JP6183612B2 - Operation method of sintering machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for operating a sintering machine, and in particular, a DL type sintering machine of a type in which a sintering compound raw material is charged onto a pallet via a sloping chute having a magnet on the back surface or a drum chute with a magnet inside. It is related to the operation method.

  In general, it is known that in the production of sintered ore, the influence of the amount of coke in the sintered blending raw material is large. In particular, when paying attention to the sintering raw material layer on the pallet, even if the amount of coke in the lower layer portion is reduced, the yield is not significantly affected, but it is known that the reducibility is rather improved. . On the other hand, in the upper layer portion of the sintering raw material layer, the yield is greatly improved when the amount of coke is increased, but the reducibility is not significantly changed. From this, it is considered that while increasing the coke ratio in the upper layer part, decreasing the coke ratio in the lower layer part can improve the yield and also improve the reducibility of the sintered ore. It has been.

  As described above, when producing sintered ore, the coke segregation (distribution) state in the upper and lower layers of the sintering raw material layer indicates the productivity (yield) and quality (cold strength) of the product sintered ore in the sintering operation. , Reducibility, reductive disintegration). Table 1 summarizes the coke ratios of the upper, middle and lower layers of the sintering raw material layer on the pallet in the prior art, and the reducibility (JIS-RI) and reductive disintegration (RDI) of the sintered ore.

  As shown in Table 1, in the downward suction type DL sintering machine, since the upper layer portion of the sintering raw material layer is usually sintered at a low temperature of 1300 ° C. or lower, the yield and cold strength are low, Conversely, reducibility (JIS-RI) and reductive decay (RDI) are good. The reason is that when the upper layer portion is sintered at a low temperature, the coalescence of the pores does not proceed as much as the lower layer portion having a higher temperature, and the fine pores that adversely affect the yield increase. However, since these fine pores generated in the low temperature region become a flow path for reducing gas during the reduction, the reducibility is rather improved, and the production of secondary hematite that deteriorates the reductive decay property does not occur. The reductive disintegration is also good. Therefore, it can be seen that if the amount of coke in the entire sintered blending raw material is reduced and sintered at a low temperature, the reducibility and reductive disintegration are improved, leading to stability of the blast furnace and reduction of the fuel ratio. However, in this case, since the yield and cold strength are reduced, the coke amount cannot be reduced.

  Under such a background, a method for distributing a large amount of coke to the upper layer portion of the sintered raw material layer has been attempted so far. For example, in Patent Document 1, another feed hopper is provided in the direction of travel of the pallet, and the raw material layer is blown into the upper layer of the feed layer by transporting the sintered blended raw material with an increased amount of coke from the feed hopper by gas. Proposing technology. Patent Document 2 discloses a technique in which a sintered blending raw material with an increased amount of coke is gas transported and blown into an upper layer portion. However, these technologies require two transporting routes for the sintering raw material from the feed hopper to the sintering machine in parallel, which necessitates the installation of a drum mixer and conveyor. Investment is required. However, in this case, the operation cost, that is, the operation cost is increased. In addition, when the sintered blended raw material is transported by gas, there is a problem that the sintered raw material wears and adheres in the pipe and cannot be used stably for a long time.

  In addition, in Patent Document 3, a ferromagnetic raw material and a solid fuel are granulated in advance, and the granulated material is placed on the pallet by a plate-type sloping chute in which a plurality of permanent magnets are arranged in series along the vertical direction on the back side. Has been proposed to increase the proportion of solid fuel in the upper layer. In this method, there is a problem that it is necessary to granulate the ferromagnetic raw material and the solid fuel in advance, requiring labor and facilities, and adding a binder or the like causes an increase in cost.

JP-A-8-73951 Japanese Patent Laid-Open No. 7-18345 JP 2000-328148 A

  The object of the present invention is to solve the above-mentioned problems of the prior art, and to produce a product sintered ore that is excellent not only in yield but also in quality without requiring equipment for granulation. The purpose of this is to propose a DL-type sintering machine operation technique.

