JPS63128128A - Manufacture of sintered ore - Google Patents

Abstract

PURPOSE:To reduce briquetting energy and also to improve sintered-ore quality, by screening starting material for sintering and by using the oversize product as a sole to be used at the time of sintered ore manufacture and also using the undersize product as a sintering material. CONSTITUTION:Ore as centering material in which that of <=3.0wt% content of water of crystallization and >=5mm grain size comprises >=20wt% and which is comparatively reduced in heat crack characteristic is classified by means of a 4-6mm sieve (e.g., 5mm sieve) 9 into the oversize and the undersize product. Next, the oversize product is fed to a sole hopper 1 of a DL-type sintering machine and, on the other hand, the undersize product is fed to drum mixer 8 to undergo pelletization with the addition of water and then fed into a surge hopper 2 as sintering material. Subsequently, the sole hopper is supplied from the sole hopper 1 onto a moving pallet 4 of the DL-type sintering machine until a thickness of about 60mm is reached, and then, the sintering material is fed onto the above from the surge hopper 2 so that a thickness of about 450mm is reached, followed by downward suction at a pressure of about 1,000mmH2O so as to carry out sintering with high efficiency.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for producing sintered ore using sintered raw materials of 4 to 6+
This invention relates to a method for producing sintered ore, which is classified using W+S and the sintered ore is used as bedding ore.

[Conventional technology]

Generally, in the production of sintered ore from iron ore, as shown in Fig. 4, in the DL type sintering machine, sintered ore with a thickness of 4 to 6 mm or more is placed on a moving pallet 4 from a bedding hopper 1. 10 to 5 (1wm thick) on the grate, and on top of it from the surge hopper 2, the raw material for sintering and granulation processing (firing raw material)
After laying the ignition furnace 3 with a thickness of about 300 to 600 mm+,
The surface of the raw material layer is ignited, and firing is performed by downward suction. 5 is a crusher, 6 is a sieve, 7 is a sintering raw material hopper, and 8 is a mixer.

In this case, the material laid directly above the grate is called bedding ore, which means that sintering progresses from the top surface to the bottom surface, and when the sintering is completed and the ore is discharged, the bottom grate and the sintered material are separated from each other. It has the role of preventing it from becoming stuck due to burn-in. In other words, bedding ore does not contain coke powder, which serves as a fuel, unlike the granulation raw material, so it does not melt and has the function of preventing molten material dripping from above from penetrating to the grate surface. By being located between the sintered material and the grate, it is possible to prevent the sintered material from seizing on the surface of the grate.

Now, sintered ore with a diameter of 4 to 6 mm or more is usually used for this bedding ore, and the reason for this is that the gap between the openings of the grate is 4 to 6 mm.
This is related to the fact that the diameter is about mm, and if the diameter is mainly 4 to 6 mm, most of it will fall under the grate. In addition, the reason why the material is sintered ore is that sintered mineral products are usually classified into 4 to 6 mm, and the sieved product has a particle size of 4 to 6 mIIt or more, which matches the particle size, and there is no thermal cracking property. caused by.

In addition, some materials are disclosed in Japanese Patent Application Laid-Open No. 54-125103.
Some use lump iron ore having thermal crackability, as shown in Japanese Patent Application Laid-open No. 71306/1982, and others use limestone, as shown in Japanese Patent Application Laid-Open No. 71306/1983.

[Problem that the invention seeks to solve]

However, in the method of using material that has already been agglomerated as bedding, the finished product undergoes heat treatment in the process, and also undergoes transportation and crushing steps before being recovered as a sintered product, which deteriorates and becomes return ore, which can be recycled again. A loss occurs due to the agglomeration process. In addition, hot-cracked iron ore or limestone undergoes significant deterioration and collapse due to sintering heat treatment, and most of it becomes return ore.
Similar losses occur. In other words, using lump ore or finished sintered ore, which can be directly charged into the blast furnace without sintering, as bedding ore, reduces the amount charged in the blast furnace by the amount that deteriorates and becomes powder in the sintering process. decreases and causes loss.

Now, as shown in Figure 3, the raw materials used in the production of sintered ore are generally subsieve ore of pellets and lump iron ore, ore of grain size for sintering (sinter feed), and ore of grain size for pellets (sinter feed). These include pellet feed), miscellaneous raw materials generated at steel mills, slag-forming agents (lime-Ni slag, etc.), return ore, and coke powder.

Although the pellets and lump iron ore are sized using mine light, due to incomplete sieve classification and pulverization during transportation, approximately 10% of the iron ore is finely divided, which is undesirable for direct charging into the blast furnace. is mixed in. Therefore, before charging the blast furnace,
It is classified using a sieve of about 10 mm, and this sieve ore is used as a sintering raw material.

Furthermore, Ginturf and Eid are raw materials for sintering that have been classified by mine light, and some of these raw materials have a diameter of 4 to 6 mm or more. For the above reasons, as shown in Table 1, the sintering raw material contains about 10% of 5rRm or more, and 1% or less of 10nuw or more.

