TWI619568B - Operation method of sintering machine - Google Patents

Abstract

The invention provides a method for operating a sintering machine. When sintering a sintering blended raw material containing a magnetic fine powder raw material, the sintering raw material charging layer can have good air permeability and improve the sinterability. The operation method of the sintering machine of the present invention loads the sintering preparation raw material into a trolley of the sintering machine through a chute provided with a magnet on the back side for sintering, and loads the magnetically fine powder raw material in the sintering preparation raw material to When the speed of the sintered blended raw material when the magnetic force is not applied to the chute is zero, the speed is set to ν ₁ , and the speed of the magnetically fine powdered raw material at the lower end of the chute is set to ν ₁ . A mode in which ν becomes a speed of 1 / 5ν ₁ to 4 / 5ν ₁ adjusts the magnetic force F _M of the magnet.

Description

Operation method of sintering machine

The present invention relates to a method for operating a sintering machine having a characteristic in a method for loading a sintered raw material. The present invention particularly proposes a method for operating a sintering machine that sinters and mixes magnetically fine powder-containing raw materials such as magnetite-based fine iron ore or sintering return ore, which are easier to magnetize than ordinary sintering raw materials. The raw materials are loaded on a pallet of a sintering machine and sintered.

As shown in FIG. 1, the sinter ore, which is the main raw material of the blast furnace ironmaking method, is produced by sieving the recovered powder and sintered ore in an ironmaking plant except for iron ore powder, crumbs, and ironmaking dust. In addition to powder (sintering and returning to ore), it also contains sintering and mixing raw materials such as limestone or dolomite containing CaO-containing raw materials, granulation aids such as quicklime, carbon materials such as coke powder, and anthracite (solid fuel). The sintering is carried out on a trolley of a DL sintering machine. As the sintering preparation raw material, a plurality of sintering raw material powders are mixed with a drum mixer or the like, and then granulated to form quasi-particles having an arithmetic mean diameter of 6.0 mm or less. The raw material for sinter ore production thus obtained, that is, the raw material for sinter preparation is a raw material for loading into a trolley of a sintering machine to form a sintering raw material loading layer called a loading layer.

Generally, the thickness (height) of the sintering raw material charging layer is about 400 mm to 800 mm. After that, the sintering raw material charging layer is placed on the trolley. In the square igniter, the carbon material contained in the sintered raw material charging layer is ignited, and then the air in the sintered raw material charging layer is sucked downward through a bellows arranged under the trolley, whereby The carbon materials charged in the sintering raw material layer are sequentially burned, and the movement of the combustion cooperation trolley is gradually performed downward and forward, and the sintering preparation raw material is melted by the combustion heat generated at this time to become a sintered block. After that, the obtained sintered block is pulverized and then cooled by a cooler and granulated to form a finished sintered ore including aggregates (agglomerate) having a predetermined particle size (for example, 5.0 mm or more).

The production amount of sintered ore is generally determined by sintering productivity (t / hr.m ² ) × sintering machine area (m ² ). However, the production amount of the sintered ore varies depending on the width or length of the sintering machine, the thickness of the raw material accumulation layer (thickness of the sintered raw material layer), the bulk density of the sintered blended raw material, the sintering (burning) time, and the yield. Further, in order to increase the production amount of the sintered ore, it is effective to improve the air permeability (pressure loss) of the sintering raw material charging layer and shorten the sintering time, or to increase the cold strength of the sintered block before pulverization to improve the yield and the like.

In recent years, with regard to the iron ore powder blended in the sintered blending raw material, there has been an increase in the grain size components such as Al ₂ O ₃ and SiO ₂ , while the Fe content tends to decrease. Therefore, the amount of slag generated in the blast furnace or the converter is increased, and the processing of the slag becomes a large burden. On the other hand, effective use of materials called so-called magnetic fine powder raw materials has attracted attention. For example, magnets with many iron components (FeO) and fine powder (250 μm or less) have not been used as raw materials for sintering. Mineral powdered iron ore, crumbs, ironmaking dust, etc.