  The basic idea of the present invention is that when a sintering compound material containing a ferromagnetic material is sintered in the operation of a DL type sintering machine in which a sintering compound material is charged onto the pallet using magnetic force, the pallet By supplying not only solid fuel such as coke but also diluted gaseous fuel to the upper brittle layer portion of the sintered raw material layer deposited on the sintered raw material layer in the vertical direction of the sintered layer and the sintered raw material layer Sintering so that the temperature history is substantially uniform (preventing lowering of the upper layer temperature) improves the yield (productivity) of the final product sintered ore, The aim is to improve quality characteristics such as strength, reducibility and reductive disintegration.

That is, the present invention was developed under this concept is return ores, magnetite ore, Mirusuke - Le, a ferromagnetic material is steel dust or reduced iron powder 10～30Mass% seen including, and in the solid fuel sintering is sintered blend material of carbonaceous material formed by interior, the sintering material layer on the pallet obtained by charging through the sloping chute or drum chute and formed by disposing a magnet on a sintered pallet When the sintered raw material layer upper layer portion in which the concentration of the solid fuel is relatively reduced due to segregation of a large amount of the ferromagnetic raw material, the diluted gaseous fuel diluted below the lower combustion limit concentration , sintering led to combustion of Risumi material and diluted gaseous fuel by the blowing on the basis of the relationship between segregation range ferromagnetic material in the height direction of advance sought force and sintering the raw material layer of the magnet With features This is the operation method of the sintering machine.

  According to the operation method of the sintering machine according to the present invention configured as described above, it is possible to eliminate the influence of the upper fragile layer of the sintering raw material layer without incurring excessive capital investment and an increase in manufacturing cost. . That is, by making the temperature history in the vertical direction of the sintered raw material layer uniform by carrying out the operation method as described above, in the present invention, it is possible to improve the production and yield of the product sintered ore. In addition, cold strength, reducibility and reductive decay characteristics can be improved.

It is explanatory drawing of the adjustment method of a sintering mixing | blending raw material. It is sectional drawing which shows the sintering mixing | blending raw material charging method by the plate type sloping chute which arranged the some permanent magnet in series along the up-down direction of the back surface side. It is sectional drawing of the drum chute incorporating a magnet. It is a graph which shows the relationship between the sinter reduction rate and gas utilization rate in a blast furnace. It is a graph which shows the relationship between the gas utilization rate and fuel ratio in a blast furnace. It is a graph which shows the relationship between the coke addition ratio of a sintering raw material, and JIS-RI. It is a graph which shows the relationship between the coke addition ratio of a sintering raw material, and the yield of sintered ore. It is a graph which shows the relationship between a powder coke ratio and the layer thickness of a sintering raw material layer. It is a graph which shows the relationship between the yield of a sintered ore, and the layer thickness of a sintering raw material layer. It is a graph which shows the relationship between JIS-RI and the layer thickness of a sintering raw material layer. It is a graph which shows the relationship between RDI and the layer thickness of a sintering raw material layer. Is a graph showing the relationship between the Fe ₃ O ₄ distribution in the sintering bed height.

  The background to the development of the present invention and an embodiment will be described below with reference to the drawings. In the operation of the DL sintering machine according to the present invention, as shown in FIG. 1, first, a ferromagnetic raw material 1 such as return or magnetite ore and a solid fuel 2 such as coke powder, anthracite, or blast furnace dust are compared. Interior of carbonaceous material containing a ferromagnetic raw material that is granulated with a drum mixer 4 after adjusting to other raw materials 3 such as powdery iron ore, mill scale, limestone, serpentinite, etc., and 7% by weight moisture. The sintered compounding raw material 6 of the mold is prepared, and this is transported to a feed hopper 5 attached to the DL type sintering machine and stored. And as shown in FIG. 2, the said sintering compounding raw material 6 containing the carbonaceous material which is a solid fuel is cut out from the feed hopper 5 with the drum feeder 7, for example, a some permanent along the up-down direction of a back surface side. The magnet 10 is cut out and loaded on a pallet of a sintering machine through a plate-type sloping chute 8 and the like arranged in series.

