WO1998007891A1 - Method of manufacturing sintered ore and sintering machine therefor - Google Patents

Abstract

A method of manufacturing sintered ore by charging a blended raw material, which contains a raw powder ore, solvent and fuel, onto a pallet of a sintering machine to form a raw material packed bed and then igniting a surface of the raw material packed bed to effect sintering reaction downward from above. In the method of manufacturing sintered ore and the sintering machine, when an upper layer of the raw material packed bed is adequately fired, a mass flow rate of oxygen containing gas supplied to the raw material packed bed is changed to be 1.01 to 2.6 times the mass flow rate of oxygen containing gas supplied in the range, in which the upper layer of the raw material packed bed is fired, to effect sintering, thereby obtaining a high yield and a product having an excellent quality. More preferably, when a tip end of a region, in which a combustion fusing band is formed, reaches a position below 20 % of a height of the raw material packed bed from the upper layer of the raw material packed bed, a mass flow rate of oxygen containing gas supplied to the raw material packed bed is changed in the above manner to effect sintering.

Description

 Description Sinter production method and sintering machine

 The present invention relates to a method and a sintering machine for producing a sintered ore, which is a raw material of a blast furnace production method, and more particularly to a method for transferring a combustion molten zone from the upper side to the lower side of a sintering pallet. After obtaining the sintered layer, the supply rate of the oxygen-containing gas is increased, the differential pressure is increased, the traveling speed of the combustion melting zone is extremely accelerated, the production rate is increased, and the product is increased. The present invention relates to a method for producing a sinter which improves quality and yield and a sintering machine therefor. Conventional technology

 For sintering iron ore, Dwight toroid type sintering machines are widely used. This is done by adding a solvent such as limestone or silica stone, a fuel such as coke breeze, and water to the raw ore powder, mixing and granulating the mixture, and filling the mixture on a sintered pallet arranged in the shape of a villa. The sintering pallet is sequentially moved horizontally to ignite the surface of the packed bed in the ignition furnace, and then sucked from below to burn the fuel such as coke in the blended raw material The generated heat melts and solidifies the raw material ore, gradually moving the combustion zone from the surface layer to the lower layer and sintering it.The sintering time is about 20 to 40 minutes.

Compared to other batch type sintering machines such as a green type sintering machine, the Dwight Toroids type sintering machine is a continuous type and is suitable for mass production because it is widely used. is there. Current Dowai toroid type sintering machine is increased in size, width 5 m X rather force is up to things like the length 1 00 m, the production rate is 34 ~ 43 t Z d Z m 2 approximately. Considering the global resource situation, there is a remarkable shortage of supply of lump ore, which is a raw material for the blast furnace manufacturing method, and the price of lump ore is increasing accordingly. Use is required. However, increasing the number of sintering machines or increasing the size of sintering machines in order to increase the production of sinter ore requires not only large capital investment but also exhaust gas emissions. Problems such as the increase in volume and the unfavorable environment occur. For this reason, there is a strong demand for improved productivity of sintering machines. However, in the production of sintered ore, the production rate is maximized while maintaining the quality of the product sintered ore required by the blast furnace production method, the unit fuel consumption and the unit ignition fuel are minimized, and NOx emissions are reduced. It is required to operate the plant as much as possible. Therefore, in the actual operation, as long as the quality of the sinter is maintained, silica stone and serpentine, limestone, and coke breeze and anthracite added as fuel are added as auxiliary materials. It is better to reduce the amount, such as coke oven gas and pulverized coal, which is the fuel for ignition.

However, good results cannot be obtained by unnecessarily reducing the mixing ratio of the auxiliary material and the fuel to the sintering raw material and the amount of the ignition fuel. Deterioration of RDI (reduced pulverization rate) and return of minerals increased, which in turn led to deterioration of fuel consumption and ignition fuel consumption. Furthermore, NOx conversion rate worsened and NOx emissions decreased. Conversely, it will increase. Also, the S i 0 ₂ sinter 5. when the Omas s% or less in the low made, is also well known that the RD 1 is deteriorated greatly.

In Japanese Patent Publication No. 55-19299, "The first half of the upper part of the strand is provided with the first half of the negative pressure, the second half of the upper part of the strand is provided with the second half of the pressure, By circulating the exhaust gas in the second half by the pressure in the first half and the negative pressure in the first half, it is possible to reduce the amount of exhaust gas, reduce power costs and prevent a drop in productivity. " However, in this method, the part to be sintered in the second half of the atmosphere is covered with a positive pressure hood, and the second half is sintered. The purpose is to remove the blower following the wind box and reduce the amount of exhaust gas by means of exhaust gas circulation equipment that minimizes equipment costs. No attempt was made to increase it to increase productivity. Furthermore, based on the disclosed exhaust gas composition, exhaust gas characteristics, drawings, etc., the sintering completion point in this method is in the early stage of the latter half of the hood, and on the strand in the remaining range of the latter half. I can only imagine that they are doing cooling in the country. Therefore, the sintering completion point is not as close as possible to the mining section, and the entire strand is not used to maximize the production rate.

 In Japanese Patent Publication No. 56-19956, "A positive pressure hood for forming a pressure sintering zone is provided, and a negative pressure zone is formed by suction at an end of the supply and discharge side of the positive pressure hood. If a negative pressure hood is provided, productivity and operating costs can be improved by the pressure sintering method without requiring an airtight housing that covers the entire equipment. " However, this method is a problem in the conventional pressure sintering method, in which the starting point of raw material supply into the housing on the moving path of the sintering pallet and the end of sintering ore discharging from the housing are performed. The purpose is to prevent pressurized air from flowing out into the atmosphere, and there is no mention of actively increasing the transfer speed of the sintering zone in the raw material packed bed to improve productivity. Was something. In addition, in order to form a negative pressure zone by suction at the end of the feeder side, the suction flow rate at this location must be higher than the suction flow rate of the conventional method of sucking air. For this reason, the shortage of the high-temperature holding time in the baking of the upper layer of the raw material layer, which has been a problem in the past, is promoted, and the yield and quality of the upper layer of the raw material layer are deteriorated, so that the total productivity is greatly increased. It didn't make it.

Japanese Patent Application Laid-Open No. 61-243131 discloses that “the upper surface of a sintered ore on an endless pallet is used in order to eliminate the need for a large hermetic housing required for the pressure sintering method. A cost can be reduced by providing a hood in the hood, forcing air into the hood, and creating a negative pressure in the wind box below the endless pallet. " However, the purpose is to reduce the total power of the conventional exhaust fan power combined with the push-in and exhaust fan power, and to increase the transfer speed of the combustion zone in the packed bed to increase productivity. No attempt was made to improve the quality of the project. In other words, in order to maintain a constant pressure difference between the upper and lower parts of the raw material bed, which is the air pressure required for the process, in the entire strand from the ignition part to the exhaust part, the push-in fan and the exhaust fan are used. By balancing, the current sintering machine exhausts the entire volume of the high-temperature air that has expanded in volume, while the room temperature air is pushed in and blown to reduce the total power, thereby improving productivity. It does not positively increase the transition speed of the combustion zone in the required raw material bed.

