KR100433253B1 - Method for manufacturing sintered core by controlling the quantity of the MgO - Google Patents

Abstract

The present invention relates to an operation method for manufacturing a sintered ore by adjusting the addition ratio of serpentine used to adjust the MgO component in the manufacture of the sintered ore using a DL (dwight lloyd) type sintering machine after mixing iron ore, secondary raw materials and fuel, The method of manufacturing a sintered ore by sintering iron ore, a subsidiary material including silica sand and serpentine, and a fuel mixed compound is prepared by maintaining the MgO content in the sintered ore component at 1.21 to 1.36 wt% It is characterized by maintaining at 1.00 ~ 1.32%.

Description

Method for manufacturing sintered ore by adjusting the magnesium oxide composition {Method for manufacturing sintered core by controlling the quantity of the MgO}

The present invention relates to an operation method for manufacturing a sintered ore by adjusting the addition ratio of serpentine used to adjust the MgO component in the manufacture of the sintered ore using a DL (dwight lloyd) type sintering machine after mixing iron ore, secondary raw materials and fuel, In particular, the present invention relates to a sintered ore manufacturing method for increasing the strength of the sintered ore using a change in the sintered ore mineral phase when the MgO component changes.

As shown in FIG. 1, in general, iron ore, the main raw material, a limestone as a CaO source, a serpentine rock as an MgO source, and a SiO ₂ source in order to produce a bulk sintered ore of a size suitable for blast furnaces for fine iron ore in a DL type sintering process. As a result, subsidiary materials such as silica sand and fuels such as coke or anthracite coal are discharged at a constant rate from the CFW in the lower part of the raw material storage tank, mixed in a mixer, assembled by adding water, and then sintered through a charging device. It is loaded on the pallet.

Subsequently, the raw material and the sub-raw materials are heated by the heat generated when the flame proceeds downward while the coke or anthracite in the blended raw material is burned while the pallet is advancing while the mixed fuel of the upper part of the pallet is ignited in the ignition furnace. React with each other to form a new melt.

This melt binds fine iron ores. The combined ore is called sintered ore, and when the sintered ore is used in the blast furnace (blast furnace) to make water, the sintered ore with high impact resistance is required to improve the air permeability inside the blast furnace.

The sintered ore manufactured in the sintering machine pallet sends the sintered ore (normally 5 ~ 50mm particle size) of a certain particle size to the blast furnace through cooling, crushing, and sorting process, but part is crushed while passing through the chute during the transfer process, and then used again after the sorting process. The sintered ore with a particle size of 5mm or less is sent to the sintering process to be recyclized to the sintered raw material.

In this process, when the strength of sintered ore is low, the amount of sintered ore with small particle size in the sintering process increases, and the amount of semi-mineral returned from the blast furnace increases, which leads to an increase in manufacturing cost due to a decrease in sinter recovery rate and weakening of breathability in the blast furnace process. Inhibits.

Conventional methods for increasing the strength of sintered ores include the following several methods.

First, the strength of the sintered ore is a method of increasing the slag component to increase the binding of iron ore, that is, a method of improving the strength by increasing the slag component that acts as a bond between the ore particles by increasing the CaO, SiO ₂ , MgO component. .

Second, it is a method of increasing the amount of heat input, the method of improving the strength by increasing the binding force through the increase in the amount of solution production of slag through the increase of the input amount of coke, the heat source for the production of sintered ore.

Third, there is a method of increasing the layer thickness under reduced production speed.

However, the above methods have the following problems.

The problem with the first method is to increase the input of subsidiary materials that act as binders to increase the strength of the sintered ore, thus increasing the cost of producing the sintered ore.

In the second method, the input calories in the sintering process is powdered coke, but the increased input of powdered coke increases the production cost of sintered ore and increases the amount of powdered coke that contains a large amount of sulfur. Increase

The third method is difficult to apply to actual operation because deterioration of air permeability of the sinter bed by raising the layer after raising the layer after operation while reducing the production speed.

The present invention has been made to solve the conventional problems as described above, by adjusting the MgO component in the sintered ore by controlling the use of the serpentine as an auxiliary material to change the mineral structure generation ratio in the sintered ore to increase the intensity of the sintered ore It is an object of the present invention to provide a sintered ore manufacturing method capable of improving the strength of the sintered ore while improving the production cost of the sintered ore.

According to an embodiment of the present invention, in order to achieve the above object, a method of manufacturing a sintered ore by sintering the iron ore, the subsidiary materials including silica sand and serpentine, and the blended material mixed with the fuel is a method of MgO The content of the serpentine is maintained at 1.00 to 1.32% to maintain the content at 1.21 to 1.36% by weight.

1 is a view showing the flow of a sintered ore manufacturing process of a general DL type sintering machine.

2 is a view schematically showing a sintered optical port tester.