  By the way, under the raw material charging system as described above, the sintered compounding raw material 6 falls because it is affected by the magnetic brake due to the magnetic field of the permanent magnet 10 when sliding down on the sloping chute 8. As a result, a part of them, that is, a ferromagnetic raw material such as return ore is drawn to the sloping chute 8 side, and as a result, when it is charged into the pallet 11, These (the ferromagnetic raw material 12 such as return mineral) are deposited in a segregated state.

  Similarly, in the case of a drum chute as shown in FIG. 3 that is not of a plate type, the sintered blending raw material 6 cut out from the feed hopper 5 through the drum feeder 7 is also a magnet (permanent magnet or electromagnet) 13. Therefore, when the material is loaded onto the pallet 11, the ferromagnetic raw material 12 such as return ore is attracted to the drum chute 16 side, and the plate-type sloping chute 8 is loaded. In the same manner as in the above, segregation occurs in the upper layer portion of the sintering material layer 9 on the pallet 11.

  Then, the carbon material of the surface layer part of the sintering raw material layer 9 is ignited by an ignition burner (not shown) disposed above the sintering raw material layer 9, and the air above the sintering raw material layer 9 is ignited. The sintering raw material layer 9 is sintered in the process of advancing the pallet 11 toward the rear end side of the sintering machine while sucking downward from the gap of the great bar of the pallet 11 with an exhaust fan (not shown). To produce sintered ore.

  One of the quality characteristics of sintered ore produced in this way is reducibility, and it is known that the quality of this reducibility greatly affects the operation of the blast furnace. That is, as can be seen from FIG. 4 and FIG. 5, there is a strong correlation between the reduction rate of the sintered ore and the fuel ratio in the blast furnace through the relationship with the gas utilization rate in the blast furnace. It can be seen that the fuel ratio in the blast furnace decreases when the reduction rate of the ore is improved. In addition, the reducibility of the sintered ore (according to the definition of JIS, hereinafter referred to as “JIS-RI”) has a negative correlation with the coke addition ratio in the operation of the sintering machine, as shown in FIG. is there.

  Moreover, as shown in FIG. 7, the yield of sintered ore is different in the upper layer portion-middle layer portion-lower layer portion of the sintering raw material layer 9, and it is known that the influence of the amount of coke addition (distribution) is large. Yes. According to the knowledge of the inventors, in the lower layer portion of the sintering raw material layer 9, even if the amount of coke added is reduced, the influence on the yield is relatively small. However, as shown in FIG. It is good. On the other hand, in the upper layer portion, increasing the coke addition amount greatly improves the yield, but has little influence on the reducibility. Therefore, from the experimental results shown in FIGS. 6 and 7, the coke addition layer is increased for the upper layer portion, while the effect on the yield is reduced even if the coke addition amount is decreased for the lower layer portion. On the other hand, it was found that the reducibility of a certain level or more can be secured as a sintered ore.

  As described above, in the operation of a sintering machine for producing sintered ore, the coke segregation (distribution) state of the sintered raw material layer 9 depends on the productivity, yield and quality (cold strength, coverage) of the product sintered ore. It can be seen that it has a great influence on the reducibility and reductive disintegration).

