JPS5811747A - Manufacture of sintered ore - Google Patents

Abstract

PURPOSE:To obtain a sintered ore of a good quality, which is high in its reduced property and low in its low temperature reduction pulverization rate, by partitioning an ignition surface into 3 zones, and heating a igniting a sintering material in each section under prescribed conditions. CONSTITUTION:In a material advancing direction of an ignition furnace 3 of a continuous sintering machine, a pre-heated temperature raising zone 7, a tempera ture equalizing zone 8 and an ignition heat holding zone 9 are provided, and a furnace partition wall 5 and a wind box partition plate 6 are provided so as to correspond to each boundary of these 3 zones. Also, in said temperatur raising zone 7, the surface layer of a sintering material 2 is pre-heated to a temperature of 400-600 deg.C under <=5% oxygen concentration. Subsequently, in the equalizing zone 8, the material 2 is subjected to a high calory temperature rise by 1.05- 1.3 air ratio by use of a burner 22. After that, in the heat holding zone 9, mixed fuel is ignited by setting the atmospheric oxygen concentration to >=16% and by heat blast of >=800 deg.C temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing sintered ore for blast furnaces.
, (,1lFeO1) This relates to a method for producing high-quality sintered ore with high reducibility and low low-temperature reduction powdering rate with good productivity.

As is well known, the generally used downward suction type continuous sintering machine loads the sintering raw material 2 onto an endless rut truck 1 and sequentially moves it to the ignition furnace and/or storage, as shown in Fig. 1 (-). It is transported into a thermal furnace 3 (hereinafter referred to as the furnace 3). Inside the furnace 3, gaseous fuel or liquid fuel (hereinafter referred to as fuel) is supplied.
The fuel is supplied to a group 4 and burned, and the surface layer of the sintering raw material 20 is preheated and heated by the combustion heat of the fuel, and the blended fuel mixed in the sintering raw material 2 is ignited. Thereafter, the blended fuel is combusted with residual oxygen in the combustion gas to form a combustion zone, thereby sintering the sintering raw material.

The oxygen concentration and gas temperature supplied to the combustion zone generated during this sintering process greatly influence the mineral structure produced. For example, the surface layer of the sintered ore layer sintered in the furnace 3
It is well known that the quality of the middle and bottom layers, which are baked outside, is significantly weaker than the quality of the middle and bottom layers.

Therefore, the present inventors conducted a detailed investigation and study on the temperature increasing ignition mechanism in the furnace 3, and found that in the conventional ignition furnace, 0. As shown in Figure 1 (C), the shudder decreases significantly in the high-temperature section 41) shown in Figure 1 (B) to below 5 -, and the blended fuel in the surface layer is not able to burn simply by increasing its temperature. It has become clear that this has not been achieved.

It was also found that the area where the O1 concentration in the furnace 3 recovered to 21g4, which is similar to that in the atmosphere, was near the outlet of the furnace 3, and the effective sintering reaction area was reduced.

The present invention utilizes various experimental studies based on these findings.
This is a method for producing sintered ore, which was completed in 2007.The feature is that the ignition zone during the production of sintered ore is divided into two zones: a preheating temperature rising zone, a uniform temperature rising zone, and an ignition holding zone. A furnace body partition wall and a wind box partition plate are provided corresponding to each boundary of the zone, and in the preheating temperature zone, the surface layer of the sintered raw material is
Preheat to 0°C to 600°C.
and the air ratio is 1.05 to 1.30, the sintering raw material is heated by a high amount of heat, and the atmospheric oxygen concentration is reduced to 1 in the ignition and holding zone.
The purpose is to ignite the blended fuel with hot air of 10°C or higher while maintaining the temperature at 6- or higher.

