JPH10317069A - Sintering raw material processing method - Google Patents

Abstract

(57) [Summary] [Problem] Even when preliminarily granulating by dividing a sintering material having low granulation property such as fine ore and dust, it is possible to obtain an optimum granulated material and improve air permeability. It is an object of the present invention to provide a sintering raw material processing method capable of improving productivity and quality. SOLUTION: The sintering raw material processing method of the present invention comprises a raw material tank 1;
After one or more of fine ore and dust are added to a part of the sintering raw material cut out from the pre-granulation, the pre-granulated material is mixed with the remaining sintering raw material cut out from the raw material tank 1. This is a method for treating a sintering raw material to be mixed or mixed and granulated, wherein a nucleus raw material provided for a pre-granulation step satisfies the following conditions. Al ₂ O ₃ content ≦ 2 wt%, content of particle size 1 mm or less ≦ 50 wt%, water of crystallization in ore ≧ 5 wt%

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a sintering raw material, which promotes the formation of pseudo-particles during sintering of the sintering raw material and improves productivity by improving air permeability.

[0002]

BACKGROUND OF THE INVENTION Among blast furnace charges, sinter ore is the largest, and its production and quality have a great effect on blast furnace operation. Here, in a Dwyroid type sintering machine (hereinafter referred to as “DL type sintering machine”), 400 to 6
After igniting the sintering raw material layer supplied with a layer thickness of about 00 mm from the front side, air is sucked from the upper part to the lower part of the sintering raw material layer, and the coke mixed in the raw material is sequentially burned, The heat generated here promotes the sintering reaction and the melting reaction between the raw ore particles, and the mixture is fired. By cooling this, a massive sintered ore having a high porosity is obtained.

In the production of sintered ore using this DL-type sintering machine, sintering involves charging a mixture of sintering raw materials and coke breeze on a pallet and firing it. Improving air permeability in the raw material zone and the sintering zone in the above leads to improvement in productivity and quality.

Therefore, as a measure for improving air permeability on a DL-type sintering machine, for example, Japanese Patent Application Laid-Open No.
Using fine ore containing particles of 125 mm or less in an amount of 70 wt% or more and one or more of limestone powder, quicklime, or slaked lime having an average particle size of 1.50 mm or less, based on the weight of the finished sintering raw material And at least 1.0 wt% of fine ore, and at least 0.5 wt% of one or more of limestone powder, quicklime and slaked lime, and the weight of coarse ore of coarse ore / (fine ore + limestone powder) + Quicklime + slaked lime) weight = pre-granulated with an amount in the range of 20/80 to 60/40,
A method has been proposed in which this is mixed with a sintering main material or mixed and granulated.

As a measure for improving the yield at the time of blending high-crystal water ore, for example, Japanese Patent Application Laid-Open No.
Using high goethite ore with T.Fe ≤ 0.03 as part of the sintering raw material, the total or part of high goethite ore and MgO-containing
After mixing the SiO ₂ auxiliary raw material powder and the solid carbon powder with each other so that the mixing condition of -1 mm portion satisfies the following formula, and then performing humidity control and granulation,
A method of blending with other raw materials has been proposed. 1% + {(-1 mm part bound water% -8%) / 15} ≦ Cwt% ≦ 3% + {(− 1 mm part bound water% -8%) / 15} 0.12 ≦ {MgO-SiO ₂ containing Raw material wt% (decoupled water)｝ / high goethite ore wt% (decoupled water) ≦ 0.5…

[0006]

However, in recent years,
The sintering raw material tends to be finely divided and the amount of dust tends to be increased. Therefore, the sintering raw material is divided and pre-granulated in order to suppress a decrease in granulation property. However, although the pre-granulation promotes the pseudo-granulation of the fine powder sintering raw material, the effect of the pre-granulation has not yet been sufficiently brought out. In such a tendency, the granulated material in the pre-granulation is affected by the degree of pseudo-granulation due to the stickiness of a brand as a core raw material and the fluidity of the melt at the time of sintering due to its components.

[0007] Also, Japanese Patent Application Laid-Open No. 60-248827 describes that granulation is improved by pre-granulation and blending with quick lime, etc. However, this method allows some degree of pseudo-granulation. However, there was a problem that the effect of pre-granulation could not be sufficiently obtained because the amount of raw materials serving as the core of the granules was small.

In the above-mentioned Japanese Patent Application Laid-Open No. 3-47927, the use of goethite ore, which has been difficult to use effectively as a sintering raw material, makes it possible to produce a sintered ore having a good resistance to reduction and powdering. Although it is described that it is manufactured with good productivity, sinter obtained by arranging goethite that was basically unsuitable as a sintering raw material is dehydrated to remove bound water at that time. In addition to the necessity of adding a process, it is necessary to include solid carbon powder in the sintering raw material.

[0009] Further, in the operation of the blast furnace, Al_TwoO_Threeof
It is not used for sintering, even if the iron content is large and the particle size is fine.
The situation is unavoidable. In such a situation
And Al _TwoO_ThreeGranulation without limitation as a raw material for sintering
Has an adverse effect on the reduction pulverizability of wastes and blast furnace slag viscosity
There is a problem that the furnace condition may worsen due to the increase.

