KR100411271B1 - Method for mixing lime stone dust into raw material of sintering - Google Patents

Abstract

The present invention relates to a method of using limestone dust collected in a dust collector as a sintering raw material in the production of quicklime produced in a lime firing plant, the purpose of which can prevent the component deviation of the blended raw materials while reducing environmental pollution due to scattering dust. It is to provide a uniform mixing method of sintered raw materials.

In order to achieve the above object, the present invention provides a method of manufacturing a sintered ore comprising the step of mixing the raw material storage tank blending material conveyed to the conveyor belt and granulated in the mixer, and forming a groove having a predetermined size in the compounding material on the conveyor belt. The technical gist of the present invention relates to a method for uniformly mixing limestone dust for sintered raw materials, which comprises covering limestone dust in the groove immediately with the addition of limestone dust into the groove.

Description

Method for mixing lime stone dust into raw material of sintering

The present invention relates to a method of using limestone dust of a lime firing plant as a sintered raw material, and more particularly, to prevent scattering when limestone dust is added to a sintered raw material, thereby reducing the variation of CaO component in the blended raw material. The present invention relates to a homogeneous mixing method of limestone dust for sintering raw materials capable of stabilizing quality.

The sintered ore used in the blast furnace is, as shown in Figure 1, after mixing the main raw material (iron ore), secondary raw materials (limestone, silica, serpentine, quicklime), and coke as fuel in the mixer (2) as shown in Figure 1 6), which is loaded into a sintering machine cart 8 through a drum feeder and ignited through an ignition furnace 7, and then a blended raw material is manufactured through a sintering process while the sintering machine is in progress.

In FIG. 1, reference numeral 3 denotes an upper light storage tank, 4 a dust collector, 5 a main exhaust fan, 6 a compound material storage tank, 9 a crusher, and 10 a cooler.

Quicklime, which is used as a raw material for sintered ore in an auxiliary material, is produced by heating limestone to 900 to 1200 ° C through a firing furnace in a lime firing plant. Limestone dust generated during quicklime manufacturing is collected in a cyclone dust collector, and the composition and particle size of limestone dust are shown in Table 1.

ingredient(%) Particle size (%) SiO ₂ Al ₂ O ₃ CaO MgO -0.125mm Average particle size (mm) 0.5 to 0.8 0.1-0.3 78.0-81.0 2.5 to 3.0 69.0-73.0 0.35 to 0.38

As shown in Table 1, limestone dust was landfilled as a waste of fine particles having a particle size of -0.125mm occupying 69-73%. However, since the CaO content of the limestone dust is 78-81% high and the CaO component is 1.4-1.5 times higher than the limestone, the amount of limestone can be reduced, and thus it has been used as a raw material for sintering in recent years.

The limestone dust is formed on the conveyor belt 16 by the particle feeder 11 installed at the inlet side of the mixer when the raw material of the raw material storage tank 1 of the sintering machine is supplied to the mixer 2 through the conveyor belt 16 as shown in FIG. 2. Is being supplied to. In this supply process, when limestone dust is loaded on the conveyor belt, scattering occurs, and when the housewife raw material and the subsidiary material are poured into the upper part where limestone dust is loaded, a large amount of dust is continuously scattered by the impact. In order to prevent the scattering dust from contaminating the inside of the factory, the entire conveyor belt is sealed in the form of a box, and the scattering dust is collected by a duct 14 connected to the upper portion.

Although this facility prevents the scattering of limestone dust, the slag content of sintered ore is increased by increasing the variation of CaO component in the sintered ore because the limestone dust blended to supply CaO to the sintered raw material is scattered and sucked into the dust collector. There is a problem that the sintered ore quality is deteriorated since this is reduced. In order to solve this problem, the sintered raw material is first loaded on the conveyor belt and sprinkled immediately after the limestone dust is put therein, but there is still a problem in that the quality of the sintered ore is deteriorated due to the dispersion of the sintering compound ratio. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above conventional problem, and provides a uniform mixing method of sintered raw materials which can prevent the component deviation of the blended raw materials while reducing environmental pollution due to scattering dust.

