KR960000054B1 - Making method of sintering ore - Google Patents

Abstract

The manufacturing method improves room temperature strength and productivity of a sintering ore by substituting lime stone with recycled limestone sludge. The manufacturing method comprises: mixing the powder dust with limestone sludge in the ration of 0.5˜2 to 1; roasting the mixed material at 1150˜1250 deg.C and preparing the additives mainly composed of calcium ferrite; and substituting limestone with the additives within the range of 10 to 30 percentage.

Description

Sintered Ore Manufacturing Method

1 is a state diagram showing calcium ferrite formation.

2 is an X-ray diffraction analysis after firing and mixing dust and limestone sludge.

3 is a comparison of productivity and room temperature strength.

4 is a heat history curve comparison.

The present invention relates to a method for producing sintered ore, and more particularly, to a method for producing a sintered ore that reuses the dust of the electrostatic precipitator discharged during the sintering operation and the limestone sludge generated at the time of washing with limestone before sintering.

As environmental pollution is increasing around the world, the recycling of various wastes generated in the steel making process is becoming an important issue.

Particularly, dust generated from the electrostatic precipitator of the sintering machine has a high content of alkali (Na, K) and is finely ground, so it is difficult to recycle to the sintering process. It is difficult to recycle the back, rather than being recycled.

However, as shown in Table 1, dust generated during the sintering operation can be regarded as a resource that can be reintroduced into the entire industry when recovered, and lime sludge generated during the quicklime manufacturing process is also a component of Table 1 It is necessary to consider it in terms of resource recycling.

TABLE 1

Conventionally, as a method of recycling them, a method of assembling separately and charging them into a sintering machine, or in the case of sintered electrostatic precipitator dust, has been proposed to remove the alkali component and then to charge the blast furnace or converter. However, the method of assembling separately and charging into the sintering machine has a problem in that they are separately charged, and the method of firing after assembling and charging into the blast furnace or converter has a large amount of fine powder so that the incidence of secondary dust when used as a raw material in the manufacture of sintered ore Has a high problem, sintering contractors have been reluctant to use these methods.

An object of the present invention is to solve the shortcomings of the conventional methods, a method of properly mixing and firing the dust of the electrostatic precipitator generated during the sintering operation and the limestone sludge generated during washing with limestone before use as a preparation agent for the sintering process Is to provide.

It is still another object of the present invention to provide a method of manufacturing a sintered ore having improved room temperature strength and productivity by partially replacing the crude agent with limestone, which is a raw material for sintering.

Hereinafter, the present invention will be described.

The present invention is a method for producing a sintered ore using iron ore, limestone, semi-ore, coke, etc. as a blending raw material, the ratio of the dust / limestone sludge generated during the washing of the electrostatic precipitator discharged during the sintering operation and the washing water before limestone firing 0.5-2 after mixing so as to prepare a crude material of calcium ferrite as the main mineral phase by firing at a temperature range of 1150 to 1250 ° C, and the crude agent is 10-30 to the weight of the limestone as a raw material in the sintered raw material. The present invention relates to a method for producing a sintered ore in which some replacement is added in the% range.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In the early blast furnace operation, when a lot of lumps were used in the blast furnace operation, a large amount of calcite was added to adjust the basicity in the blast furnace. However, since the limestone involves endothermic reaction absorbing enormous heat in the process of changing to CaO, excessive amount of calcite is produced. The manufacture of soluble sintered ore by adding limestone powder is currently dominating the sintering industry.

The main mineral phase of the prepared sintered ore is composed of hematite (primary and secondary), magnetite, calcium silicate, calcium ferrite and glassy slag, the most important of which is calcium ferrite.

Iron ore and limestone added during sintering react during sintering to form calcium ferrite as shown in the following equation.

CaCO ₃ CaO + CO ₂

Ca (OH) ₂ heating CaO + H ₂ O

CaO + Fe ₂ O ₃ → CaO Fe ₂ O ₃ . (One)

₂ CaO Fe ₂ O ₃ ... (2)

CaO ₂ Fe ₂ O ₃ . (3)

1 shows that iron ore and limestone react in the blast furnace to form calcium ferrite.

Since the CaO and Fe ₂ O ₃ as shown in the formula and a first degree of creating a new gwangmulsang of calcium ferrite when combined with each other, and which conventional chairs soluble ores major gwangmulsang The product is prepared to spend a gwangmulsang externally In this case, it is possible to manufacture high-quality sintered ore by making the binding force between iron ore particles more smooth by utilizing the characteristics as a preparation agent with thermal history.

SUMMARY OF THE INVENTION The present invention focuses on this point, and relates to a method of mixing calcium granules by mixing the electrostatic precipitator dust and the limestone sludge, firing them, and using the synthesized calcium ferrite as a raw material for sintering.

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

Example 1

After the sintered electrostatic precipitator was mixed with dust and limestone sludge, briquettes were prepared and fired at a temperature range of 1150, 1200, and 1250 ° C. The results of X-ray diffraction analysis are shown in FIG.

Firing temperature 1150-1250 ℃ when the ratio of electrostatic precipitator dust and limestone sludge is 1: 1, firing temperature 1250 ℃ when the ratio of electrostatic precipitator dust and limestone sludge is 1: 2, ratio of electroprecipitator dust and limestone sludge 2: 1 When the calcination temperature ranged from 1150 ° C, the reaction proceeded as calcium ferrite. Calcium ferrite is difficult to produce at low temperatures of less than 1150 ° C when electrostatic precipitator dust and limestone sludge are 2: 1 to 1: 2, and when the ratio of electrostatic precipitator dust and limestone sludge is 2: 1 to 1: 2 at 1250 ℃ or higher Hematite crystallized upon cooling, which was disadvantageous because the amount of calcium ferrite decreased.

Example 2

Calcium ferrite prepared by the above process was replaced by lime 10%, 30%, 50% by weight in the limestone of the sintered ore raw material so that each component composition as shown in Table 2.

TABLE 2

After sintering the components of Table 2, their productivity and room temperature strength were measured and shown in FIG. As shown in FIG. 3, the productivity of sintered ore increased by about 1% at the replacement ratio of 30%, and the room temperature strength of the sintered ore quality was also the highest by about 1% in the replacement ratio of about 30%. At room temperature, the sintered ore quality was also improved by about 5% at 30% replacement rate. The reason for the improved productivity and room temperature strength is to shorten the time required for the addition of raw materials and to melt even with a small amount of heat, thereby facilitating the bonding between particles, resulting in an effect of increasing the amount of the binder. Because.

4 is a comparative measurement of high temperature holding time in the case of using calcium ferrite as a preparation agent of the present invention and in the usual case. In Figure 4, it can be seen that the case of using the calcium ferrite of the present invention is longer than the high temperature holding time. Therefore, when the calcium ferrite used in the present invention is used as a refilling agent, a reduction effect of coke ratio may be expected at the same time.

Claims (1)

In the method of manufacturing sintered ore using iron ore, limestone, semi-ore, coke, etc., the dust / lime sludge ratio of 0.5 ~ 2 is increased in the dust of the electrostatic precipitator discharged during the sintering operation and the limestone sludge generated when washing with limestone. After mixing to make the first firing in the temperature range of 1150 ~ 1250 ℃ to prepare a calcium ferrite crude mineral phase, the crude agent in the range of 10 ~ 30% relative to the weight of the limestone as a secondary raw material in the sintered raw material Sintered ore manufacturing method characterized in that the addition.