Japanese Patent Publication No. 5-55574 discloses that “a plurality of wind boxes are divided in the longitudinal direction of the pallet, and the sintering raw material charged and laminated on the pallet is divided into a plurality of wind box groups. In response to the sintering reaction, the suction negative pressure decreases in the early stage of the sintering reaction compared to the suction negative pressure in the normal operation, and increases in the middle period up to the end of the firing reaction. By controlling so as to decrease at the final stage from the vicinity of the point, the yield, drop strength (SI) and RDI of the upper part of the sintering bed can be improved, and in addition, the exhaust power can be reduced. The sensible heat of the sinter can be recovered efficiently. " However, the sinter in the upper part of the sintering bed has already improved the RDI and SI compared to the sinter in the lower part, and in order to further improve the quality of the entire sinter, 'It is more important to improve the sinter in the lower layer. Even if the yield in the upper part of the sintering bed can be improved, the quality of the sinter ore can be reduced, and the power consumption can be reduced somewhat, the balance of the air intake volume at the beginning, middle and late stages of sintering can be improved to save energy. Also There were also adverse effects such as lower yield in the middle part and lower SI in the lower part.

 In order to increase the sensible heat recovery energy of the sinter, it is necessary to increase the temperature of the product sinter at the end of sintering, and the height of the red tropical zone (combustion melting zone) The width in the direction must be increased. For this reason, the ventilation resistance of the red tropics becomes extremely large, and the transition speed of the red tropics, which largely controls the production rate, cannot be increased, which adversely affects the production rate at the end of firing. However, a significant increase in the total production rate could not be expected.

 Furthermore, in order to secure the production rate in the middle stage of the firing reaction, the suction negative pressure is increased.According to the disclosed explanatory diagram, the exhaust gas flow rate in the middle It is thought that this does not significantly increase the total production rate, as it is smaller than the conventional method. Disclosure of the invention

 All of the above-mentioned conventional technologies are intended to improve the economical efficiency of equipment and the operating cost. Therefore, in all cases, it is assumed that the mixed raw material is filled on the sintering pallet to a thickness of about 400 to 600 mni, and that the fuel in the raw material is ignited in the ignition furnace under the current operating conditions.

The production rate of the sintering machine largely depends on the transition speed when the combustion zone in the raw material packed bed gradually transitions from the surface layer to the lower layer. The problem in improving the sintering production rate is that the sintering machine is in the process of firing from the upper layer to the lower layer of the raw material bed in the strand from the ignition section to the mining section. That is, the transition speed of the combustion melting zone is slow. Therefore, if the transition speed of the combustion melting zone is the same as before, increasing the layer thickness of the packed bed and the moving speed of the sintering pallet will increase the length of the sintering machine required to complete sintering. As the sintering time increases, the production rate does not increase.

 On the other hand, if the transition speed of the combustion zone is too high, the amount of heat required for sintering cannot be secured due to insufficient coke combustion, which may lead to deterioration in yield and quality. Therefore, it is important to secure the heat required for the sintering reaction and to increase the transition speed of the combustion melting zone in order to greatly increase the production rate of the sintering machine. Furthermore, in the raw material bed, since the ventilation resistance of the combustion zone is large, if the thickness of the combustion zone in the height direction of the raw material bed is minimized, the air permeability is improved and coke combustion is performed. By increasing the speed, the transition speed of the combustion melting zone can be increased. Thus, controlling the cooling rate of the cooling zone above the combustion zone and the transition speed of the combustion zone in a well-balanced manner is also important for greatly improving the production rate of the sintering machine.

 Generally, in order to increase the transition speed of the combustion melting zone, it is considered to increase the suction flow rate by increasing the negative pressure of the blower to increase the supply amount of oxygen to the raw material packed bed. .

 However, in order to prevent the yield of the upper layer of the raw material packed layer and the deterioration of the quality of the sintered ore, it is necessary to maintain the high temperature holding time of the upper layer of the raw material packed layer. The transition speed of the combustion and melting zone before the consolidation strand cannot be increased from the current level. In addition, due to the increase in the negative pressure of the blower, gravity and blowing pressure are superimposed, compressing the raw material packed bed and obstructing ventilation, and further increasing the amount of exhaust air and leakage. There is no significant increase in the negative pressure of the blower.

Meanwhile, in order to reduce the slag of the high pulverized coal ratio during operation of the blast furnace, but the production of low S i 0 ₂ sintered ore is sought, deterioration of production rate and RDI that manifested in this case, N 0 Problems such as an increase in X emissions were not solved. Therefore, the present invention is to reduce the thickness of the raw material packed layer and the moving speed of the sintered pallet. It is an object of the present invention to provide a method for producing a sintered ore, a method for producing a low SiO ₂ sintered ore, and a sintering machine used for these methods, which can greatly increase the productivity of the sintering machine by increasing it.

 The gist of the present invention that achieves the above objects is as follows.

 (1) A blended raw material containing raw material ore, a solvent and a fuel is charged on a sintering machine pallet to form a raw material packed bed, which is then ignited on the surface of the raw packed bed and lit from above. In the method of producing a sintered ore by performing a sintering reaction downward, the mass flow rate of the oxygen-containing gas to be supplied to the raw material packed bed is determined when the upper layer of the raw material packed bed is sufficiently fired. The sintering is performed by changing the mass flow rate of the oxygen-containing gas supplied in the range of sintering the upper layer to 1.0 to 2.6 times, and sintering. Concentration production method.

 (2) The raw material ore, the solvent, and the blended raw material containing the fuel are charged on the sintering pallet to form a raw material packed bed, and then the raw material packed bed surface is ignited and ignited from above to below. In the method of continuously producing sintered ore while shifting the combustion melting zone, the leading end of the formation range of the combustion melting zone reached below the position of 20% of the height of the raw material packed bed from the surface layer of the raw material packed bed At this point, the mass flow rate of the oxygen-containing gas supplied to the raw material packed bed was changed to 1.01 to 2.6 times the mass flow rate of the oxygen-containing gas supplied in the range where the raw material packed bed was fired. A sinter ore production method for obtaining a product having excellent product yield and quality characterized by sintering.

 (3) A pressurized hood for pressurizing an oxygen-containing gas is provided on the raw material packed bed on the sintered pallet, and the pressure in the pressurized hood is increased to 100 to 3000 mmAci with respect to the atmospheric pressure. (1) or suction from the lower part of the raw material packed bed at a pressure of 20001 mmAq with respect to atmospheric pressure.

The method for producing a sintered ore according to (2).

(4) On the raw material packed bed on the sintered pallet, in the pallet width direction A pressurized hood for supplying oxygen-containing gas under pressure within the range of 5 to 95% of the pressure is provided, and the inside of the pressurized hood is pressurized to 100 to 3000 dragon Aq against atmospheric pressure. The sinter production method according to any one of (1) to (3).

 (5) From the top to the bottom of the raw material packed bed, after the tip of the formation range of the combustion melting zone reaches below the position of 20% of the raw material packed bed height from the surface of the raw material packed bed. A pressure hood for pressurizing and supplying an oxygen-containing gas is provided on the raw material packed layer in the range, and the inside of the pressure hood is pressurized to 100 to 3000 mmAq with respect to the atmospheric pressure. 3) or the method for producing a sintered ore according to (4).

 (6) The firing method according to any one of (3) to (5), wherein the sintering exhaust gas is circulated through a pressurized hood that pressurizes and supplies an oxygen-containing gas provided on the raw material packed bed. Concentration production method.

 (7) Sintering is performed using a Dwight toroid type sintering machine provided with a plurality of plate-shaped sinter cake supporting stands on the grate of the sintering pallet substantially parallel to the pallet traveling direction. The method for producing a sintered ore according to any one of (1) to (6), characterized in that:

(8) sinter process according to any one of to manufacture sintered ore containing 3.9~ 4.9mass% of Si0 ₂ as chemical components from and wherein (1) (7).

