JPH08269584A - Production of sintered ore - Google Patents

Abstract

PURPOSE: To provide a process for producing sintered ore capable of maintaining high productivity at a low cost without being accompanied with difficulty when a large quantity of ores contg. water of crystallization at a high ratio, such as pisolite ores, as raw material ores are used. CONSTITUTION: Pseudo particles are formed by forming coating layers 2 mainly composed of hardly meltable ores, for example, magnetite ores, sand iron and solid fuel, contg. >=80wt.% of particles having a grain size of <=0.25mm on the surface layers of particles 1 mainly composed of the ores contg. water of crystallization at a high ratio and the assistant raw material contg. CaO at the time of producing the sintered one by using the ores contg. water of crystallization at a high ratio as the raw material ores. These pseudo particles are sintered.

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 a sinter that uses a large amount of a high crystal water content ore such as pisolite ore as a raw material ore.

[0002]

2. Description of the Related Art Conventionally, high-quality ore such as hematite or magnetite has been used as a raw material for sinter, but in recent years, goethite (Fe ₂ O ₃ .H ₂ O) has been used.
The amount of pisolite ore (containing fish-like tissue) containing a large amount of is increasing. This pisolite ore has many problems in maintaining the productivity of sintering, and the technical development corresponding to this has been desired.

[0003] Pisolite ore contains 4% or more of water of crystallization, and the pisolite ore obtained by dissociating the water of crystallization at 300 ° C becomes porous. Therefore, in the sintering process at 1200 ° C. or higher, the porous pisolite ore easily reacts with the flux as compared with the ordinary ore, and an excessive melt is generated. It has been reported that this excess melt deteriorates the ventilation of the sintered layer and reduces the productivity.

Therefore, as a technique for dealing with such a problem, M-bearing material such as serpentine around a coarse-grained high goethite ore is used.
After forming a coating layer made of gO-SiO2 auxiliary raw material powder,
A method of sintering has been proposed (Japanese Patent Publication No. 5-83620).
Issue). As a result, it is reported that when the temperature is 1200 ° C. or higher in the sintering process, the densification of the high goethite ore proceeds before the calcium ferrite melt comes into contact with the high goethite ore.

Further, in Japanese Patent Laid-Open No. 5-339652, after CaO is partially attached to the surface of coarse-grained pisolite ore, the remaining CaO, pisolite powdered ore and other powdered ores are attached. A method has been devised in which pseudo particles composed of two adhering layers are sintered. According to this, 2
By adjusting the ratio of CaO in the adhered layer of the layer to a predetermined ratio, the amount of melt generated is optimized.

[0006]

As described above, when pisolite ore is blended and sintered, excessive melt generation causes deterioration of air permeability of the sintered layer, thus lowering productivity.

In order to solve this problem, according to the technique disclosed in the above-mentioned Japanese Patent Publication No. 5-83620, a coating layer composed of MgO-SiO2 auxiliary raw material powder such as serpentine is formed around a coarse-grained high goethite ore. After the formation of sinter, it is sintered, but the addition of serpentine increases the amount of SiO ₂ in the product sinter,
The slag treatment cost in the blast furnace increases.

Further, in order to control the amount of melt produced, the technique disclosed in the above-mentioned Japanese Patent Laid-Open No. 5-339652 sinters pseudo particles composed of two adhering layers. A process is needed to separate the ore into fines and coarses. Further, in this method, since the easily meltable pisolite ore is used as the coating ore, it is necessary to secure a large amount of fine pisolite ore in order to control the melt formation.

The present invention has been made in view of the above circumstances, and when a large amount of high crystal water-containing ore such as pisolite ore is used as a raw material ore, the cost is high and the difficulty is high. An object of the present invention is to provide a method for producing a sinter that can maintain productivity.

[0010]

Means and Actions for Solving the Problems In order to solve the above problems, the present invention provides a method for producing a sintered ore using a high crystal water-containing ore as a raw material ore, which comprises: On the surface layer of particles mainly composed of CaO-containing auxiliary material,
A pseudo particle is formed by forming a coating layer mainly composed of a refractory ore containing 80 wt% or more of particles having a particle diameter of 0.25 mm or less and a solid fuel, and sintering the pseudo particle. A method for producing a sintered ore is provided.

