KR101525068B1 - Method for adjusting precursor powder for sintered ore, and precursor powder for sintered ore - Google Patents

Abstract

According to the present invention, the mixing ratio [(C)] of the iron ore raw material mass (F) having a grain diameter of 0.5 mm or less to the minute coke mass (C) having a grain size of 0.5 mm or less in the powder coke, / F) × 100] is adjusted in the range of 7 to 8%, it is possible to adjust the raw material for sintered ores, which does not depend on the quality of the iron ore and is excellent in the production efficiency of the sintered ores.

Description

METHOD FOR ADJUSTING PRECURSOR POWDER FOR SINTERED ORE, AND PRECURSOR POWDER FOR SINTERED ORE <br> <br> <br> Patents - stay tuned to the technology METHOD FOR ADJUSTING PRECURSOR POWDER FOR SINTERED ORE,

The present invention relates to a method of adjusting a precursor powder for a blast furnace for a blast furnace and a raw material for sintering obtained thereby.

It is important to use high-quality sintered ores having excellent properties such as cold strength, reducing ability and anti-reduction-disintergration property for the stable and highly efficient operation of the blast furnace. However, such sintered ores have many control items at the time of production, and various problems have arisen in order to improve the yield and productivity of the finished product.

Generally, sintered ores are produced by the following method.

First, CaO-containing raw materials such as coke or lime stone as a coagulating material, SiO ₂ -containing raw materials such as nickel slug and the like are added to iron ores having a grain size of about 10 mm or less and mixed with appropriate water And the mixture is mixed and granulated by a disk pelletizer or the like. Thereafter, the obtained pelletized raw material for sintered ores is charged on a pallet of a sintering machine together with a coke breeze to form a raw material layer for sintered ores on the pallet. Subsequently, the raw material layer for sintering is ignited through the solid fuel at the surface layer portion. Then, the action of air causes the solid fuel in the raw material layer for sintered ores to burn successively and sinter to form a sinter cake. The sintered cake is uniformly-sized particles, and then the sintered cake is conveyed to the blast furnace as a sintering furnace for blast furnace.

That is, the sintered ores are made by pelletizing iron ore by agglomeration and reaction melting with a slug component such as CaO or SiO ₂ .

Here, the growth of demand for steel materials in emerging countries including all countries in Asia has recently become particularly noticeable. The demand for iron ore, which is a raw material of sintering furnace for blast furnace and sintering furnace for blast furnace, is also continuously growing.

The above-mentioned growth in the demand for iron ores causes a problem that has not occurred in the past. In other words, the quality of the iron ore to be supplied can not be freely selected. In particular, iron ores or the like having a large variation in particle size distribution are often supplied.

In addition, as described above, there still remains a problem of improving the yield and productivity of the finished product, which is a conventional problem. That is, at present, it is desired to improve the production efficiency of the sintered ores more than the conventional ones, while the deviation of the grain size of the iron ores is large.

Here, when producing the sintered ores, the minute coke in the raw material is burned by the air passing through the raw material layer for sintered ores. That is, it can be said that the productivity is determined by the passing air volume (air permeability) of the raw material layer for sintered ores. The air permeability is largely divided into the cold air permeability before sintering determined by the particle size of iron ore and the hot air permeability after sintering determined by the pore diameter of the sintered cake which is the flow path of the air generated through the flow of the melt , The cold air permeability before sintering determined by the grain size of iron ore and the like is easily influenced by the deviation of the quality of the ore raw material described above and recently has been a great problem especially for the improvement of the productivity.

However, at present, effective measures have not been proposed for the above-mentioned problems.

The present invention has been developed in consideration of the above-described phenomenon, and it is an object of the present invention to provide a method of adjusting raw material powders for sintered ores used for a sintered ores used in blast furnaces, Min. &Lt; / RTI &gt;

The inventors of the present invention have conducted extensive studies to solve the above problems. As a result, it has been found that adjusting the mixing ratio of the iron ore raw material of the predetermined shape and the partial coke of the predetermined shape in the predetermined range in the raw material for sintering raw material in mixing or the like with the disk pelletizer improves the production efficiency of the sintered ores And that it works well for That is, in the present invention, particularly, the cold air permeability before sintering is improved by changing the property of the partial coke in accordance with the quality (deviation of particle diameter) of the iron ore raw material. As a result, (JPU index) of the pseudo-granulated sintered ores (raw material for the sintered ores) is achieved, thereby improving the production efficiency of the sintered ores.

The present invention is based on the above-described recognition, and the structure of the subject matter is as follows.

1. In producing sintered ores for blast furnace by mixing and assembling iron ore raw material, minute cokes and subsidiary materials with a disk pelletizer, charging them into a sintering machine, and sintering,

(C / F) x 100] of the iron ore raw material mass (F) having a grain size of 0.5 mm or less and the one-minute coke mass (C) having a grain size of 0.5 mm or less in the above- To 8% by weight of the raw material powder.

