JP2022039966A - Manufacturing method of sintered ore and production apparatus of sintered ore - Google Patents

Abstract

[Problem] Improving the permeability of the sintering raw material charging layer in a sintering factory and sintering of sintered ore without depending on particle size or component conditions or requiring advanced operational management. To propose a method and equipment for manufacturing sintered ore with excellent productivity by improving speed. [Solution] A blending step of blending an iron-containing raw material, an auxiliary raw material, and a coagulant to form a blended raw material, and a charging raw material that is mainly composed of a granulated and sintered raw material by granulating the blended raw material in a granulator. a granulation step in which the charged raw material is charged into a sintering machine and ignited; and a sintering step in which the charged raw material is sintered to produce sintered ore after the ignition step. In the method of manufacturing sintered ore through the steps of: the granulation step and the ignition step, a temperature measurement step of measuring the temperature of the charged raw material; and heating the charged raw material with a heating device. A heating step is provided, and the charging material is heated by the heating device based on the temperature of the charging material measured in the temperature measuring step. [Selection diagram] Figure 1

Description

The present invention relates to a method for producing sinter and a facility for producing sinter, in which a granulation raw material for sintering obtained by granulating a sinter compounding raw material is sintered by a sinter machine.

In the steelmaking process, sinter is used as a raw material to be charged into the blast furnace. The amount of sinter ore used tends to increase due to recent changes in raw material conditions. The sinter is generally produced using a dwightroid type sinter (hereinafter, simply referred to as "sinter") or the like. It is known that the production amount of the sinter is greatly affected by the air permeability of the sinter raw material charging layer (sinter bed) charged in the sinter machine. This is because poor air permeability of the sintered raw material charging layer causes a decrease in the amount of air passing through the sintered raw material charging layer, resulting in a decrease in the firing rate of the sintered raw material. This will lead to a decrease in sinter production.

As a technique for improving the air permeability of the sintering raw material charging layer charged on the pallet of the sintering machine, the methods described in Patent Documents 1-3 below are known.

Japanese Unexamined Patent Publication No. 2007-169780 JP-A-2019-123919 International Publication No. 2019/16788

In the methods described in Patent Document 1 and Patent Document 2, a sintered raw material for sintering, which is produced by granulating a sintered compound raw material with a granulator, is charged with the sintered raw material through water adjustment and preheating. It is a technology to improve the air permeability of the layer and suppress the wet zone area to improve the sinter production and the strength. However, the effect can be enjoyed only under these specific particle sizes and binder components described in Patent Document 1 and Patent Document 2, and it cannot cope with the granulation of other sintered compound raw materials. There was a case.

Further, the method described in Patent Document 3 is a proposal for a granulation raw material for sintering manufactured by heating and humidifying with steam, and has an action of reducing the wet zone in the layer in which the sintering raw material is charged by the amount of humidification. There is a risk that it will be diminished, and there is a problem that the sintering operation becomes difficult.

Therefore, an object of the present invention is to improve the air permeability of the sintering raw material charging layer in the sintering factory, regardless of the condition of the particle size and the condition of the component, and without the need for advanced operation control, and to perform firing. The purpose of the present invention is to propose a method and a manufacturing facility for producing a sinter having excellent productivity by improving the firing speed of the ore.

As a result of diligent research to solve the above-mentioned problems of the prior art and to realize the above-mentioned object, the inventors have developed the present invention described below. That is, the present invention basically comprises a blending step of blending an iron-containing raw material, an auxiliary raw material and a coagulant to obtain a blended raw material, and granulating the blended raw material with a granulator to obtain a granulated sintered raw material. After the granulation step of obtaining the main charged raw material, the ignition step of charging the charged raw material into a sintering machine and igniting, and the ignition step, the charged raw material is sintered and sintered ore. In the method of manufacturing the sintered ore through the sintering step of manufacturing, the temperature measuring step of measuring the temperature of the charged raw material and the charged raw material are performed between the granulation step and the ignition step. A sintering step is provided in which heating is performed by the heating device, and the charged raw material is heated by the heating device based on the temperature of the charged raw material measured in the temperature measuring step. It is a method of manufacturing ore.

Further, in the method for producing the sinter according to the present invention,
(1) In the heating step, heating is performed so as to maintain the temperature of the charged raw material within a predetermined range.
(2) Omitting the adjustment of the amount of coke breeze in the compounding step,
(3) The heating step is to heat using a drum mixer or a rotary heating device which is a rotary kiln.
(4) The heating by the heating device shall be performed so that the temperature on the exit side of the charging raw material is 10 to 50 ° C higher than the temperature on the inlet side of the heating device.
(5) The heating device uses one or more heating media selected from hot water, steam, other gaseous steam excluding steam, and high-frequency heating.
Is a more preferred embodiment.