The following is a side view showing an example of an advantageous device for applying the method of the present invention to a downward suction type continuous sintering machine.
In the direction of movement, there is a preheating temperature rising zone 7, a temperature increasing uniformity zone, and a ignition holding zone 9.
A furnace body partition wall 5 is provided between each of these zones, extending from the ceiling wall to the immediate vicinity of the surface passage line of the porcelain inside the skeleton armchair truck 1. Front wall 11.
A wind box partition plate 6 is provided below each of the rear walls 12.
・Control @14 to furnace pressure detection @13 installed in each zone
The electric tongue A-15 that responds via the wind box 1 corresponding to each band
0 to each lie/leg 16 to control the ventilation amount of the raw material layer 2 in the noglet cart 1 for each band, and to control the furnace pressure.
This makes it possible to advantageously control the temperature inside the furnace.

The preheating temperature rising zone 7 is an internal combustion type hot blast furnace 1 installed on the side of the scissors sintering machine.
The exhaust duct 18 for Moki waste gas of No. 7 is connected, and the same duct 1
8 is provided with a flow rate control valve 20 that responds to a thermometer 19 in the preheating temperature rising zone T via a controller 41, whereby the temperature of 400° C.
The combustion waste gas of 600°C, 0, ≦5- is supplied so that the inside of the preheating temperature rising zone 7 reaches a predetermined temperature within the range of 600°C to 400°C.

A nozzle 22 is provided in the temperature increasing uniform zone 8, and a COG gas supply pipe 21 as a fuel gas and a combustion air supply pipe 2 are connected to this.
3 are connected in communication, and although not shown, these container pipes 22.2
A controller controls the ratio of the flow rate regulating valve provided at 3 to maintain the air ratio at a predetermined value within the range of 1.05 to 1.30.

The ignition insulation zone 9 has a temperature of 0.1 at 800° C. or higher, which is indirectly heated by introducing the air between the combustion chamber of the internal combustion hot blast stove 1γ and the outer wall of the furnace body.
A pipe 24 for pressurizing high-temperature air of 64 or more is connected in communication,
The piping 24 has a surface thermometer 25 installed inside the ignition insulation zone 9.
A diluent air introduction pipe 28 having a flow rate control valve 27 which responds to the pressure sensor 13 via a controller 26 is connected to the pressure sensor 13, and a flow rate control valve 30 which responds to the pressure sensor 13 via a controller 29 is connected to the pressure sensor 13. It is interposed on the downstream side of the pipe 28 connection part.

Further, in FIG. 3(a), the ignition furnace 3 installed next to the raw material supply device (not shown) has a preheating temperature rising zone 7 and a temperature increasing uniform zone 8 in the traveling direction of the endless pallet truck 1 charged with the raw material 2. , ignition and insulation zones 9 are sequentially installed, and between each of these zones, a furnace partition wall 5 is installed that extends from the ceiling wall to the immediate vicinity of the surface passage line of the raw material in the pallet truck 1, and in front of each partition wall 5 and the ignition furnace 3 A wind box partition plate 6 is provided below each of the wall 11 and the rear wall 12.
At the same time, an electric damper A-15 that responds to the furnace pressure detection 513 provided in each zone via the controller 14 is installed in each win P/leg 16 of the wind box 10 corresponding to each zone. The amount of ventilation of the pallet truck 1 and the raw material shoe 2 in the pallet truck 2 is controlled for each band, thereby making it possible to advantageously control the furnace pressure and the temperature inside the furnace.

The preheating temperature rising zone is provided with an A-ner 31, to which a BPQ gas supply pipe 32 as a fuel gas and a combustion air supply pipe 33 are connected in communication, and flow rate regulating valves 35.35 are interposed in these container pipes 32.33. ' is controlled by the controller 36, and the temperature inside the furnace is 4.
00℃~600℃, 0. The gas is burned so that the concentration meets a predetermined condition of 5- or less.