1 is a manufacturing process diagram of sintered ore

Figure 2 is a schematic diagram of adding a conventional limestone dust as a raw material

Figure 3 is a schematic diagram of the input of limestone dust according to the present invention

* Description of the symbols for the main parts of the drawings *

1 ..... Raw material storage tank 2 ..... Mixer

12 ... Blended material 16 .. Conveyor belt

20 ..... particle feeder 22 ..... outlet

30..Drag 40..Cover plate

In order to achieve the above object, the present invention provides a method of manufacturing a sintered ore comprising the step of mixing the raw material storage tank blending material conveyed to the conveyor belt and granulated in the mixer, and forming a groove having a predetermined size in the compounding material on the conveyor belt. And immediately after the limestone dust is introduced into the groove, covering the limestone dust in the groove with the compounding material.

Hereinafter, the present invention will be described in detail.

The present invention forms a groove in the blended raw material and immediately covers the limestone dust in the groove with the blended raw material on the outer side of the groove immediately after charging limestone dust in the groove, thereby preventing the scattering of limestone dust to prevent a certain amount of the blended raw material. The limestone dust is contained to uniformly mix the components of the sintered blend raw material.

First, the main raw material, subsidiary material and fuel (coke) in the raw material storage tank 1 are supplied to the conveyor belt and transferred to the mixer 2, while the groove having a predetermined depth and a constant width in the loading layer of the compounding material on the conveyor belt ( 35) It is preferable that the center line of the grooves coincide with the center of the compounding material layer, and the width of the grooves is 38 to 50% of the width of the compounding material, and the depth thereof is to be 40 to 50% of the thickness of the compounding material layer. This is set in consideration of the amount of limestone dust supplied and the damage of the conveyor belt.

This groove may be formed with the drag 30 shown as an example in FIG. The other end 30 is fixed to the shaft connected to the bearing block on the upper support 34, and one end is installed to be inserted into the compounding material so that the conveyor belt is transported so that the groove 35 is formed in the loading layer of the compounding material. . Drag 30 is installed so that damage to the conveyor belt does not occur.

A groove is formed in the compounding material conveyed by the conveyor belt as described above, and then limestone dust is introduced into the groove, and the limestone dust in the groove is immediately covered with the compounding material on both sides of the groove. As shown in Table 2, the amount of limestone dust contained is 1.1 to 1.5% in the sintered blended raw material in order to reduce the amount of limestone used and increase productivity. Table 2 below shows the limestone usage rates according to the limestone dust content.

Content of Limestone Dust in Blended Raw Materials ≤0.5 0.6 to 1.0 1.1 to 1.5 1.6 to 2.0 Change of Sintered Ore Components SiO ₂ - - 0.01 or less 0.02 or less CaO 0.40 to 0.45 0.90 to 1.00 1.30-1.40 1.75-1.85 MgO 0.02 or less Less than 0.04 0.06 or less Less than 0.08 Limestone Variable Cost 0.8 to 0.9 1.55-1.75 2.35-2.65 3.10 to 3.50

The injection of limestone dust causes the limestone dust to be introduced into the grooves formed by installing the particle feeder 20 in the rear extension line of the dragger 30.

In addition, the cover plate 40 shown as an example in FIG. 3 can be used for covering the compound raw material with the limestone dust in a groove | channel. Cover plate 40 may be applied to a variety of shapes to prevent the scattering of limestone dust while covering the limestone dust in the groove 35 with the compounding material. First, in order to insert the compounding material into the grooves, both ends of the lower end of the cover plate 40 are in contact with the compounding raw materials on both sides of the groove to push the compounding material into the grooves, and the upper end extends to the discharge pipe of the particle feeder to surround the discharge pipe. It is desirable to design.

When the cover plate is formed integrally, the upper end of the cover plate can be in contact with the discharge pipe to completely prevent scattering. In addition, the cover plate may be formed in the shape of a wing of two plates separated as shown in FIG.

According to the present invention, the raw material in which the limestone dust is mixed is immediately added to the mixer and mixed with water. Therefore, the limestone dust can be prevented from being exposed to the outside to prevent dust from scattering, and the loss of the limestone dust can be prevented to eliminate variations in the mixing ratio.

Hereinafter, the present invention will be described in more detail with reference to Examples.

EXAMPLE

In a small sintering machine having an effective image area of 40 m2 and a sintered layer of 450 mm, as shown in Table 4, the sintered ore was manufactured under primary and secondary raw material conditions, and the general conditions of the sintered ore were examined.