Further, the present invention comprises a blending machine in which an iron-containing raw material, an auxiliary raw material and a coagulant are blended and used as a blending raw material, and a device in which the compounding raw material is granulated by a granulator and the granulated sintered raw material is mainly used. It has a granulator as a raw material to be charged and a sintering machine provided with an ignition device for sintering the raw material to be charged, and further, between the granulator and the ignition device of the sintering machine, A temperature measuring device for measuring the temperature of the charged raw material and a heating device for heating the charged raw material are arranged, and the heating is performed based on the temperature of the charged raw material measured by the temperature measuring device. It is a granulated ore manufacturing facility characterized in that the charged raw material is preheated by the apparatus.

In the sinter manufacturing equipment according to the present invention,
(1) The heating device is a rotary device.
(2) The heating device is to supply and heat one or more kinds selected from hot water, steam, gas other than steam, and high frequency heating.
Is a more preferred embodiment.

According to the present invention configured as described above, it is possible to surely improve the air permeability of the raw material charging layer formed in the sintering machine and contribute to the reduction of the wet zone, which in turn has high strength. Sintered ore can be manufactured with high productivity.

It is a schematic diagram which shows an example of the sinter manufacturing equipment to which this invention applies. It is a conceptual diagram of the manufacturing method of the sinter which concerns on this invention. It is a figure explaining the heating method according to this invention of the charge raw material by a heating apparatus.

FIG. 1 is a schematic diagram of a dwightroid type sinter machine used for producing a sinter to which the present invention is applied. In general, the manufacturing process of sinter is mainly a compounding process in which a sintered raw material is blended and used as a compounding raw material, a granulation step in which the compounded raw material is granulated to obtain a granulated sintered raw material, and the obtained granulation. It usually consists of a sintering process in which a charging raw material consisting of a sintering raw material or a return ore is charged into a sinter machine and sintered to obtain a sinter. The blending step is a step of blending an iron-containing raw material such as powdered iron ore with an auxiliary raw material such as lime powder and a coagulant such as powdered coke in a predetermined ratio to obtain a predetermined blending raw material. The granulation step is a step of granulating the compounded raw material into particles of a predetermined size using a granulator such as a drum mixer or a pelletizer to obtain a granulated sintering raw material, that is, a charging raw material. .. Then, in the sintering step, the charged raw material mainly composed of the granulated sintering raw material is charged on the pallet of the sintering machine to a predetermined thickness, and the powder coke in the obtained sintered raw material charging layer is charged. This is a process of igniting using an ignition device to calcin and sinter it into sinter. After firing, it is crushed, sized, and cooled to obtain a product sinter.

In the dwitroid type sintering machine 1, the charging raw material made of the granulated sintering raw material or the like is charged onto the pallet 2 running endlessly via the surge hopper 5, and the ignition device 3 puts the charging raw material on the pallet 2. By igniting the coagulant (powder coke) in the sinter raw material deposition layer (raw material charging layer) and burning it, the charged raw material is burned with the combustion heat to produce sinter. It is a device.

In the sintering machine, a wind box 4 is arranged under the pallet 2, and air in the sintering machine is sucked from above to below by a main gas duct 6 and a blower 7 connected under the wind box 4. I am doing it. As a result, while the combustion gas in the raw material charging layer 11 on the pallet 2 shown in FIG. 2 is sucked downward through the window box 4, the combustion gas is the charged raw material in the raw material charging layer 11. With the movement of the pallet 2, the firing of the charged raw material proceeds in the process of being sucked from the upper side to the lower side. That is, the charged raw material on the pallet 2 is sequentially fired from the upper side to the lower side to become a sinter.

Here, if the air permeability of the raw material charging layer 11 on the pallet 2 deteriorates, the air volume passing through the raw material charging layer 11 is lowered, and the firing speed of the raw material charging layer 11 is lowered. Then, when such a firing speed decreases, the speed of the pallet 2 traveling endlessly is usually reduced so that the air volume passing through the pallet 2 does not decrease. Therefore, the deceleration of the pallet 2 leads to a decrease in the sinter production amount.