2. The method for adjusting the raw material powder for sintering as described in 1 above, wherein the mixing ratio [(C / F) x 100] is in the range of 7.2 to 7.8%.

3. As raw material for sintering furnace for blast furnace consisting of iron ore raw material, coke, and additives,

(C / F) x 100] of the iron ore raw material mass (F) having a grain size of 0.5 mm or less and the minute coke mass (C) having a grain size of 0.5 mm or less in the above- % Of raw material powder for sintered ores.

4. The raw material powder for sintering ornamental according to 3 above, wherein the mixing ratio [(C / F) x 100] is in the range of 7.2 to 7.8%.

According to the present invention, even when there is a deviation in the quality (particle size distribution) of the iron ore raw material, the air permeability (JPU index) of the raw material for sintered ores in the sintered pallet stably achieves an improvement in the production efficiency of the sintered ore .

1 is a graph showing the relationship between the mixing ratio [(C / F) x 100] of iron ore raw material and partial coke and JPU.

(Mode for carrying out the invention)

Hereinafter, the present invention will be described in detail.

In the present invention, an iron ore raw material, a partial coke and a subsidiary raw material are mixed and assembled with a disc pelletizer to prepare a sintered raw material for sintering, and the sintered raw material is charged into a sintering machine and sintered to produce a sintered ore for a blast furnace . At this time, particularly, as described below, the iron ore raw material and the partial coke are appropriately combined in consideration of the grain size thereof, so that the productivity in sintering, that is, the raw material fraction for sintered ores in the sintered pallet obtained by the following formula (1) (JPU index, hereinafter simply referred to as &quot; JPU &quot;). In addition, JPU means that the larger the numerical value is, the better the air permeability is, and the value of 22 or more is a value that is considered good from the viewpoint of the productivity at the time of producing the sintered ores.

(JPU) = [Air volume (m3 / min) / Firing area (m2)] [Layer thickness (mm) / Negative pressure (mmAq)] ^0.6

···(One)

Here, in the formula,

Amount of air: The amount of air passing through the raw material for sintering in a certain firing area,

Firing area: The area of the raw material powder for sintering,

Layer thickness: The layer thickness of the raw material powder for the sintered ore at the place where the air flow rate was measured,

Negative pressure: Pressure of the suction part under the raw material for sinter ore

Respectively. Further, 1 mmAq = 9806.38Pa.

In the present invention, the particle diameter is measured by a sieve classification method (JIS R6001 (1998)).

The iron ore raw material used in the present invention may be selected from the group consisting of hematite ore from South America, magnetite ore from North America, South American magnetite, Australian pisolite ore and Marra Mamba ore. And the like.

In the present invention, the mixing ratio [(C / F) x 100] of the iron ore raw material mass (F) having a grain size of not more than 0.5 mm and the one-minute coke mass (C) 7 to 8%. However, the mass of the iron ore raw material when calculating the above F is calculated without including the mass of the return ore.

The mechanism for achieving a good JPU by controlling the mixing ratio [(C / F) x 100] can be considered as follows.

When the mixing ratio is small, that is, when the mixing ratio is less than 7, it means that the particle size of the ore is large with respect to the particle size of the coke. Therefore, if the particle size of the minute coke becomes too small, the sintering speed increases but the width of the sintering melting zone also increases, thereby deteriorating the air permeability in the hot state. On the other hand, when the mixing ratio is large, that is, when the mixing ratio is large, that is, when the particle size is larger than 8, the particle size of the minute coke is assembled, and pseudoparticles having minute coke as the nuclear particles are remarkably produced in the assembling process. Since the pseudocarticles having the minute coke as the nuclear particles have low wettability of the minute coke, the strength of the pseudo-particles is not expressed, and the pseudo-particles tend to collapse during the handling process until they are charged into the sintered pallet, The pseudo-particles charged into the pallet are refined to deteriorate the breathability.

Therefore, it is clear that there is an appropriate range of the particle size of the minute coke to the ore particle size, but the range can be represented by a value of C / F x 100, which is 7 to 8% as described above. The preferable range of the value of C / F x 100 is 7.2 to 7.8%.

In the present invention, the sub-raw material includes CaO-containing sub-materials such as limestone, SiO _2- containing sub-materials such as nickel slug, and the like, but there is no particular limitation, and conventionally known additives such as subsidiary materials used for sintered ores It is assumed that the impurities which become impurities are also included.

The mixing ratio is determined so that CaO / SiO ₂ (= basicity) in the sintered ores is close to 2.0.

The disc pellet tie used in the present invention may be a conventional disc pelletizer used for manufacturing (assembling) a raw material for sintered ores. In addition, a drum mixer may be used in a conventionally known method, such as preliminary mixing or a lime outer case after assembly.

The sintering machine used in the present invention is preferably a downwash Lloyd type sintering machine. In addition, a known sintering machine for producing raw material powder for sintered ores can be used.

As described above, according to the present invention, it is possible to obtain raw material for sintered ores for blast furnace, which is made of an iron ore raw material, a partial coke and an additive, and is excellent in production efficiency.

