KR102044979B1 - Manufacturing method of sintered ore - Google Patents

Abstract

Preparing pseudo particles by adding water to a sintered blended raw material including a raw material, a fuel material, a semi-ore, and a secondary raw material; Mixing the Finex sludge and the assay lime to prepare a mixture; Coating the mixture on the surface of the pseudoparticle; And sintering the coated pseudo particle; wherein the weight ratio of the Finex sludge and the analyte in the step of preparing the mixture is 5: 5 to 7: 3.

Description

MANUFACTURING METHOD OF SINTERED ORE}

The present invention relates to a method for producing a sintered ore excellent in strength and excellent in reducibility.

Generally, in the DL (Dwight Lloyd) type sintering process, as illustrated in FIG. 1, powdered iron ore, secondary raw material, semi-ore, and sintered fuel (powdered coke, anthracite coal), etc., cut out from the raw material storage tank 1 are mixed in the drum mixer 2. And humidity control (raw material weight ratio of about 7 to 8%) to make the sintered blended raw material pseudo-particles, charged to the sintering machine trolley (8) to a certain height (6), and air from the lower side after the surface ignition by the ignition furnace (7) Firing of the sintered blended raw materials proceeds with forced suction, and a sintered ore is produced.

After the sintering is completed, the sintered ore is crushed through the sintering machine crusher 10 of the light distribution unit, cooled in the sintering machine cooler 11, and then passed through the crusher 12 and the screen 13 to easily load and react in the blast furnace. 5 to 50 mm), the sintered ore 14 is transferred to the blast furnace.

At this time, the spectral of less than 5mm generated during the sintering and sintering process of the sintered ore is classified as semi-mineral and reused as sintered raw material, the amount of semi-mineral determines the sinter recovery rate. Factors influencing the strength of the sintered cake include the matrix structure strength, pore structure and crack formation of the sintered ore. The matrix structure strength of the sintered ore depends on the constituent mineral phase composition, and the pore structure exhibits a difference in strength depending on the amount, shape and distribution of the pores.

In addition, in the blast furnace operation, it is required to secure the air permeability / liquid permeability of the bottom of the furnace under a large amount of pulverized coal operation, and to suppress heat loss.

In general, when the reducibility of the sintered ore is improved, the softening melting temperature difference (ΔT) corresponding to the width of the blast furnace is reduced, and thus the operation efficiency may be improved, such as improved air permeability and lower fuel cost in the furnace.

It is to provide a method for producing a sintered ore excellent in strength and excellent in reducibility.

Sintered ore manufacturing method according to an embodiment of the present invention comprises the steps of preparing the pseudo-particles by adding moisture to the sintered blended raw materials, including raw materials, fuel materials, semi-ores and secondary raw materials; Mixing the Finex sludge and the assay lime to prepare a mixture; Coating the mixture on the surface of the pseudoparticle; And sintering the coated pseudoparticle; wherein the weight ratio of the Finex sludge and the analyte in the step of preparing the mixture is 5: 5 to 7: 3.

In the step of preparing the mixture, the average particle size of the Finex sludge is 50 to 100㎛, the average particle size of the analysis lime may be 1mm or less.

In the step of preparing the mixture, it may be mixed so that the content of CaO in the mixture is 20 to 25% by weight.

In the coating step, the mixture may be added 1 to 5% by weight based on 100% of the total weight of the coated pseudo-particles.

In the sintering step, a calcium ferrite sintered melt may be produced.

In the sintering step, the sintering time may be 43.7 minutes or less.

The coated pseudo-particles may include at least one selected from 58 to 63 wt% of raw materials including iron ore, 3 to 5 wt% of fuel materials, quicklime, limestone and silica sand including at least one of coke and anthracite. It may include 9 to 13% by weight of the sub-material, 18 to 22% by weight semi-gloss, 2 to 4% by weight of moisture and 1 to 5% by weight of the mixture.

Sintered low melting point calcium ferrite system (CaO-Fe ₂ O ₃ , CaO-Fe ₂ O ₃ -SiO ₂ -Al ₂ O ₃ ) The amount of melt produced can be increased. As a result, it is possible to produce a sintered ore having excellent strength and improved reducibility.

1 is a diagram illustrating a conventional sintering process.
2 is a view showing a sintered ore manufacturing method according to an embodiment of the present invention.
Figure 3 is a diagram showing a cross-sectional view of the sintered ore prepared in accordance with an embodiment of the present invention.

Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, the first portion, component, region, layer or section described below may be referred to as the second portion, component, region, layer or section without departing from the scope of the invention.