 (9) The method for producing a sintered ore according to any one of (1) to (8), wherein the thickness of the material-filled layer is set to 600 to 1500 pixels.

(10) In a downward suction type sintering machine in which a plurality of wind boxes at the lower part of the sintering stand are connected in parallel to a suction duct, and a main blower is provided in the suction duct, It is necessary to additionally provide a blower that sucks from the duct within the range of 30% of the suction duct length from the ignition part to the mining part and the sintering completion point, and discharges it to the suction duct. Characterized sintering machine. (11) The suction duct, which is composed of a plurality of lead boxes connected in parallel at the lower part of the sintering strand, is connected to the sintering completion point at a strand length of 30% from the ignition section to the mining section. The sintering machine is characterized in that the sintering machine is divided into an area within the range and a remaining area, and each of them is provided with an independent blower.

 (12) The sintering machine according to (10) or (11), wherein a pressurized hood for supplying an oxygen-containing gas under pressure is provided on the raw material packed bed of the sintering pallet. .

 (13) From the top to the bottom of the raw material packed bed, the leading end of the formation range of the combustion melting zone reaches below the position of 20% of the height of the raw material packed bed from the surface layer of the raw material packed bed. The sintering machine according to (10) or (11), wherein a pressurized hood for pressurizing and supplying an oxygen-containing gas is provided on the raw material packed bed in the range after the above.

 (14) A pressurized hood for pressurizing and supplying an oxygen-containing gas within a range of 5 to 95% of the width of the pallet is provided on the raw material packed layer on the sintered pallet. And the sintering machine according to (12) or (13).

 (15) The sintering exhaust gas is circulated through a pressurized hood provided on the raw material packed layer and pressurized to supply an oxygen-containing gas, wherein (12) to (14). The sintering machine according to 1.

 (16) The sintering machine according to any one of (12) to (15), wherein a seal mechanism is provided at a lower end of the hood for supplying the oxygen-containing gas under pressure.

(17) The structure of the downward suction type sintering machine is characterized in that a plurality of plate-shaped sinter cake support stands are provided almost parallel to the pallet traveling direction on the sintering pallet. The sintering machine according to any one of (10) to (16). BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a view showing an embodiment of a sintering machine according to Examples la and 3a of the present invention.

 FIG. 2 is a view showing an embodiment of a sintering machine according to Embodiment 1b of the present invention.

 FIG. 3 is a diagram showing an embodiment of a sintering machine according to Examples lc to le and 3b of the present invention.

 FIG. 4 is a diagram showing an embodiment of a sintering machine according to Examples 2a to 2d and 3c of the present invention.

 FIG. 5 is a view showing another embodiment of the sintering machine of the present invention.

 FIG. 6 is a view showing a sealing mechanism of a pressurized hood of the sintering machine according to the present invention. FIG. 7 is a view showing a plate-shaped thin cake supporting stand of the sintering machine according to the present invention. is there.

 FIG. 8 (a) is an explanatory diagram showing the transition of the combustion melting zone in the pallet according to the present invention. FIG. 8 (b) is a sectional view taken along the line AA ′ of the combustion melting zone in the pallet according to the present invention. FIG. 8 (c) is an explanatory diagram showing the transition of the combustion melting zone at the time of cooling on the strand according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Generally, sinter ore is prepared by charging a blended raw material containing raw ore powder, a solvent and a fuel on a pallet of a Dwight toroid type sintering machine to form a raw material packed layer, and then igniting in an ignition section. In addition, the oxygen-containing gas is sucked from below and moved to the mining section to produce. Therefore, sintering is performed from the upper side to the lower side of the raw material packed layer. However, since it can be expressed in comparison with the strand length direction and is easy to understand, the following description uses the strand length. The present invention will be described. FIG. 8 (a) is an explanatory view showing one example of a raw material packed bed sintering process of the present invention. In this figure, I is the initial raw material zone, Π is the wet (condensed water) zone, m is the dry zone, w is the combustion zone, V is the melting zone, and VI is the sintering zone. No.

FIG. 8 (b) is a sectional view taken along the line AA ′ in the center of FIG. 8 (a). In addition, point B indicates a position closest to the ignition furnace where an initial combustion melting zone is formed in the present invention and the supply amount of the oxygen-containing gas in the raw material packed bed is changed and increased, and point C is the combustion completion point. Is shown. In normal operation, operation is performed so that the sintering completion point is constant in order to use the entire strand efficiently and stably produce. When the production volume is important, the sintering completion point should be as close as possible to the mining side, and when yield and quality are to be emphasized, allowance for one or two wind boxes should be provided. The sintering completion point should be kept close to the ignition furnace side to keep the sintering constant. However, when cooling on a strand, for example, as shown in Fig. 8 (c), the operation where the sintering completion point C 'is changed to the middle part of the strand Is performed. In this case, the supply amount of the oxygen-containing gas may be changed based on the layer thickness or the position in the strand length direction based on the present invention disclosed below. Further, in the following description, an example is shown in which the sintering completion point is located at a position where the strand length is 95% from the ignition portion. The blowing or suction pressure is shown as the pressure with respect to the atmospheric pressure.

The range of 30% or less of the strand length from the ignited part is almost equivalent to the firing area of the upper 20% of the raw material packed bed, and the yield and quality of the upper layer of the raw material packed bed are generally lower and middle. Inferior to. This is because the coke combustion rate, which gives the calorific value necessary for the calcination reaction, is not sufficient because it is just after ignition. In addition, it is due to the heat dissipated from the surface. Therefore, it is necessary to secure the amount of heat required for the sintering reaction. Increasing the amount is not preferable for reasons such as yield and quality deterioration.Therefore, in the present invention, the range of 30% or less of the strand length from the ignition portion, which is the firing area in the upper layer of the raw material packed layer, is less than the conventional range. With the same suction negative pressure as above, the high temperature holding time of the upper part of the raw material packed bed can be secured, so that the yield and quality of the upper part of the raw material packed bed can be secured. In order to positively improve the yield and the quality of the upper part, the calorific value of the part may be increased. For this purpose, it is preferable to lower the suction negative pressure at the site, to enhance the coke segregation at the upper part of the raw material packed layer, or to add a please to the surface layer. In addition, heat can be applied from the outside of the raw material packed layer. For example, hot air can be sucked into the portion, or induction heating by microwave or the like can be performed.

The range of 30 to 95% of the strand length from the ignition part corresponds to the firing area in the lower part of the raw material packed bed. The sintered zone in the upper part of the raw material packed bed has low air resistance. On the other hand, in the middle to lower layers of the raw material-filled layer, the thickness of the combustion-melting zone having a high airflow resistance increases, so that the airflow resistance increases. In particular, at a strand length of 50 to 95%, the air permeability deteriorates and the calorific value becomes excessive. The mass flow rate of the oxygen-containing gas is forcibly supplied from above to the combustion zone with a large pressure loss in the range from the middle to the lower part (within the range of 30 to 95% of the strand length from the ignition part). Is increased to 1.0 to 2.6 times the oxygen-containing gas supplied to the raw material bed in the range of the strand excluding the above range, the coke combustion rate in the middle to lower layers is increased, and the combustion melting zone is increased. In addition, the cooling speed of the cooling zone above the combustion melting zone is increased by increasing the cooling speed, and the calorie required for sintering is secured, and the thickness of the combustion melting zone is reduced and the air permeability is improved. in this way It is important to control the calorific value and air permeability depending on the temperature of the combustion melting zone and the thickness in the height direction of the raw material packed bed in order to improve the sintering production rate. In the present invention, the mass flow rate represents the mass of gas flowing per unit time, and the unit is expressed in kgZ s or the like. The generally used flow rate is a volume flow rate, which indicates the volume of gas flowing per unit time, and the unit is expressed in m ³ Z s or the like. For the same mass flow, the volume flow varies with temperature and pressure according to the equation of state of the gas.

