JPH05247545A - Pseudo particle for raw material of sintered ore and raw material of sintered ore - Google Patents

Abstract

PURPOSE:To provide such pseudo particle for the raw materials of sintered ore and the raw material for sintered ore from which the high-strength sintered ore can be produced without increasing heat consumption even if high-water-of- crystallization-contg. ore is used as the raw material of the sintered ore for blast furnaces. CONSTITUTION:The pseudo particle for the raw material of the sintered ore is constituted by pelletizing the water-of-crystallization-contg. ore and solid fuel while satisfying either or both of the following requirements: (a) The solid fuel be stuck to the surface of the water-of-crystallization-contg. (b) The solid fuel be mixed with the water-of-crystallization-contg. ore. The desired raw material of the sintered ore is obtd. by further mixing CaO-contg. auxiliary raw materials and SiO2-contg. auxiliary raw materials with such pseudo particle for the raw material of the sintered ore as mentioned above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raw material for producing a sintered ore as a main iron ore raw material in a blast furnace operation, and a pseudo particle for a sintered ore raw material for obtaining the sintered ore raw material. is there.

[0002]

2. Description of the Related Art Sintered ore as a blast furnace raw material is generally manufactured by the following method. First, powdered ore of 10 mm or less, CaO-containing auxiliary materials such as limestone, SiO ₂ such as silica stone and serpentine
The contained auxiliary raw material and a solid fuel such as coke (hereinafter, represented by coke) are mixed, and an appropriate amount of water is added thereto to granulate. The granulated blended raw material is filled on a pallet of a Dwightroid type sintering machine, and the solid fuel in the surface layer of the packed bed is ignited. After ignition, the solid fuel is burned while sucking air downward, and the compounded raw materials are sintered by the combustion heat generated at that time to produce a sintered cake. This sinter cake is then crushed and sized, and sinter having a particle size of 3 mm or more is used as a blast furnace raw material.

In order to operate the blast furnace stably,
High-quality sinter is required, and cold strength, reducibility, and resistance to reduction powder are strictly controlled. From the viewpoint of sinter production cost, yield and productivity are also important management items.

[0004]

As the raw material ore of the sintered ore, hematite (hematite, Fe ₂ O ₃ ) and magnetite (magnetite, Fe ₃ O ₄ ) are mainly used. With the decrease in stone production, the amount of limonite containing a large amount of goethite (Fe ₂ O ₃ .H ₂ O) tends to increase. However, as is clear from the chemical formula of goethite, this iron ore contains a large amount of crystal water (usually 4% by weight or more), and when used in large amounts as a raw material for sinter, it is consumed to remove the crystal water. Not only the amount of heat increases, but also coarse air holes and cracks are generated during firing, which reduces the yield, strength, and productivity of products.

The reason why such a problem occurs can be considered as follows. In the sintering process, the crystal water of high crystal water containing ore decomposes and dehydrates from about 300 ℃, and cracks occur to change to a porous structure, but when it further rises to about 1200 ℃, CaO reacts with hematite. Then a melt is generated, and this melt immediately penetrates into the pores and cracks in the iron ore, so the amount of melt necessary for the bonding of the iron ore particles is insufficient, and the bonding between the particles is obstructed. To be done. Moreover, since the contact area between the particles and the melt is large, a part of the hematite particles dissolves into the melt at a high speed (assimilation reaction). As a result, the sintered ore after cooling becomes a state in which a large amount of granular hematite, a binder phase composed of calcium ferrite and slag, and a large amount of coarse air holes are mixed. This coarse air hole reduces the strength and yield of the product sinter, and also deteriorates the air permeability in the melt generation zone in the sintering bed, which delays the combustion of carbonaceous materials such as coke and reduces productivity. Conceivable.

As described above, it is problematic to use an ore containing a large amount of water of crystallization as it is as a raw material for sinter.
It is of great significance to develop effective utilization of ores containing high crystal water. For these reasons, various techniques have been proposed for the effective use of ores containing high crystal water, but all of them involve problems. For example, in Japanese Patent Laid-Open No. 59-197528, for a limonite ore containing a large amount of goethite, particles having a particle size of 3 mm or more, which are likely to remain as an original ore, are crushed to reduce the amount ratio and There is disclosed a technique of promoting melt generation and preventing a fragile ore from remaining as a base ore by controlling a mixing ratio of fine particles having a diameter of 0.5 mm or less to 20 to 30% by weight. However, this technique has a serious drawback in that the permeability of the packed bed is lowered due to an increase in the fine particle sample in the blended raw material, which leads to a decrease in productivity.

