TW202346608A - Granulation device, method for producing granulated sintering starting material, and method for producing sintered ore - Google Patents

Abstract

The present invention provides: a granulation device which is capable of efficiently heating a sintering starting material by blowing steam into the sintering starting material; a method for producing a granulated sintering starting material; and a method for producing a sintered ore, the method using the method for producing a granulated sintering starting material. The present invention provides a granulation device for granulating a sintering starting material that contains an iron-containing starting material, a CaO-containing starting material and a coagulating agent, the granulation device comprising: a cylindrical drum which rotates about a rotation axis that matches the lateral direction, while being provided with a feed port through which the sintering starting material is input and a discharge port through which a granulated sintering starting material is discharged; a steam pipe which is provided within the drum only in a posterior part from a position in between the feed port and the discharge port to the discharge port; and a plurality of nozzles which are connected to the steam pipe so as to eject the steam onto a deposition surface of the sintering starting material.

Description

Granulating device, method for producing granulated sintering raw material, and method for producing sintered ore

The present invention relates to a granulating device for granulating sintered raw materials, a method for manufacturing granulated sintered raw materials, and a method for manufacturing sintered ore.

As raw materials for blast furnaces, sinter is generally made of iron-containing raw materials such as iron ore powder, recycled powder from iron-making plants, and sinter screening powder, CaO-containing raw materials such as limestone and dolomite, and carbon materials (solid fuels) such as coke powder or anthracite coal. It is a sintering raw material and is produced using a Dwight-Lloyd sintering machine (hereinafter, sometimes referred to as a "sintering machine") which is a circular moving sintering machine. The sintering raw materials are loaded into the annular movable tray of the sintering machine to form a loading layer. The thickness (height) of the loading layer is approximately 400 mm to 800 mm. Thereafter, the carbon material on the surface of the charging layer is ignited by an ignition furnace installed above the charging layer. By sucking air downward through a bellows arranged under the tray, the carbon materials loaded into the layers are burned sequentially. The combustion gradually proceeds downward and forward as the pallet moves. By the combustion heat generated at this time, the sintering raw material is burned and melted, and a sintered block is generated. Thereafter, the obtained sintered lumps are crushed in the ore discharging section, cooled by a cooler, and sized to become finished sintered ore.

In the production of sintered ore using the above-described sintering machine, there is known a technique of preheating and drying the sintered raw material to reduce the proportion of the wet zone in the loading layer, thereby improving the air permeability of the loading layer and improving the Productivity of sinter. For example, Patent Document 1 discloses a method for producing a granulated sintering raw material in which steam such as water vapor is blown into the sintering raw material during granulation and the sintering raw material is heated. According to Patent Document 1, by granulating the sintered raw material while blowing water vapor, the sintered raw material is preheated and dried, thereby improving the air permeability of the loading layer and improving the productivity of sintered ore. [Prior art documents] [Patent Document]

Patent Document 1: International Publication No. 2019/167888 Patent document 2: Japanese Patent Application No. 2022-39966

[Problem to be solved by the invention]

The method disclosed in Patent Document 1 is a method of granulating the sintered raw material while blowing steam. However, it does not disclose or suggest that the steam is blown into the downstream region (the latter half) of the tumble mixer where the sintered raw material moves. Therefore, when the method disclosed in Patent Document 1 is used, the temperature of the granulated and sintered raw material drops before being discharged from the discharge port. In addition, the method disclosed in Patent Document 2 uses a heating device to heat the granulated raw material. Therefore, even after passing through the heating device, the target temperature may not be reached due to difficulty in heat transfer to the inside of the raw material. sex. The present invention was made in view of such prior art problems, and its object is to provide a granulating device that can efficiently heat the sintering raw material by blowing steam into the sintering raw material, a method for manufacturing the granulated sintering raw material, and a method using the same. A method for producing granular sinter raw materials and a method for producing sintered ore. [Means to solve the problem]

