In Comparative Example 2 in which two-stage ignition was used, the productivity was improved compared to Comparative Example 1 in which the normal sintering method (one-stage charging and one-stage ignition) was performed, but the strength of the sintered ore in the lower layer was lowered.
In addition, in the case of Comparative Example 3 in which the ignition time of the upper layer was increased by 1.5 times compared to Comparative Example 2 and the amount of heat input by ignition to the upper layer was increased, the strength of the sintered ore in the upper layer did not change, and the strength of the sintered ore in the lower layer decreased. On the other hand, in the case of Invention Example 1, in which the ignition time of the lower layer was increased by 1.5 times as compared with Comparative Example 2 to increase the amount of heat input by ignition to the lower layer, the effect of improving productivity was obtained. It was possible to improve the strength of the sintered ore in the lower layer. However, in the case of Invention Example 2 in which the ignition time of the lower layer was further extended three times as compared to Comparative Example 2, the strength of the sintered ore in the lower layer was improved to the same extent as in Invention Example 1, but productivity decreased. was confirmed.

(Discussion on test results)
It is considered that the decrease in the strength of the sintered ore in the lower layer in Comparative Example 3 is affected by the extension of the ignition time in the upper layer. While the upper layer is being ignited and when combustion is started in the upper layer, oxygen is consumed in the combustion, and the oxygen concentration in the exhaust gas supplied to the lower layer is extremely reduced. Therefore, it is considered that the lower layer did not sufficiently raise the temperature due to the combustion reaction of the carbonaceous material, resulting in a decrease in the reaching temperature and a decrease in the strength of the sintered ore in the lower layer. The improvement in the strength of the sintered ore in the lower layer in Invention Examples 1 and 2 is because the amount of heat required for sintering was supplied by sufficiently burning the carbon material in the lower layer due to the increase in the amount of heat input by ignition. it is conceivable that. The decrease in productivity in Invention Example 2 is considered to be due to the fact that the amount of heat input to the lower layer due to ignition was excessive, causing excessive melting in the lower layer and deteriorating air permeability. Table 3 below confirms these considerations.

(measurement temperature)
Table 3 shows the maximum temperature measured at each position (60 mm, 150 mm, 300 mm, 450 mm) of the lower layer (lower pan) of each case. In this test, as described above, after confirming the temperature rise at the 150 mm position of the lower layer, the upper layer is ignited. In , the exhaust gas after combustion of the upper layer is used for the combustion of carbonaceous material. A temperature of 1200° C. or higher is required to advance the sintering reaction.

(About measured temperature)
As shown in Table 3, in Comparative Example 2 imitating a normal sintering process with two-stage ignition and Comparative Example 3 in which the ignition time of the upper layer was extended, the positions below the 150 mm position (300 mm position and 450 mm position) , the maximum temperature drops below 1200° C. and does not reach the temperature required for sintering. On the other hand, in Invention Examples 1 and 2 in which the ignition time of the lower layer was extended, the maximum temperature of approximately 1200° C. or 1200° C. or higher was maintained at almost all positions. Since the ignition time of the lower layer was extended to increase the amount of heat supplied (input heat amount) to the lower layer, the temperature reached a higher level and was maintained at 1200°C. It is believed that this improved the strength.

(Conversion from the test results of the sintering pot test to the actual machine)
Table 4 shows typical input heat amounts in sintering operations using a conventional continuous sintering machine (Dwight Lloyd (DL) type sintering machine). As shown in Table 4, the heat sources for sintering (melt generation) are the fuel from the ignition furnace (e.g., coke oven gas) and the carbonaceous material (e.g., coke dust). In a normal continuous sintering machine, the ratio of the amount of heat input by the ignition furnace to the amount of heat input by the condensing material is 1.25%. The unit calorific value of coke oven gas indicates the lower calorific value.

As carried out in the above test, the amount of heat input from the ignition furnace in Comparative Example 1 and the amount of heat input from the ignition furnace to the lower layer in Comparative Example 2 are the same. The ignition time of the lower layer was extended by 1.5 times. Converting these to the conditions of the actual machine, it corresponds to setting the ratio of the amount of heat input by the ignition furnace to the amount of heat input by the condensing material to be 1.875% and 3.75%, respectively. In Invention Example 1, the productivity was improved, and in Invention Example 2, the productivity was lowered. As described above, the amount of heat input from the lower stage ignition furnace 1C is set to 1.8% or more, preferably 3.7% or less, of the amount of heat input by the condensate in the lower stage raw material packed bed.

100 Sintering machine 1A Lower drum mixer 1B Lower hopper 1C Lower igniter 1D Lower raw material tank group (lower raw material tank 1D ₁ to 1D _X ) 2A Upper drum mixer , 2B Upper hopper 2C Upper igniter 2D Upper raw material tank group (upper raw material tank 2D ₁ to 2D _X ) 10 Lower layer 10A Lower layer combustion zone 20 Upper layer 20A ... upper layer combustion zone, 3 ... sintering section, 5 ... pallet traveling direction, 6 ... downward suction

Claims (2)

A step of charging the raw material of the sintered ore containing the coagulant into the sintering machine so as to form two layers in the layer height direction to form a lower raw material packed bed and an upper raw material packed bed. ,
igniting the lower raw material packed bed and the upper raw material packed bed with a lower ignition furnace and an upper ignition furnace, respectively, and sucking an oxygen-containing gas from below the lower raw material packed bed;
In the lower raw material packed bed, the amount of heat input from the lower ignition furnace is 1.875 % or more of the amount of heat input by the coagulant in the lower raw material packed bed. Ore production method. 4. The lower raw material packed bed, wherein the amount of heat input from the lower ignition furnace is 3.75 % or less of the amount of heat input by the condensate in the lower raw material packed bed. 1. The method for producing sintered ore according to 1.

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