Another cause of deteriorating the air permeability of the raw material charging layer 11 is the combustion melting zone constituting the raw material charging layer 11 and the combustion located above the raw material charging layer in the layer thickness direction. The presence of a large amount of water caused by the temperature difference from the wet zone (the zone where the coke breeze has not yet burned) existing below the melting zone can be mentioned. Generally, in the charged raw material, in addition to the water content of the charged raw material itself, there is also water added in the process of granulation. Therefore, the temperature of the charged raw material in the combustion melting zone during firing becomes 1000 ° C. or higher, but in the wet zone below the middle in the vertical direction of the raw material charging layer, the coke breeze has not yet burned. The temperature of the charged raw material is low and the water content remains high. In this state, the water generated in the upper combustion melting zone rides on the flow of air sucked downward and heads toward the lower part of the pallet 2, where the coke breeze comes into contact with the unburned charged raw material and is cooled to release water vapor. As a result of returning to water, the wet zone is formed. In this wet zone, the moisture reduces the porosity, that is, the ratio of the gaps between the charged raw materials, and the air flow is impaired.

Therefore, if the temperature of the charged raw material charged on the pallet 2 of the sintering machine can be raised as high as possible, it becomes difficult for water vapor to return to water, and the formation of the wet zone can be suppressed. It is. That is, if the formation of the wet zone can be suppressed, the amount of air passing through can be increased, and as a result, the pallet speed is not reduced and the production amount of sinter can be increased.

Conventionally, as one of the methods for raising the temperature of the charged raw material, a method of blowing exhaust gas or steam in the granulation process has been adopted. For example, Patent Document 3 discloses a method of injecting steam into a granulator to raise the temperature of a granulating sintering raw material. However, in the method disclosed in Patent Document 3, even if the temperature of the charged raw material (granulation and sintering raw material) is initially high, the charged raw material is conveyed to the ignition device 3 of the sintering machine 1. During that time, the temperature may drop, and as a result, it may not be possible to expect an increase in sinter production. In order to avoid this situation, in the past, a heat insulating means such as a cover was provided on the transport path of the charged raw material, but even if this is the case, if the traveling distance is long, the temperature of the charged raw material will still decrease. It wasn't a drastic solution.

Therefore, in the present invention, a heating step is provided between the granulation step and the ignition step (ignition device of the sintering machine) in order to raise the temperature of the raw material to be charged, and the raw material is charged onto the pallet of the sintering machine. We decided to raise the temperature of the raw material to be charged in advance. FIG. 2 is a diagram for explaining the method of the present invention and the equipment for carrying out this method. As shown in FIGS. 1 and 2, in the present invention, the charged raw material sent to the sintering machine through the granulation step is preheated on the pallet of the sintering machine 1 before the charged raw material is charged. I decided to do it. Therefore, in the present invention, it is decided to install the heating device 9 together with the temperature measuring device 10 between the granulator and the ignition furnace of the sintering machine.

As described above, in the sinter manufacturing equipment according to the present invention, the heating device 9 is installed between the granulator and the ignition device of the sinter, and the temperature is measured at any time by the temperature measuring device 10. The charged raw material was preheated so that it could be fed to the position of the ignition device on the pallet of the sintering machine while maintaining its temperature high. It is preferable that the heating device 9 is arranged at a position as close to the sintering machine (ignition device) as possible. Further, by arranging the heating device 9 at a position closer to the sintering machine (ignition device), the energy required for heating the charged raw material by the heating device 9 can be reduced.
A separate heat insulating device may be provided so that the temperature of the charged raw material does not drop until the temperature of the charged raw material drops from the heating device 9 to the sintering machine (ignition device).

As the heating device 9, a device capable of applying high-frequency heating or the like is adopted in addition to hot water, high-temperature steam, and high-temperature gas other than steam. Of these, it is preferable to use high-temperature steam or the like in consideration of cost, supply amount, equipment, and the like. Further, a high-temperature gas is also effective in reducing the amount of water in the charged raw material. It should be noted that the above heating means may be used in a plurality of combinations.

Further, equipment having various shapes can be applied to the heating device 9. For example, when hot water is used, it is preferable that the hot water can be sprayed uniformly onto the charged raw material. When steam is used, a space covering the transport path may be provided on the transport path through which the charged raw material passes, and steam may be supplied to the space by a nozzle or the like. The same applies to the case of high temperature gas. Further, a high frequency heating device may be installed so that the high frequency reaches the charged raw material directly.