A method for solving the above problems is as follows. [1] A granulating device for granulating sintering raw materials including iron-containing raw materials, CaO-containing raw materials and coagulation materials, the granulating device having a cylindrical drum and an inlet for inputting the sintering raw materials. And a discharge port for discharging the granulated sintered raw materials, and rotates with the transverse direction as the rotation axis; the steam pipe is in the drum and is only installed from the middle position of the input port and the discharge port to the The rear half between the discharge ports; and a plurality of nozzles connected to the steam pipe and ejecting steam onto the accumulation surface of the sintering raw material. [2] A method of manufacturing a granulated and sintered raw material, which uses a granulating device to granulate a sintered raw material containing an iron-containing raw material, a CaO-containing raw material and a coagulated material. In the method of manufacturing a granulated and sintered raw material, the granulating material is granulated. The granulation device has a cylindrical drum. The cylindrical drum is provided with an input port for inputting the sintering raw material and a discharge port for discharging the granulated sintering raw material. The cylindrical drum rotates with the transverse direction as the axis of rotation. When the drum is Within, and only in the second half between the middle position of the input port and the discharge port to the discharge port, steam is blown into the sintering raw material to produce granulated sintering raw material. [3] The method for producing granulated and sintered raw materials according to [2], wherein when the temperature of the granulated and sintered raw materials discharged from the granulation device is 60° C. or higher, further adding to the sintered raw materials is Moisture content of 0.5 mass% or more and 4.5 mass% or less. [4] A method for producing sintered ore, which uses the method for producing granulated and sintered raw materials described in [2] or [3], and sinters the granulated granulated and sintered raw materials with a sintering machine to produce sintered ore. [Effects of the invention]

By using the granulation device of the present invention, steam can be blown into the sintering raw material to efficiently heat it, so the amount of steam used during granulation can be reduced. By using the heated granulated and sintered raw material, the air permeability of the loading layer is improved and the productivity of sintered ore is improved. Therefore, by using the granulating device of the present invention, it is possible to improve the productivity of sintered ore and the sintered ore. suppression of rising manufacturing costs.

Hereinafter, the present invention will be described based on the embodiments of the invention. FIG. 1 is a schematic diagram showing an example of the sinter production equipment 10 including the drum mixer 32 as the granulation device according to this embodiment. The iron-containing raw materials 12 stored in the site 11 are transported to the mixing tank 22 by the transfer conveyor 14 . The iron-containing raw materials 12 include various types of iron ore and dust generated in iron-making plants.

The raw material supply part 20 includes a plurality of mixing tanks 22, 24, 25, 26, and 28. The iron-containing raw material 12 is stored in the mixing tank 22 . The CaO-containing raw material 16 containing limestone, quicklime, etc. is stored in the mixing tank 24, and the MgO-containing raw material 17 containing dolomite, refined nickel slag, etc. is stored in the mixing tank 25. The mixing tank 26 stores a coagulated material 18 containing coke powder or anthracite that is crushed into a particle size of 1 mm or less using a rod mill. The mixing tank 28 stores sintered ore return ore with a particle size of 5 mm or less (sintered ore sieved powder) that has fallen through the sieve. A predetermined amount of each raw material is cut out from the mixing tank 22 to the mixing tank 28 of the raw material supply part 20, and these are mixed to become a sintering raw material. The sintering raw materials are conveyed to the drum mixer 32 by the conveyor 30 . The MgO-containing raw material 17 is an arbitrarily blended raw material, and may or may not be blended into the sintering raw material.

The drum mixer 32 is a granulating device that granulates the sintering raw material while blowing steam thereon. The drum mixer 32 has a cylindrical drum 33 rotating with the transverse direction as a rotation axis, a steam pipe 36, and a plurality of nozzles 37 connected to the steam pipe 36 and spraying water vapor 38 onto the deposition surface of the sintering raw material. Furthermore, water vapor is an example of steam. The rotation axis in the drum mixer 32 may be set substantially horizontally. In addition, in order to efficiently discharge the pseudo particles, the rotation axis may be tilted so that the discharge port 35 is located below the input port 34 in the vertical direction.

The cylindrical drum 33 is provided with an input port 34 and a discharge port 35. The input port 34 is provided on one end side of the drum 33 for inputting sintering raw materials. The discharge port 35 is provided on the other end of the drum 33. The end side is used to discharge the granulated granulated sintering raw materials (hereinafter, described as pseudo particles). The steam pipe 36 is provided in the drum 33 only in a region from the middle position between the input port 34 and the discharge port 35 to the rear half of the discharge port 35. From this position to the accumulation surface of the sintering raw material through the plurality of nozzles 37 Blow in steam.