The present invention will be described in detail below.

In the present invention, an ore containing a high amount of crystal water, such as a pisolite ore, is used as a raw material ore, and fine particles of the ore are positively reacted, but coarse particles are densified and left as a residual original ore. It is based on the idea. That is, in the present invention, pseudo particles are formed by forming a coating layer mainly composed of a finely powdered hardly-melting ore and a solid fuel on the surface layer of particles mainly composed of a highly crystallized water-containing ore and a CaO-containing auxiliary raw material. However, this coating layer prevents excessive melting of fine grains of ore containing high crystal water and suppresses the intrusion of the melt into the coarse grains to promote the densification of the coarse grains, thus ensuring an appropriate melt. To do.

The pseudo particles in the present invention have a structure as shown in FIG. Here, the high crystal water containing ore, for example, the pisolite ore is composed of fine and coarse ores, and therefore two types of quasi-particle morphologies of (a) and (b) in FIG. 1 are conceivable. (A) of FIG. 1 is a pseudo particle in which a coating layer 2 composed of a fine powder refractory ore and a solid fuel is formed on the surface layer of an aggregate particle 1 composed of a fine grained highly crystalline water ore and a CaO-containing auxiliary raw material, 1 (b) is a coarse-grained highly crystalline water ore 3
It is a pseudo particle in which the surface layer of the particles to which the CaO-containing auxiliary raw material 4 is attached is coated with the coating layer 5 made of fine powder of infusible ore and solid fuel. Here, the standard of the particle size of the high crystal water containing ore is a fine particle or a coarse particle is about 1 mm.

When quasi-particles containing fine crystal water ore (for example, pisolite ore) as shown in FIG. 1 (a) are sintered, the crystal water in the crystal water ore at 300 ° C. dissociates and becomes porous. . Further, the combustion of the solid fuel in the surface layer of the pseudo particles and the oxidation of the fine powder of the refractory ore progresses, and the heat generated at this time raises the temperature further. Then, at 1200 ° C. or higher, a large amount of melt is generated by the reaction between the porous highly crystalline water ore and the auxiliary raw material inside the pseudo particles. At this time, the melt tends to flow out of the pseudo particles, but is suppressed by the coating layer 2 containing the fine powder of the hardly-melting ore formed on the surface layer. That is, unlike the conventional method, even if a large amount of melt is generated, the melt acts to confine it inside the pseudo particles, so that it is possible to suppress deterioration of the air permeability of the sintered layer.

On the other hand, when pseudo particles containing coarse-grained high crystal water ore (for example, pisolite ore) as shown in FIG. 1B are sintered, the crystal water in the high crystal water ore dissociates at 300 ° C. Become quality. Then, heat is generated due to the combustion of the solid fuel in the coating layer 5 of the pseudo particles and the oxidation of the finely-melted ore,
It becomes even hotter. At 1200 ° C. or higher, the coarse-grained high crystal water ore 3 and the adhering auxiliary material 4 react with each other, but most of them remain without reacting because the adhering auxiliary material is small. 1 more
When the temperature is 300 ° C. or higher, densification of the porous highly crystalline water ore proceeds, and the strength is recovered. At this time, the coating layer 5 containing the fine powder of hardly-melting ore formed on the surface layer of the high crystal water ore has an effect of suppressing the intrusion of the melt from the outside.

Incidentally, FIG. 1 shows a typical example of fine and coarse particles of an ore containing high crystal water in order to easily understand the structure of the pseudo particles. In FIG. 1B for explaining the structure of coarse particles,
The state in which the CaO-containing auxiliary raw material is attached to the surface of one particle is shown.

In the present invention, a fine powder of infusible ore and a solid fuel are used as the coating layer. The reason why the refractory ore is used for the coating layer is to effectively exhibit the above-mentioned functions of the coating layer. The reason why the surface layer of the pseudo particles is coated with the solid fuel is to increase the burning rate of the solid fuel. Thereby, the solid fuel plays a role of efficiently dissociating the crystal water of the high crystal water-containing ore and densifying the porous high crystal water-containing ore at an early stage. The solid fuel is contained in the coating layer as described above, but a part thereof may be supplementarily contained in the inner layer from the viewpoint of improving the sinterability.