Table 1 shows ordinary iron ore A, iron ore B, and magnetite-based fine iron An example of the chemical composition and average particle size of magnetic fine powder raw materials such as ore, sintering re-ore, slag, ironmaking dust (blast furnace dust, steelmaking dust, etc.). These magnetic fine powder raw materials are generally characterized by containing more iron components (FeO) than fine iron ore. However, as shown in FIG. 2, although the particle size of magnetic fine powder raw materials such as magnetite-based fine iron ore or ironmaking dust is not as fine as that of a pellet feed, it is smaller than that of ordinary sintering fine iron ore. The fine stone is liable to cause deterioration of the air permeability in the sintering process step, so there is a concern that the productivity of the sintered ore may be reduced.

When using a fine powder raw material as a sintering raw material, an attempt has been made to effectively use ordinary fine powder iron ore. For example, Patent Document 1 proposes a method of adjusting the ratio of the finely powdered iron ore to the nucleated fine iron ore in the preparation stage to form quasi-particles that the finely pulverized ore efficiently adheres to the periphery of the core, and This improves the granulation property of the raw material and suppresses the deterioration of the air permeability.

Furthermore, Patent Document 2 proposes a technique for producing a sintered blended raw material, that is, when a fine powder ore is used, the fine powder ore is used in another production line. The granulation is improved by pulverizing and stirring, and mixing the binder.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2008-101263

[Patent Document 2] Japanese Patent Laid-Open No. 2007-77512

As described above, in the prior art, when using finely powdered iron ore or the like as a constituent component of a sintered blending raw material, first, research to achieve improvement in granulation property was performed. For example, in the method of Patent Document 1, if the content of the molybdenum component of the fine ore or the use amount of the fine ore is further increased in the future, the ratio of the core particles and the fine powder that are used to form the quasi-particles is not suitable and becomes a core. The ratio of fine ore becomes a limitation of productivity. Furthermore, in Patent Document 2, the magnetite-based fine powder iron ore is not as small as the granular powder ore, and therefore there are still problems in that the cost needs to be increased by re-pulverizing the powder and using a binder.

Therefore, an object of the present invention is to provide a method for operating a sintering machine, which can improve the sinterability of the sintering raw material charging layer when sintering the sintering preparation raw material containing the magnetic fine powder raw material, so that the sintering property can be improved.

The present invention has been developed in order to solve the above-mentioned problem, which is a problem when using a sintered blended raw material that contains a large amount of a magnetically fine powdered raw material that causes the air permeability deterioration of the sintered raw material charging layer. That is, the present invention is a method for operating a sintering machine. The sintering and preparing raw materials are loaded into a trolley of a sintering machine and sintered through a chute formed by magnets on the back side. The method of operating the sintering machine is characterized in that: 5 to 30% by mass of the sintered preparation raw material is a magnetically fine powder raw material, that is, the content of FeO is 4.5% by mass or more, and the particle diameter has a size of 0.2 mm to 2.5 mm in terms of the arithmetic mean diameter, and wherein The amount of fine powder of 250 μm or less is 60% by mass or less in terms of weight ratio. When the magnetic fine powder raw material is loaded on a trolley, the magnetic force (F _M ) is not applied to the chute (F _M = 0). When the speed of the sintered preparation raw material at the lower end of the chute is set to ν ₁ , the speed of the magnetic fine powder raw material ν _m at the lower end of the chute is set to a speed of 1 / 5ν ₁ to 4 / 5ν ₁ To adjust the magnetic force F _M of the magnet.

In the method for operating the sintering machine according to the present invention, a more preferable configuration is as follows: (1) the amount of the fine powder of 250 μm or less is 5% by mass or more in terms of weight ratio, and (2) the position of the lower end of the chute The speed ν _m of the magnetic fine powder raw material is a speed of 2 / 5ν ₁ to 3 / 5ν ₁ ; (3) the speed ν _m of the magnetic fine powder raw material at the lower end of the chute is in the range of 0.0004N to 0.01N. Internally adjust the magnetic force F _{M of} the magnet, (4) the magnetic force F _{M of} the magnet is a value obtained by the following formula,

m: mass (kg)

g: acceleration of gravity (m / s ² )

θ: chute angle (rad)

μ: friction coefficient between raw material and chute (-)

kv ² : air resistance (N)

v ₀ : initial speed (m / s)

v ₁ : speed at the lower end of the chute (m / s)

L: Chute length (m)

L _M : length of magnet plate (m)

F _M : magnetic force (N)

(5) In the magnetic fine powder raw material, at least 5 mass% to 15 mass% of the raw material is sintering return ore, and the remaining portion includes any one of magnetite-based fine powder iron ore, rolling slag and ironmaking dust the above.

