KR910003881B1 - Making process for sintered ore - Google Patents

Abstract

The dried iron ore is divided into the classes of porous iron ore having over 13% volume porosity ratio and dense iron ore having up to 13% volume porosity ratio. A pseudonoise particle consists of nuclear grain and adhesion layer. The porous iron ore as nuclear grain heightens components of limestone and magnetite, and lowes components of cokes and quicklime. The dense iron ore as nuclear grain heightens components of cokes and quicklime, and lowers componets of limestone and magnetite.

Description

Manufacturing method of sintered ore

1 is a process diagram showing a sintered ore manufacturing process according to the present invention.

Figure 2a is a shape of the pseudo particle in the sintered ore production according to the conventional method, (b) is a shape of the pseudo particle in the sintered ore production according to the present invention.

3 is a graph showing the quality and recovery of the sintered ore produced by the conventional method and the present invention.

The present invention relates to a method for producing a sintered ore used as a high soil charge feedstock, and more particularly, to a method for producing a sintered ore having an excellent Reduction Degradation Index (RDI). As the quality of the sintered ore to obtain suitable properties as a high soil charge raw material, room temperature intensity, low temperature reduction rate and reduction rate are managed. Among them, the amount of slag and magnetite has been increased to raise the temperature rate of low temperature reduction. In this case, not only the cost of sintering ore manufacturing increases, but also the reduction rate is deteriorated, which causes the blast furnace fuel rise. Therefore, in the manufacture of sintered ore, the management of low temperature reduction hatching rate is important and a method of improvement thereof is required.

Conventionally, in order to improve the low temperature reduction rate, limestone is increased to generate calcium-ferrite in a large amount, thereby reducing the amount of secondary hematite, or improving the air permeability of the sintered layer by quicklime to cool. Methods have been used to suppress the oxidation of magnetite and to increase magnetite and coke ratio to increase the amount of magnetite and to strengthen the structure of the sintered ore. However, these conventional methods have a problem in that the production cost of the sintered ore is increased because the amount of the raw material having a relatively high price is increased, and the reduction rate is relatively decreased due to the hard reducing ability of a high-strength structure such as magnetite.

Therefore, the present invention classifies the porous iron ore and dense iron ore and sinters each of the ore as nucleus particles with different particle sizes and the composition of the raw material in the adhesion layer, thereby maintaining the reduction rate of the sintered ore at the same sintering raw material blending ratio. It is to improve. That is, reduction reduction of sintered ore is known to be caused by secondary hematite and fragile structure of sintered ore. Therefore, in order to prevent this, the reduction of hematite to magnetite is suppressed or Calcium-ferrite is produced in large quantities. The purpose of the present invention is to enhance the sintering ore operation by reducing the amount of chahematite and promoting the melting of weak areas.

Hereinafter, the present invention will be described in detail.

According to the present invention, in the method for producing sintered ore using iron ore as a nuclear particle, it is classified into a porous iron ore of 13% or more and a dense iron ore of 13% or less based on the volume porosity after high temperature drying, and the porous iron ore is a nuclear particle. The composition of limestone and magnetite is increased in the adhesion layer of pseudo-particles, the composition of coke and quicklime is made small, and the adhesion layer of pseudoparticles with dense iron ore as nucleus particles is sintered so as to be formed in the reverse form of the case of porous iron ore. It relates to a sintered ore manufacturing method.

In the present invention, the ratio of the limestone amount of the porous iron ore portion and the dense iron ore portion is 3.57: 1, the ratio of the magnetite amount is 3.61: 1, the ratio of the quicklime amount is 0.38: 1, and the amount of coke is 0.4: A more preferable effect can be obtained by forming the adhesion layer of a pseudoparticle so that it may become 1. The present invention will be described in detail through a flowchart.

IBG (under) or Riodoce (fine) ore Harmersley (fine) or Mountain newman (fine) or MBR (fine) ore used for hematite in sintered ore is dried at 450 ° C for 2 hours and then cooled to measure porosity The volume pores (hereinafter referred to as "hot volume porosity") were measured by an apparatus (Autoscan-33 Porosimeter) and are shown in Table 1 below.

TABLE 1

As shown in Table 1, IBG (under) or Riodoce (fine) ore having a porosity of 13% or less as a dense ore, and Harmersley (fine) ore, Mountain Newman (fine) ore and MBR having a porosity of 13% or more (fine) Ore is classified as porous iron ore. As can be seen in FIG. 1 showing the process of sintering raw materials, the raw material of class B mainly composed of dense iron ore is assembled separately, and when the raw material assembly of class A mainly composed of porous iron ore is completed, the raw material of class B is completed. Add and mix to use as sintered feedstock.

Here, the raw material of class A is composed mainly of porous iron ore, and the mixing ratio of limestone and magnetite is smaller, the mixing ratio of coke and quicklime is smaller than that of class B, which is mainly composed of dense iron ore, and the other raw material mixing ratio is Both are the same.

