JPS6012412B2 - Method for producing molded agglomerate with excellent properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing shaped agglomerates such as briquettes or pellets that have excellent properties as a raw material for blast furnaces, and specifically, the present invention relates to a method for producing shaped agglomerates such as briquettes or pellets that have excellent properties as raw materials for blast furnaces. The pore diameter is about the size of a rib.
It has a porosity of 5 to 35% and is mainly composed of diffusion bonds of hemi-calcium ferrite phase and hematite phase, and is made into slag by fixing unformed low-grade original shark in the network of these diffusion bonds. It is an object of the present invention to provide a method for producing shaped agglomerate ore having a form that suppresses this.

Conventionally, ore and pellets have been known as agglomerate ores for blast furnaces.

Although the properties of these agglomerate ores are excellent as blast furnace raw materials, they also have drawbacks, leaving room for improvement. Table 1 below shows the properties and structure of the above-mentioned rain agglomerate ore. 1st
From Table 1 above, the difference in properties between sintered ore and pellets is due to the difference in their structures.

That is, it is desired for calcined tayaite to improve the reducing properties in high-temperature castles and to reduce the amount of slag for reducing the blast furnace fuel ratio, and for pellets, it is desired to improve high-temperature reducing properties and swelling properties during reduction. The present invention was made in response to the above-mentioned needs, and its gist is that Si0
Powdered iron ore adjusted to 22-5%, basicity 1.5-2.0 and lime-based soot solvent are mixed with charcoal, formed into briquettes or pellets, fired in a grate furnace, and made into blast furnaces. When producing agglomerate ore, the briquette or pellet molding is made by adding less carbonaceous material to the core and more to the surface layer.
A double-layer molded product of 0 to 2 Deng Misakishin is used, and when fired in the grate furnace, the molded product with a large amount of added carbon material is placed in the upper layer of the grate, and the molded product with a small amount of added carbon material is placed in the lower layer of the grate.
The molded product is charged and the heat pattern in the layer reaches 1 in the grate furnace.
This is a method for producing shaped agglomerated ore with excellent properties, characterized by calcination not exceeding 300 qo.

Furthermore, when mixing iron ore and a lime-based solvent, it is an object of the present invention to mix part or all of the lime-based solvent before the pulverization process when the iron ore is crushed. This will make the improvement of properties of molded agglomerates even more effective. In addition, in the present invention, when adopting the manufacturing method for obtaining the above-mentioned shaped agglomerated ore, the particle size of 11 grains is 70 mm as a raw material.
% or more, T. Fe56-60%, Fe02-5%, A
So2031~2%, SjO22~5%, Ca04~8%
, M guy 1-2%, CI. It is preferable to use one having a composition of 0 to 3.5%.

In addition, part or all of Ca○, a lime-based soot solvent, is pulverized and mixed with high-grade iron ore (if both raw materials are powdered, only mixed), and a core is formed. Next, a mixed raw material of relatively low-grade iron ore is molded on the outside as a surface layer. In this way, make 10 to 2 briquettes or berets. In this case, the effects of the present invention can be made more pronounced by increasing the amount of coal added to the surface layer than the core, and by increasing the amount of carbon material added to the molded material charged into the upper layer of the great furnace than the lower layer. . In the present invention, the reason why the raw materials are adjusted to have Si022 to 5% and basicity 1.5 to 2.0 is that if Si02 is less than 2%, the desired effect of the present invention cannot be obtained.
This is because if it exceeds 5%, the JIS return rate will drop.

Also, the reason for adjusting the basicity to 1.5 to 2.0 is 1.
．． This is because if it is less than 5, the desired effect of the present invention cannot be obtained, and if it exceeds 2.0, it will be difficult to operate the blast furnace. Further, the reason why the temperature inside the layer during firing is not set to exceed 1300q○ is that it has been confirmed through experiments that the effects of the present invention cannot be obtained if the temperature exceeds 1300q○. Next, examples of the present invention and comparative examples will be shown.

Example 1-1 side is 80%, Si02 content is 2.5
% powdered iron ore, 7.5% quicklime as a Ca0 source and 3% light calcined dolomite as an Mg0 source, and
．． 5-1. A double-layer briquette is formed using powdered coke with a 63% coke content, 20% less in the core of the briquette and 80% more in the surface layer, and dried in an upward and downward direction in a grate furnace. The structure and porosity of the molded agglomerates, self-fusing pellets, and racebanded ores obtained by the method of the present invention by firing and cooling the layer temperature are as shown in Table 2 below,
The properties were as shown in Table 3.