According to the operation method of the sintering machine of the present invention, when a sintering compounding material containing magnetic fine powder raw materials is loaded on a trolley of a sintering machine using a chute formed with a magnet disposed on the back surface, the sintering compounding material in the sintering compounding material can be reliably made. The magnetic fine powder raw material is selectively deposited (segregated into the upper layer portion of the sintering raw material charging layer), so that deterioration of the air permeability of the sintering raw material charging layer can be suppressed. As a result, it is possible to improve quality such as productivity, yield, and cold strength in the production of sintered ore.

10‧‧‧ Carbon-based solid fuel (coke powder)

12‧‧‧ Limestone

14‧‧‧ Powdery Iron Ore

16‧‧‧ Granulator

18‧‧‧ Sinter

20‧‧‧ Chimney

22‧‧‧ Suction fan

24‧‧‧Sintering machine

26‧‧‧ Dust Collector

28‧‧‧Ignition stove

30‧‧‧ Crusher

32‧‧‧ sieve

34‧‧‧ Loading device

36‧‧‧ air

38‧‧‧combustion‧melting zone

40‧‧‧Exhaust Fan

42‧‧‧ from magnetic ingredients

44‧‧‧inclined chute

46‧‧‧Magnet

48‧‧‧ from magnetic fine powder raw materials

50‧‧‧ Sintered raw material particles

52‧‧‧hopper

54‧‧‧Belt Conveyor

56‧‧‧ trolley

58‧‧‧Motor

60‧‧‧Sampling box

FIG. 1 is a schematic diagram illustrating a DL sintering process.

FIG. 2 is a diagram showing a particle size distribution of raw materials such as magnetic fine powder.

FIG. 3 is a diagram showing the distribution of temperature and pressure in the sintering raw material charging layer.

FIGS. 4 (a) to 4 (c) are diagrams of temperature distribution and yield distribution in the sintering raw material charging layer in the sintering machine.

FIG. 5 is a schematic diagram showing a state in which the magnetic fine powder raw material is segregated and loaded into an upper layer portion of a sintered raw material loading layer.

FIG. 6 is a schematic diagram illustrating the movement of particles on a chute.

FIG. 7 is a view showing a deposition state when a magnetic fine powder raw material is loaded while changing a magnetic force (F _M : 0.01N).

FIG. 8 is a view showing a state of accumulation when a magnetic fine powder raw material is loaded while changing a magnetic force (F _M : more than 0.01 N).

FIG. 9 is a diagram showing a deposition state when a magnetic fine powder raw material is loaded while changing a magnetic force (F _M : 0.004N).

FIG. 10 is a view showing a state of accumulation when a magnetic fine powder raw material is loaded while changing a magnetic force (F _M : 0N).

FIG. 11 is an outline view of a loader used in the test device.

FIG. 12 is a graph showing the accumulation results of the magnetically fine powder raw materials when loaded using a test device.

FIG. 13 is a graph showing the relationship between the blending ratio of magnetic fine powder raw materials and productivity.

It is known that the pressure loss in the sintering raw material charging layer deposited on the trolley is as follows As shown in Fig. 3, the sintering reaction occurs in a region (reaction zone) in which the loaded wet raw material is accumulated (wet zone) and a carbon material such as coke powder is burned to perform a sintering reaction of the sintered preparation raw material. The area where the completed sinter exists (sinter zone) hardly causes pressure loss. In order to improve the sinterability, it is important to reduce the pressure loss as a whole and to improve the air permeability of the entire raw material charging layer.

In this specification, 10 indicates a carbon-based solid fuel (coke powder), 12 indicates limestone, 14 indicates powdery iron ore, 16 indicates a granulator, 18 indicates a sintered ore, 20 indicates a chimney, 22 indicates a suction fan, and 24 indicates Sintering machine, 26 is a dust collector, 28 is an ignition furnace, 30 is a pulverizer, 32 is a sieve, 34 is a loading device, 36 is air, 38 is a combustion and melting zone, 40 is an exhaust fan, and 42 is a raw material of magnetic components. 44 indicates an inclined chute, 46 indicates a magnet, 48 indicates a magnetic powder raw material, 50 indicates a sintered raw material particle, 52 indicates a hopper, 54 indicates a belt conveyor, 56 indicates a trolley, 58 indicates a motor, and 60 indicates a sampling box.