In this way, the sintered raw material is granulated while blowing water vapor into the sintered raw material in the rear half of the drum 33, thereby producing pseudo-particles with an average particle diameter of about 3.0 mm at a higher temperature than the sintered raw material granulated without blowing water vapor. The pseudo particles are transported to the sintering machine 40 by the transport conveyor 39 . In this embodiment, the average particle diameter of the pseudo particles is the arithmetic mean particle diameter Σ (Vi×di) (where Vi is the existence ratio of particles located in the i-th particle size range, and di is the representative particle diameter of the i-th particle size range ) defined particle size. In addition, the drum mixer 32 is an example of a granulation device that granulates sintering raw materials.

The sintering machine 40 is, for example, a downward suction type Wei-Lloyd sintering machine. The sintering machine 40 includes a sintering raw material supply device 42 , a circularly movable pallet trolley 44 , an ignition furnace 46 , and a wind box 48 . The sintering raw materials are loaded into the pallet trolley 44 from the sintering raw material supply device 42 to form a loading layer of the sintering raw materials. The loading layer is ignited by an ignition furnace 46 . By sucking air through the air box 48, the coagulated material 18 is burned in the charging layer, and the combustion/melting zone in the charging layer is moved below the charging layer. Thereby, the loading layer is sintered to form a sintered block. In this embodiment, a gas fuel supply device 47 may be included. The gas fuel supplied from the gas fuel supply device 47 is selected from the group consisting of blast furnace gas, coke oven gas, blast furnace/coke oven mixed gas, converter gas, town gas fuel gas, natural gas, methane gas, ethane gas, propane gas, and leaf rock gas. and any flammable gas in these mixed gases.

The sintered lump is crushed by the crusher 50 to become sinter. The sinter crushed by the crusher 50 is cooled by the cooling machine 52 . The sinter cooled by the cooler 52 is screened by a screening device 54 having a plurality of screens, and is screened into finished sinter 56 with a particle size exceeding 5 mm and return ore 58 with a particle size below 5 mm. The finished sinter 56 is used as blast furnace raw material. On the other hand, the returned ore 58 is transported to the mixing tank 28 of the raw material supply part 20 by the transport conveyor 60 . In this embodiment, the particle size of the finished sinter 56 and the particle size of the returned ore 58 refer to the particle size sieved by a sieve. For example, the so-called particle size exceeding 5 mm refers to sieving using a sieve with a hole diameter of 5 mm. To the particle size above the sieve, the so-called particle size below 5 mm refers to the particle size sieved to the size below the sieve using a sieve with a hole diameter of 5 mm. Each value of the particle size of the finished sintered ore 56 and the returned ore 58 is only an example and is not limited to this value.

In this manner, in the production of sintered ore using the sintered ore production equipment 10 , the sintered raw material is granulated while being heated by blowing water vapor into the sintered raw material using the drum mixer 32 . Thereby, the air permeability of the layer in which the sintering raw material is loaded is improved, and the productivity of the sintering raw material is improved.

FIG. 2 is a graph showing the relationship between the rising temperature of the pseudo particles loaded into the pallet trolley 44 of the sintering machine and the rate of increase in productivity of sintered ore. The horizontal axis of FIG. 2 represents the rising temperature (°C) of the pseudo particles when loading into the pallet trolley 44 of the sintering machine. The rising temperature is the difference between the average temperature of the pseudo-particles granulated by blowing water vapor and the average temperature of the pseudo-particles granulated without blowing water vapor when loading into the pallet trolley 44 . Furthermore, the average temperature of the pseudo particles granulated without blowing water vapor is 18.3°C. The average temperatures of the pseudo particles when loaded into the pallet trolley 44 are 38.0°C, 35.0°C, 35.5°C, and 45.0 at each point in the figure. ℃, 51.0 ℃ example. In addition, the vertical axis of Fig. 2 represents the productivity improvement effect (%) of sintered ore, and is a value calculated from the following formula (1).

(T2-T1)×100/T1･･･(1) In the above formula (1), T1 is the productivity of sinter when producing sintered ore using pseudo particles that are granulated without blowing water vapor (t/( hr×m ² )), and T2 is the sinter productivity (t/(hr×m ² )) when producing sinter using pseudo-particles granulated by blowing water vapor.