  By the way, when the solid fuel such as powdered coke is charged through a general sloping chute having no magnet, it is finer than other raw materials such as iron ore. Due to the above-mentioned particle size segregation, the upper layer part of the sintered raw material layer is segregated. However, if a sintered compounding material containing a ferromagnetic material is charged by applying a magnetic force with a sloping chute provided with a magnet, the amount of the ferromagnetic material (returning or the like) in this sintered compounding material However, since the ferromagnetic raw material occupying about 10 to 30 mass% is segregated in the upper layer portion instead of the solid fuel, the concentration of the solid fuel (powder coke, etc.) in this upper layer portion is Conversely, it decreases. Therefore, in order to improve the yield and the like, there arises a problem that the concentration of the powder coke and the like is lowered in the upper layer portion where the powder coke is necessary. Therefore, it is necessary to solve the above problem when using a sintered blending material containing a ferromagnetic material.

  Therefore, in the present invention, the carbonaceous material-containing sintered compounding material 6 containing a ferromagnetic material is placed on the pallet 11, and then the sintering material layer 9 deposited on the pallet 11 with an ignition burner. When the surface layer portion is ignited and sintered, in combination with the ignition to the surface of the sintering raw material layer 9, diluted gaseous fuel such as LNG diluted to a lower combustion limit concentration or less (about 2.4 vol.% Or less) is used. It was made to respond by injecting from above. By doing so, when the air above the sintering raw material layer 9 is sucked into the wind box under the pallet, this diluted gas fuel is simultaneously sucked into the upper portion of the sintering raw material layer 9 containing the ferromagnetic raw material at the same time. As a result, especially in the upper layer portion of the sintered raw material layer 9 (a large amount of ferromagnetic raw material is distributed), in addition to the carbon material in the original sintered blended raw material 6 The gaseous fuel will also burn. As a result, in the upper layer portion of the sintered raw material layer 9, the diluted gas is used in a range where a shortage of solid fuel (powder coke) occurs when a ferromagnetic raw material (hereinafter also referred to as “magnetized component”) is charged. Combustion of fuel makes it possible to compensate for the lack of heat.

  The concentration of the diluted gas fuel can be adjusted freely afterwards (unlike the carbon material in the raw material), so that smooth sintering can be performed at any time without causing insufficient combustion during ignition. As a result, it is possible to obtain the same yield improvement effect as when the powder coke is segregated in the upper layer of the sintered raw material layer.

  The range in which the diluted gas fuel that produces such an effect is supplied is that the concentration of solid fuel is relative to that of other parts due to segregation of a large amount of the ferromagnetic raw material 12 that is charged through, for example, sloping with a magnet. It is a sintering raw material layer upper layer part which falls to. The range (vertical direction) of the upper part of the sintering raw material layer is the magnetic force (F: 0.1 to 0.5 Tesla) of the permanent magnet disposed on the back surface of the sloping chute and the upper part of the sintering raw material layer. The relationship with the segregation (distribution) of the ferromagnetic raw material (magnetization component) in the height direction is obtained in advance, and the range in which the diluted gaseous fuel is supplied (the combustion range of the gaseous fuel) is adjusted based on the relationship. It is preferable.

  As described above, the dilution gas fuel injection is determined in consideration of the relationship between the magnetic force (F) of the magnet and the range in which the ferromagnetic raw material is segregated. In this case, for example, a certain amount of dilution gas fuel is injected. As shown in FIG. 2, the inclination angle (also referred to as the charging angle) A of the sloping chute 8 is changed, or the sloping chute 8 and the permanent magnet 10 disposed on the back side thereof are provided. It is preferable that effective dilution gas fuel can be blown by changing the magnetic force (0.1 to 0.5 Tesla) on the surface of the sloping chute 8 by adjusting the interval of.

The range (upper layer part) in which a large amount of ferromagnetic raw material is segregated during charging of the sintered blending raw material is the vertical direction in which the amount of magnetization components in the sintered blending raw material used is more than the average value. In the present invention, the diluted gas fuel is supplied over the range. FIG. 12 shows an example of the measurement result of the Fe ₃ O ₄ distribution in the height direction of the sintered raw material layer when the magnetic force is set to 0.1 Tesla. The average value of Fe ₃ O ₄ in the sintered raw material layer 9 is 18.5 mass%, and the range showing the value higher than this average value, that is, the portion of the sintered raw material layer 9 above about 0.3 m is ferromagnetic. This is a range in which a large amount of the raw material is segregated, and the dilute gas fuel is blown in such a manner as to spread over there.