Therefore, in the present invention, when the sintering preparation raw material includes a magnetic fine powder raw material such as a magnetite-based fine powder iron ore that deteriorates permeability due to a large amount of fine powder components, the magnetic fine powder raw material is intentionally made. This problem is solved by accumulating (segregating) the upper layer portion of the sintering raw material charging layer, thereby ending the sintering reaction in advance, and minimizing the deterioration of air permeability when a large amount of the magnetic fine powder raw material is prepared.

This aspect of the present invention can be understood from FIGS. 4 (a) to 4 (c). That is, FIG. 4 (a) shows the sintering process of the sintering compounding material on the sintering raw material loading layer (hereinafter also simply referred to as “loading layer”) on the sintering machine trolley. (B) of 4 shows the temperature distribution (heat pattern) of the sintering process in the built-in layer, and (c) of FIG. 4 shows the yield distribution of the sintered block. As can be seen from FIG. 4 (b), the upper layer portion of the charging layer of the sintered blended raw material tends to have a higher temperature than the lower layer portion, and tends to have a shorter holding time in the high temperature region. Therefore, in the upper part of the loading layer, the combustion-melting reaction (sintering reaction) is insufficient, and the strength of the sintered block is reduced. As shown in FIG. 4 (c), it becomes a factor that results in a low yield and a decrease in productivity. .

According to research by the inventors, this problem can be solved by performing so-called segregation charging, which is an easy magnetization magnetization containing more FeO in the sintered blending raw material. When the component is obtained from a powdery raw material (from a magnetic fine powder raw material), when the raw material is loaded on a trolley, the raw material is selectively deposited on the upper part of the loading layer. Generally known in (Transaction of American Institute of Mining, Metallurgical, and Petroleum Engineers (Trans.AIME) 218 (1960), 116), the components representing the sintering reaction In the state diagram of the influence of Fe, as the FeO content increases, the melting point (liquidus temperature) of the melt required for the sintering reaction decreases. Therefore, if the upper layer portion of the sintering raw material charging layer is segregated and loaded with magnetic fine powder raw materials such as magnetite-based fine iron ore containing a large amount of FeO, it can be promoted even if the temperature of the upper layer portion does not easily rise. The sintering reaction can also improve the yield or strength.

In addition, the sintered blended raw material is formed by loading the sintered blended raw material on the trolley, that is, the loading layer. Generally, the permeation during sliding down on the chute is accompanied by the penetration layer. The particle size segregation caused by (percolation), the sintering raw material loading layer has a large amount of fine sintered blended raw materials with a small particle size distributed in the upper and middle layers, and the lower layer has a large sintered coarse particle size. The raw materials were prepared to cause segregation of the charged layer. However, in the case where more fine (mostly -260 μm) fine powder is contained, the segregation state is insufficient, and the present invention can correctly solve the problem when a sintered blended raw material containing more such fine magnetic powder raw material is loaded.

That is, in the present invention, it is assumed that the magnetite-based finely powdered iron ore shown in FIG. 2 has a high content of FeO (4.5% by mass to 60% by mass), and the particle size has an arithmetic value. For those having an average diameter of 0.2 mm to 2.5 mm and a size of 250 μm or less, a magnetic fine powder raw material having a cumulative weight ratio of 60% by mass or less is used for a part of the sintered preparation raw material. In addition, the present invention is a method for solving the above-mentioned problem. The problem is that when a sintered blended raw material containing 5 to 30% by mass of the magnetic fine powder raw material is loaded on a trolley using a chute shown in FIG. 5. problem.

When implementing such a loading method, it is effective to arrange a permanent magnet or an electromagnet on the back surface of the chute so that a magnetic force acts on the sintered blending material flow on the chute. With this, regarding the ferromagnetic fine powder raw materials such as ferromagnetic magnetite-based fine powder iron ore or sintering remineralization, slag, ironmaking dust (blast furnace dust, steelmaking dust, etc.) contained in the sintered blending raw material, Due to the magnetic force, the speed is reduced (suppressed). Therefore, when it is on the surface of the chute (slide down), it is guided and deposited on the upper layer side of the sintering raw material charging layer (B). In this case, a common sintering preparation material having a large particle diameter is deposited on the lower layer.