On the other hand, Japanese Patent Laid-Open No. 3-10027 discloses a ore containing a large amount of goethite at a temperature of 1200 ° C. or higher for a certain period of time to densify the ore and to improve yield, strength and production due to coarse air holes and cracks. A technique for preventing a decrease in sex is disclosed. However, in this technique, since the raw material is preheated, there is a problem that the amount of heat consumed increases and the production cost of the sintered ore increases. As described above, conventionally, it has been difficult to produce a sintered ore containing a large amount of ore containing a high amount of crystal water without lowering productivity while maintaining high thermal efficiency.

The present invention has been made under these circumstances, and its purpose is to achieve high strength sintering even when a high crystal water containing ore is used as a raw material for a sinter for a blast furnace. It is an object of the present invention to provide a pseudo particle for a sintered ore raw material and a sintered ore raw material that can produce ore without increasing the heat consumption.

[0009]

Means for Solving the Problems The present invention which has achieved the above-mentioned object is to use a crystal water-containing ore and a solid fuel in the following (a),
This is a pseudo particle for a sintered ore raw material, which is characterized in that it is granulated while satisfying one or both of the requirements of (b). (a) To attach solid fuel to the surface of ore containing water of crystallization. (b) Mixing ore containing water of crystallization with solid fuel. In addition to the above-mentioned pseudo particles for sintering ore raw material, Ca
By mixing the O-containing auxiliary material and the SiO ₂ -containing auxiliary material, the desired sintered ore raw material is obtained.

[0010]

The operation and effect of the present invention will be described below along with the background of the completion of the present invention. First, the inventors
A hematite-based ore layer with a crystal water content of 3% or less is used to determine the temperature change of a plain layer of a high crystal water content ore containing 4% or more crystal water by the time of sinter production. In the case of, the comparison was made under the condition that the coke content was constant.

The results are shown in FIG. 1. As is apparent from FIG. 1, the highest temperature reached by the ore plain layer containing high crystal water is lower than that by the hematite ore layer, and a melt is generated to cause a sintering reaction. The temperature range above 1192 ° C that contributes is extremely small. This is because a large amount of heat was consumed in the decomposition / dehydration reaction of crystal water, and the main reason for the significant inferior sinterability of high crystal water-containing ores was the lack of heat directly involved in the sintering reaction. Is considered to be.

As a method of eliminating the insufficient heat quantity during sintering, a method of compensating for the heat quantity required for the decomposition / dehydration reaction of crystal water by increasing the amount of coke can be considered. However, with this method, the manufacturing cost increases as the amount of coke increases. Therefore, in order to improve the strength and productivity of the product sintered ore without increasing the amount of coke, it is necessary to effectively input heat.

Therefore, the inventors of the present invention, by satisfying one or both of the requirements (a) and (b) described above, by granulating the crystal water-containing ore and coke in advance, the crystal water which is a heat absorbing substance. The idea that the contained ore can be selectively heated was obtained, and it was found that by adopting such a configuration, the decomposition / dehydration reaction of crystal water is promoted without increasing the amount of coke, and the strength of the product sintered ore can be improved. The present invention has been completed.
The present invention contains high crystal water (for example, 4% by weight or more).
The ore is assumed, and the present invention is most effective when such an ore is targeted, but the ore targeted by the present invention is not limited to one containing a large amount of crystal water, and Three
The application to the case of using an ore containing about% or less of water of crystallization is not excluded.

It is premised that the amount of coke used in the present invention is not increased more than in the prior art, but not only when all of the planned amount of compounding is compounded during the granulation step, but also when the amount of crystal water is decomposed
The amount considered to be necessary for evaporation may be added during the granulation process, and the balance may be additionally mixed with the auxiliary raw materials. The amount of heat required to decompose and evaporate 1% by weight of water of crystallization is 11.8 kcal with respect to 1 kg of ore containing water of crystallization. Therefore, it is preferable that the minimum required amount of coke used for granulation be at least an amount equivalent to the amount of heat generated.

