JPH05311256A - Manufacture of sintered ore - Google Patents

Abstract

PURPOSE:To manufacture the sintered ore where the porosity is high, the fluctuation of the porosity is small, and the quality is stable in the manufacture of the sintered ore by the air-suction type sintering method. CONSTITUTION:P is calculated by the formula 1. The downward force to be applied to the combustion melting zone of the sintering is controlled so that the value may be the porosity of the target sintered ore. The formula 1 is expressed as P=P0-a(bWsc+cWdp). Where, P: porosity of sintered ore, P0: porosity of sintered ore when the downward force to the combustion melting zone is zero, Wsc: weight of the sinter cake per unit area, Wdp: gravity-converted value of the downward force to be applied to the combustion melting zone of the sintering based on the pressure difference to be caused on the sintered cake part of the sintering bed by the suction load, a, b, c: proportional constants.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an iron ore sintered ore and a non-ferrous metal sintered ore by an air suction type sintering machine such as DL type and GW type.

[0002]

2. Description of the Related Art In the DL type iron ore sintering method, air is sucked downward and the powder coke contained in the raw material is burned by this air, so that the raw material on the pallet has a thickness of several mm to several tens of mm. The sintering reaction proceeds in such a manner that the combustion zone of No. 1 moves downward. In the non-ferrous metal sintering method, coke powder is not used and the heat of oxidation of the sulfur component in the ore is used, and air is operated by pressing, but the sulfur in the internal fuel is oxidized by the air passing through the sintering bed. There is no change in the basics of the process of generating heat to generate heat and sintering.

In such self-combustion type sintering, the product is inevitably a porous sintered body. Porosity is not preferable because it is a defect in terms of material strength, but when it is used in a metallurgical furnace such as a blast furnace, it is generally more advantageous in terms of reducibility that it has many pores.
As described above, porosity is an important factor that affects the quality of sinter, but in actual sinter production technology, porosity is not controlled, and it depends on changes in raw material conditions and production conditions. The current situation is that it fluctuates each time and there is nothing to adjust. This is one of the causes of fluctuations in quality, and eventually fluctuations in the operation of metallurgical furnaces such as blast furnaces, and it is desirable to stabilize it. Further, in the conventional sinter, the reducibility as a metallurgical property is remarkably excellent, and the high porosity and high reducibility of the sinter having a porosity of 50% or more have strengths due to fluctuations in the porosity. It became unstable and was difficult to produce practically.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above problems and stabilizes a stable quality ore having a small fluctuation in porosity, and a high-porosity sintered ore preferable for a metallurgical furnace. To stabilize the operation of metallurgical furnaces such as blast furnaces, reduce the energy consumption rate, stabilize the quality of hot metal, and improve the environment.

[0005]

The gist of the present invention is as follows.

In the method for producing a sintered ore by the air suction type sintering method, P is calculated from the pressure gradient difference W _dp based on the suction blower pressure and the load W _{sc of the} sinter cake by Formula (1) Formula 3 and A method for producing a sinter having a constant porosity by controlling a downward force applied to a combustion melting zone of sintering so that the value becomes a target porosity of the sinter.

[0007]

Equation 3] _{P = P 0 -a (bW sc} + cW dp) ... (1) P: sinter porosity P _0: baked when downward force to the combustion melting zone is sintered at zero state Porosity of sinter W _sc : Weight of sinter cake per unit area W _dp : Gravity conversion value of downward force applied to combustion melting zone of sintering based on pressure difference generated in sinter cake portion of sintering bed due to suction load a , B, c: proportional constant

In the method for producing a sintered ore by the air suction type sintering method, depending on the pressure gradient difference W _dp based on the suction blower pressure and the downward force applied to the combustion melting zone of the sintering by the load W _sc of the sinter cake. Upward force W _Lift
From the force acting on these combustion melting zones,
A method for producing a sinter having a constant porosity by calculating P by Equation 4 and controlling the value so as to be the target porosity of the sinter.

[0009]

Equation 4] _{P = P 0 -a (bW sc} + cW dp -W Lift) ... (2) P: sinter porosity P _0: downward force to the combustion melting zone is sintered at zero state Porosity of sintered ore at this time W _sc : Weight of sinter cake per unit area W _dp : Gravity of downward force applied to the combustion melting zone of sintering based on the pressure difference generated in the sinter cake part of the sintering bed due to suction load Converted value W _Lift : Upward force acting on the sinter cake a, b, c: Proportional constant

[0010]

The operation will be described with reference to the drawings.