The formation of the stacking structure is based on the fact that when the sintered blended raw materials containing a large amount of magnetic fine powder raw materials are loaded into the trolley through the chute, these raw materials are permanently arranged on the back side of the chute. The magnetic force of a magnet or an electromagnet. That is, with regard to the magnetically fine powder raw material which is susceptible to magnetic influence due to its large iron component and small particle size, the speed at which it slides down on the chute decreases. As a result, non-magnetic raw materials (ordinary The sintering raw material) first forms the lower layer portion. On the other hand, in response to the decrease in speed, the magnetic fine powder raw material is delayed by the action of the magnetic force, and thus is deposited on the upper layer portion of the sintering raw material charging layer.

If the content of FeO in the magnetic fine powder raw material is less than 4.5% by mass, it is difficult to be affected by the magnetic force of a magnet disposed on the back surface of the inclined chute, and it is difficult to obtain a speed adjustment (reduction) effect. On the other hand, as long as the upper limit of the FeO content can be changed by magnetic force adjustment, there is no need to make a special rule, and the FeO content of the magnetic fine powder raw material is about 60% by mass at the maximum.

Moreover, regarding the particle diameter of the raw material, when the arithmetic average particle diameter of the magnetically fine powdered raw material is 2.5 mm or more, the particle size difference from the non-magnetically generated raw material is reduced, and it is difficult to segregate the magnetically fine powdered raw material well to the packaging. Into the upper part of the layer. On the other hand, when the arithmetic mean diameter of the magnetic fine powder raw material is less than 0.2 mm, or when the proportion of the fine powder having a particle diameter of 250 μm or less exceeds 60% by mass based on the cumulative weight ratio, the sintering layer (sintering) The influence of the bed) on the air permeability is increased, and even if the magnetic fine powder raw material is deposited on the upper layer portion of the sintering raw material charging layer, the productivity of the sintering machine may be reduced. If the fine powder having a particle diameter of 250 μm or less is less than 5 mass%, the effect of the present invention is weakened. As having 250 μm The preferable lower limit of the fine powder having the following particle diameter is about 15% by mass.

FIG. 6 is a diagram illustrating the movement of particles when a sintered blended raw material containing a large amount of magnetic fine powder raw materials is loaded through a chute provided with a magnet on the back surface. As shown in the figure, when the sintered blended raw material containing the magnetic fine powder raw material slides down on the chute, the force acting on the raw material particles is set to (1) as the particle motion direction component of gravity, and gravity and magnetic force. When the induced frictional resistance is (2) and the air resistance accompanying the particle motion is (3), the equation of motion in the particle motion direction (the horizontal direction of the chute) can be expressed as follows.

m: mass (kg)

g: acceleration of gravity (m / s ² )

θ: chute angle (rad)

μ: friction coefficient between raw material and chute (-)

F _M : magnetic force (N)

C _D : coefficient of resistance (-)

S: Particle cross-sectional area (m ² )

ρ: density of air (kg / m ³ )

v: relative velocity of particles relative to air (m / s)

The general formula of the magnetic force F _M in the formula (1) is the following formula (2).

m: mass (kg)

X: magnetic susceptibility (-)

H: magnetic flux density (T)

χ: distance between the groove surface and the magnet (m)

Therefore, the formula of the magnetic force F _M caused by the magnets of the formula (1) and the formula (2) when the magnetic fine powder raw material slides down on the chute can be further processed as follows.

That is, whenever a sintered blended raw material containing a magnetic fine powder raw material is loaded, the FeO content or particle size of the magnetic fine powder raw material is provided, and the blending ratio of the magnetic fine powder raw material is provided, and the distance between the magnet and the surface of the chute is provided. (χ), chute angle (θ), chute length (L), and constant gravity acceleration (g), friction coefficient (μ), drag coefficient (Cp), and air density ( ρ) and relative velocity (v) of the particles with respect to air, the equations of motion of the above formulas (1) and (2) can be processed as the energy conservation formula of the following formula (3).

m: mass (kg)

g: acceleration of gravity (m / s ² )

θ: chute angle (rad)

μ: friction coefficient between raw material and chute (-)

kv ² : air resistance (N)

v ₀ : initial speed (m / s)

v ₁ : speed at the lower end of the chute (m / s)

L: Chute length (m)

L _M : length of magnet plate (m)

F _M : magnetic force (N)