That is, the mixing ratio [(C / F) x 100] of the iron ore raw material mass (F) having a grain size of 0.5 mm or less and the one-minute coke mass (C) The raw material powder for sintered ores, which is in the range of 7 to 8%, preferably in the range of 7.2 to 7.8%, can be obtained.

In addition to the materials specially defined in the above, materials such as raw material powders, production equipment, operating conditions and the like can be produced according to the commercial method.

(Example)

[Example 1]

The raw material powder for sintered ores was adjusted under the conditions shown below. Subsequently, using the obtained raw material for sintered ores, the sintered material was charged into a dewatering type sintering machine of a downward sucking to produce an sintered ores. JPU in sintering the raw material powder for sintered ores was investigated to confirm the effect of the present invention.

Iron ore raw material

Unit of raw material of iron ore: 1100 ~ 1200 (kg / t-sr)

Ratio of raw material of iron ore of 0.5mm or less: 20 ~ 35 (%

Minute coke

Minute coke's basic unit: 45 to 50 (kg / t-sr)

Percentage of minute cokes below 0.5 mm: 30-50 (% large coke)

Mixing ratio [(C / F) x 100]: 6.5 to 8.2%

The subsidiary material is limestone: 6 ~ 10% (raw materials for loading)

Disk pelletizer: 7.2 m diameter

Fig. 1 shows the relationship between the mixing ratio [(C / F) x 100] of the iron ore raw material of 0.5 mm or less and the minute coke of 0.5 mm or less and JPU. From the same drawing, the JPU of the raw material powder for sintered ores made of the blend ratio [(C / F) x 100] satisfying the conditions of the present invention shows a good value of about 22 or more.

On the other hand, JPU was in the range of 19 to 21, that is, 21 or less, as shown in Fig. 1, and the JPU was inferior to the JPU in that the mixing ratio [(C / F) x 100] did not satisfy the conditions of the present invention.

[Example 2]

An embodiment in which the present invention is applied to a real machine will be described.

Usually, the iron ore raw material used in the sintering process is automatically sampled in a raw material yard and then the particle size distribution is measured according to Japanese Industrial Standard JIS 8706.

With regard to the minute coke, the lump coke produced in the ordinary coke factory was sieved, or the purchased anthracite was received in the sintering plant and pulverized until the particle size distribution suitable for the operation was obtained and used in the sintering process.

The pulverization was carried out by a device such as a rod mill, a cage mill, and a ball mill. Subsequently, the crushed coke was sampled with a sampler installed at the transfer point of the belt conveyor, and then dried with a drier to measure the particle size distribution on a Ro-tap type sieve shaker.

According to the present invention, the crushing conditions of the minute coke were adjusted according to the particle size constitution of the iron ores, that is, the presence ratio of 0.5 mm or less, and the existence ratio of 0.5 mm or less in the minute coke was changed.

Table 1 shows the mixing ratio [(C / F) x 100] between the iron ore raw material (ore) of 0.5 mm or less and the partial coke of 0.5 mm or less and the measurement results of JPU. The ratio of the coke to the coke is A (kg / t) and the content of the ore is B (kg / t). The ratio of the coke to the coke is 0.5% , Then C = A x a and F = B x b.

From Table 1, the JPU of the raw material powder for sintered ores made with the mixing ratio [(C / F) x 100] within the range satisfying the conditions of the present invention shows a good value of about 22 or more.

On the other hand, as shown in Table 1, JPU was lagging at about 19 to 21, that is, 21 or less in JPU, because the mixing ratio [(C / F) x 100] did not satisfy the condition of the present invention.

Further, when the iron ore is classified and has a line capable of crushing, the mixing ratio of C / F represented by the inventive method can be realized by adjusting not only the crushing conditions of the minute coke but also the granulation conditions of the iron ores It is possible to do.

According to the present invention, raw material powder for sintered ores having excellent production efficiency of sintered ores can be obtained. Further, in addition to the improvement of the productivity, the air permeability is maintained, so that the lump yield and strength of the sintered ores are improved, and therefore, stable and highly efficient operation of the blast furnace can be achieved.

Claims (4)

In producing sintered ores for blast furnace by mixing and forming iron ore raw material, powdered cokes and subsidiary materials with a disk pelletizer, loading the sintered material into a sintering machine, and sintering,
A mixing ratio [(C / F) x 100] of an iron ore raw material mass (F) having a grain diameter of 0.5 mm or less and a minute coke mass (C) Is adjusted to a range of 7 to 8%. The method according to claim 1,
Wherein the mixing ratio [(C / F) x 100] is set in the range of 7.2 to 7.8%. As a raw material for sintered ores for a blast furnace comprising an iron ore raw material, a minute coke and an additive,
(C / F) x 100] of the iron ore raw material mass (F) having a grain size of 0.5 mm or less and the minute coke mass (C) having a grain size of 0.5 mm or less in the above- % Of raw material powder for sintered ores. The method of claim 3,
Wherein the mixing ratio [(C / F) x 100] is in the range of 7.2 to 7.8%.

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