  On the other hand, in the case where charging of the sintered blending raw material is performed using the drum feeder 7 in consideration of the segregation range described above, the drum feeder 7 is provided with a rotational speed of the drum feeder 7 and a permanent magnet built in the drum feeder 7. 7 Determined based on the relationship with the magnetic force (0.1 to 0.5 Tesla) on the surface.

  However, in the case where the above-described dilution gas fuel injection range is limited by the equipment arrangement, the segregation range of the ferromagnetic material is changed to the sloping chute 8 and / or the sloping champ 8 is changed in the sloping chute 8. By adjusting the gap B between the permanent magnet 10 disposed on the back surface side of the chute 8 and the sloping chute 8 and adjusting the magnetic force (F) on the surface of the sloping chute 8 within the above range, a predetermined value obtained in advance. It is preferable that the segregation range is adjusted so as to coincide with the supply range of the diluted gas fuel. That is, the segregation is strengthened by reducing the inclination angle of the sloping chute 8 (small inclination angle) and / or the gap B between the permanent magnet 10 and the sloping chute 8 disposed on the back side of the sloping chute 8 is reduced. By doing so, the segregation range is adjusted to be small by adjusting to increase the magnetic force on the surface of the sloping chute 8.

  When the drum chute shown in FIG. 3 is used, the rotational speed of the drum feeder 7 is reduced, and / or the permanent magnet or electromagnet 13 incorporated in the drum feeder 7 is moved to the ferromagnetic side. The segregation range can be adjusted to be small by switching to the one and increasing the magnetic force on the surface of the drum feeder 7, and when the segregation range is enlarged, it can be realized by performing the reverse operation to the above operation. .

  The adjustment of the range of segregation of ferromagnetic raw materials and the range of blowing of diluted gas fuel may be performed when the ore to be imported is analyzed and the content of the magnetization component is greatly changed from that of a normal sintered raw material. What is necessary is just to obtain | require previously by performing the said test in the step in which the compounding quantity of the binding raw material was determined. In addition, when the content of the magnetization component is changed from the ore used as a normal sintering raw material, the above test is performed for each blending amount while changing the blending amount of the sintering blending raw material containing the ore. It may be obtained in advance.

  The dilute gas fuel is supplied so that a smooth sintering reaction proceeds in a range where the ferromagnetic raw material affected by the magnetic force of the sloping chute with magnets is segregated, and it is considered in consideration of the movement of the pallet 11. It is preferable to carry out over the entire machine width direction if possible within a predetermined range in the machine length direction (pallet movement direction) (for example, 2 m to 30 m from the end of the ignition furnace, but in the case of a machine length of 90 m).

  Based on the operation method of the sintering machine described above, the sintering tester is used to sinter the blended raw material with solid fuel, but the sintered blending material containing 18.5 mass% of the magnetization component, that is, the ferromagnetic material, has a magnetic force of 0. .2 m from the ignition furnace in the machine length direction while charging and depositing on the pallet using a sloping chute with two 1 Tesla magnets installed in the vertical direction and sintering while sucking from below the great bar of the pallet 11 Dilute gas fuel (LNG diluted to 0.4%) is placed in the upper part of the sintering raw material layer from a distant position, and exhausted from the ignition furnace side 1/3 in the entire pallet width direction and in the machine length direction. The pallet 11 was advanced to the rear end side of the sintering machine while blowing over the range of the ignition furnace side 1/3) of the length up to the part, and sintering was performed to produce a sintered ore.

  And in the obtained product sintered ore, the yield (%) in the height direction, reducible JIS-RI (%) and reductive disintegration RDI (%) were measured. The results are shown in Table 2 and FIGS.