Table 1 (Example of particle size composition of sintering raw materials) However, because these iron ores with sizes of 4 to 6 III and 11 or more are coarse particles during the sintering process, the melting required for sintering is hardly done, and the melt remains and the quality deteriorates. This is a factor that worsens the situation. It is also a factor that deteriorates the yield of sintered ore.

In other words, originally, the particle size of the iron source material charged into a blast furnace must be 4 to 6 mm or more due to air permeability, but when hydrated iron ore is classified using 4 to 6Al111, a large amount of fine powder is mixed in. do. Therefore, mine light is usually 10~12a
Classify with a sieve of +a+ grade, pellets and lump ore,
The sifter is used as sinter feed and is supplied to steel mills. At the steelworks, the pellets and lump iron ore are classified again, and the sieve ore and sinter feed are used as raw materials for sintering.

Therefore, since the 4-6 mm classification of the water-containing raw material is incomplete, the minimum size of pellets and lump iron ore increases, deteriorating the yield, and at the same time, in the sinter production side, the raw material coarse grain ratio increases and the quality of the raw material increases.・There was a drawback that the yield was deteriorated.

Means for Solving Problem C] The present invention for solving the above problems classifies part or all of the raw material for sintering at 4 to 6m+a, and passes over this sieve into a part or part of bedding ore. It is characterized in that it is used as a whole, and the bottom of the sieve is used as a raw material for sintering and firing.

[Specific structure of the invention] The method of the present invention will be explained in more detail below.

First, the raw material for sintering is classified through a 4 to 6III11 sieve. However, in a water-containing state, complete classification is difficult, and about 10 to 50% of powder of 4 to 6 ml11 or less is mixed into the sieved product.

The sifted product is generally 4 to 6 ml or less, and other sintering raw materials and coke powder are added thereto and granulated to create a firing raw material. And on the sintering machine pallet grate, the height is approximately 10IIl111~100III1
In step 1, the sieved product is charged as bedding ore, and the fired raw material is charged thereon at a height of approximately 300 mm to 700 mm,
Sintering is performed by igniting the surface layer and suctioning it from below. The raw materials for sintering are sintered, the bedding ore is subjected to heat treatment, and the ore is discharged. The discharged sintered cake and bedding ore are sent to a 4-6 mm sieve classification equipment after a crushing process. In this classification, the classified product is subjected to baking heat treatment, so it is in a dry state and does not cause clogging, so the classification efficiency on the sieve is good, and the product on the sieve has almost no paddy contamination of 4 to 6 mm or less. It is composed of sintered mineral products of 4 to 6 mm or more and ore that has undergone bedding heat treatment. The sieved product is then charged into a blast furnace as a finished product. On the other hand, the sieved product here is 4
It is composed of crushed pieces of sintered cake, crushed pieces of bedding ore, and mixed rice, with a volume of ~6 ml or less.

This sieved product is used as a return ore as a raw material for sintering and firing.

That is, in the method of the present invention, by using the 4-61 sieve product ore, which has a problem of contamination with powder of 4-6 mm or less, as bedding ore in the sintering process, it is subjected to heat treatment and then classified through the sieve in the sintering process. It has the feature that it can be charged into the blast furnace by utilizing the equipment and without mixing powder with a diameter of 4 to 6 mm or less. This feature has four advantages:

■ Ore of 4 to 6 a+m or more used as bedding is heat treated but not sintered, so compared to the usual sintering method including 4 to 6 III+ or more,
Sintering treatment (granulation, addition of coke powder, air blowing) is not necessary for ores larger than ~6 mm.

■ Compared to sintered cakes and products made from raw materials with a diameter of 4 to 6 mm or more, sintered cakes and products made from raw materials that do not have a diameter of 4 to 611101 or more improve product yield and quality. can be achieved.

(2) Compared to the case where sieved ore classified at 4 to 6 mm is directly charged into the blast furnace, since classification is performed after heat treatment, mixed rice can be removed and only rice grains of 4 to 6 mm or more can be charged into the blast furnace.

■ Compared to charging fully classified ore of 4 to 6 mm or more directly into the blast furnace, classification is performed after heat treatment, so thermal cracking is caused in advance, which prevents the generation of thermal cracking powder in the blast furnace. can.

By the way, as the type of raw material ore to be classified by 4 to 6IllIII to obtain the bedding, those having the following properties are preferable because they bring out the above-mentioned advantages.