When the raw materials are assembled in accordance with the method according to the present invention, as shown in FIG. 2b, there are many limestones and magnetite in the attachment layer of the pseudo-particles having the porous iron ore as the nuclear particles, There is a lot of coke and quicklime.

At this time, as the granular iron ore is less granulated than the porous iron ore, in order to compensate for this, the quicklime ratio is increased in the B-type raw material containing the dense iron ore.

Figure 2a is a pseudo-particle granulated during conventional sintered ore manufacturing, showing the same composition of the adhesion layer without distinguishing between the porous iron ore and dense iron ore. In the case of sintering by mixing the pseudoparticles as shown in FIG. As a result, the total amount of secondary hematite produced can be reduced as compared with conventional pseudoparticles such as 2a. In addition, since the limestone ratio around the porous iron ore with excellent reactivity is high, the production efficiency of calcium-ferrite is increased during sintering compared to the conventional pseudo-particles, which also has the effect of suppressing the production of secondary hematite by reducing the reduced magnetite. Since the magnetite ratio is easy to be melted at this site, the melting of calcium-ferrite is enhanced by low melting point FeO, thereby forming a relatively stronger structure than the calcium-ferrite produced by sintering conventional pseudoparticles. Therefore, the sintered ore produced by the present invention has less secondary hematite and fragile sintered structure, so that the low temperature reduction differentiation rate is improved compared to the sintered ore produced by the conventional method. On the other hand, in FIG. 2B, the pseudo-particles having the dense iron ore as the nucleus have low magnetite and limestone ratios in the adhesion layer, so that the connective tissue may be vulnerable due to the deterioration of the meltability. It is compensated by the increase in the melt amount.

Hereinafter, the present invention will be described in detail through examples.

EXAMPLE

The particle size of the raw materials used in the sintering and (200mmø × 500mmH) experiments was the same as those used in the sintering industry, and the raw material mixing types of Class A and B classified by porous iron ore and dense iron ore, respectively, are as follows. The sintered ore was prepared by changing as shown in Table 2, and the reduction rate, low-temperature reduction rate, rotational strength and recovery rate of each sintered ore were measured, and the measured values are shown in FIG.

TABLE 2

* Hematite shows the porosity of Table 1 above

* * Coke's ratio is based on total formulation.

As shown in Table 2, the pseudo particle of the comparative material a corresponds to a form similar to the pseudo particle in the conventional sintered ore manufacturing process, the raw material composition of the A1 and B1 is the same, the comparative material b is the whole of the lime sheet Although the amount of use is the same as that of comparative material a, the ratio of limestone mixture is controlled to be greater in the adhesion layer of class A raw material containing porous iron ore as the nuclear particles than in the adhesion layer of raw material B which uses dense iron ore as the nuclear particles. c and the comparative material d is different from the combination of magnetite and coke, respectively, and the invention material is different from the combination of limestone, magnetite and coke.

As shown in FIG. 3, the low temperature reduction differentiation rate of the comparative material a having the same pseudoparticle form as that of the conventional method was 42.3%, while the low temperature reduction differentiation rate of the comparative material b, the comparative material c and the comparative material d was respectively 38.9% and 39.5% and 40.2%, respectively. The low temperature reduction rate of the inventive material by the method of the present invention was 36.6%. At this time, in the raw material adhesion layer of class A of porous iron ore as a nuclear particle and of class B of dense iron ore as nuclear particle, comparative materials b and c which differed in only one combination of limestone, magnetite and coke are different. And the low temperature reduction differentiation rate of the invention material which changed all three than d was remarkably improved.

The reduction rates of comparative materials b, c and d were 70.4%, 69.7%, and 69.2%, which were slightly lower than 73.0% of comparative material a, but the invention material was 74.3%, showing similar values to comparative material a. In the case of the invention material, 77.2% and 52.8%, respectively, compared with 77.2% and 55.8% of comparative material a. As a result, the sintered ore produced by the present invention has an effect of improving the low-temperature reduction differentiation rate of 13-14% compared to the sintered ore manufactured by the conventional method without large variation in recovery and other qualities.

As described above, the present invention is classified into porous iron ore and dense iron ore on the basis of the high-temperature volume porosity of iron ore, and the low temperature reduction differentiation rate of sintered ore is improved by improving the structure of pseudo particles by differently assembling each raw material mixing form. This can be a great improvement.

Claims (1)

In the method for producing sintered ore using iron ore as a nucleus particle, it is classified into a porous iron ore of 13% or more and a dense iron ore of 13% or less based on the volume porosity after high temperature drying, and the attachment of pseudo particles using the porous iron ore as a nuclear particle. A method for producing a sintered ore characterized in that the composition of limestone and magnetite is increased in the layer, the composition of coke and quicklime is made small, and the adhesion layer of the pseudoparticles having dense iron ore as a nucleus particle is formed in the reverse form of the case of porous iron ore.

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