  As is clear from Table 2 and FIGS. 8 to 11 and Table 1 above, in addition to the solid fuel embedded in the sintering blended raw material, a book in which dilution gas fuel blowing is additionally used from above the sintering raw material layer. By adopting the method according to the invention, it was confirmed that the segregation of coke, which is a solid fuel in the sintered raw material layer, hardly changed, but the yield of sintered ore was improved by 1% on average in all layers. Furthermore, in the lower layer where the reducibility and reductive disintegration were poor, remarkable improvement was observed, and the reducibility was improved by 2% and reductive disintegration by about 2% on the average of all layers.

In this example, liquefied natural gas (LNG, low heating value 41.6 MJ / Nm ³ based on JIS-K2301) was vaporized and used as the gaseous fuel. The gaseous fuel used is 0.5 Nm ³ / ts, which corresponds to 20 Nm ³ / ts as a calorific value. Reduced solid fuel (0.3% is equivalent to 3 kg / ts, and its calorific value is 27 MJ / kg (measured according to JIS-M8814)) is used because it corresponds to 81 MJ / ts. This is equivalent to about four times the amount of heat of the gaseous fuel, leading to a reduction in the amount of heat used by the entire sintering machine. That is, the amount of heat of the gaseous fuel used could be 50% or less of the amount of heat of the solid fuel to be reduced.

  As described above, according to the present invention, a sintered raw material formed on a pallet by charging a sintered blended raw material containing a ferromagnetic raw material through various chutes provided with magnets. Even if the ferromagnetic material is segregated in the upper part of the layer, and the concentration of solid fuel in the sintered compounding material may be reduced, air containing gaseous fuel diluted below the lower combustion limit concentration is placed under the pallet. Sintering without causing heat shortage even in the upper layer by burning the gaseous fuel and carbonaceous material in the sintering raw material layer by sucking in the installed wind box and introducing it into the charging layer can do. As a result, the sinterability of the upper layer part of the sintering raw material layer charged on the pallet is improved, the yield of the ore and the cold strength can be improved, and the reduction of the product sintered ore is reduced. It has been found that the effect of improving the properties and reductive disintegration can be obtained. Furthermore, it has also been found that by using a solid fuel and a gaseous fuel in combination, the thermal efficiency can be improved and the amount of heat consumed in the sintering process can be reduced.

  The operation technology of the sintered powder according to the present invention is basically premised on application to a DL sintering machine not equipped with granulation equipment, but of course, it can also be applied to the case with granulation equipment. is there.

DESCRIPTION OF SYMBOLS 1 Ferromagnetic iron-containing raw material 2 Solid fuel 3 Other sintering raw materials 4 Drum mixer 5 Feeding hopper 6 Sintering mixing raw material 7 Ram feeder 8 Slowing chute 9 Sintering raw material layer 10 Permanent magnet 11 Pallet 12 Ferromagnetic raw material 13 Magnet 14 Preliminary construction Granulator 15 Pseudo-particle raw material 16 Drum chute (built-in magnet type)

Claims (1)

Return ores, magnetite ore, Mirusuke - Le, steel dust or ferromagnetic material is reduced iron powder 10～30Mass% saw including a and sintering mixed material formed by interior a carbonaceous material is a solid fuel, the magnets When the sintering raw material layer on the pallet obtained by charging on the sintering pallet through a sloping chute or drum chute formed is sintered, the solid is caused by segregation of a large amount of the ferromagnetic raw material. The diluted gas fuel diluted below the lower combustion limit concentration with respect to the upper portion of the sintering raw material layer in which the concentration of the fuel is relatively lowered , the magnetic force of the magnet required in advance and the height direction in the sintering raw material layer operation method of sintering machine, wherein sintering led to combustion of Risumi material and diluted gaseous fuel by the blowing on the basis of the relationship between segregation range ferromagnetic material in.

Images