The present invention will be described in more detail with reference to the following examples, but the following examples are not intended to limit the present invention, and any modification of the design can be made according to the gist of the preceding and the following. It is included in the target range.

[0016]

[Example] Using a high crystal content water ore of the chemical composition of Table 1,
A sintered ore raw material was obtained by the equipment shown in FIG. In FIG. 2, 1 is a high crystal water containing ore, 2 is a coke, 3 is a granulator, 4 is a drum mixer, and 5 is other raw materials (CaO-containing auxiliary raw material, SiO ₂ -containing auxiliary raw material, etc.).

[0017]

[Table 1]

Highly crystalline water-containing ore 1 and coke 2 (4.07% by weight) were granulated in advance using a granulator 3 and then mixed with another raw material 5 using a drum mixer 4 to obtain a sintered ore raw material. And Using the sintered ore raw material obtained above and the sintered ore raw material mixed by the usual method, these are 100 mm in diameter and
It was filled in a 350 mm sintering pot. Next, the top surface of the layer is ignited, and firing is performed while suctioning air with a suction pressure of 360 mm H ₂ O,
Sintered ore was manufactured, and the drop strength and production rate of the obtained ore were investigated. At this time, since the sintered ore raw material layer according to the present invention had good air permeability, the suction pressure was set to 300 mm H ₂ O.
The drop strength and the production rate were measured by the following methods.

(Drop strength) A product sinter is dropped from a height of 2 m onto an iron table at once. After repeating this operation 4 times, screen the whole amount with a 4.8 mm sieve and calculate the drop strength from the following formula. Drop strength = (weight on sieve / weight before test) × 100 (production rate) A value showing the production amount of product sinter per unit area of pallet and per unit time, which is calculated by the following formula .. However, the sintering time depends on the CO ₂ concentration in the exhaust gas.
The end time was defined as the time when it became 0.1% or less. Production rate = (cake weight × yield) / (pallet area × sintering time) The results are shown in Table 2. For comparison, Table 2 also shows the results when the coke was added to the sinter ore raw material mixed by the usual method to compensate for the amount of heat required for the decomposition of water of crystallization.

[0020]

[Table 2]

As is apparent from Table 2, when the sintered ore raw material of the present invention is used, the same strength as when compensating for the amount of heat required for the decomposition of water of crystallization is obtained without increasing the amount of coke. I understand. Although the production rate has not changed much, this is because the suction pressure is controlled to be low as described above, and it is considered that the production rate is improved by making the suction pressure equal to that of the untreated raw material.

[0022]

EFFECTS OF THE INVENTION The present invention is constituted as described above, and even a high crystal water content ore which has been difficult to use as a raw material for sinter ore for a blast furnace can be effectively utilized. Pseudo particles for sinter ore raw material and sinter ore raw material capable of producing high-strength sinter with low heat consumption were obtained.

[Brief description of drawings]

FIG. 1 is a graph showing temperature changes in a highly crystalline water ore layer and a hematite-based ore layer during a sintering process.

FIG. 2 is a schematic explanatory diagram of equipment used for manufacturing a sintering raw material in Examples.

[Explanation of symbols]

 1 Ore containing high crystal water 2 Coke 3 Granulator 4 Drum mixer 5 Other raw materials

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiko Igawa 1 Kanazawa-machi, Kakogawa City Kobe Steel, Ltd. Kakogawa Works

Claims (2)

[Claims] 1. A crystal water-containing ore and a solid fuel are prepared according to the following (a),
Pseudo-particles for sintered ore raw material, characterized by being granulated while satisfying one or both of the requirements shown in (b). (a) To attach solid fuel to the surface of ore containing water of crystallization. (b) Mixing crystal water containing ore with solid fuel. 2. A sintered ore raw material, wherein the pseudo particles for a sintering raw material according to claim 1 are further mixed with a CaO-containing auxiliary raw material and a SiO ₂ -containing auxiliary raw material.