 Further, the oxygen-containing gas in the present invention includes not only the atmosphere but also the exhaust gas discharged from the sintering machine and the exhaust gas from other processes, etc., as well as the mixed gas of the atmosphere and the exhaust gas and the oxygen-enriched gas. It also contains gas, and gas with an oxygen concentration of 12 to 40 vol% is preferred.

 Here, the mass flow rate of the oxygen-containing gas supplied to the raw material storage layer within the range of 30 to 95% of the length of the strand from the ignition part is set to the range of the raw material charge in the range of the strand excluding the above range. The reason why the mass flow rate of the oxygen-containing gas supplied to the 塡 layer is adjusted to 1.01 to 2.6 times is that when the mass flow rate is less than 1.01 times, the transition speed of the combustion melting zone hardly changes. If it is more than 6 times, the gas flow velocity will increase too much and the combustion melting zone will be supercooled, or the raw material packed bed will be compacted due to the increase in the differential pressure above and below the raw material packed bed, and the gas permeability will be impaired. In addition, the mass flow rate of the oxygen-containing gas sucked into the raw material packed bed within the range of 50 to 85% of the length of the strand from the ignition part is adjusted to the range of the raw material filled in the range of the strand excluding the above range. It is particularly preferable to adjust the mass flow rate of the oxygen-containing gas supplied to the bed to 1.1 to 1.8 times from the viewpoint of improving the productivity of sinter.

When the air is sucked into the atmosphere as an oxygen-containing gas to increase the transition speed of the combustion and melting zone, in order to achieve the above-mentioned mass flow rate, the length of the strand from the ignition part must be 30 to 95%. Thickness direction of raw material packed bed within the range Is preferably 1.1 to 5.0 times the pressure difference in the thickness direction of the raw material packed bed in the range of the strand excluding the above range. Here, in the range of the strand length of 30 to 95%, the ventilation resistance is about 1.5 to 5 times larger than that of the other range. Therefore, if the differential pressure is less than 1.1 times, the effect of promoting the transition speed of the combustion and melting zone by increasing the air flow rate is small, and if the differential pressure exceeds 5.0 times, the gas flow velocity becomes too large, and Since the speed is greatly increased, it becomes impossible to secure a high-temperature holding time, and the raw material packed layer is undesirably densified and the air permeability is deteriorated. Further, it is particularly preferable to increase the pressure difference to 1.2 to 2.0 times from the viewpoint of improving productivity. It is preferable that the gas supply is gradually increased from the ignition section to the ore removal section to make the transition speed of the combustion melting zone and the cooling speed close. If the supply rate is rapidly increased, the cooling rate will be faster than the coke burning rate for a short period of time, and some parts will not be able to maintain a sufficient amount of calcining heat. This is because the quality of the sinter is deteriorated.

 As described above, if the mass flow rate is increased by increasing the differential pressure of the raw material bed within the range of 30 to 95% of the strand length from the ignition part, the production rate of sinter As well as improving the yield, it is possible to obtain products with excellent yield and quality. If the pressure difference is increased and the gas supply is increased, the amount of exhaust gas discharged from this part also increases in tandem with this. However, since the firing reaction is active and the oxygen consumption efficiency is high, the oxygen consumption efficiency may be reduced. Just

In addition, the unit of airflow can be reduced by minimizing the supply of excess gas in the upper part and in the vicinity of the mining part.

The present inventors avoid the deterioration of air permeability caused by the consolidation of the raw material packed bed by increasing the mass flow rate of the oxygen-containing gas by combining the downward suction of the raw material packed bed and the pressurization from above. Then, the mass flow rate of the oxygen-containing gas to be supplied to the raw material packed bed within the range of 30 to 95% of the length of the strand from the ignition section is reduced to the range of the raw material in the range of the strand excluding the above range. Acid supplied to packed bed 1.01 to 2.6 times the mass flow rate of the element-containing gas, and more preferably, the differential pressure in the thickness direction of the raw material packed bed in the range of the strand excluding the above range By adjusting the pressure difference in the thickness direction of the packed bed to 1.1 to 5.0 times, the transfer speed of the combustion zone can be increased, and the product yield and quality can be improved. Was found.

 A pressurized hood is provided to cover the raw material packed bed loaded on the sintering pallet, the inside of the hood is pressurized, and oxygen-containing gas is blown from above to the raw material packed bed. In particular, the air is sucked and exhausted from the wind box just below the pallet, and the pressure difference between the upper part of the raw material packed bed and the lower part of the raw material packed bed is controlled. Let the gas flow. Thus, in the present invention, the static pressure in the raw material packed bed is higher than the static pressure in the raw material packed bed formed by suctioning the raw material packed bed from below at atmospheric pressure. Can be increased. If the pressure difference between the upper and lower portions of the raw material packed bed is the same as that of the conventional method of sucking the atmosphere, the present invention can increase the mass flow rate to be supplied into the raw material packed bed compared to the conventional method. Gas density can be made higher than before. As a result, the supply amount of the oxygen-containing gas into the raw material packed bed increases, the coke burning rate in the raw material packed bed increases, the calorific value of the combustion zone increases, and the transition speed increases. To increase the cooling zone transition speed. If the static pressure in the raw material packed bed increases, the heat transfer rate between the gas and the solid also increases, which can promote the transition of the combustion melting zone and the cooling of the cooling zone.

In addition, in the case of forced air blowing from above, gas can be supplied to the combustion melting zone where a reaction has occurred by forming a uniform gas flow through the sintered zone having low airflow resistance. On the other hand, when gas is supplied by suction from below, gas is subjected to relatively high ventilation resistance in the wet zone with relatively high ventilation resistance and the combustion and melting zone in which the calcination reaction is occurring. Flow, forming an uneven gas flow This is a state in which the reaction efficiency between the body and the solid tends to deteriorate. Therefore, the gas flow pushed in from above forms a more uniform gas flow than the gas flow sucked from below, so that the oxygen consumption efficiency is improved and the unit air volume required for sinter production can be reduced. .

 In addition, increasing the pressure difference of the raw material bed within the range of 30 to 95% of the strand length will have the effect of increasing the mass flow rate by increasing the pressure difference and the effect of increasing the static pressure level. The productivity improvement effect will be very large.

 In order to increase the mass flow rate and the static pressure level in the raw material packed bed compared to the conventional method, the pressure hood provided above the raw material packed bed must be 100 to 3000 mm.