Table 2 Table 3 Note that the sintered ore of the comparative example is the same raw material as the agglomerated ore of the present invention, except that the amount of coke added is increased to maintain strength.

In addition, Fig. 1 is a micrograph (x200) showing the structure of the competitive ore of the comparative example shown in Tables 2 and 3, and Fig.
A micrograph (×20
0).

As is clear from Tables 2 and 3 and Figures 1 and 2 above,
Compared to sintered ore, the agglomerated ore obtained by the method of the present invention not only has a structure superior in fineness and quantity of calcium ferrite crystals, and also has superior porosity, as well as JIS reduction rate and reduction powdering rate. It can be seen that the high-temperature properties are also excellent.

Example 2 Only the Si02 content was changed stepwise from 2.5 to 5%, the blending ratio of other compositions and the particle size of the raw material powdered iron ore were the same as in the example, and the manufacturing conditions were also the same as in the example 1. Several types of double pellets are granulated, and the temperature inside the bed is 130℃ in a grate furnace.
The agglomerated ore of the present invention was calcined so as not to exceed 0 qo, and several types of scale ore having the same composition as above were calcined as comparative examples.

Their normal temperature properties and high temperature properties were as shown in FIG. As is clear from Figure 3, the Si02 content is 2
%. In addition, the various properties basically show similar trends for the pellets according to the present invention and the Akatsuki concretion, but as shown in Tables 1 and 2 and Tables 1 and 2 above,
From the figure, it can be seen that there are differences in the structure, and that the properties have also been considerably improved. Since the agglomerated ore produced by the method of the present invention is formed into briquettes or pellets before firing, it has a higher density of 3.0 to 3.0 mm compared to sintered ore. Tsunagi/
Very high cc. Therefore, the amount of carbonaceous material added can be reduced, and fusion bonding during the firing process is less likely. Furthermore, it is clear from FIG. 2 that almost no tamite is generated in the multi-component system in which Si02 and A203 generated by melting are dissolved. As a result, reduction powdering properties were improved compared to competitive coalescence. Furthermore, as the number of fused bonds decreases, the micropores increase and the calcium ferrite becomes finely structured, improving the reducing properties.At the same time, the gangue mainly composed of low-grade ferrite, which leads to a decrease in strength, is replaced with hemicalcium ferrite. Since it is fixed in the diffusion bond as a main body, the decrease in the effect due to this is suppressed.

[Brief explanation of drawings]

FIG. 1 is a micrograph showing the structure of comparative example sinter. FIG. 2 is a micrograph showing the structure of the agglomerated ore according to the present invention. Figure 3 shows the comparison example Hiru condensate and the product Si of the example of the present invention.
FIG. 2 is a graph showing the relationship between 02 content and properties at room temperature and high temperature. Figure 1 Figure 2, Figure 3

Claims (1)

[Claims] 1. Powdered iron ore adjusted to 22 to 5% SiO and basicity 1.5 to 2.0 and a lime-based solvent are mixed with carbonaceous material, formed into briquettes or pellets, and heated in a grate furnace. In order to produce agglomerate for blast furnaces, the briquette or pellet molded product is a double layer molded product with a diameter of 10 to 20 mmψ in which the amount of carbon material added is small in the core part and large in the surface layer,
During firing in the grate furnace, a molded product with a large amount of added carbon material is charged into the upper part of the grate, and a molded product with a small amount of added carbon material is charged into the lower part of the grate, and the in-layer heat pattern is created in the grate furnace. A method for producing shaped agglomerate ore with excellent properties, characterized by firing at a temperature not exceeding 1300°C. 2 As a raw material for the agglomerate ore, the particle size of −1 mm is 70% or more, and T. Fl56~60%, FeO2~5%, Al_
2O_31-2%, SiO_22-5%, CaO4-8
%, MgO 1 to 2%, and C 1.0 to 3.5%. 3. A patent claim characterized in that when the iron ore and the lime-based solvent are mixed, when the iron ore is crushed, part or all of the lime-based solvent is mixed before the pulverization process, and then the iron ore is crushed. A method for producing shaped agglomerated ore having excellent properties as described in item 1.