KR100415926B1 - STRUCTRE OF MINI-PELLET HAVING GOOD EFFECTS OF DECREASING SOx IN THE SINTERING WITH HIGH MIX RATIO OF IRON BEARING DUSTS AND MANUFACTURING METHOD THEREOF - Google Patents

Abstract

The present invention relates to a method for reducing the amount of SOx generated during sintering when high-mixing iron-containing dusts are used as a sintering raw material, and more particularly, to a method for reducing the amount of SOx generated by designing a pseudo particle structure.

The present invention provides a minipellet structure characterized by having a dual structure in which iron ore is sheathed with a raw material mixed with iron dust and quicklime as nuclear particles.

In addition, the fine iron-containing dust and quicklime are mixed and put into a rotating pelletizer, and the water is sprayed and assembled into nuclear particles of a predetermined size. Provided is a method for producing mini pellets having an excellent effect of reducing SOx in a sintering operation in which a high concentration of iron-containing dust is assembled.

Description

Structure of mini-pellets with excellent sulfur oxide reduction effect in sintering operation with high mixing of iron dusts and its manufacturing method THEREOF}

The present invention relates to a method for reducing the amount of SOx generated during sintering when high-mixing iron-containing dusts are used as a sintering raw material, and more particularly, to a method for reducing the amount of SOx generated by designing a pseudo particle structure.

In general, in the integrated steelmaking process, various types of gun dust and wet dust are generated in each unit process. Since these dusts have a serious impact on environmental pollution in recent years, regulations on them have been tightened, and the amount of dust generated by increasing the facilities for collecting dust and increasing the efficiency of dust collection equipment has been increasing. have.

The dusts generated in this way are generally extremely fine and contain a large amount of harmful components (K2O, Na2O, S, Zn, etc.), and in the case of wet dust, there is a lot of moisture in handling such as transportation. . However, since these dusts contain valuable elements such as iron and carbon, it is necessary to take into account the recovery and calorie contribution to these components, so dust generated from the steel mill is recycled in the steel mill itself and its recycling rate Many researches have been carried out to increase the number.

As mentioned above, these dusts contain a large amount of harmful components.Alkali elements such as K ₂ O and Na ₂ O form compounds with chlorides during sintering to reduce dust collection efficiency for dusts generated during sintering, thereby reducing the sintering plant. Increase the amount of dust in the flue gas emitted to the chimney.

On the other hand, a significant amount of S is converted to SOx during sintering and released to the outside, and the amount of SOx generated is proportional to the S content in the fuel raw material blended during sintering. Restrict the use of and reduce the use of coke or anthracite coal having a higher S content than iron ore raw materials, but if the amount of fuel used is reduced, the amount of calories during sintering is lowered, which lowers the strength of the sintered ore and reduces productivity.

It is also possible to reduce the amount of SOx generated by changing the sintering operation. Increasing the operation improves the air permeability of the sintered layer, which increases the oxygen supply rate, where S is the amount of SOx in the exhaust gas generated and released as sulfate. Is lowered. In addition, there is a method of reducing the negative pressure during sintering and a method of bringing the sintering temperature low, but this also affects the sinterability and the quality of the sintered ore as much as the sintering operation is affected.

In addition, there is a method in which an additive such as urea is contained in the sintered compounding material and S is left in the sintered ore through reaction with the additive, which adversely affects the cost increase due to the additive and the molten iron quality in the subsequent process. There is this.

The present invention is to solve the above conventional problems,

It is an object of the present invention to provide a method of reducing the amount of SOx generated by high back pressure of iron-containing dusts regardless of the amount of fuel and the sintering operation by designing a pseudo-particle structure by improving only the assembly method for iron-containing dusts.

Figure 1. Photo showing the structure of a mini-pellet containing iron dust

Figure 2. Graph showing the relationship between mini pellet size, SOx generation amount and sintered ore room temperature strength

Figure 3. Graph showing the relationship with SOx reduction rate according to iron ore sheath thickness

The present invention for achieving the above object provides a mini-pellet structure characterized in that the raw material mixed with iron dust and quicklime as a nuclear particle and has a dual structure in which the iron ore is sheathed.

In addition, the fine iron-containing dust and quicklime are mixed and put into a rotating pelletizer, and the water is sprayed and assembled into nuclear particles of a predetermined size. Provided is a method for producing mini pellets having an excellent effect of reducing SOx in a sintering operation in which a high concentration of iron-containing dust is assembled.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Raw materials used in the present invention are divided into iron dust, iron ore and quicklime. Iron-containing dust is composed of sintered environment dust and steelmaking sludge and is extremely finely divided. The chemical composition of each raw material is shown in Table 1.

Chemical Composition of Iron Dust, Quicklime and Iron Ore Kinds T-Fe SiO2 CaO Al2O3 MgO K2O Na2O Zn S Sintered Dust 46.39 6.85 11.97 2.79 1.62 0.07 0.24 0.01 0.19 Steel Sludge 59.93 1.26 8.29 0.10 1.12 2.03 0.78 0.93 0.14 quicklime - 2.00 91.24 0.20 2.54 0.01 0.28 - - ironstone 67.34 1.26 0.07 .88 0.05 0.01 0.01 0.002 0.005

In the present invention, by designing the structure of the pseudo-particles by varying the assembling method for the raw materials as shown in Table 1 and measuring the amount of SOx generated during sintering, in the pseudo-particle structure, the size of the pseudo-particles, iron-containing dust And the internal or external structure of the iron ore and the thickness when the interior and exterior are shown as Tables 2-5.