As shown in FIG. 2 , as the average temperature of the pseudo particles when loading into the pallet truck 44 becomes higher, the productivity increase rate of the sinter becomes higher. This result shows that the productivity of sintered ore can be improved by blowing water vapor into the sintered raw material using the drum mixer 32 to form high-temperature pseudo-particles and using the pseudo-particles to produce sintered ore.

On the other hand, when the average temperature of the pseudo particles becomes 60° C. or higher, water evaporates, and pseudo particles with a predetermined particle size are no longer granulated. If the particle size of the pseudo particles decreases, the air permeability of the loading layer will deteriorate, and the productivity of sintered ore will significantly decrease.

FIG. 3 is a graph showing the moisture content of the sintering raw materials in Experimental Examples 1 to 3. FIG. In FIG. 3 , the bar graph represented by diagonal hatching represents the moisture content (mass %) of the sintering raw material on the input side of the drum mixer, and the bar graph represented by horizontal hatching represents the moisture content (mass %) of the sintering raw material when charged into the sintering machine. Moisture content (mass %). Experimental Example 1 is a production example using pseudo particles in which the average temperature of the sintering raw material when charged into the sintering machine is 33°C. Experimental example 2 is a production example using pseudo particles in which the average temperature of the sintering raw material when charged into the sintering machine is 60°C. Experimental example 3 is a production example using pseudo particles whose average temperature of the sintering raw material when charged into the sintering machine is 62°C.

As shown in Figure 3, it can be seen that Experimental Example 1 and Experimental Example 3 can ensure that the raw material moisture content is 6.5 mass% when loading into the sintering machine. On the other hand, in Experimental Example 2, a moisture content of 6.5% by mass was ensured on the input side of the drum mixer. However, the moisture evaporated due to heating, so the moisture content dropped to about 5.5% by mass when loading into the sintering machine. .

FIG. 4 is a graph showing the particle diameter of the pseudo particles in Experimental Examples 1 to 3 and the air permeability index JPU of the inclusion layer. In Figure 4, the bar graph represented by diagonal hatching represents the particle diameter (mm) of pseudo particles, and the bar graph represented by horizontal hatching represents the permeability index JPU (-) ((-)). dimensionless). In addition, the particle diameter of the pseudo particles is the calculated average particle diameter, and the air permeability index JPU of the built-in layer is an index calculated using the following formula (2).

JPU = ^V / ^{[ S} , h is the loading layer height (mm), ΔP is the pressure loss (mmH ₂ O).

As shown in FIG. 4 , in Experimental Example 1 and Experimental Example 3, pseudo particles with a particle diameter of approximately 3 mm were granulated, but in Experimental Example 2, only pseudo particles with a particle diameter of approximately 1 mm were granulated. It is considered that the decrease in the particle diameter of the pseudo particles in Experimental Example 2 is caused by the decrease in the moisture content of the raw material shown in Fig. 3 . In Experimental Example 3, high-temperature pseudo-particles with a particle diameter of approximately 3 mm were granulated, so the air permeability index of the inclusion layer was approximately 17. In Experimental Example 1, pseudo particles with the same particle diameter were granulated. However, since the average temperature of the pseudo particles was low, the air permeability index of the inclusion layer was about 15. In Experimental Example 2, although high-temperature pseudo-particles were obtained, only pseudo-particles with a particle diameter of about 1 mm were granulated, so the air permeability index of the inclusion layer dropped significantly to about 12.

FIG. 5 is a graph showing the productivity of sintered ore in Experimental Examples 1 to 3. FIG. The sinter production rate is the amount of finished sinter produced in 1 hour per 1 m ² of charging layer (t). As shown in FIG. 5 , compared with the productivity of Experiment 1 which was 1.29, the productivity of Experiment 3 was 1.39, and the productivity of sinter was greatly increased. It is considered that the improvement in productivity in Experimental Example 3 is due to the improvement in air permeability shown in Fig. 4 . On the other hand, in Experimental Example 2, the air permeability of the loading layer was significantly reduced, sintering did not proceed, and the sintering raw material was not agglomerated.