The terminology used herein is for reference only to specific embodiments and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used in the specification, the meaning of “comprising” embodies a particular characteristic, region, integer, step, operation, element and / or component, and the presence of another characteristic, region, integer, step, operation, element and / or component or It does not exclude the addition.

When a portion is referred to as being "on" or "on" another portion, it may be directly on or on the other portion or may be accompanied by another portion in between. In contrast, when a part is mentioned as "directly above" another part, no other part is intervened in between.

Unless defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Commonly defined terms used are additionally interpreted to have a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted in an ideal or very formal sense unless defined.

In addition, unless otherwise indicated,% means weight% and 1 ppm is 0.0001 weight%.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Sintered ore  Manufacturing method

As shown in Figure 2, the sintered ore manufacturing method according to an embodiment of the present invention is the step of preparing a pseudo particle by adding moisture to the sintered blended raw materials including the raw material, fuel material, semi-ore and secondary raw material, Finex sludge and powder Mixing limestone to prepare the mixture, coating the mixture on the pseudo particle surface, and sintering the coated pseudoparticle, wherein the weight ratio of the Finex sludge and the analyte is 5 in the preparation of the mixture. : 5 to 7: 3.

First, in the preparation of the pseudo particle, a sintered blend raw material including a raw material, a fuel material, a semi-ore, and a secondary raw material is prepared.

Raw materials may include iron ore. Specifically, it may include hematite ore, brown iron ore and maramamba ore. The balance may be made of raw materials.

The hematite-based ore may have a Fe content of 61 to 66 wt% and a derivative ratio of 0.15 mm or less in average particle size of 19 to 26 wt%. Limonite ore may have a Fe content of about 58% by weight and a fine fraction of about 0.15 mm or less in average particle size. The maramamba-based ore may have a Fe content of about 61% by weight and a derivative ratio of 0.15 mm or less in average particle size of about 19% by weight.

The fuel material may include one or more of the coke and anthracite coal. Semi-glossy is a small sintered ore which is classified as a sintered semi-reflective and used again as a sintered raw material. The secondary raw material may include one or more of quicklime, limestone and silica sand.

The raw material, fuel material, semi-ore and subsidiary materials thus prepared are mixed with moisture and assembled to produce pseudo particles. Specifically, of the two drum mixers constituting the sintered ore manufacturing apparatus, the first drum mixer is assembled by adding moisture to the sintered blended raw material.

Next, in the step of preparing the mixture, the mixture is prepared by mixing Finex sludge and analyte. The step of preparing the mixture may be performed simultaneously with the step of preparing the pseudo particle, it may be performed sequentially. It doesn't matter in order.

Finex sludge uses the spectroscopy and powdered coal to produce molten iron by the melt reduction method. It is collected sludge.

Such Finex sludge is mainly composed of iron-containing minerals (FeO, Fe ₃ O ₄ , Fe ₃ C, etc.) and a small amount of gangue components (CaCO ₃ , SiO _2, etc.), the average particle size is about 50 ~ 100㎛ It may be minutes. The total Fe content in the chemical composition of Finex sludge is about 52.7% by weight, and the content of slag (SiO ₂ , CaO, MgO, Al ₂ O ₃ ) is about 15.8% by weight, and the C content that can be used as a heat source during the sintering process. Is contained in about 6.9% by weight.

Analytical lime is limestone (CaCO ₃ ) commonly used in the sintering process, the CaO content is about 50.4% by weight, and the particle size used may be 1 mm or less.

On the other hand, the mixing ratio of Finex sludge and analyte in the mixture is 5: 5 to 7: 3. For example, based on the total weight of the sintered ore, when 5% by weight of the mixture is included, the Finex sludge may be 2.5 to 3.5% by weight, the analyte may be 1.5 to 2.5% by weight.

Specifically, in the step of preparing the mixture may be mixed so that the content of CaO in the mixture is 20 to 25% by weight.

When the mixing ratio of Finex sludge and analyte is controlled at 5: 5 to 7: 3, and the content of CaO in the mixture is controlled to be 20 to 25% by weight, it is possible to prepare a low melting point high reducing sintered melt production accelerator. Do.

Specifically, the low melting point calcium ferrite (CaO-Fe ₂ O ₃ , CaO-Fe ₂ O ₃ -SiO ₂ -Al ₂ O ₃ ) sintered melt by the reaction of CaO present in Finex sludge and analyte in the sintering process Can be generated. This sintered melt is a substance that improves the strength and the reducing property of the sintered ore.