Furthermore, in the present invention, the magnetic force F _{M of the} formula (3) acting on the magnetic fine powder raw material on the surface of the chute needs to make the speed ν _{1 at the} lower end of the chute greater than zero (0), that is, the ratio When the magnetic force F _M is not applied to the chute, the speed of the non-magnetizing raw material is slow. Therefore, the formula (3) can be further processed as the formula (4).

m: mass (kg)

g: acceleration of gravity (m / s ² )

θ: chute angle (rad)

μ: friction coefficient between raw material and chute (-)

kv ² : air resistance (N)

v ₀ : initial speed (m / s)

v ₁ : speed at the lower end of the chute (m / s)

L: Chute length (m)

L _M : length of magnet plate (m)

F _M : magnetic force (N)

In summary, the present invention is a method that operates in such a way that adjustment (increase Large) The resistance when the magnetically fine powdered raw material that is easily magnetized slips on the chute, that is, the speed of the magnetically fine powdered raw material in the sintered blended raw material is suppressed, and the powder is segregated into the upper part of the sintered raw material loading layer.

In addition, it is unfavorable to increase the magnetic force F _M indefinitely, that is, to prevent the easily magnetizable fine powder raw material from adhering to the chute. Table 2 shows the relationship between the magnetic force F _M at the lower end of the chute and the speed ν _m at the lower end of the chute from which the magnetic fine powder raw material is investigated using the discrete element method when F _{M is} set to 0 × 10 ^-3 N to 10.5 × 10 ^-3 N. Simulation results. As shown in this table, in the example (S1: 0 / 5ν ₁ ) where the magnetic force (F _M ) is too large and the friction resistance becomes too large, the magnetic fine powder raw material is attached to the chute. Thereby, there is a possibility that the mounting in the width direction becomes uneven, or in the worst case, the chute may be blocked due to the adhered substance and the mounting itself may not be performed. On the other hand, in the example (S6: 5 / 5ν ₁ ) where no magnetic force was applied at all, segregation loading could not be performed at all. On the other hand, S2 has a large braking effect due to the magnetic force (F _M = 10.0 × 10 ^-3 N), so the density of the raw material loading layer is too low (the porosity is increased), the air permeability is good, and the productivity is improved, but Yield decreases. In S5, the results show that the magnetic force (F _M = 0.4 × 10 ^-3 N) is weak, the loading speed ν _{m is} large, and the effect of the segregation loading is poor. Therefore, it can be seen that it is effective to adjust the magnetic force F _M in association with the speed ν _m of the lower end portion of the chute from which the magnetic fine powder raw material is fed. In addition, the segregation conditions of S3 and S4 are both good, and the density of the raw material loading layer does not decrease too much (the porosity increases), so the air permeability is good, and the yield and productivity are also good.

Based on the above, the adjustment of the magnetic force F _M is performed based on the following criteria. That is, the suitable range of the magnetic force F _M is preferably adjusted in the following manner, that is, based on the magnetically fine powder raw material and the non-magnetically coarse material at the lower end of the chute. The speed difference (speed ratio) of the fine-grained raw materials is segregated on the sintering trolley and deposited on the upper part of the sintered raw material charging layer.

Therefore, in the present invention, in the formula (4) as the energy conservation formula, when the speed (initial speed) to the drop position on the chute is set to ν ₀ and the magnetic force is not applied to the lower end of the chute. When the speed is set to ν ₁ (same as the speed of the non-magnetic raw material), the magnetic force F _M is adjusted so that the speed ν _m of the magnetic fine powder raw material at the lower end of the chute is within the following range.

The relationship between the magnetic force F _M and the speed ν _m at the lower end of the chute is set to 0, 1 / 5ν ₁ , 2 / 5ν ₁ , 3 / 5ν ₁ , 4 / 5ν according to the speed of the lower end of the chute from the magnetic fine powder raw material. _1, test _1, v (S1 ~ S6) of, and results shown in table 2 can be seen. That is, as shown in Table 2, when the speed ν _m at the lower end of the chute of the magnetic fine powder raw material is in the range of 1 / 5ν ₁ to 4 / 5ν ₁ , the state of the segregation loading is good, especially 2 / 5ν _The yield is better in the range of ₁ to 3 / 5ν ₁ .