In this way, when the average temperature of the pseudo particles discharged from the granulation device is 60° C. or higher, water evaporates due to this temperature. Therefore, the water required for granulation is insufficient, and pseudo particles with a predetermined particle size cannot be granulated. On the contrary, The air permeability of the loading layer deteriorates. Therefore, the amount of moisture evaporated when the pseudo particles discharged from the drum mixer 32 were heated to an average temperature of 60°C or more and less than 80°C was confirmed. As a result, the moisture content after granulation was confirmed to be 0.5% by mass or more and 3.0% by mass. The water content within the range of mass % or less evaporates. Furthermore, when the average temperature of the pseudo particles discharged from the drum mixer 32 was heated to 80° C. or higher, the amount of moisture evaporated was confirmed. As a result, it was confirmed that the moisture content after granulation was 2.0 mass % or more and 4.5 mass %. % or less of the water content evaporates.

Based on these results, when the average temperature of the pseudo-particles discharged from the granulation device is 60° C. or higher, it is preferable to further add 0.5 mass of moisture based on the post-granulation moisture content to the sintering raw material being granulated. % or more and less than 4.5% by mass. With this, even if the pseudo particles are heated to 60°C or above, the amount of moisture required for granulation can be ensured, and pseudo particles with a particle diameter of about 3 mm that are heated to 60°C or above can be produced from sintered raw materials. By using the heated pseudo-particles to produce sinter, the air permeability of the loaded layer is improved, thereby improving the productivity of sinter. Furthermore, when the average temperature of the pseudo particles is 60°C or more and less than 80°C, it is preferable to further add to the sintering raw material during granulation a moisture content after granulation of 0.5% by mass or more and 3.0% by mass. When the average temperature of the pseudo particles is 80° C. or higher, it is preferable to further add moisture of 2.0 mass % or more and 4.5 mass % or less based on the moisture content after granulation.

The amount of moisture to be added can be determined within the above range by measuring the moisture content of the pseudo particles discharged from the drum mixer 32 at predetermined intervals. In addition, regarding the addition of moisture, factory water, hot water, or condensed water may be added to the sintering raw material during granulation.

Next, the installation position of the steam pipe 36 in the drum mixer 32 will be described. Table 1 shows the results of an experiment in which water vapor was blown into the sintering raw material while the installation position of the steam piping 36 was changed to the input port side and the discharge port side. In addition, the temperature on the output side of the discharge port in the table is the average temperature of the pseudo particles discharged from the drum mixer 32 .

[Table 1] Project unit Experimental example 11 Experimental example 12 Experimental example 13 Experimental example 14 Experimental example 15 Raw material delivery volume t/h 650 650 650 650 650 Steam injection amount t/h 6.5 7.5 6.5 7.5 5.4 Steam piping installation location Input port side Input port side Discharge port side Discharge port side Discharge port side Discharge port output side temperature ℃ 51.1 60.3 62.2 68.5 51.4

Experimental examples 11 and 12 are granulation examples in which the steam pipe 36 is installed only in the front half from the input port 34 to the intermediate position between the input port and the discharge port, and water vapor is blown into the sintering raw material to perform granulation. Experimental examples 13 to 15 are granulation examples in which the steam piping 36 is installed only in the second half between the intermediate position of the input port 34 and the discharge port 35 to the discharge port 35, and water vapor is blown into the sintering raw material to perform granulation. .

According to the comparison between Experimental Example 11 and Experimental Example 13, and the comparison between Experimental Example 12 and Experimental Example 14, the average temperature on the outlet output side of the pseudo-particles granulated by installing the steam piping 36 in the second half and blowing water vapor is higher than that in the first half. The average temperature on the output side of the outlet of the pseudo-particles produced by partially installing the steam piping 36 and blowing water vapor into the granulated particles is 8°C to 11°C higher. In addition, according to the comparison between Experimental Example 11 and Experimental Example 15, if the temperature on the output side of the discharge port of the pseudo particles is the same, the amount of water vapor injection used in granulation can be reduced by 17% when the steam pipe 36 is installed in the rear half. %. From these results, it was confirmed that by providing the steam pipe 36 having a plurality of nozzles 37 only in the rear half of the drum mixer 32 and blowing steam from the nozzles 37 to the sintering raw materials, the other parts of the drum mixer 32 Compared with the case of installing a steam pipe having a plurality of nozzles, the sintering raw material can be heated more efficiently.