Since the refractory ore used for the coating layer needs to adhere to pseudo particles, it needs to be a fine powder containing 80% by weight or more of particles having a particle size of 0.25 mm or less. .

It is preferable to use an ore containing 10% by weight or more of FeO as the fine powder of the hardly fusible ore used for the coating layer. Examples of such ores include magnetite-based fine powder ores containing magnetite. An ore containing 10% by weight or more of FeO typified by the magnetite type fine powder ore is produced from Fe ₃ O ₄ to Fe in the temperature rising process during sintering.
_The crystal structure changes to ₂ O _3, and rearrangement of the crystal structure occurs. At this time, the fine ores in the coating layer are partially bonded by a sintering reaction to enhance the coating effect. Further, the heat of oxidation of magnetite also has the effect of promoting sintering. Where FeO
The content of 10% by weight or more is because if it is less than this, the function of enhancing the covering effect by rearrangement of the crystal structure becomes insufficient.

FeO represented by magnetite ore
It is preferable that the mixing ratio of the refractory ore containing 10% by weight or more is 3 to 30% by weight based on the entire raw material ore. The reason is that if the coating amount of fine ore is less than 3% by weight, the effect of suppressing the melt from flowing out of the pseudo particles is small,
On the other hand, when it exceeds 30% by weight, the melt flowing out to the outside of the pseudo particles disappears, so that the melt necessary for bonding between the pseudo particles becomes insufficient and the yield of the sintered ore decreases.

In addition to the above-mentioned ones, an ore containing 4% by weight or more of TiO ₂ can be preferably used as the finely powdered, hardly-melting ore used in the coating layer in the present invention. Such ores include iron sand and ilmenite (FeTiO 3
₃ ) can be mentioned. Thus ores containing TiO ₂ 4 wt% or more, by the action of TiO _2, for reactivity with the melt generated inside the pseudo particles is small, the coating effect of sufficiently cover layer be the mixing ratio is low Can be demonstrated. Specifically, the effect of suppressing the outflow of the melt appears when the content of the raw ore is 1% by weight, and when it exceeds 10% by weight, the melt necessary for bonding the coated particles is insufficient and the yield is high. Cause a decline. Therefore, in this case, the blending ratio of the refractory ore to the entire raw material ore needs to be 1 to 10% by weight. It should be noted that the iron sand and ilmenite exemplified above each contain 1% FeO.
It contains 0% by weight or more, and also fulfills the same function as that of the above-mentioned magnetite-based fine ore.

In the present invention, the high crystal water content ore refers to one containing approximately 4% by weight or more of crystal water. Further, the compounding ratio of the high crystal water-containing ore to the entire raw material ore is about 20% by weight or more. If the amount of water of crystallization is less than 4% by weight, or even if it is 4% by weight or more and the compounding ratio is less than 20% by weight, there is no problem of productivity reduction during sintering.

As the solid fuel, coke, anthracite, char, waste plastic and the like can be used, and these may be used alone or in combination. Of these, coke is preferred. The particle size of the solid fuel is not particularly limited, but it is preferably 3 mm or less in order to enhance the covering effect.

At the time of actual sintering, the raw material having the above-mentioned pseudo-particle structure is charged on a sinter machine pallet to form a sintered layer (sinter bed), and a coke oven gas or the like is formed therein. Is supplied to ignite and sinter. Here, if the solid fuel amount is charged so as to segregate in the vertical direction of the sintered layer, the effect of further improvement will be exhibited. Specifically, by increasing the amount of solid fuel of the pseudo particles in the upper layer of the sintered layer with insufficient calorific value, and reducing the amount of the solid fuel of the pseudo particles in the lower layer of the sintered layer with excessive calorific value,
The amount of heat in the vertical direction of the sintered layer becomes uniform. By homogenizing the amount of heat in this way, it becomes easy to control the melt generation by the above-mentioned pseudo particle design.