An example of the operating state of sintering is shown in FIG. The sintering raw material stored in the sintering raw material surge hopper 1 is charged in the sintering machine 2 by the raw material charging device 3 and then ignited in the ignition furnace 4, and sequentially sintered from the surface layer to the lower layer. After passing through the ignition furnace 4, the sintering is completed from the upper layer of the sintering bed along with the progress of the strands, solidification and cooling are performed, and a sinter cake is formed. The one-dot chain line shows the combustion melting zone where the sintering reaction is performed, the upper part of this line is the so-called sinter cake part where the sintering reaction is completed, and the lower part is the part in the raw material state. The porosity of the sintered ore is determined in this combustion melting.

Although the porosity of the sintered body can be measured from the true specific gravity and the bulk weight, C described in JP-A-61-1110729 is disclosed.
Method for measuring porosity of sintered body by T,
It can also be measured by a conventionally known method such as the vacuum packing method described in JP-A-2-269040.

The porosity of the sinter depends on the porosity of the raw material and the molten state in the combustion melting zone. At the same time, the pressure gradient caused by the suction negative pressure and the gravity load of the sinter cake are applied to this combustion melting zone. Since the sintering reaction takes place in the state of receiving such a downward force, it was considered that it depends on the way of receiving this reduction. Therefore, by measuring the pressure distribution in the sintering bed in detail, the magnitude of the pressure gradient to the combustion melting zone caused by the suction negative pressure is almost constant regardless of the location in the strand direction. Turns out to take half of. Further, the weight load of the sintering cake increases in inverse proportion to the height of the combustion melting zone in the bed height direction when the bulk density of the raw material is determined by measuring the stress distribution in the sintering bed with a load cell. There was found. The inventors conducted various studies on the relationship between the downward force applied to the sintering combustion melting zone in the sintering bed and the porosity of the sintered body measured after the completion of the sintering reaction. It was found that there is a strong relationship of the number 5.

[0014]

[Number 5] _{P = P 0 -a (bW sc} + cW dp) ... (1)

P is the porosity of the target sinter, and P
₀ is the porosity of the sintered ore when it is sintered in the state where the downward force on the combustion melting zone is zero, and can be obtained by an off-line pot test if the raw material and the charging density are determined. It is a standard raw material used in Japan and is about 55% at a normal raw material charging density of around 1.8, and it does not change significantly even if the raw material conditions and charging density change slightly, so once measured, it is a constant on a daily basis. Can also be treated as W _sc is the weight of the sinter cake per unit area and is proportional to the layer thickness. Although the weight of the sinter cake on the combustion melting zone varies depending on the height of the sintering bed,
It was found that the effect on porosity formation is equivalent to the fact that a load of a fraction of the total weight of the sinter cake per unit area is constantly applied, and if this coefficient is b, the sinter cake per unit area is The porosity corresponds to the state in which the total weight is multiplied by the coefficient b and a load is constantly applied. It has been found that normally about half of the total load is applied and can be a constant. W _dp is a gravity-converted value of the downward force applied to the combustion melting zone based on the pressure difference generated in the sinter cake portion of the sintering bed under negative suction pressure. The magnitude of the pressure gradient to the combustion melting zone caused by the suction negative pressure is almost constant in the strand direction regardless of the location, and a force proportional to W _dp is applied. This proportionality coefficient was set to c. It has been found that usually about half of the total negative pressure is applied, and can be a constant. a is a proportional coefficient between the downward force applied to the combustion melting zone and the porosity of the sinter, and can be obtained by an off-line pot test. Usually a
Is about 1% under a load of 10 kg / m ² .

From the relation of the formula (1), the operating conditions for producing the sintered ore having a desired constant porosity can be selected, and it is negative considering the production rate other than the porosity, the yield, and the quality comprehensively. The pressure and layer thickness conditions can be determined.

According to the formula (1), it is possible to operate the sinter according to the target porosity. However, in the past, the load was excessive and the porosity was generally low, so the sintering operation itself suffered from air permeability, and in such a state the ventilation was unevenly distributed, and a non-uniform pore structure was formed, resulting in large variations. ,
Usually, it is difficult to manufacture the one with the target porosity. For example, the stand sintering method described in JP-A-2-293586, Japanese Patent Application Nos. 2-242544 and 3
Combined with the technique of applying an upward force to the sinter cake such as the magnetic levitation sintering method according to No. 124532, according to the formula (2) number 6, the ventilation is stable, and the high level of the unprecedented high porosity sintered ore is obtained. Stable production is possible.

[0018]

## EQU6 ## P = P ₀ −a (bW _sc + cW _dp −W _Lift ) (2)

W _Lift indicates the amount of the force applied to the combustion melting zone, which combines the pressure gradient and gravity load, reduced by supporting the sinter cake with a stand material or applying an upward force to the sinter cake by magnetic levitation. ..