3 is a bar graph showing a distribution change of the sintered ore mineral structure according to the MgO component change.

<Description of Symbols for Major Parts of Drawings>

A: Hood

B: anemometer

C: Sintering Pot

D: raw ore

E: roadbed

F: Windbox

G: Thermocouple

H: Great Bar

I: pressure gauge

J: Barometer

K: Damper Valve

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

The chemical composition of serpentine rock used as an auxiliary material in the sintering industry is composed of components and other impurities as shown in Table 1, where the main components are composed of MgO and SiO ₂ components.

Table 1

When serpentine is heated, it undergoes pyrolysis as follows.

3MgO.2SiO ₂ .2H ₂ O

↓ (570 ~ 760 ℃, endothermic reaction)

3MgO.SiO ₂ + SiO ₂ + 2H ₂ O

↓ (800 ~ 840 ℃, exothermic reaction)

2MgO.SiO ₂ + MgO.SiO ₂

(forsterite) (enstatite)

In other words, the serpentine rock forms free SiO ₂ according to the dehydration phenomenon of the crystal water at 570 to 760 ° C., and forms a structurally stable forsterite and ensectite at 800 to 840 ° C. by dehydration. In addition, MgO has a high melting point in the high-temperature region during sintering and improves fluidity by reducing the viscosity of the melt, thereby shortening the high temperature holding time during the cooling process and stabilizing the magnetite.

In the present invention, a sintering pot test was first performed for a practical process of manufacturing a sintered ore.

The mixing conditions of the raw materials are shown in Table 2, and the mixing ratio of the jet rock was reduced from 1.76 to 0%, leading to a decrease of MgO in the sintered ore.

TABLE 2

In the sintering pot test, the raw materials were mixed in the mixing ratio of Table 2, and then charged into a small drum mixer, and divided into three stages for mixing and granulation. The moisture content of the blended raw materials was constantly added at 7.0% by weight and charged in the sintering pot. At the same time as the ignition furnace preheated to 0 ° C., the blower was operated to maintain the negative pressure at 1500 mmAq to proceed with sintering.

The schematic and operating conditions of the sintering pot are shown in Figure 2 and Table 3 below.

TABLE 3

The chemical composition of the sintered ore according to the serpentine compounding ratio is shown in Table 4 below.

Table 4

As a result of reducing the sintered blend ratio of serpentine rock from 1.76 wt% to 0 wt%, the MgO content in the sintered ore decreased from 1.49 wt% to 0.85 wt%, and the slag component of the sintered ore, that is, CaO + SiO ₂ + MgO, was 17.15 wt% At 16.32% by weight.

In addition, the operation results of the sintering pot is shown in Table 5 below.

Table 5

As can be seen in Table 5, the strength was increased from 76.4% by weight to 79.2% by weight as the quality of the sintered ore decreased with the decrease of the mixing ratio of the jet rock, and the recovery was also increased from 68.5% by weight to 71.0% by weight.

This is because, when the ratio of serpentine is decreased, the melt production rate is increased under the same caloric condition and the calcium ferrite, which is the main mineral phase of the sintered ore, is increased due to the decrease in the melt generation temperature in the sintered bed.

The reducibility of sintered ore was also greatly improved because the amount of magnetite, which is a hard-ring mineral phase, was reduced and the amount of calcium ferrite with good reducibility was increased.

Sintering productivity also has the effect of being improved by the increase of a recovery rate.

In order to measure the distribution ratio of the mineral structure of the prepared sintered ore, the distribution state and shape of each mineral phase in the sintered ore were measured using an image analyzer. As a result, the mineral structure distribution ratio is shown in FIG. 3.

When the MgO component in the sintered ore was reduced from 1.76 wt% to 1.16 wt%, hematite and secondary hematite tended to increase, indicating that the distribution ratio of residual ore hematite was decreased. In addition, the magnetite which adversely affects the reducing property and strength decreases, and calcium ferrite having good reducing and strength tends to increase.

Therefore, according to the present invention, the minerals of sintered ores are lowered by lowering the MgO component of the sintered ores by controlling the use of serpentine, which is a subsidiary material, in the sintered blended fuel without increasing fuel and increasing the amount of subsidiary materials. It is effective to reduce sintered ore manufacturing cost by increasing the strength of sintered ore by changing the structure.

The foregoing is merely illustrative of preferred embodiments of the present invention and those skilled in the art to which the present invention pertains may make modifications and changes to the present invention without departing from the spirit and spirit of the invention as set forth in the appended claims. It should be recognized.

Claims (3)

In the method for producing a sintered ore by sintering the iron ore, the subsidiary material including silica sand and serpentine, and the blended material mixed with fuel, Sintered ore manufacturing method characterized in that the compounding ratio of the serpentine is maintained at 1.00 ~ 1.36% to maintain the content of MgO in the components of the sintered ore to 1.21 ~ 1.36% by weight. delete delete