As in FIG. 2(a), the temperature increasing uniform zone 8 is provided with a nozzle 31, to which a BFG gas supply pipe 32 as a fuel gas and a combustion air supply pipe 33 are connected in communication, and these container pipes 22. 2
The controller 38 controls the ratio of the flow control valves 37 and 37' provided at the air flow rate control valves 3 to maintain the air ratio at a predetermined value within the range of 1.05 to 1.30.

The ignition retaining zone 9 is provided with a nozzle 31, to which a BFG gas supply pipe 32 as a fuel gas and a combustion air supply pipe 3 are provided.
A flow rate control valve 39.3 is connected to the flow control valve 39. The BCJ ratio is controlled by a controller 40 to create an atmosphere in the furnace of 800° C. or higher and 0°C or higher.

Each controller 36, 38, 40 is controlled by a higher-level controller CPU. The control device CPU includes temperature detectors 42, 43.44.0 . Concentration detector 45.46.4
Introducing the detection signals from 7 and 79-7 of each phase so that the preset target temperature and O1 concentration of each phase are achieved.
The controller 36, 38, and 40 are instructed to set the air-fuel ratio of the fuel tank 31.

Next, the reason for limiting the conditions in the present invention will be explained.

In the present invention, the surface temperature of the sintered raw material in the preheating temperature rising zone 7 is limited to a temperature rise within the range of 400°G to 600°C, which does not reach 750°C, which is well known as the ignition temperature of blended fuel such as coke powder and anthracite coal. This was done in order to dry the surface moisture of the sintered raw material, improve air permeability within the layer, and increase productivity.Also, the reason for keeping the atmospheric oxygen concentration below 5% was to reduce the moisture generated in the blended fuel. Solution for C + CO, → 2CO, suppresses loss reactions, suppresses advance ineffective consumption of blended fuel, enables effective use of blended fuel, achieves a low unit coke breeze consumption, and improves blending by local temperature rise. This is to suppress partial combustion of fuel and realize homogeneous firing within the sintering raw material layer.

Next, the reason why a 2-ner is used in the uniform temperature raising zone 8 is to uniformly finish the sintering raw material whose temperature has been preheated and raised in the preheating temperature raising zone 7. In general, the surface of the sintered raw material layer does not have uniform properties, and when the various conditions of the raw material are taken into consideration, it contains many non-uniform and non-uniform elements. Therefore, when raising the surface temperature of the sintered raw material to the ignition temperature of 750°C of the blended fuel, unless the surface temperature is made uniform in the width direction, the progress of the subsequent sintering reaction will be uneven, which will prevent the production of homogeneous sintered ore. . For this reason, a combustion air ratio of m=1. High heat amount obtained by controlling O2N2.30 (
1500 to 9500 Km/Nun'/am) to uniformly finish the entire surface of the sintered raw material layer.

In addition, the oxygen concentration in the ignition retention zone 9 is desirably 16% or more.
The purpose of supplying high-temperature thermal fluid with a content of 5% or less and a temperature of 800°C is to ignite the blended fuel for the first time and actively burn it. The temperature at which high-quality sintered ore can be produced,
In other words, it produces acicular calcium ferrite that has excellent reducing properties and strength, and turns into skeleton-like rhombus that worsens the low-temperature reduction powdering rate!
Temperature 1.1 to decrease tightness and increase 1 patchy hematite
00°C to 1,350°C, which inevitably results in a high temperature range in conventional methods, resulting in the formation of plate-shaped calcium ferrite with poor reducibility.

In addition, since the Ota degree is low, the blended fuel on the surface of the sintered raw material layer is not effectively used as a heat source, and this is to improve the problem and reduce the fuel consumption rate.

In addition, installing a partition wall 5 in the furnace 3 and a corresponding partition plate 6 of the wind box 10 at the boundary between the three phases prevents intrusion of air, suppresses interference between each zone, and separates each phase. This is to further enhance the effect of control corresponding to the purpose of each phase by applying equilibrium ventilation control to the phase.

Examples of the present invention are described below.