When the softening temperature is low, the melting temperature is low, and the deviation is not large between the two temperatures, a low melting point calcium ferrite sintered melt may be generated during the sintering process. Softening temperature is defined as the temperature when it becomes 95% of the total height based on the shape of the initial cylindrical sample (diameter 2mm, height 3mm), and melting temperature is the width / height ratio of the sample. It is defined as the temperature when it reaches 3.0.

After preparing the mixture, the method may further include stirring the mixture. At this time, the stirring speed of the mixed solution may be 1000 to 10000rpm.

Next, in the step of coating the mixture on the pseudo particle surface, the coating may be performed such that the prepared mixture is coated onto the pseudo particle surface. In this case, the amount of the mixture added may be 1 to 5% by weight, based on 100% of the total weight of the coated pseudoparticles.

If less than 1% by weight, the amount of sintered melt produced is insufficient, and the effect of improving productivity and quality may be insignificant. On the other hand, when the content exceeds 5% by weight, the amount of sintered melt generated is excessive, resulting in air permeation resistance in the sintered layer, thereby increasing the sintering time, thereby reducing productivity and quality.

Specifically, in the two drum-type mixers constituting the sintered ore manufacturing apparatus, the mixture of the mixture on the pseudo particle surface in the second drum-type mixer can be made.

After coating the mixture on the pseudo particle surface, the coated pseudo particles may be charged into a sinter and sintered to complete the manufacture of the sintered ore. In some cases, the molten iron may be directly supplied to the molten iron manufacturing process to produce molten iron.

Coated pseudoparticles comprise at least one of 58 to 63% by weight of raw materials including iron ore, 3 to 5% by weight of fuel materials including at least one of coke and anthracite, quicklime, limestone and silica sand. 9 to 13% by weight of sub-materials, 18 to 22% by weight of semi-gloss, 2 to 4% by weight of moisture and 1 to 5% by weight of a mixture.

In the sintering step, a calcium ferrite sintered melt (CaO-Fe ₂ O ₃ , CaO-Fe ₂ O ₃ -SiO ₂ -Al ₂ O ₃ ) may be generated, thereby improving the strength and reducibility of the sintered ore. .

It can be sintered using a downward suction dwight lloyd (DL) sintering machine.

On the other hand, the sintering time may be shortened due to the addition of the mixture in which the weight ratio of the Finex sludge and the analyte is controlled so that the sintering time may be 43.7 minutes or less. On the other hand, the recovery rate of the sintered mineral product can be improved to increase the overall productivity. Specific values will be described through the following examples.

As shown in Figure 3, the sintered ore according to an embodiment of the present invention is a form in which the coating layer is formed on the surface of the pseudo-particle consisting of nuclear particles (ferrous ore) and adhesion particles (reflected light, fuel material, etc.) by weight, T.Fe : 58.1%, CaO: 10.1%, SiO ₂ : 5.7%, MgO: 0.7%, Al ₂ O ₃ : 1.9%, and residual unavoidable impurities.

The amount of slag is 18.4%, and the basicity (CaO / SiO ₂ ) may be 1.76.

Slag quantity is determined by the sum of CaO, SiO _2, MgO and Al ₂ O _3.

Hereinafter, specific examples of the present invention will be described. However, the following examples are only specific examples of the present invention, and the present invention is not limited to the following examples.

Example

1) Preparation of Sintered Ore

A sintered ore having a composition component according to Table 1 below was prepared.

Pseudoparticles were assembled by adding moisture to the sintered blended raw material in the first drum mixer, and in the case of the example, the mixture was prepared with a weight ratio of Finex sludge and analyte of 6: 4. For the comparative example, no separate mixture was prepared.

The components of the iron ore contained in the raw material were as shown in Table 2 below, and the components of the Finex sludge and the analysis lime were as shown in Table 3 below.

Then, the mixture was coated on the surface of the pseudoparticles in a secondary drum mixer, and sintered to prepare a sintered ore. Charged into a sintering pot (diameter 330 mm, height 700 mm), the ignition furnace preheated to a temperature of 1100 ° C. was moved to the upper part of the pot and ignited for 1 minute, and then sintering was performed by maintaining the negative pressure constant at 1700 mmAq. The sintering time was determined based on the time when the flue gas reached the maximum temperature.