Main raw material (wt%) Subsidiary Material (wt%) HAM.F CAJ.F HIY.F RBR.F Scale burr Serpentine Limestone quicklime 18-20 22-25 23-26 9 to 11 3 to 5 0.3 or less 2.0 to 2.4 14-16 1.4 to 1.6

division Comparative Example 1 Comparative Example 2 Inventive Example 3 Comparative Example 4 Amount of limestone dust (%) 0.5 or less 0.6 to 1.0 1.1 to 1.5 1.6 to 2.0 CaO (%) in dust collector dust 8.2-8.3 8.2-8.3 8.2-8.3 8.3 to 8.5 CaO deviation in sintered ore (%) 0.2 to 0.3 0.2 to 0.3 0.2 to 0.3 0.2 to 0.4 -0.125mm in blended raw material 9.0-9.2 9.0 to 9.3 9.1-9.4 9.1 to 9.5 Productivity (T / D / ㎡) 38.0-39.5 38.0-39.5 38.0-39.5 37.0-38.5 burglar(%) 90.0 to 90.2 90.0 to 90.3 90.1 to 90.4 90.1 to 90.5 Limestone Cost (%) 14.0 to 16.0 12.5-14.5 11.5-13.5 10.0-12.5

In Table 5, Comparative Example (1) and (2) used 1.0% limestone dust, and there was no change in productivity and quality. Inventive Example (1) added 1.1 to 1.5% of limestone dust, in which case the fine particles (0.125 mm or less) mixed in the blended material increased by 0.1 to 0.2%, the porosity was reduced, and the strength was improved by 0.1 to 0.2%. Limestone used as sintered feedstock was able to reduce the use cost of 2 ~ 2.5%. In Comparative Example (3), 1.6 to 2.0% of limestone dust was added, and the fine particles (0.125 mm or less) mixed in the blended material increased by 0.1 to 0.3%, and the strength was better than that of Inventive Example (1). Productivity is reduced by 0.5 to 1.0 T / D / m 2 because of an increase of 0.1 to 0.2% and deterioration of breathability.

As a result, it has been found that the use of limestone dust in accordance with the present invention can reduce the use ratio of limestone by 2 to 2.5% without changing the chemical composition and quality of the sintered ore. Comparing the operation results according to the present invention and the conventional operation results are shown in Table 6 below.

division Dust collection dust CaO (%) CaO deviation in sintered ore (%) -0.125mm during blending raw material productivity burglar Limestone Cost Conventional example (1) 8.40 0.40 9.1 37.5 89.9 14.0 Conventional example (2) 8.60 0.50 9.2 37.0 89.7 15.0 Conventional example (3) 8.30 0.30 9.1 38.0 90.0 13.0 Conventional example (4) 8.50 0.45 9.0 37.8 89.8 14.0 Inventive Example (2) 8.25 0.25 9.3 38.5 90.3 12.5 Inventive Example (3) 8.20 0.20 9.2 39.5 90.4 11.5 Inventive Example (4) 8.30 0.30 9.0 38.0 90.1 13.0 Inventive Example (5) 8.25 0.21 9.1 39.0 90.2 13.5

As can be seen from Table 6, in the present invention, the CaO deviation of the chemical composition of the sintered ore is reduced to 0.30% or less, so that the productivity is increased by 1.5T / D / m2 and the strength is increased by 0.3% due to the particle size stability of the ingredients and the blended raw materials. The operation performance could be improved more than the method.

As described above, in the present invention, the limestone dust to be disposed of can be recycled by adding it to the blended raw material, and the chemical composition and strength of the sintered ore are stabilized by reducing the variation in the blending ratio and the component ratio lost during the transport of the blended raw material. There is a useful effect to reduce the amount of use.

Claims (3)

delete delete In the method of manufacturing a sintered ore, which includes conveying a blended raw material of a raw material storage tank to a conveyor belt and mixing the mixed raw material into a mixer, a groove having a predetermined size is formed in the blended raw material on the conveyor belt, and the limestone dust is blended into the groove. A homogeneous mixing method of limestone dust for sintered raw materials, comprising covering the limestone dust in the groove with the blending raw material immediately after it is added so as to contain 1.1 to 1.5% of the raw material.