[0010] The present invention has been made in view of the above circumstances, and by specifying the chemical composition and particle size of the core raw material in the pre-granulation treatment, it is possible to improve the productivity and quality. It is an object of the present invention to provide a method for treating a binding material.

[0011]

In order to achieve the above object, a method for treating a sintering raw material according to the present invention is characterized in that a core raw material provided at the time of pre-granulation has an Al ₂ O ₃ content ≦ 2 wt%, Content of 1 mm or less ≦ 50 wt%, water content of crystallization in ore ≧
It was specified as 5 wt%. Thereby, the quality of the granulated product as a whole before firing can be improved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The method for treating a sintering raw material according to the present invention is characterized in that one or more of fine ore and dust are added to a part of a sintering raw material cut out from a raw material tank and pre-granulated. A method for treating a sintering raw material in which the pre-granulated material is mixed with or mixed with the remaining sintering raw material cut out from the raw material tank, wherein the core raw material supplied to the pre-granulation step satisfies the following conditions. Things. Al ₂ O ₃ content ≦ 2 wt% Content of those with a particle size of 1 mm or less ≦ 50 wt% Crystal water content in ore ≧ 5 wt%

In the above method, the reasons for each limitation on the nuclear raw material are as follows. 1) Reason for setting Al ₂ O ₃ content ≦ 2 wt% When Al ₂ O ₃ becomes a nucleus and pseudo particles are formed, the pseudo particles are segregated in a lower layer portion of a later sintering raw material layer. The quasi-particles maintain air permeability in the lower layer portion until the fusion zone is reached, but when the pseudo particles reach the fusion zone, the viscosity is further increased and the air permeability is reduced. Therefore, in the present invention, the Al ₂ O ₃ content is set to 2 wt% or less.

2) Content of particles having a particle size of 1 mm or less ≦ 50 wt
In recent years, there has been a tendency to use fine powder materials such as dust,
If the content of particles having a particle size of 1 mm or less is more than 50 wt%, the amount of raw material acting as the core of the granulated material is small, and the granulation rate is reduced. Therefore, in the present invention, the content of particles having a particle size of 1 mm or less is set to 50% by weight or less.

3) Reason for setting crystallization water content in ore ≧ 5 wt% Ores containing crystallization water serve as nuclei to form pseudo-particles. When segregated, the cohesive zone that enlarges in the lower part is suppressed by the crystallization water. Then, the sintered ore after gasification of the water of crystallization becomes porous and can be reduced. However, when the content of water of crystallization is less than 5% by weight, the above effect cannot be obtained. Therefore, in the present invention, the content of crystallization water in the ore is set to 5 wt% or more.

Although not always necessary, the lower part of the sintering material layer has a low viscosity in the cohesive zone, and in order to secure air permeability in the cohesive zone, the reverse of Al ₂ O ₃ is required. By adding the condition that the content of SiO ₂ having properties is 3 wt% or more, a more suitable granulated product can be obtained.

The pre-granulation step in the sintering raw material processing method of the present invention comprises two mixers including a high-speed stirring mixer. As described above, by using the high-speed stirring mixer, the sintering raw material is further agitated and the mixing unevenness is eliminated, and the sintering material is further mixed by the next mixer to improve the granulation property.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the sintering raw material processing method of the present invention will be described below with reference to FIGS. FIG. 1 shows a sinter ore production line for implementing the sintering raw material processing method of the present invention. FIG.
Indicates a granulation rate of 2 mm or less in particle size when the core material brand is changed. FIG. 3 shows the characteristics of the granulated material when each core brand is adopted.

In FIG. 1, reference numeral 1 denotes a raw material tank for a sintering raw material, and the sintering raw material cut out from the raw material tank 1 is usually mixed and adjusted by a primary drum mixer 2 by mixing water and quick lime. Wet and granulated, the moisture is finely adjusted by the secondary drum mixer 3, the granulation is strengthened, and the blended raw material having predetermined physical properties is obtained. Then, the pallet is charged on the pallet 5a of the sintering machine 5 via the compounding raw material tank 4, ignited from the front side by the ignition furnace 6, and thereafter, by the suction by the main exhaust fan 7, the pallet 5a is sequentially moved with the movement of the pallet 5a. Fired toward the bottom.
In addition, 8 is a dust collector.

However, according to the sintering raw material processing method as described above, if the sintering raw material is refined or the sintering reuse of dust collected from an environmental point of view increases, the air permeability deteriorates. However, the firing rate is reduced and the cooling rate is also reduced, so that productivity and quality deteriorate.

Therefore, in the raw material processing method of the present invention, all of the sintering raw material cut out from the raw material tank 1 is subjected to the conventional system processing.
Instead of processing in the secondary drum mixer 2 and secondary drum mixer 3, a part thereof, for example, 20 wt.
% As a pre-granulation treatment, is introduced into a high-speed stirring mixer 9 and a tertiary drum mixer 10 for processing.