(1) Those with a crystal water content (C, W, ) of 3.0 wt% or more (2) Those containing 20 wt% or more of grains with a grain size of 5 ms or more (3) Those that do not have much thermal crackability Ore with a water content of 3.0 wt% or more requires a large amount of heat to thermally decompose crystallized water in the sintering reaction, and therefore has the disadvantage of requiring a large amount of coke breeze in the sintering process. Therefore, the ore with a high crystallization water content is not used as a raw material for sintering, but is used as an ore that does not require the addition of coke.
It is advantageous to charge the blast furnace as a product of III11 or higher. In addition, those with a particle size of 4 to 6+++m or more are
The reason why ores containing more than -t% and having little thermal crackability are desirable is that when the ores are heat-treated after bed charging, discharged, and classified, a large amount becomes sieved products. In other words, ore that is classified for bedding and has a particle size of 4 to 6 mm or more has a small proportion of powder mixed in, and those that do not have much thermal cracking property are those that crack under heat to a size of 4 to 6 mm or less. This is because the amount of sintered products 4 to 611111 produced under the sieve is small, and the amount of products on the sieve increases.

In addition, the sieve size for obtaining bedding ore in nature is 4 to 61111.
The reason for this is related to the fact that the sieve size of the finished product is currently 4 to 6 ml11, and basically it needs to be the same size as the sieve size of the finished product. In this sense, it corresponds to the requirements of blast furnaces and is preferably about 5+u+.

〔Example〕

(Example 1) The entire sintering raw materials shown in Table 2 were used as shown in Figure 1.
Classification was performed using a 5 mm sieve 9, and the material was divided into upper and lower sieves. The sieved product is sent to DL type sintering machine bedding hopper 1. On the other hand, the unsieved product was sent to the drum mixer 8, water was added thereto, granulated, and then sent to the surge hopper 2 as a raw material for firing. Next DL
In the mold sintering machine, bedding ore is first laid on the moving pallet 4 from the bedding hopper 1 to a thickness of 60 mm, then firing raw materials are laid from the surge hopper 2 to a thickness of 450 am,
It was fired with downward suction at a pressure of 1000 m and 100 O.

After completion of firing, the ore was discharged, crushed by a crusher 5, and then classified by a sintered product sieve 6 at 5+m.

On the other hand, as shown in Fig. 4 of the conventional method, sintered ore is supplied from the sintered product line as bedding ore, and as shown in Fig. 5, <25~811IllO hot-crackable iron ore and limestone are separately prepared and bedded. The effect was compared with the case where the material was sent to the laying line and fired.

As shown in Table 3, the method of the present invention was able to supply agglomerated products of 5III11 or more to the blast furnace with less energy consumption than the conventional method.

In this case, in the method of the present invention, the particle size of limestone and coke powder in the blended raw materials was 51 or less, and almost no limestone or coke powder was observed to be mixed into the bedding ore. Therefore, no burning occurred between the grate and the bedding ore.

In addition, although some paddy was mixed into the bedding ore, since most of the paddy was larger than 5 mm, there was little that fell under the grate.

(Example 2) As shown in Fig. 2, iron ore 11 for sintering raw material was passed through 51 sieves 1
0, and the sieved product was supplied to the bedding line where the finished product was returned. The sifted product is sent to the sintering raw material line, where it is mixed, humidified, and granulated together with other ores, limestone, and coke powder as a sintering raw material in a mixer 8, and sent to a surge hopper 2 for supplying firing raw materials. Ta.

Next, in the OL type sintering machine, bedding is first laid on the movable pallet 4 from the bedding hopper 1 in an amount that balances the feeding amount, then the firing raw materials are laid down to a thickness of 450 mm, and a pressure of 1000 m and 100 O is applied. It was fired using downward suction.

After completion of firing, the ore was discharged and crushed by a crusher 5, and then classified by a sintered product sieve 6 to a size of 5 mm.

After classification, the sifted material was sent to the raw material bin as return ore, while some of the sieved material was sent as bedding ore, and the rest was sent to the blast furnace as a finished product.

In this method, sintering raw materials were selected under the conditions shown in Table 4, and production was performed using the same conditions for the finished product bedding usage.
As shown in Table 4, we were able to significantly improve energy usage per unit of product production, as well as improve quality. Among these, C, W, ore with a value exceeding 3.0%, 5f
The improvement effect was particularly great in cases where ores with fiII+ or higher grain sizes exceeding 20% and ores with low thermal crackability were classified for bedding.

〔Effect of the invention〕

As described above, according to the method of the present invention, 5
The agglomeration energy per agglomerated product amount of 1111 or more can be reduced, and the quality of sintered ore can be improved.

[Brief explanation of the drawing]

Figures 1 and 2 are process flow diagrams of the method example of the present invention;
The figure is a flow diagram of sintering raw materials, and FIGS. 4 and 5 are flow diagrams of conventional processing methods.

Claims (2)

[Claims] (1) A sintered ore characterized by classifying the raw material for sintering through a 4-6 mm sieve, using the sieved product as a bedding during the production of sintered ore, and using the unsieved product as a sintering raw material. manufacturing method. (2) Part of the powdered iron ore for sintering is classified through a 4-6 mm sieve, and the sieved product is used as part or all of the bedding during the production of sintered ore, and the sieved product is used as a raw material for sintering. A method for producing sintered ore, characterized in that it is used as a part of sintered ore.