Pressurize in the range of Aq, and supply gas at -2000 1 mmAq from below the raw material packed bed. If the pressure above the raw material bed is less than 100 Aq, the productivity will not change much compared to the conventional operation. If the pressure above the raw material bed exceeds 3000 mmAq, the raw material will be charged. This is preferable because the pressure difference between the top and bottom of the layer becomes too large, and the force of compressing the raw material bed increases due to the superposition of gravity and the blowing pressure, and the raw material packed layer becomes more compact and the air permeability deteriorates. Absent. In addition, as the pressure is increased, air leakage from the hood to the object in contact with the hood increases, making sealing difficult and requiring large-scale equipment. Happens. The suction negative pressure of the wind box just below the pallet is set in the range of 12000 to 1 mmAq, due to the setting of the differential pressure pattern above and below the raw material packed bed. If the pressure is less than 2000 mmAq, the static pressure level in the raw material bed will not be much higher than in the conventional method even if the upper part of the raw material bed is pressurized. The increase in heat transfer rate due to an increase in gas density is small. If it exceeds 1 nunAq, the exhaust gas cannot be sucked.The upper and lower sides of the raw material packed bed within the range of 30 to 95% of the strand length from the ignition part It is preferable that the pressure difference be between 1,000 and 3000 mmAq, which depends on the layer thickness and the pallet speed. When the pressure difference between the upper and lower parts of the raw material bed is less than 1 000 Aq, the pressure difference in the raw material bed is smaller than in the conventional method, and the gas flow rate is lower than the effect of increasing the static pressure. This is because the adverse effects increase. It is preferable to make the pressure difference in the raw material bed more than 3000 mmAq because the gravity and the blast pressure are superimposed to compress the raw material bed, so that the raw material bed becomes denser and the air permeability deteriorates. Not good.

By providing a pressurized hood that is divided into multiple parts in the length direction of the strand in the entire range from the ignition section to the mining section, the strand length is within the range of 30 to 95% from the ignition section. The mass flow rate of the oxygen-containing gas sucked into the raw material bed in the above-mentioned range is 1.01 to 1.01 with respect to the mass flow rate of the oxygen-containing gas supplied to the raw material bed in the range of the strand excluding the above range. 2. The pressure difference in the layer thickness direction of the raw material packed bed is increased by a factor of 6 with respect to the pressure difference in the layer thickness direction of the raw material packed bed in the strand range excluding the above range. It can be easily adjusted by a factor of 0. As described above, in the range of the strand length of 30% from the ignition part, it is necessary to maintain the high-temperature holding time in order to prevent the yield of the upper part of the raw material layer and the deterioration of sinter quality. In the firing of the upper layer, the transition speed of the combustion zone cannot be increased from the current level. In the case of the conventional layer thickness of 400 to 600 mm, the area with a strand length of 30% or less from the ignition part is blown from the upper part of the raw material packed bed with 100 to 100 mmAq under pressure and directly below the pallet. The negative suction pressure for suction and exhaust from the wind box force is set to 11,000 to 11 mmAq, and the differential pressure between the upper and lower parts of the raw material bed is adjusted to 300 to 2,000 nnnAq to obtain the differential pressure of the conventional downward suction. If the pressure difference is the same or a small pressure difference, the high-temperature holding time can be secured or increased, and the calorific value required for firing can be obtained. At this time, the oxygen supply rate of the upper layer of the raw material packed bed is increased, so that the same effect of improving coke combustibility as oxygen enrichment can be obtained, and the yield and quality of the upper layer of the raw material packed bed can be improved. You can do more. However, since the effect of increasing the production rate by the normal downward suction is relatively small except for the raw material packed bed with a strand length within the range of 30 to 95%, the pressurized feed is moved from the ignition section to the It is preferable to set the length within a range of 30 to 95% in terms of simplification of equipment. Furthermore, if the pressurized hood is divided into a plurality of pieces in the length direction of the strand, the mass flow rate can be changed stepwise from the igniting section to the mining section.

 Furthermore, the transition speed of the combustion melting zone is high because the vicinity of the side wall within 5% in the pallet width direction from the pallet side wall of the raw material packed layer has less airflow resistance than the center part. For this reason, if a pressure hood is provided within the range of 5 to 95% of the width of the raw material packed bed and gas is supplied so that the transition speed of the combustion melting zone becomes uniform in the width direction, the combustion melting zone The effect of increasing the transition speed is even greater.

 The pressure hood is installed above the moving sintering pallet. It is preferable to provide a seal mechanism at the lower end of the pressure hood to avoid air leakage. As shown in FIG. 6, the sealing mechanism is such that the sheet 24 provided at the lower end of the hood is pressed against the upper surface of the raw material-filled layer 7 by the internal pressure of the pressurizing hood 19 to seal, A structure in which the pallet is slid on the raw material packed layer 7 as it moves is preferable. In addition, a structure having several stages of sealing mechanisms 23, a structure in which air is blown from the outside of the pressure hood 19 between the pressure hood 19 and the raw material packed layer 7, a side wall of the pallet 6, and the like are provided. It is also possible to provide a sealing mechanism by utilizing it, and it is not limited to these examples.

The oxygen concentration should be between 12 and 21 in the pressurized hood in the range of 30-95% of the strand length from the igniter, and particularly preferably in the range of 60-80% of the strand length. Supplying a gas adjusted to less than vol% promotes the generation of magnetite that improves RD1 and suppresses the oxidation of nitrogen in coke to NOx, improving RDI and reducing NOx. It is effective in controlling the occurrence You. To adjust the oxygen concentration in the pressurized hood to less than 12 to 21 vol%, part of the exhaust gas from the sintering machine can be recycled. In this case, the capacity of the blower for exhaust gas circulation is designed by taking into account the suction negative pressure, the air flow, and the size of the equipment so that the air flow from the upper part of the raw material packed bed can be sent to the exhaust gas treatment equipment.

 When the oxygen concentration is less than 21 vol%, RD! Is improved by promoting the generation of magnetite, and when the oxygen concentration is low, the oxidation of nitrogen in the coke to NOx is suppressed. If it is less than 10%, the adverse effect of the decrease in productivity becomes remarkable. Therefore, the oxygen concentration is preferably 12 vol% or more and less than 21 vol%. In particular, when the oxygen concentration is less than 18 vol%, the effects of improving RDI and suppressing NOx generation become more remarkable.

During sintering using a sintering machine described in JP-A-4-1168234, in which a plurality of plate-shaped sinter cake supporting stands are installed in the width direction parallel to the pallet traveling direction, the sintering is performed. By supporting one cake, the load of the sinter cake is not applied to the lower part of the raw material bed, and the air permeability of the lower part of the raw material bed is improved, and the production rate is greatly improved. I do. Furthermore, as the load on the sinter cake is reduced, the pressure difference between the upper and lower layers of the raw material bed can be increased, and the production rate can be further improved. Fig. 7 shows an example of the Sinter Cake support stand. The optimal number of plate-shaped sinter cake support stands 21 depends on the size of the pallet 6, for example, a 4 m wide and 2 m long pallet. At the conclusion, it is 2 to 10 sheets and the height is preferably 200 to 400. The more the number of sinter cake support stands, the more the sinter cake support effect can be exhibited. However, if the number of sheets exceeds 10, the volume occupied by the sinter cake support stand will increase, and conversely, the adverse effect on the production rate will begin to appear, and the production rate will begin to decline. If the sinter cake is supported by the sinter cake support stand, breathability is improved. Furthermore, the amount of CO generated increases due to the increased coke combustion rate, and the reaction to reduce the generated NO with CO gas becomes more active, thereby suppressing the generation of NOx. . As described above, by installing a plurality of sinter cake support stands in the present invention, it is possible to suppress the generation of NOx, which was difficult to achieve at the same time, to improve the production rate, improve the product yield, and improve the sinter quality. Can be realized simultaneously.