[0025]

EXAMPLES Table 1 shows the compounding conditions of the conventional method and the examples. The compounding ratio is shown as a weight ratio when the total ore is 100%. Under all experimental conditions, the amount of pisolite ore used as a high crystal water content ore was 40%, and the amount of quick lime added was 0.5.
%, And the amount of coke added was 3.8%. Further, A ore, B ore and limestone were adjusted to have a basicity of 1.8 and a silica content (target value) in the product sintered ore of 5.3%. Note that the ore A and the ore B have different components, and the ore A has more SiO ₂ . The reason why two kinds of ores are used is to control the silica content of the sinter.

In Example 1, the magnetite-based fine ore and the outer layer mainly composed of coke were composed of 40% of pisolite ore.
The inner layer contained was coated on the outside. Further, quick lime was added to the outer layer, but this was for the purpose of enhancing the granulation property, and the addition amount was 0.5% so as not to participate in the reaction.

In Example 2, an outer layer mainly composed of iron sand and coke was coated on the outer side of the inner layer, and 0.5% quicklime was added to the outer layer as in Example 1.

[0028]

[Table 1] The experimental flow is shown in FIG. In the conventional method, as shown in (a), all the raw materials 14 were charged into the mixer 11, mixed, and then granulated while adding water in the mixer 12. On the other hand, in Examples 1 and 2, after mixing the raw material 15 for the inner layer of Table 1 with the mixer 11 and granulating, the raw material 16 for the outer layer of Table 1 was charged into the mixer 12 together with the particles, and the mixer 11 The raw material 16 was coated on the surface layer portion of the particles formed in step 1 to form pseudo particles. Then, in any method, the pseudo particles were charged into the sintering device 13 and sintered.

A photograph of a cross section of the pseudo particles granulated in Example 1 is shown in FIG. FIG. 3A shows a cross section of a pseudo particle using fine pisolite ore. From this (a), it can be observed that a coating layer composed of magnetite-based fine ore and coke is formed on the surface layer of particles composed of fine pisolite ore, limestone, A ore (fine powder) and B ore (fine powder). . Further, FIG. 3B shows a cross section of a pseudo particle using coarse-grained pisolite ore. From this (b), limestone, A ore (fine powder), B ore (fine powder), pisolite ore (fine powder) is added to coarse-grained pisolite ore (porous portion in the center).
It can be seen that a coating layer composed of magnetite-based fine ore and coke is formed on the surface layer of the particles formed by adhering a small amount of.

Actually, in addition to the pseudo particles shown in FIGS. 3 (a) and 3 (b), there are also pseudo particles having coarse A ore and B ore as core particles. Since it is not involved, the explanation is omitted.

For the sintering of the pseudo particles, the pseudo particles are charged into the sintering apparatus 13 to form a sintered layer, and the coke oven gas is supplied to the sintered layer in the ignition zone to ignite the pseudo particles. It was done by burning the coke inside.

FIG. 4 shows the result of the firing test as described above using the pseudo particles formed by the above-mentioned conventional method, the method of Example 1 and the method of Example 2. FIG. 4 is a graph showing the drop strength, yield, and production rate of sintered ore obtained by sintering the pseudo particles produced by the conventional method in which the raw fuel was uniformly mixed, and the methods in Examples 1 and 2. is there.

As shown in this figure, Example 1 and Example 2
Both of the sintered ores manufactured by the method have a higher drop strength than the sintered ores manufactured by the conventional method, and in the case of Examples 1 and 2, the effect of improving the production rate was recognized as compared with the conventional method. .

Next, a magnetite ore as a raw material for the outer layer,
In order to examine the appropriate amount of iron sand, a test was conducted under the compounding conditions shown in Table 2.

In this table, the compounding ratio is 10% for all ores.
The weight ratio is shown as 0%. Under all experimental conditions, the amount of pisolite ore used was 40%, the amount of quicklime added was 0.5%, the amount of coke added was 4.0% (inner layer 1.0
%, Outer layer 3.0%). Further, A ore, B ore and limestone were adjusted to have a basicity of 1.8 and a silica content (target value) in the product sintered ore of 4.5%. A firing test was performed on this raw material according to the flow shown in FIG.

In Example 3, the amount of magnetite type fine ore in the outer layer was changed between 0 and 30%, and in Example 4, the amount of sand iron in the outer layer was changed between 0 and 15%.