As shown in FIG. 1, the heating device 9 is preferably a rotary facility. This is because the temperature of the charged raw material can be made uniform by using the rotary equipment. This is because it is advantageous for the production of sinter to make the temperature of the charged raw material as uniform as possible. This is because if the temperature of the charged raw material is non-uniform, the combustion speed during sintering will be non-uniform, and some parts will not be sufficiently sintered, resulting in unstable quality of the sinter. Because. As an example of the above-mentioned rotary heating device, a rotary kiln, a drum mixer, or the like can be exemplified, but other equipment may also be used.

Preferably, the temperature measuring device 10 is installed before and after the heating device 9. For temperature measurement, a known means such as a radiation thermometer is used, first, the temperature of the charged raw material is measured on the exit side of the granulator 8, that is, the inlet side of the heating device 9, and the temperature is loaded according to the flow shown in FIG. Determine the heating conditions for the raw material. Then, the outlet temperature of the charged raw material is measured by the temperature measuring device 10 on the outlet side of the heating device 9, it is determined whether the temperature of the charged raw material is appropriate, and if the temperature of the charged raw material is inappropriate, the charged raw material is charged. The heating device 9 is controlled so that the temperature of the raw material becomes appropriate. Hereinafter, as an example, an example in which steam is used as the heating device 9 will be described.

First, a drum mixer, a rotary kiln, or the like that temporarily stores the granulated charging raw material (granulated sintered raw material) on the transport path of the sintered compound raw material and transports the raw material while rotating is preferably the output side. A heating device 9 capable of heating from the position of is provided. As the heating device 9, a pipe for supplying steam and a pipe equipped with a nozzle for blowing steam are used. Here, the pressure of the blown steam depends on the shape and size of the heating device 9 and the amount of the charged raw material, but 0.3 to 1.5 MPa can be exemplified. If the pressure of the steam is too low, the steam does not reach the charged raw material sufficiently, while if the pressure of the steam is too high, the charged raw material may be destroyed, and further, the charged raw material is contained. Harmful effects such as excessive water content occur.

When steam is used to heat the charged raw material, the amount of the steam blown is in the range of 0.5 to 3% by mass with respect to the charged raw material, although it depends on the amount of the charged raw material. Is preferable. Within this range, the water content of the charged raw material can be appropriately controlled.

Specifically, as shown in FIG. 3, after the charged raw material is manufactured, the temperature of the charged raw material is measured on the outlet side of the granulator 8 and the inlet side of the heating device 9 arranged thereafter. Based on the measured temperature, the required heating amount is calculated and the charged raw material is heated. Usually, the temperature immediately after the production of the charged raw material is about 30 ° C. Therefore, the temperature of the charged raw material on the inlet side of the heating device 9 is also about 30 ° C. Therefore, in the heating device 9, the temperature of the charged raw material at the outlet of the heating device is set to be within a predetermined temperature range from the temperature at the inlet, that is, the temperature is set to be about 10 to 50 ° C. higher. .. As described above, in order to improve the air permeability of the raw material charging layer 11 on the pallet 2 of the sintering machine, it is desirable that the temperature of the charged raw material is high. However, if the temperature of the charged raw material is too high, the transport equipment may be damaged. Therefore, it is preferable to measure the temperature again on the outlet side of the heating device 9 to confirm whether or not the charged raw material has reached a predetermined temperature. On the other hand, if the charged raw material is lower than the predetermined temperature, The heating means is controlled to maintain and adjust the temperature of the charged raw material within a predetermined range.

In addition, by controlling the temperature of the charged raw material to be transported to the sintering machine to a constant level, the amount of powdered coke input has conventionally been increased in response to temperature changes (temperature change, rainfall, snow cover, etc.) of the charged raw material. Where adjustment was necessary, in the heating process of the charged raw material, by heating so as to maintain the temperature within the above range, it is no longer necessary to adjust the amount of the powdered coke, and as a result, the quality is improved. And has the effect of contributing to the stabilization of yield.

As another embodiment of the present invention, both the temperature measuring device 10 and the heating device 9 may be arranged for the granulator 8 for producing the granulation sintering raw material (charged raw material). In this example, the temperature is measured during the granulation of the compounded raw material, and depending on the temperature, means such as hot water, steam, and high-frequency heating are used to heat the compounded raw material during granulation as necessary. It is preferable to use it. This is because in the granulation process, moisture is added to the compounded raw material to produce the granulated sintered raw material, so if steam is used here, heating and moisture adjustment (addition) can be realized at the same time. be.