Therefore, in the present invention, when the sintered blended raw material containing the prescribed amount (5 mass% to 30 mass%) of the magnetically fine powdered raw material is loaded on a sintering trolley, the FeO content and grains of the magnetically fined powder raw material are considered. If the mass m or magnetic susceptibility X changes, the magnetic flux density (H) of the used magnet, the distance between the chute surface and the magnet, and the chute angle are adjusted in advance. The sliding speed ν _m of the magnetic fine powder raw material at the lower end of the chute is in a certain range (when the speed of the lower end of the chute of the non-magnetic raw material is ν ₁ , it is 1 / 5ν ₁ ~ 4 / 5ν ₁ ). By adjusting the magnetic force F _M caused by the magnet, only the sintering raw material in the sintering preparation raw material can be selectively deposited on the upper part of the layer of the sintering raw material charging layer.

As a result, under the provided conditions (the content of FeO from the magnetic fine powder raw material, the average particle size, the blending ratio of the raw material, etc.), the ideal range of the magnetic force F _M is to keep the magnetic fine powder raw material only The condition that the sintering machine can be stably operated by being deposited on the upper part of the sintering raw material charging layer means that the speed of the magnetically fine powdered raw material at the lower end of the chute is 1 / 5ν ₁ to 4 / 5ν ₁ In the method, the magnetic force F _M caused by the magnet is in the range of 0.0004 to 0.01, and it is desirable to adjust the range of 0.004 to 0.009 to load the sintering compounding material, so that the operation of the sintering machine is stable.

FIG. 7 shows the results of a simulation in which, as the magnetizing fine powder raw material in the sintering preparation raw material, for sintering remineralization containing 15% by mass of FeO at 7.0% by mass, and 5% by mass of FeO at 4.7% by mass of magnetite It is a raw material of fine powder iron ore, and the magnetic force F _M in the formula (4) is set to 0.01N, and it is found that the speed on the chute of the magnetic fine powder raw material decreases, and most of it accumulates on the sintering raw material. The upper part of the layer.

Next, in FIG. 8, as the magnetizing fine powder raw material in the sintering preparation raw material, the magnetite-based fine powder iron containing 15% by mass of FeO and 7.0% by mass of sintering remineralization, and 5% by mass of FeO being 4.7% by mass of magnetite. Similarly, the raw material of the ore was simulated by setting the magnetic force F _M to more than 0.01 N, and as a result, the charging of the sintering preparation material at a certain speed could not be carried out, which hindered the operation of the sintering machine.

Next, in FIG. 9, as the magnetizing fine powder raw material in the sintering preparation raw material, magnetite-based fine powder iron containing 15% by mass of FeO at 7.0% by mass and 5% by mass of FeO at 4.7% by mass The raw material of the ore was similarly set to have a magnetic force F _M of 0.004 N, and it was found that it was ideally segregated.

Next, FIG. 10 is an example in which, as a magnetizing fine powder raw material in the sintering preparation raw material, a magnet containing 7.0% by mass of FeO with 15% by mass of FeO and 4.7% by mass of FeO with 5% by mass of FeO The raw materials of the ore-based fine-powder iron ore were generally loaded, and the magnetic force F _{M was} set to 0 for simulation. It was found that the segregation of the magnetic fine-powder raw materials could not be expected at all.

[Example]

In the examples described below, an experimental device that simulates the physical loading device shown in FIG. 11 was used to carry out the loading experiment of the sintered blended raw materials. In this experiment, sintered blended raw materials including magnetite-based finely powdered ore or sintered remineralized raw materials such as magnetite-based finely-powdered ore or sintered remineralized were prepared as shown in Table 3. Furthermore, the hopper provided above the simulator was filled with the sintered blended raw materials, and was loaded on a simulation trolley using a chute under the conditions shown in Table 4. The upper layer part, middle layer part, and lower layer part of the loading layer obtained from loading on the simulation trolley are respectively prepared by sintering and blending materials, and the segregation status of the magnetite composition (FeO) is investigated by chemical analysis. Then, the loaded sintering preparation materials were transferred to a sintering pot tester to perform a sintering test, and the influence on productivity was investigated.

The magnetic force (F _M ) and the velocity (ν _m ) of the lower part of the chute in this example are shown in Table 3. Under the conditions (T1 to T6) suitable for the present invention, it is 6.0 × 10 ^-3 N, and this The speed ν _m is a condition of 3 / 5ν ₁ .