division Example 1 Example 2 Example 3 Comparative example weight% Granularity weight% Granularity weight% Granularity weight% Granularity ironstone A 9.3 -8mm 9.1 -8mm 8.9 -8mm 8.7 -8mm B 7.6 -8mm 7.4 -8mm 7.2 -8mm 8.0 -8mm C 4.2 -8mm 4.0 -8mm 3.8 -8mm 4.8 -8mm D 32.3 -8mm 32.1 -8mm 31.9 -8mm 31.7 -8mm E 7.6 -8mm 7.4 -8mm 7.2 -8mm 8.0 -8mm mixture One -1mm 3 -1mm 5 -1mm 0 -1mm Raw materials quicklime 1.5 -1mm 1.5 -1mm 1.5 -1mm 1.5 -1mm Limestone 8.5 -4mm 8.5 -4mm 8.5 -4mm 9.1 -4mm Quartz sand 0.2 -1mm 0.2 -1mm 0.2 -1mm 0.2 -1mm Semi-gloss 20.6 -5mm 19.6 -5mm 18.6 -5mm 20.8 -5mm cokes 2.1 -3mm 2.1 -3mm 2.1 -3mm 2.1 -3mm hard coal 2.1 -3mm 2.1 -3mm 2.1 -3mm 2.1 -3mm Added moisture 3.0 - 3.0 - 3.0 - 3.0 -

ironstone Ingredient (% by weight) Granularity T.Fe FeO SiO ₂ Al ₂ O ₃ CaO MgO M.S (mm) -0.15mm A 65.15 0.96 3.94 0.82 0.05 0.01 2.07% 26.5% B 61.57 0.08 3.50 2.32 0.07 0.03 2.33% 19.3% C 66.07 0.00 4.63 0.34 0.09 0.05 0.39% 21.9% D 58.70 0.22 4.49 1.51 0.05 0.05 2.68% 5.3% E 61.11 0.07 4.32 2.28 0.03 0.02 1.85% 19.9%

division Ingredient (% by weight) Granularity
(mm) importance
(g / cc) T-Fe M-Fe FeO SiO ₂ CaO MgO Al ₂ O ₃ C S Finex
Sludge 52.73 2.90 20.46 6.47 4.57 0.74 4.09 6.97 0.29 -0.5 1.75 Analysis meeting 0.35 - - 2.54 50.44 2.74 0.56 - 0.01 -1.0 1.70

In Tables 1 to 3, 'particle size' means average particle size, and '-' means below. In Table 2,% means wt%.

2) Property evaluation

Table 4 shows the test evaluation results according to the examples and the comparative examples.

division Example 1 Example 2 Example 3 Comparative example Finex Sludge +
Assay mixture (% by weight) One 3 5 - Sintering time (min.) 42.3 42.6 43.7 43.8 Sintered Productivity (ton / day.m ² ) 28.3 28.6 27.5 26.7 Rotating strength of sintered ore (wt%) 71.9 72.8 73.6 71.5 Sintered mineral product recovery rate (wt%) 75.9 77.0 77.5 74.5 Sintered ore RI (% by weight) 71.5 74.1 75.4 70.6 Sintered ore RDI (wt%) 41.3 40.4 41.8 41.6

Sintering productivity can be expressed by the following formula (1). Higher numbers indicate better productivity.

[Equation 1]

Sintered Productivity (ton / day xm ² ) =

The weight (ton) / {sintered image area (m ² ) X sintering time (day)}

The sintered ore rotational strength may be expressed by the following Equation 2. In the following Equation 2, 15kg means the amount of charged samples for measuring the rotational strength.

[Equation 2]

Rotational strength (%) =

Weight of sintered ore with average particle size of 6.3mm or more (kg) after the tumbler 200 rotations / weight of sintered ore with average particle size of 10mm or more (15kg)

Sintered mineral product recovery rate can be expressed by the following equation 3. The higher the value, the higher the recovery rate, and the better the productivity.

[Equation 3]

Sintered mineral product recovery rate (%) =

Weight of the sintered ore (kg) / weight of the total sintered ore manufactured (kg) x 100

Sintered ore RI can be represented by the following formula (4). In Formula 4 below, 500 g means the amount of charged samples for RI measurement.

[Equation 4]

Sintered ore RI (% by weight) =

After reduction and tumbling at 900 ° C. for 30 minutes, the weight (g) of the sintered ore having an average particle size of 2.8 mm or less (g) / the weight of the sintered ore having an average particle size of 15 to 20 mm (500 g)

Sintered ore RDI can be represented by the following formula (5). In Formula 5 below, 500 g means the amount of charged samples for RDI measurement.