Table IK of blended raw materials used in the experiment and fineness.

The conditions of the experiment are shown in Table 2, and the results of the experiment are shown in Table 3.

Table 1 Table 2 Table 3 As is clear from the results in Table 3, the present invention corporation.

Compared to the conventional method, the cold strength of the method B was improved by about 4%, the product yield was improved by about 4.5-1, the JI8 reduction rate was improved by about 6%, and the low-temperature reduction powdering rate was improved by about 3-3%. The production rate was also improved by about 10%, and a reduction in the basic unit δ of the blended fuel was observed.

As described above, by carrying out the method of the present invention, it is possible to produce sintered ore of storm quality with high reducibility and low low-temperature reduction powdering rate with good productivity, and a great effect on energy saving can be obtained.

[Brief explanation of the drawing]

FIG. 1(a) is a side sectional view showing a conventional ignition furnace/Mataha heat retention furnace, and FIG. 1(b) is the furnace in FIG. 1(a) and FIG. 1(a) showing a reverse internal temperature distribution. The graph shown corresponding to the ignition furnace/Mataha heat retention furnace, Figure 1 (e) is the same as Figure 1 (a).
The 02 concentration distribution in the furnace is shown in Figure 1 (a).
1 and 2 are graphs or graphs shown corresponding to the positional relationships of the heat retention furnaces. 2 and 3 show embodiments of the present invention, and FIG. 2(a)
2(b) is a side cross-sectional view showing an example of the configuration of the preheating temperature rising zone, uniform temperature rising zone, and ignition holding zone of the present invention, and FIG. 2(b) shows the temperature distribution in the furnace in FIG. 2(a). The graph shown in FIG. 2(C) corresponding to the positional relationship of each zone in a) corresponds to the positional relationship of the six zones in FIG. 2(a), which is the in-furnace 02 concentration distribution in FIG. Associate with the graph shown. FIG. 3(a) shows the preheating temperature rising zone, uniform temperature rising zone, and (a) of the present invention.
) is a graph showing the temperature distribution in the furnace in correspondence with the positional relationship of the six zones in Fig. 3(a), and Fig. 3(C) is a graph showing the temperature distribution in the furnace in
) in the furnace 0. 3 is a graph showing the concentration distribution in correspondence with the positional relationship of the six bands in Figure 3(a). In the figure, 3 is the furnace, 5 is the furnace body partition wall, 6 is the wind box partition wall, 7 is the preheating temperature rising zone, 8 is the temperature rising uniform zone, 9 is the ignition holding zone, and 22.31 is the nozzle. . Agent: Patent attorney Masamitsu Akizawa and 2 others

Claims (4)

[Claims] (1) The ignition zone during the production of sintered ore is divided into two zones: a preheating temperature rising zone, a uniform temperature rising zone, and an ignition holding zone, and a furnace partition wall and a wind box partition are installed corresponding to each boundary of the two zones. In the preheating temperature zone, the surface layer of the sintered raw material is
The sintering material is preheated to 00°C to 600°C, and the sintering material is heated to a high temperature using a non-heater in the uniform heating zone and its air ratio is 1.05 to 1.30, and the atmospheric oxygen concentration is increased in the ignition and holding zone. A method for producing sintered ore, which comprises maintaining the temperature at 16 minutes or more and igniting the blended fuel with hot air at 800°C or higher. (2) The method according to claim 1, characterized in that combustion exhaust gas from a hot stove or the like is used in the preheating temperature rising zone. (3) Oxygen concentration in the ignition retention zone is 16- or more, preferably
21. The method according to claim 1 or 2, characterized in that heated air from a hot stove at a temperature of 800° C. or higher is supplied at 21-. (4) The method according to claim 1, characterized in that a heater is installed in two zones: a preheating temperature increasing zone, a uniform temperature increasing zone, and an ignition holding zone, and the air ratio is adjusted.