[0037]

[Table 2] The influence of the coating amount of the refractory ore on the production rate at this time is shown in FIGS. FIG. 5 shows the case of using magnetite type fine powder ore as the refractory ore, and FIG. 6 shows the case of using iron sand.

As shown in these figures, it became clear that there is an appropriate value for the coating amount of fine ore. Although the sintering time is shortened and the production rate is improved by increasing the coating amount of the fine ore, when the coating amount of the fine ore is further increased, the production rate is reduced due to a decrease in yield due to lack of melt.
Judging from FIG. 5, the optimum value of the coating amount of the magnetite-based fine ore is 30% at maximum with respect to the total ore amount, and judging from FIG. 6, the appropriate value of the coating amount of sand iron is against the total ore amount. The maximum is 10%.

[0039]

As described above, according to the present invention,
Even if a large amount of pisolite ore, which has been difficult to use as a sintering raw material in the past, is used, it becomes possible to manufacture a high quality sintered ore while maintaining high productivity.

[Brief description of drawings]

FIG. 1 is a schematic view showing the structure of pseudo particles formed by the method of the present invention, where (a) uses fine-grained pisolite ore, and (b) uses coarse-grained pisolite ore. Is shown.

FIG. 2 is a schematic diagram for explaining a production flow of a sintered ore, (a) showing a conventional flow and (b) showing a flow of an embodiment of the present invention.

3A and 3B are photographs showing the particle structure of the pseudo particles prepared in Example 1, where FIG. 3A shows the one using fine pisolite ore, and FIG. 3B shows the one using coarse pisolite ore. .

FIG. 4 shows the drop strength of the sinter produced according to the conventional method, Example 1 and Example 2, and the yield and production rate when producing the sinter according to the conventional method, Example 1 and Example 2. The figure shown in comparison.

FIG. 5 is a graph showing the relationship between the amount of magnetite-based fine ore contained in the coating layer (outer layer) and the production rate.

FIG. 6 is a diagram showing the relationship between the amount of iron sand contained in the coating layer (outer layer) and the production rate.

[Explanation of symbols]

 1 ... Aggregate particles 2 ... Coating layer 3 ... Highly crystalline water ore 4 ... CaO-containing auxiliary raw material 5 ... Coating layer 11, 12 ... Mixer 13 ... Sintering device 14, 15, 16 ... Raw material

Claims (9)

[Claims] 1. A method for producing a sinter using a high crystal water-containing ore as a raw material ore, wherein the surface layer of particles mainly composed of the high crystal water-containing ore and a CaO-containing auxiliary material has a grain size of 0. Two
A sintered ore characterized by forming a pseudo particle by forming a coating layer mainly composed of a refractory ore containing 80% by weight or more of particles of 5 mm or less and a solid fuel, and sintering the pseudo particle. Manufacturing method. 2. The refractory ore contains 10% by weight or more of FeO and has a compounding ratio of 3 to 3 with respect to the entire raw material ore.
30% by weight of the method for producing a sintered ore. 3. The method for producing a sintered ore according to claim 2, wherein the refractory ore contains magnetite. 4. The refractory ore contains TiO _{2 in an amount} of 4% by weight or more, and has a compounding ratio of 1 to the entire raw material ore.
A method for producing a sintered ore, which is 10% by weight. 5. The method for producing a sintered ore according to claim 4, wherein the refractory ore contains iron sand or ilmenite. 6. The method for producing a sintered ore according to claim 1, wherein the ore containing high crystal water contains 4% by weight or more of crystal water. 7. The sinter according to any one of claims 1 to 6, wherein the high crystal water-containing ore has a compounding ratio of 20% by weight or more with respect to the entire raw material ore. Manufacturing method. 8. The sinter according to claim 1, wherein the solid fuel contains one or more of coke, anthracite, char, and waste plastic. Manufacturing method. 9. When sintering the pseudo particles in a sintering furnace, the solid fuel amount of the pseudo particles in the upper layer of the sintering layer of the sintering furnace is larger than the solid fuel amount of the pseudo particles in the lower layer of the sintering layer. 2. A method of charging the sintering machine in a large number and sintering the same.
A method for manufacturing the sintered ore according to claim 8.