The present invention is of particularly useful for the production of low Si0 ₂ sinter containing Si0 ₂ 3.9~ 4.9mass% is, Si0 ₂ is a call want underlying limestone blending ratio becomes below 4.9Mass% and a CaO Si0 ₂ of the influence of the reduction of slag main component begin to remarkable deterioration of the production rate and RD1, because can not improve the production rate and RD! exacerbated also by the present invention and is less than 3.9mass%.

 According to the present invention, the mass flow rate of the oxygen-containing gas sucked into the raw material packed bed within the range of 30 to 95% of the length of the strand from the ignition section in the strand from the ignition section to the mining section Can be increased up to 2.6 times the mass flow rate of the oxygen-containing gas sucked into the raw material packed bed in the range of the strand excluding the above range, so that the conventional layer thickness of 400 to 600 mm can be obtained. In the sintering operation, the moving speed of the sintering pallet can be increased 2.0 times or more compared to the conventional method. In addition, the thickness of the material-filled bed can be as large as 600 to 1500 mm, which is more than twice the conventional thickness, thereby increasing the production rate of the sintering machine up to 2.0 times the conventional sintering production rate. It has the tremendous effect of improving the production rate as well as improving the product yield and quality, and reducing the basic unit of exhaust gas flow rate. In addition, the production rate can be kept constant, and the product yield and sinter quality can be improved, and the exhaust gas flow rate can be reduced.

Further, as the suction negative pressure sucked from below the raw material packed bed is reduced, the inflow of outside air from the sliding portion between the pallet and the wind box can be reduced. Therefore, the effective air volume for firing increases, and Because of the reduction, productivity can be further improved and the unit air volume can be reduced. As a sintering machine used in the method for producing a sintered ore of the present invention, a plurality of wind boxes at the lower part of a sintering strand are connected in parallel to a suction duct, and In addition to the conventional structure with a blower, a blower is added, and suction is performed from any point within the range of 30 to 95% of the suction duct length from the ignition section to the mining section, and the suction duct is used. The mass flow rate of the oxygen-containing gas supplied to the raw material packed bed within the range of 30 to 95% of the length of the strand from the ignition part is reduced by the range of the strand excluding the above range. 1.0 to 2.6 times the mass flow rate of the oxygen-containing gas to be sucked into the raw material bed, and the pressure difference in the thickness direction of the raw material bed except for the above range It can be adjusted to 1.1 to 5.0 times the pressure difference in the thickness direction of the raw material packed bed in the range of the command.

 Furthermore, the suction duct is divided into a range of 30 to 95% of the length of the strand from the ignition part and the remaining range, and the structure in which the blowers are installed independently is the mass flow rate and the differential pressure. It is preferable in terms of adjusting the position. Although three blowers may be provided for the front, middle and rear stages of the strand, the front and rear stages do not need to change the differential pressure, so the front and rear stages are connected to each other, and the strand length is 30 It is preferable to use two aircraft for the middle stage within the range of ~ 95% and for the other range.

 When combined with pressurization from above, a hood is provided on the raw material bed to be pressurized, and the inside of the hood is pressurized and the pressure in the hood and the pressure in the window box below It is preferable to measure Further, it is desirable to provide a seal structure between the hood and the raw material packed bed and between the hood or the hood and the pallet. Example

The present invention will be described in more detail with reference to Examples 1, 2, and 3. Sintering area 500 meters ² in the sintering pallet width 5 m actual sintering machine was modified part respectively, were run of one level for 7 days.

 Example 1

 1 to 3 are views showing an embodiment of the sintering machine of the present invention. The sintering blended raw material 1 is continuously supplied from the surge hopper 2 to the pallet 6 via the drum feeder 3 and the raw material charging device 5, and is layered on the pallet 6 as a raw material filling layer 7. It is laminated. During this time, the sprocket 4 on the raw material supply side is rotated to move the pallet 6 at a predetermined speed, and at the same time, a plurality of wind boxes 8 and a main box provided below the pallet 6 are provided. 9, Intake by the blower 11 through the exhaust gas dust collector 10 and exhaust from the chimney 12. Further, a sub duct 13 is connected to a part of the main duct 9, and the sub duct 13 is taken in by a blower 15 through an exhaust gas dust collector 14, and the exhaust gas is returned to the main duct 9. Exhaust gas taken in by the probe 15 can also be discharged from the chimney 12. Further, it is desirable that the main body 9 be provided with a damper 16 for adjusting the negative pressure in the duct.

 The ignition furnace 27 ignites the upper surface of the raw material packed bed 7 and controls the speed so that the raw material packed bed 7 on the pallet 6 completes the sintering reaction over the whole bed while reaching the mining section. Continuous operation is performed. Exhaust gas can be circulated to the pressurized hood 19 by the blower 18 from the front of the chimney 12, and air can be mixed at the same time. When pressurizing the inside of the pressurized hood 19, a seal mechanism 23 as shown in FIG. 6 is provided between the surface layer portion of the raw material packed bed and the lower end of the hood. Maintain internal pressure. The length in the pallet traveling direction and the length in the pallet width direction can be set freely. Further, in this apparatus, the thickness of the raw material-filled layer 7 can be 600 to 1500 mm, which makes it possible to make the raw material-filled layer 7 thicker than before.

Blending raw materials, without particular for the manufacture of a low Si0 ₂ sinter, one conventional As a general formulation, various iron ore and limestone, quicklime, serpentinite, miscellaneous raw materials such as scale, return ores, Si0 ₂ is 5.8Mass% in sinter coke breeze, A 1 ₂ 0 ₃ Was adjusted to 1.8 mass%, and the basicity was adjusted to 1.7. The return ratio was set at 15% based on the total of 100 new materials, and the coke ratio was set at 4.2% based on the total of 100 new materials. The same formulation was used for both the comparative example and the example.

 After returning ore and fine coke to the raw materials, water was added, mixed with a mixer, granulated, and charged into a sintering machine. In the operation, the pallet speed was adjusted so that the sintering completion point was immediately before the mining section.

 In Example 1a, the layer thickness was 550 hidden, the length of the strand from the ignition section was 30%, and the length from the strand length of 95% to the mining section was 1500 mmAq. The air was sucked downward at a pressure of 2500 mmAq between 30 and 95%, and the upper part of the raw material packed bed was opened to the atmosphere. In this case, the mass flow ratio was 1.26 and the differential pressure in the layer thickness direction was 2500 Aq in the other range within the range of the strand length of 30 to 95%.

 In Example 1b, the layer thickness was 550 mm, the area from the ignition section to the mining section was suctioned downward at -1000 mmAq, and the pressurized hood on the upper portion of the raw material packed bed having a strand length of 30 to 95% was drawn. The inside was pressurized to 1500 mmAq. In this case, the mass flow ratio was 1.27 and the differential pressure in the layer thickness direction was 2500 mmAq in the range of the strand length of 50 to 95% with respect to the other range.

In Example 1c, the layer thickness was 550 mm, the length from the ignition section was 30% of the strand length, and the section from the 95% strand length to the mining section was suctioned downward at -500 mmAq. In this range, the pressure hood is further continued and the pressure in the pressure hood is increased to 500 Aq. At the same time, the pressure in the pressure hood was increased to 2000 mniAq. In this case, the mass flow ratio is 1.77 and the pressure difference in the layer thickness direction is 3000 when the strand length is within the range of 30 to 95%. Aq.