As described above, the drum mixer 32 as the granulation device of this embodiment can blow steam into the sintering raw material to efficiently heat it. Therefore, if the steam usage is the same, the sintering raw material can be heated to a higher temperature, and if the temperature on the outlet side is the same, the sintering raw material can be heated with a smaller steam usage. In this way, by using the granulation device of this embodiment, the sinter raw material can be heated to a predetermined temperature and the amount of steam used in the production of sinter can be reduced. Therefore, the productivity of the sinter can be improved and the production of sinter can be achieved. suppression of rising costs.

10: Sinter manufacturing equipment 11:Venue 12: Iron-containing raw materials 14:Transport conveyor 16: CaO-containing raw materials 17: Raw materials containing MgO 18:Condensation material 20:Raw material supply department 22: Mixing tank 24: Mixing tank 25: Mixing tank 26: Mixing tank 28: Mixing tank 30:Transport conveyor 32:Roller mixer 33:Roller 34:Input port 35:Discharge outlet 36:Steam piping 37:Nozzle 38:Water vapor 39:Transport conveyor 40:Sintering machine 42: Sintering raw material supply device 44:Pallet trolley 46: Ignition stove 47: Gas fuel supply device 48: Bellows 50: Crusher 52:Cooler 54:Screening device 56:Finished sinter 58:Return to Mine 60:Transport conveyor

FIG. 1 is a schematic diagram showing an example of the sinter production equipment 10 including the drum mixer 32 as the granulation device according to this embodiment. FIG. 2 is a graph showing the relationship between the temperature rise amount of pseudo particles when loaded into a tray of a sintering machine and the productivity increase rate of sintered ore. FIG. 3 is a graph showing the moisture content of the sintering raw materials in Experimental Examples 1 to 3. FIG. FIG. 4 is a graph showing the particle diameter of the pseudo particles in Experimental Examples 1 to 3 and the air permeability index JPU of the inclusion layer. FIG. 5 is a graph showing the productivity of sintered ore in Experimental Examples 1 to 3. FIG.

10: Sinter manufacturing equipment

11:Venue

12: Iron-containing raw materials

14:Transport conveyor

16: CaO-containing raw materials

17: Raw materials containing MgO

18:Condensation material

20:Raw material supply department

22: Mixing tank

24: Mixing tank

25: Mixing tank

26: Mixing tank

28: Mixing tank

30:Transport conveyor

32:Roller mixer

33:Roller

34:Input port

35:Discharge outlet

36:Steam piping

37:Nozzle

38:Water vapor

39:Transport conveyor

40:Sintering machine

42: Sintering raw material supply device

44:Pallet trolley

46: Ignition stove

47: Gas fuel supply device

48: Bellows

50: Crusher

52:Cooler

54:Screening device

56:Finished sinter

58:Return ore

60:Transport conveyor

Claims (4)

A granulating device for granulating sintering raw materials including iron-containing raw materials, CaO-containing raw materials and coagulation materials, the granulating device has: A cylindrical drum is provided with an input port for inputting the sintering raw material and a discharge port for discharging the granulated sintering raw material, and rotates with the transverse direction as the rotation axis; The steam piping is inside the drum and is only provided in the rear half between the middle position of the input port and the discharge port to the discharge port; and A plurality of nozzles are connected to the steam pipe and eject steam onto the accumulation surface of the sintering raw material. A method for manufacturing granulated and sintered raw materials, which uses a granulating device to granulate sintered raw materials including iron-containing raw materials, CaO-containing raw materials and coagulation materials. In the method of manufacturing granulated and sintered raw materials, The granulation device has a cylindrical drum, and the cylindrical drum is provided with an input port for inputting the sintering raw material and a discharge port for discharging the granulated sintering raw material, and rotates with the transverse direction as the rotation axis, In the drum, steam is blown into the sintering raw material only in the second half between the intermediate position between the input port and the discharge port and the discharge port, thereby producing granulated sintering raw material. The method for producing granulated and sintered raw materials according to claim 2, wherein when the temperature of the granulated and sintered raw materials discharged from the granulation device is 60° C. or higher, 0.5% by mass is further added to the sintered raw materials. More than 4.5% by mass of moisture. A method for producing sintered ore, which uses the method for producing granulated and sintered raw materials as described in claim 2 or 3, and uses a sintering machine to sinter the granulated granulated and sintered raw materials to produce sintered ore.