[Equation 5]

Sintered ore RDI (% by weight) =

3 hours reduction at 900 ° C., weight reduction amount (g) / weight of sintered ore with an average particle size of 15 to 20 mm (500 g)

Compared to the comparative example, the sintering productivity (26.7 t / dm ^2- > 27.5 to 28.6 t / dm ² ) was increased due to the shortening of the sintering time and the increase in the recovery rate according to the addition of 1 to 5 wt% of the Finex sludge and the analyte. In addition, the present invention promotes the production of low melting point sintered melt (CaO-Fe ₂ O _{3 type} , CaO-Fe ₂ O ₃ -SiO _{2 type} ) during the sintering process, thereby increasing the bonding strength between the sintered raw material particles (71.5). %-> 71.9 ~ 73.6%).

On the other hand, the RI index (70.6%-> 71.5 ~ 75.4%), which shows the reducibility of sintered ore in the blast furnace, was improved, and the RDI index (41.6%-> 40.4 ~ 41.8%), which shows the reduction differentiation in the lower part of the blast furnace, was improved. The same level was maintained.

The reduction of the sintered ore was improved by the addition of the sintered melt generation accelerator, and the amount of the low melting point calcium ferrite (CaO-Fe ₂ O ₃ , CaO-Fe ₂ O ₃ -SiO ₂ -Al ₂ O ₃ ) sintered melt was increased. This is due to an increase in fine pores in the sintered ore.

3) Weight ratio of Finex sludge to analyte

In order to compare the softening temperature and the melting temperature value according to the weight ratio of the Finex sludge and the analytical lime, a sintered ore having the same component as in Example 3 of Table 1 was prepared, but the weight ratio of the Finex sludge and the analyte was shown in Table 4 below. Different.

Weight ratio (% by weight) Ingredient (% by weight) Softening Temperature (℃) Melting temperature (℃) division Finex Sludge Analysis meeting T.Fe CaO SiO ₂ Al ₂ O ₃ MgO C Comparative example 90 10 47.5 9.2 6.1 3.7 0.9 6.3 1348 1449 Comparative example 80 20 42.3 13.7 5.7 3.4 1.1 5.6 1184 1291 Example 70 30 37.0 18.3 5.3 3.0 1.3 4.9 1222 1224 Example 60 40 31.8 22.9 4.9 2.7 1.5 4.2 1202 1210 Example 50 50 26.5 27.5 4.5 2.3 1.7 3.5 1232 1276

Compared with the comparative example, in the case of the example, the softening temperature is basically low, the melting temperature is low, it can be seen that the deviation between the softening temperature and the melting temperature is not large. As a result, a low melting point calcium ferrite sintered melt may be generated during the sintering process.

The present invention is not limited to the above embodiments and / or embodiments, but may be manufactured in various forms, and a person of ordinary skill in the art to which the present invention pertains may change the technical spirit or essential features of the present invention. It will be appreciated that it can be practiced in other specific forms without doing so. Therefore, it is to be understood that the embodiments and / or embodiments described above are illustrative in all respects and not restrictive.

Claims (7)

Preparing pseudo particles by adding moisture to a sintered blended raw material including a raw material, a fuel material, a semi-ore, and a secondary raw material;
Mixing the Finex sludge and the assay lime to prepare a mixture;
Coating the mixture on the surface of the pseudoparticle; And
Sintering the coated pseudoparticle;
In the step of preparing the mixture, the weight ratio of the Finex sludge and the analyte is 6: 4 to 7: 3,
Sintered ore manufacturing method which is mixed so that the content of CaO in the mixture is 18.3 to 22.9% by weight. The method of claim 1,
In the step of preparing the mixture,
The average particle size of the Finex sludge is 50 to 100㎛,
Sintered ore manufacturing method of the average particle size of the analysis lime is 1mm or less. delete The method of claim 1,
In the coating step,
Sintered ore manufacturing method for adding 1 to 5% by weight of the mixture, based on 100% of the total weight of the coated pseudo-particles. The method of claim 1,
In the sintering step,
Sintered ore manufacturing method that produces a calcium ferrite sintered melt. The method of claim 1,
In the sintering step,
Sintering time is 43.7 minutes or less sintered ore manufacturing method. The method of claim 1,
The coated pseudo particle is,
58 to 63% by weight of raw materials including iron ore, 9 to 13% by weight comprising one or more of 3 to 5% by weight of fuel materials, quicklime, limestone and silica sand, including one or more of coke and anthracite A method of producing a sintered ore comprising a secondary raw material, 18 to 22% by weight of semi-glossy, 2 to 4% by weight of moisture and 1 to 5% by weight of a mixture.

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