 In Example 1d, the layer thickness was 550 nim, the area from the ignition section to the mining section was suctioned downward at a rate of 1000 mniAq, and a pallet width direction of 50 to 90% strand length 1 () to 90% Exhaust gas before the chimney was circulated in the pressure hood provided in the range, and the oxygen concentration was adjusted to 18 vol% and pressurized to 1500 mmAq. In this case, the mass flow rate ratio was 1.27 and the differential pressure in the thickness direction was 2500 dragon Aq in the range of 50 to 90% of the strand length.

 In Example 1e, four layers of plate-shaped skeleton supporters were installed evenly in the pallet width direction in parallel on the pallet with a layer thickness of 550 mm, and the distance from the ignition part to the mining part was -1000. Suction was performed using Aq, and the inside of a pressure hood provided in the range of 10 to 90% in the pallet width direction with a strand length of 5 () to 90% was pressurized to 1500 mmAq. In this case, the mass flow ratio was 1.27 and the differential pressure in the thickness direction was 2500 face Aq in the range of 50 to 90% of the strand length.

 In Example 1f, the layer thickness was 800ππη, and other settings were the same as in Example 1e. In this case, the mass flow ratio was 1.27 and the differential pressure in the layer thickness direction was 2500 mmAq in the range of the strand length of 50 to 90% with respect to the other range.

 In the comparative example, the same compounding material as in the example was sintered by the conventional method in which the atmosphere was sucked from the ignition section to the mining section at a constant layer thickness of 550 and a negative pressure of 1500 minAq. did.

Table 1 shows the production rates, product yields, RD1, and NOx emissions per unit of the sintered ore obtained in Comparative Example 1 and Examples 1a to 1f. Here, the basic unit of NOx emission is represented by the product of the exhaust gas flow rate and the NOx concentration in the exhaust gas. As can be seen from Table 1, in Examples 1a to 1f, the production rate was significantly improved as compared with the comparative example. Further, conventionally, when the production rate is improved, the product yield tends to decrease, but in the present invention, the product yield is improved. In addition, the RD1, J1S-RKJIS standard (final reduction rate) and the basic unit of NOx emission were also improved, and excellent operational and environmental effects were achieved.

 Table 1

 Example 2

 FIGS. 4 and 5 show another embodiment of the sintering machine of the present invention. The difference from the embodiment shown in FIGS. 1 and 3 is that the main duct 9 is completely removed. It is divided into independent blowers 11 and 15. In addition, a blower 29 can be provided. When setting a plurality of pressure patterns in the direction of the strand length, a plurality of blowers may be provided in this manner.

 The blending raw materials were the same as in Example 1, and the operation was adjusted for the pallet speed so that the sintering completion point was in the mining part.

In Example 2a, the layer thickness was 550ππη, the length from the ignition part to the strand length of 50% was 1 lOOmmAq, and the distance from the ignition part to the strand length of 80% to the tailing part was 1500mmAq, and was lower at 1500mmAq. Suction is performed to open the upper part of the raw material packed bed to the atmosphere, and the lower part of the strand length of 50 to 80% is suctioned at -500 mmAq, and the pressure in the pressurized hood is set to 2000 mmAq. Pressed. In this case, if the strand length is within the range of 50 to 80%, the mass flow rate is The ratio was 1.52, and the differential pressure in the thickness direction was 2500 mmAq.

 In Example 2b, the layer thickness was 550 mm, the length from the ignition section to 50% of the strand length was suctioned downward at 1 500 mmAq, and a pressure hood was further provided in this range. The pressure in the pressurized hood was set to 500 mmAq, the pressure from the strand length of 80% to the mining part was reduced by 1000 Aq, and the pressure in the hood was set to 500 mmAq. Downward suction was performed at 1500 mmAq between strand lengths of 50-80%, and the pressure in the pressure hood was increased to 100 mmAq. In this case, the mass flow ratio was 1.56 and the pressure difference in the thickness direction was 2500 mm Aq in the range of 50 to 80% of the strand length.

In Example 2c, the layer thickness was 800 mm, and other settings were the same as in Example 2a. In this case, the mass flow ratio was 1.52 and the differential pressure in the layer thickness direction was 2500 mmAq in the range of 50 to 80% of the strand length _c.

 In Example 2d, the layer thickness was set to 800, and four plate-like sinter cake support stands were installed on the pallet evenly in the width direction of the pallet. Same as a. In this case, the mass flow ratio was 1.52 and the differential pressure in the layer thickness direction was 2500 mmAq in the range of the strand length of 50 to 80%, compared to the other range.

 In Comparative Example 1, the same blended raw material as in Examples 2a to 2d was suctioned from the ignition section to the mining section at a layer thickness of 550ππη and a negative pressure of 1500 Aq, and the inside of the blended raw material layer was baked at a negative pressure. Sintered by conventional methods.

Table 2 shows the production rate, product yield, RDI, and NOx emission rate of the sintered ore obtained in Comparative Example 1 and Examples 2a to 2d. As can be seen from Table 2, the production rates of Examples 2a to 2d were remarkably improved as compared with the comparative examples. Further, conventionally, when the production rate is improved, the product yield tends to decrease, but in the present invention, the product yield is also improved. In addition, RD and JI The unit emissions of S-RI and NOx have also been improved, and excellent operational and environmental benefits have been achieved.

 The following table is a continuation of Table 2 together with a comparison with the above-mentioned known technique in Japanese Patent Publication No. 5-55574. From this table, it can be seen that Example 2d of the present invention has extremely excellent characteristics as the characteristics of the sintered ore that surpasses the values of the known technology.

 Table 2

 (Continued from Table 2)

実施例 3

Example 3

The same sintering machine as in Examples 1 and 2 was used. Blending raw materials intended for the manufacture of low S i 0 ₂ sinter, various iron ore and limestone, quicklime , Serpentine, miscellaneous raw materials such as scale, return ores, Si 0 ₂ is 4.6Mass% in sinter coke breeze, Al ₂ 0 ₃ was adjusted to be 1.85Mass%, basicity becomes 1.9 Was blended as follows. The ratio of returned ore is fixed at 15% based on the total of 100 new materials, and the ratio of coke is fixed at 3.5% with respect to the total of 100 new materials. The same formulation was used for both the comparative example and the example.

 In Example 3a, a layer thickness of 550 mni, a stroke length of 60% from the ignition part, and a stroke length of 80% from the strand length to the mining part were suctioned downward at −1500 mmAq. The air was suctioned by suctioning downward at 1,500 mm (1) between the strand lengths of 60-80%. In this case, if the strand length was within the range of 60-80%, The mass flow ratio was 1.26 and the pressure difference in the thickness direction was 2500 Aq.

 In Example 3b, the thickness of the layer was 550 mm, the initial firing period from the ignition portion to the strand length of 60%, and the final firing period from the strand length of 80% to the mining portion was-1500 mmAq. Aspirate downward, and part of the exhaust gas in that range is mixed with air and circulated to the upper part of the pallet with a strand length of 60 to 80% to an oxygen concentration of 16 vol%, and circulated downward at 2500 mmAq. Aspirated. In this case, the mass flow ratio was 1.38 within the range of the strand length of 60 to 80% and the pressure difference in the thickness direction was 2500 mmAq.