Mixing ratio of various sintered raw materials (unit:%) Comparative Example 1 Comparative Example 2 Comparison 3 Inventive Example Sintered R-EP 38.92 34.92 34.92 34.92 Steelmaking sludge 9.73 8.73 8.73 8.73 ironstone 48.65 43.65 43.85 43.65 quicklime 0.00 10.00 10.00 10.00 cokes 2.70 2.70 2.70 2.70

First, as shown in Table 2, the mixing ratio of iron-containing dust and iron ore is 50:50, which is added to a pelletizer, followed by mixing and granulating while spraying an appropriate amount of water to prepare a mini-pellet. Experiments were carried out by dividing the quasi-particle structure of the mini-pellet into four major categories as shown in FIG.

First, when iron dust and iron ore are mixed together and manufactured as mini pellets (Comparative Example 1), and second, when iron and iron dust, iron ore and quicklime are mixed and assembled together (Comparative Example 2), and third iron ore is used as nuclear particles. When iron ore is mixed with quicklime (Comparative Example 3), the fourth iron-containing dust and quicklime are mixed and used as nucleus particles, and iron ore is coated (invention example). Is shown in Table 3.

SOx generation amount according to mini pellet structure Comparative Example 1 Comparative Example 2 Comparative Example 3 Inventive Example SOx (ppm) 520 412 480 309

In the above results, when iron ore was coated with iron ore as a nuclear particle and iron ore was coated with iron ore, the concentration of SOx was relatively high at 480 ppm. , Mini pellet structure of the present invention showed the lowest value of 309ppm. This suggests that the sheathed iron ore prevented the conversion of S contained in iron dust into SOx.

Next, to determine the SOx generation amount and the room temperature strength of the sintered ore according to the particle size of the mini pellets, as shown in Table 4 below, respectively, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm, respectively, wherein the mixing ratio of iron dust and iron ore is 50: 50 was set.

SOx generation amount and room temperature intensity by particle size 1 mm 2 mm 3 mm 4mm 5 mm 6 mm SOx (ppm) 318 315 309 297 275 276 Room temperature strength 72.2 71.8 71.5 68.3 65.6 64.1

As a result of the sintering experiment as shown in Table 4, it can be seen that the room temperature strength of the sintered ore decreases at a particle size of 4 mm or more. This is because the sintered ore is composed of mini pellets, and when the particle size is small, the melting becomes easy, and the bonding between the mini pellets is strengthened. Judging.

On the other hand, the amount of SOx generated tended to decrease in the mini pellets with relatively large particle size. This is due to the amount of generation depending on the degree of reaction, that is, because the S content in the iron-containing dust is higher than iron ore as shown in Table 1. In other words, as the melting increases, the amount of reacted iron dust increases and the amount of SOx generated increases.

Therefore, the particle size of the appropriate minipellets was found to be about 2 to 3 mm under the condition that the strength of the sintered ore, that is, the properties were not affected.

In addition, the mini-pellet particle size is 2 to 3mm, and when the iron-containing dust is coated with iron ore as in the invention example of FIG. 1, the exterior thickness is 0.2mm, 0.4mm, 0.6mm, 0.8 to investigate the reduction rate of SOx generation according to the thickness. mm and 1.0 mm were sintered by the above sintering method and are shown in Table 5 and FIG.

SOx reduction rate according to iron ore sheath thickness 0.2mm 0.4mm 0.6mm 0.8mm 1.0mm SOx reduction rate (%) 25.4 33.5 40.7 42.3 42.1

As a result of the experiment, the thicker the thickness, the larger the thickness, the SOx reduction rate was significantly increased. This is most suitable when the particle size of the mini pellets mixed in the sintering operation is 2 to 3 mm as described above. Therefore, the thicker the iron ore sheath is, the lower the content of iron dust is. In order to use the generated iron dust in the sintering industry, there is a disadvantage in that a large amount of minipellets must be produced. Therefore, the iron ore sheath thickness of the present invention was determined to be the most suitable 0.5 ~ 0.7mm.

In the iron ore sintering industry, the amount of SOx generated when the iron loading with high S loading is sheathed with iron ore is reduced, and thus valuable components such as iron and carbon can be used by increasing the amount used in the sintering of iron dust. Can be recovered and used.

Claims (4)

Raw material mixed with iron dust and quicklime is used as nuclear particles, Mini pellet structure with excellent sulfur oxide reduction effect in the sintering operation of iron alloy dust, which has a double structure with iron ore. The mini pellet structure having excellent sulfur oxide reduction effect in the sintering operation in which the iron-containing dust is blended, characterized in that the thickness of the covered iron ore is 0.5 to 0.7mm. Prepare iron dust and iron ore in the same amount, and prepare quicklime less than 10% of the total amount, First, the process of assembling mini pellets, which are nuclear particles of a certain size by mixing fine iron dust and quicklime into a rotating pelletizer and spraying water; A method for producing mini pellets with excellent sulfur oxide reduction effect in a sintering operation in which iron dust is mixed with the fine particles of iron ore into the nuclear particles. 4. The method of claim 3, wherein the particle size of the minipellets is 2 to 3 mm.