At this time, pseudo-particles can be formed to some extent only by the fine powder raw material and dust, but a raw material serving as a core of the granulated product is indispensable for improving the strength and the degree of pseudo-granulation.
However, the core material is not limited to coarse particles, and the productivity and quality are evaluated in total from the viewpoint of improving the granulation rate due to its adhesion and hot air permeability due to segregation after granulation. There is a need.

Therefore, the present invention relates to a sintering raw material to be supplied to a pre-granulation system, wherein the content of Al ₂ O ₃ ≦ 2 wt%, the content of particles having a particle size of 1 mm or less ≦ 50 wt%, the content of crystal water in ore Quantity ≧ 5
Those that satisfy the wt% condition are to be provided as nuclear raw materials.

Hereinafter, the results of experiments performed to confirm the effects of the present invention will be described. First, Table 1 shows the sintering raw materials used in the experiments and their mixing ratios, and Table 2 shows the physical and chemical properties of the raw materials. Further, FIG. 2 shows the granulation rate of the particle size of 2 mm or less when the core brand is changed among the raw materials supplied to the pre-granulation system.

[0025]

[Table 1]

[0026]

[Table 2]

As shown in FIG. 2, judging only from the granulation rate, the brands used as nuclear raw materials are lobe, hammasley, yandi, newman and calajas in this order.
This is considered to be due to the water supply orientation and the adhesion orientation indicating the particle size of the nuclear raw material itself and the surface state of the nuclear raw material. Therefore,
If only cold venting is considered, productivity and quality should be in that order, as shown in FIG. 3, since the lobe has the maximum ventilation and the calajas has the minimum ventilation.

However, in practice, as shown in the results of FIG. 3, when Yandi was used as a nuclear material for a nuclear brand, the reducible RI (%) was optimal. The sintering conditions at this time are a layer thickness of 490 mm, a pallet width of 3.7 m, and a sintering speed of 3.2 m / min.

The results in FIG. 3 are due to hot venting, which has a significant effect on productivity and quality. Considering this result, when considering only the granules, as described above,
Newman and the like are considered to be good brands. However, as shown in FIG. 1, after the conventional system and the pre-granulation system have joined, the granulated material is segregated in the lower layer of the sintering material layer. And then,
If the content of Al ₂ O ₃ is high in the core material of the granulated product, the concentration of Al ₂ O ₃ in the slag that contributes to the reaction of the sinter increases.
When the concentration of Al ₂ O ₃ is increased, the fluidity of the slag is reduced, so that hot ventilation is deteriorated. Therefore, when the Al ₂ O ₃ content is 2
When the content is not more than wt%, the particle size is moderate, so that the adhesion is improved, and as a result, the productivity and quality can be improved.

Further, since Yandi is a highly crystalline water ore, the porosity increases and the RI improves, but in order to obtain such an effect, it is necessary to contain 5 wt% or more of crystallization water. Confirmed that there is.

And the particle size becomes the core of the granulated material,
In addition, it is sufficient that the coarse particles satisfy the above conditions. Therefore, when the content of the core material having a particle size of 1 mm or less is 50 wt% or less, an optimum granulated product can be obtained.

Accordingly, Yandy is a core brand satisfying the conditions of the present invention. Naturally, even if another sintering raw material which satisfies these conditions is used, good results can be obtained as in the case of Yandy shown in FIG. be able to.

[0033]

As described above, according to the sintering raw material processing method of the present invention, the core raw material provided at the time of pre-granulation is made of Al.
₂ O ₃ content ≤ 2 wt%, particle size 1 mm or less content ≤ 5
0% by weight and water content of crystallization in the ore ≧ 5% by weight. Therefore, even when pre-granulating by splitting sintering materials with low granulation properties such as fine ore and dust, optimal granulation is possible. The product can be obtained, the air permeability can be improved, the productivity and quality can be improved, and the granulation can be further improved by configuring the pre-granulation step with two mixers as necessary. Is improved.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory diagram of a sinter ore production line for implementing a sintering raw material processing method of the present invention.

FIG. 2 is a diagram showing a granulation rate of a particle size of 2 mm or less when a core brand is changed among raw materials supplied to a pre-granulation system.

FIG. 3 is a view showing characteristics at the time of sintering when various brands are used as a core material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw material tank 2 Primary drum mixer 3 Secondary drum mixer 9 High speed stirring mixer 10 Tertiary drum mixer

Claims (2)

[Claims] 1. A sintering raw material cut out from a raw material tank is added with one or more of fine ore and dust and pre-granulated, and the pre-granulated material is cut out from the raw material tank. Raw material mixed with the remaining sintering raw material to be mixed or granulated, wherein the core raw material supplied to the pre-granulation step satisfies the following conditions: Method. Al ₂ O ₃ content ≦ 2 wt%, content of particle size 1 mm or less ≦ 50 wt%, water of crystallization in ore ≧ 5 wt% 2. The method according to claim 1, wherein the pre-granulation step comprises two mixers including a high-speed stirring mixer.