 In Example 3c, the layer thickness was 550 mm, the strand length from the ignition section was 60%, and the strand length from 80% to the mining section was suctioned downward at -500 mmAq. A pressure hood is further provided in the pressure hood, the pressure in the pressure hood is set to 500 mmAq, and a pressure of 1500 mmAq is drawn downward between a strand length of 60 to 80% and pressurized. With the pressure inside the hood at 100 mmAq, a part of the exhaust gas before the chimney was blown under pressure with the oxygen concentration adjusted to 16%. In this case, the mass flow ratio was 1.56 and the differential pressure in the thickness direction was 2500 mmAq in the range of the strand length of 60 to 80% with respect to the other range.

In Comparative Example 2, the same compounding raw material as in Examples 3a to 3c was used with a layer thickness of 550ιππι and a negative The atmosphere was sucked from the ignition section to the mining section at a constant pressure of 1500 imnAq, and the inside of the mixed material layer was sintered by a conventional method of sintering at a negative pressure.

Table 3 shows the production rates, product yields, RD1 and NOx emission basic units of the sintered ore obtained in Comparative Example and Examples 3a to 3c. As can be seen from Table 3, in Examples 3a to 3c, the production rate was significantly improved as compared with the comparative example. Further, conventionally, when the production rate is improved, the product yield tends to decrease, but in the present invention, the product yield is also improved. Et al is, RDI, JIS-RI and NOx emissions per unit is also improved, as well as an excellent effect in operation plane and environmental, it could manufacture a low Si0 ₂ sinter.

 Table 3

なお、 焼結時の負圧の設定や吸引ガスの酸素濃度と吸引時間は上 記実施例に限るものではなく、 生産性指向や RDI、 J1S- RI改善指向 、 NOx排出抑制指向、 排ガス量抑制指向で変化させることができる o

The setting of the negative pressure during sintering, the oxygen concentration of the suction gas, and the suction time are not limited to those in the above-described embodiment.Productivity orientation, RDI, J1S-RI improvement orientation, NOx emission reduction orientation, exhaust gas volume reduction Can be changed by pointing o

 ADVANTAGE OF THE INVENTION According to this invention, the layer thickness of the compounding material packed bed which had been difficult conventionally can be increased greatly, and the pallet moving speed can be increased, and the production rate of the sintering machine can be greatly improved. In addition, the product yield and RD for JIS-RI are improved, and the amount of exhaust gas is reduced. As described above, the present invention simultaneously provides an incompatible improvement effect, and the effect is extremely large.

Claims

The scope of the claims 1. A mixed raw material containing raw material ore, solvent and fuel is charged on a sintering machine pallet to form a raw material packed bed, and then the surface of the raw material packed bed is ignited and fired from above to below. In the method of producing a sintered ore by a sintering reaction, the mass flow rate of the oxygen-containing gas to be supplied to the raw material packed bed is increased when the upper layer of the raw material packed bed is sufficiently fired. Ore to obtain a product with excellent product yield and quality, characterized by changing the mass flow rate of oxygen-containing gas supplied in the range of sintering to 1.0 to 2.6 times the mass flow rate. Production method.  2. After loading the raw material ore, solvent and fuel on the pallet of the sintering machine to form a raw material packed bed, ignite the surface of the raw material packed bed and burn down from above. In the method of continuously producing sinter while shifting the molten zone, the end of the formation range of the combustion molten zone reaches below the position of 20% of the height of the raw material bed from the surface of the raw material bed. At this point, the mass flow rate of the oxygen-containing gas supplied to the raw material packed bed is increased to 1.01 to 2.6 times the mass flow rate of the oxygen-containing gas supplied in the range where the raw material packed bed is baked. A sinter ore production method for obtaining a product with excellent product yield and quality characterized by changing and sintering.  3. A pressurized hood for pressurizing and supplying an oxygen-containing gas is provided on the raw material packed bed on the sintered pallet, and the inside of the pressurized hood is pressurized to 100 to 3000 mmAq with respect to the atmospheric pressure. 3. The method for producing a sintered ore according to claim 1, wherein suction is performed at a pressure of −2000 1 mmAq from below the raw material packed bed with respect to atmospheric pressure. 4. A pressure hood for supplying an oxygen-containing gas under pressure in a range of 5 to 95% in a pallet width direction is provided on the raw material packed layer on the sintering pallet; Pressure to 100 to 3000 mmA q with respect to atmospheric pressure The method for producing a sintered ore according to any one of claims 1 to 3, characterized in that:  5. After the top of the formation zone of the combustion melting zone has reached below the position of 20% of the height of the raw material bed from the surface layer of the raw material bed, from above to below the raw material bed. A pressurized hood for supplying an oxygen-containing gas under pressure is provided on the raw material packed bed in the range of The method for producing a sintered ore according to claim 3 or 4, wherein the pressure is increased to 00 to 3000 Aq.  6. The sintered ore according to any one of claims 3 to 5, wherein the sintering exhaust gas is circulated through a pressurized hood provided on the raw material packed bed and supplied with pressure of an oxygen-containing gas. Production method.  7. Sintering is performed using a Dwy Troid type sintering machine that has a plurality of plate-shaped sinter-cake supporting stands provided almost parallel to the pallet on the sintering palette in the direction of travel of the pallet. The method for producing a sintered ore according to any one of claims 1 to 6, wherein the method comprises: 8. chemical components 3. 9 4. sinter produced according to any one of claim 1, wherein, wherein 7 to produce a sintered ore containing 9 mA ss% of S i 0 ₂ Method.  9. The method for producing a sintered ore according to any one of claims 1 to 8, wherein the thickness of the raw material-filled layer is 600 to 1500 MI.  10. A plurality of wind boxes at the lower part of the sintering stand are connected in parallel to the suction duct, and in the downward suction type sintering machine provided with a main blower in the suction duct, the air is discharged from the ignition part. The sintering is characterized by further providing a blower for sucking from the duct within the range of 30% of the suction duct length to the ore part and the sintering completion point, and discharging to the suction duct. Machine. 1 1. The suction duct, in which several wind boxes at the bottom of the sintering strand are connected in parallel, is used to reduce the length of the strand from the ignition section to the mining section by 30%. A sintering machine characterized in that the sintering machine is divided into a range within a sintering completion point and a remaining range, and a blower is provided independently for each.  12. The sintering method according to claim 10, wherein a pressure hood for pressurizing and supplying an oxygen-containing gas is provided on the raw material packed bed of the sintering pallet. Machine.  13. After the top of the formation zone of the combustion melting zone has reached below the position of 20% of the height of the raw material bed from the surface layer of the raw material bed, from above to below the raw material bed 12. The sintering machine according to claim 10, wherein a pressurized hood for pressurizing and supplying an oxygen-containing gas is provided on the raw material packed bed in the range described above.  14. A pressure hood for pressurizing and supplying an oxygen-containing gas within a range of 5 to 95% of the pallet width direction is provided on the raw material layer on the sintered pallet. The sintering machine according to claim 12 or 13, wherein  15. The sintering method according to any one of claims 12 to 14, wherein the sintering exhaust gas is circulated through a pressurized hood provided on the raw material packed bed and supplied with pressure of an oxygen-containing gas. Machine.  16. The sintering machine according to any one of claims 12 to 15, wherein a sealing mechanism is provided at a lower end of the hood for supplying the oxygen-containing gas under pressure.  17. The structure of the downward suction type sintering machine is characterized in that a plurality of plate-shaped sinter cake supporting stands are provided almost parallel to the pallet traveling direction on the sintering pallet grid. The sintering machine according to any one of claims 10 to 16.