[0020]

EXAMPLES Examples of the present invention will be described below.

Example 1 A DL iron ore sintering machine having a sintering area of 600 m ² (5 m width × 120 m strand length) has a layer thickness of 600 mm and a negative pressure of 150.
There is a change in the raw material composition when operating at 0 mmaq,
Regarding the strength, the JIS room temperature strength SI was improved from 89 to 90.5, but the reducible JIS / RI was decreased from 67.4 to 66.1, and the blast furnace fuel ratio was deteriorated by 1.9 kg / tp. When the porosity of the sintered ore was measured, it was 49.3% to 48.
It had dropped to 1%. When P ₀ and a of this raw material were measured by a pan test, they were 54.5% and 0.105, respectively. The layer thickness is 500 mm and the negative pressure is 1300 mmaq.
Then, the JIS room temperature strength SI becomes 89.5,
The reducible JIS / RI was recovered to 67.8, and the blast furnace fuel ratio was also recovered to 2.1 kg / tp.

Example 2 Sintered area 280 m ² (4 m width × 70 m strand length)
DL iron ore sinter machine with a layer thickness of 500mm, negative pressure 10
Although operated at 00 mmaq, the porosity was 49.8%. When P ₀ and a of this raw material were measured by a pan test, they were 56.2% and 0.104, respectively. When the magnetic levitation device 8 shown in FIG. 2 is operated, the layer thickness is increased to 600 m, and the magnetic levitation force corresponding to the suction pressure of 1000 mmaq and the downward force of 45 kg / m ² applied to the combustion melting zone by the sinter cake is operated. A high porosity sinter having a porosity of 56.0% was obtained. Strength is JIS room temperature strength SI
Has been improved from 89.6 to 90.5, and reducible JIS / R
I increased from 66.4 to 70.1 and the blast furnace fuel ratio was 7.
It was improved by 5 kg / tp.

[0023]

As described above, according to the present invention, it has been vaguely decided by what has affected the porosity and by what operation the porosity can be controlled. However, it becomes possible to precisely control and manage the porosity. Porosity is an important structural element that influences the quality of sinter such as strength and reducibility, and since it can be controlled and managed, the quality is stabilized, fluctuations in the operation of metallurgical furnaces such as blast furnaces can be suppressed, Stable operation becomes possible. Further, by suppressing the fluctuation, the operation effect is improved and the fuel ratio can be reduced. By using a technique such as magnetic levitation to apply an upward force to the sinter cake, it is possible to manufacture unprecedentedly high-porosity sinter, and the blast furnace fuel ratio can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a state in which a magnetic levitation device is attached to a DL type sintering machine to operate.

FIG. 2 is a diagram showing details of a magnetic levitation device.

[Explanation of symbols]

 1 Sintering raw material surge hopper 2 Sintering machine 3 Raw material charging device 4 Ignition furnace 8 Magnetic levitation device 9 Magnetic levitation device support frame

Claims (2)

[Claims] 1. A method for producing a sintered ore by an air suction type sintering method, wherein a pressure gradient difference W _dp based on a suction blower pressure,
And the load W _{sc of the} sinter cake, P in Equation (1) number 1
Sintering that produces a sinter having a constant porosity by controlling the downward force on the combustion melting zone of the sinter so that the calculated value is the target porosity of the sinter. Manufacturing method of ore. [Number 1] _{P = P 0 -a (bW sc} + cW dp) ... (1) P: sinter porosity P _0: baked when downward force to the combustion melting zone is sintered at zero state Porosity of sinter W _sc : Weight of sinter cake per unit area W _dp : Gravity conversion value of downward force applied to combustion melting zone of sintering based on pressure difference generated in sinter cake portion of sintering bed due to suction load a , B, c: proportional constant 2. A pressure gradient difference W _dp based on a suction blower pressure in a method for producing a sintered ore by an air suction type sintering method,
And an upward force W _Lift is applied in response to a downward force applied to the combustion melting zone of sintering by the load W _sc of the sinter cake, and P is calculated from the force applied to the combustion melting zone by Equation (2) , A method for producing a sintered ore that produces a sintered ore having a constant porosity by controlling the value so as to be the target porosity of the sintered ore. [Number 2] _{P = P 0 -a (bW sc} + cW dp -W Lift) ... (2) P: sinter porosity P _0: downward force to the combustion melting zone is sintered at zero state Porosity of sintered ore at this time W _sc : Weight of sinter cake per unit area W _dp : Gravity of downward force applied to the combustion melting zone of sintering based on the pressure difference generated in the sinter cake part of the sintering bed due to suction load Converted value W _Lift : Upward force acting on the sinter cake a, b, c: Proportional constant