Arithmetic mean diameter: 0.29mm

250 μm or less: 53% by mass

* Sintered FeO: 5.69% by mass

Arithmetic mean diameter: 2.25mm

250 μm or less: 8% by mass

* Speed at the lower end of the chute when no magnetic force is applied (v ₁ ): 3.0 m / s

According to the results of the loading experiment of the sintering pot test device, as shown in FIG. 12, 10% by mass of the magnetite-based fine powder iron ore and 20% by mass were prepared by using a chute with a magnet disposed on the back surface. % Sintering returns, and the remainder is the sintered blended raw material obtained from powdered iron ore and limestone. A comparative example (a loading example suitable for the present invention (T6) and a chute without a magnet is provided) After comparing the segregation status of the magnetizing component (FeO) in T8), in the invention example (T6) incorporated using a chute provided with a magnet, the sintered blended raw material containing the magnetizing component was transferred to the upper layer of the loading layer. Department segregation.

Furthermore, regarding the invention examples and comparative examples of this experiment, magnetite-based fine powder was used. The change in productivity due to the iron ore blending ratio is shown in FIG. 13. According to the results shown in the figure, compared with the case where the magnetic fine powder raw material is not included (T1), under the condition (T2) in which the magnetic fine powder raw material is blended at 5% by mass, the magnetic generating component is small and cannot be obtained sufficiently. The effect of lowering the loading speed does not change much in the sintering machine. On the other hand, in the examples (T3 to T6) suitable for the present invention, the effect of reducing the loading speed caused by the magnetic fine powder raw material was sufficiently obtained, and the productivity was higher than that when the magnetic fine powder raw material was not included (T1). Improved. On the other hand, under the condition (T7) in which 40% by mass of the magnetic fine powder raw material was blended, the ratio of fine powder increased, and fine powder was mixed not only in the upper layer portion but below the middle layer portion, so the productivity could not be maintained high. Therefore, in the present invention, when the amount of the magnetic fine powder raw material in the sintered preparation raw material is 5 to 30% by mass, preferably 20 to 30% by mass, the effect can be significantly exhibited.

[Industrial availability]

When a sintered blended raw material having a larger particle size than that specified in the present invention and a small amount or a large amount of magnetic fine powder raw material is loaded, the technology of the present invention can be applied although the effect is different.

Claims (5)

A method for operating a sintering machine, wherein the sintering and preparing raw materials are loaded on a trolley of the sintering machine and sintered through a chute formed with a magnet on the back side. The operating method of the sintering machine is characterized in that: 5 mass% to 30 mass% is a magnetic fine powder raw material, the content of FeO in the magnetic fine powder raw material is 4.5 mass% or more, and the particle size of the magnetic fine powder raw material has an arithmetic mean diameter of 0.2 mm to 2.5 mm, and the amount of fine powder below 250 μm is 5 mass% or more and 60 mass% or less by weight. When the magnetic fine powder raw material is loaded on a trolley, When the magnetic force (F _M ) is applied to the groove (F _M = 0), the speed of the sintered blended raw material at the lower end of the chute is set to ν ₁ , and the speed of the magnetically finely powdered raw material at the lower end of the chute is ν _{A mode in which m} becomes a speed of 1 / 5ν ₁ to 4 / 5ν ₁ is to adjust the magnetic force F _M of the magnet. The method for operating a sintering machine according to item 1 of the scope of the patent application, wherein the speed ν _m of the magnetic fine powder raw material at the lower end of the chute is a speed of 2 / 5ν ₁ to 3 / 5ν ₁ . The method for operating a sintering machine according to item 1 or item 2 of the scope of patent application, wherein the speed ν _m of the magnetically fine powdered raw material at the lower end of the chute is adjusted within a range of 0.0004N to 0.01N. The magnetic force F _{M of the} magnet. According to the method of operating a sintering machine according to the first or second scope of the patent application, wherein the magnetic force F _{M of} the magnet is a value obtained by the following formula, m: mass (kg) g: gravitational acceleration (m / s ² ) θ: chute angle (rad) μ: coefficient of friction between raw material and chute (-) kv ² : air resistance (N) v ₀ : initial speed ( m / s) v ₁ : speed (m / s) at the lower end of the chute L: chute length (m) L _M : length of the magnet plate (m) F _M : magnetic force (N). The method for operating a sintering machine as described in item 1 or 2 of the scope of the patent application, wherein at least 5 mass% to 15 mass% of the raw material of the magnetic fine powder is sintering remineralization, and the remaining part contains Any one or more of magnetite-based fine iron ore, crumbs, and ironmaking dust.