A drum mixer, which is an example of the rotary heating device shown in FIG. 1, is arranged between the granulator and the sintering machine, and the charged raw material is heated at a predetermined position and then sintered via a surge hopper. It was loaded on the pallet of the machine. A device that blows steam from the outlet side of the drum mixer was used to heat the charged raw materials.
The moisture content of the charged raw material is closely related to the air permeability of the raw material charged layer, although it depends on the temperature of the charged raw material, and has an important effect on the production rate and the yield. Therefore, in this example, the presence or absence of heating was examined while changing the water content of the raw material. At that time, for the reason described in the above embodiment, the temperature was controlled to be maintained at 55 ° C., which is the maximum temperature due to equipment restrictions.

As can be seen from the results shown in Table 1, for Invention Examples 1 to 4, the amount of water vapor supplied was 7.4 to 22.1 kg / t-s per charged raw material, and the raw material moisture was changed. On the other hand, in the comparative example, the charged raw material was charged onto the pallet of the sintering machine without heating with steam. Under each condition, the operation was carried out continuously for 6 hours, and the production amount of the sinter was compared. The amount of sinter produced was the amount of sinter remaining on the sieve after sieving with a mesh of 5 mm.

As can be seen from the results of Invention Examples 1 to 4 and Comparative Examples 1 to 4 shown in Table 1, the firing permeability (JPU: Japan Permeability Unit) tends to increase as the water content increases, and the firing permeability (JPU) tends to increase. As the air volume increases, the firing time is shortened and the yield is reduced. From these phenomena, it can be seen that the invention example and the comparative example have a peak in the production rate at a certain water value.
Regarding the effect of reducing the wet zone due to the temperature rise by steam, the firing air permeability itself is improved by about 10% compared to the comparative example, and as explained above, the effect of improving the production rate is up to 6%. Can be enjoyed.
In addition, by using a temperature measuring device to follow the fluctuating raw material temperature for 6 hours and controlling the temperature to a constant temperature (55 ° C), the stable calorific value also contributes to the improvement of the yield. I can say.

Therefore, it is possible to improve the production rate by raising the temperature of the raw material by blowing steam under the temperature control using the apparatus suitable for the present invention.

1 Dwightroid type sintering machine 2 Pallet 3 Ignition device 4 Wind box 5 Surge hopper 6 Main gas duct 7 Blower 8 Granulation machine 9 Heating device 10 Temperature measuring device 11 Raw material charging layer

Claims (9)

A compounding process in which an iron-containing raw material, an auxiliary material, and a coagulant are compounded to obtain a compounding raw material, and
A granulation process in which the compounded raw material is granulated by a granulator to obtain a charged raw material mainly composed of a granulated sintering raw material.
An ignition process in which the charged raw material is charged into a sintering machine and ignited.
After the ignition step, a sintering step of sintering the charged raw material to produce a sinter and a
In the method of producing sinter through
Between the granulation step and the ignition step, a temperature measuring step for measuring the temperature of the charged raw material and a heating step for heating the charged raw material with a heating device are provided.
A method for producing a sinter, which comprises heating the charged raw material with the heating device based on the temperature of the charged raw material measured in the temperature measuring step. The method for producing a sinter according to claim 1, wherein in the heating step, the temperature of the charged raw material is heated so as to maintain the temperature within a predetermined range. The method for producing a sinter according to claim 1 or 2, wherein the adjustment of the amount of coke breeze in the compounding step is omitted. The method for producing a sinter according to any one of claims 1 to 3, wherein the heating step is performed by using a rotary heating device such as a drum mixer or a rotary kiln. The method according to any one of claims 1 to 4, wherein the heating by the heating device is performed so that the temperature on the exit side of the charging raw material is higher than the temperature on the entry side of the heating device by 10 to 50 ° C. The method for producing a sinter described. The firing according to any one of claims 1 to 5, wherein the heating device uses one or more heating media selected from hot water, steam, other gaseous steam excluding steam, and high-frequency heating. How to make ore. A blending machine that blends iron-containing raw materials, auxiliary raw materials, and coagulants to make a blending raw material,
A granulator that granulates the compounded raw material with a granulator and uses a granulated and sintered raw material as a charging raw material.
It has a sintering machine equipped with an ignition device for sintering the charged raw material, and has.
Further, a temperature measuring device for measuring the temperature of the charged raw material and a heating device for heating the charged raw material are arranged between the granulator and the ignition device of the sintering machine.
A sinter manufacturing facility characterized in that the charged raw material is preheated by the heating device based on the temperature of the charged raw material measured by the temperature measuring device. The equipment for producing sinter according to claim 7, wherein the heating device is a rotary device. The sinter according to claim 7 or 8, wherein the heating device supplies and heats one or more selected from hot water, steam, a gas other than steam, and high-frequency heating. production equipment.

Images