High-reducibility pellet and preparation method thereof

A technology of pellets and mass percentage, applied in the field of high reducing pellets and its preparation, can solve the problems of low strength of finished pellets, high preheating and roasting temperature, complex additive components, etc., achieve significant environmental benefits, reduce Fuel ratio, effect of improving pellet metallurgical properties

Active Publication Date: 2015-04-15
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

By adding some additives, the problems of high preheating and roasting temperature, long time and low strength of finished pellets in the preparation of oxidized pellets from refractory hematite concentrate are solved to a certain extent.
However, it is aimed at preparing acid pellets from hematite concentrate, and the additive composition is complex and difficult to manufacture
Therefore, for the production of high reducing flux pellets with hematite concentrate, it is necessary to develop a new economical and effective method to solve the problems of high preheating and roasting temperature and long time

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] The hematite concentrate is mixed with the dehydrated molten iron smelting sludge, the magnesium-containing additives and the binder at a mass percentage of 88%: 8%: 2.5%: 1.5%. The used hematite concentrate particle size is more than 75% ≤0.044mm, the molten iron sludge particle size is more than 90% ≤0.074mm, the magnesium-containing additive is 100% light burnt dolomite + 0% magnesia, and the magnesium-containing additive MgO≥35%, more than 80% of the particle size≤0.074mm. The ratio of carboxymethyl modified starch polymer compound and bentonite in the binder is 1 / 5. Then, the mixed material after mixing is moistened and ground for 9 minutes, and then pelletized and dried. After the green pellets are dried, the preheating temperature is 940℃, the preheating time is 15min, the roasting temperature is 1240℃, and the roasting time is 15min. Preheating and roasting, the compressive strength of the obtained preheated pellets is 600N·piece -1 , The compressive strength of...

Embodiment 2

[0035] The hematite concentrate is mixed with the dehydrated molten iron smelting sludge, the magnesium-containing additives and the binder in a mass percentage ratio of 90%:5%:4%:1%. More than 80% of the hematite concentrate particle size ≤0.044mm, more than 90% of the molten iron smelting sludge particle size ≤0.074mm, the magnesium additive is 80% light burnt dolomite + 20% magnesia, and the magnesium additive MgO≥45%, and the particle size ≤0.074mm is greater than 85%. The ratio of carboxymethyl modified starch polymer compound and bentonite in the binder is 1 / 3. Then, the mixed material is moistened and ground for 6 minutes, and then pelletized and dried. After the green pellets are dried, the preheating temperature is 970℃, the preheating time is 12min, the roasting temperature is 1280℃, and the roasting time is 10min. Preheating and roasting, the compressive strength of the obtained preheated pellets is 620N·piece -1 , The compressive strength of the fired pellets is 28...

Embodiment 3

[0037] The hematite concentrate is mixed with the dehydrated molten iron smelting sludge, the magnesium-containing additives and the binder in a mass percentage ratio of 91%: 3%: 5%: 1%. The hematite concentrate used is more than 85% with a particle size of ≤0.044mm, more than 95% of the molten iron smelting sludge with a particle size of ≤0.074mm, and the magnesium-containing additive is 75% light burnt dolomite + 25% magnesia. MgO≥45%, more than 90% of the particle size≤0.074mm. The ratio of carboxymethyl modified starch polymer compound and bentonite in the binder is 1 / 3. Then the mixed material after mixing is moistened and ground for 2 minutes, and then pelletized and dried. After the green pellets are dried, the preheating temperature is 980℃, the preheating time is 12min, the roasting temperature is 1280℃, and the roasting time is 15min. Preheating and roasting, the compressive strength of the obtained preheated pellets is 650N·piece -1 , The compressive strength of cal...

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Abstract

The invention relates to a preparation method of a high-reducibility pellet. In the method, hematite concentrate, dehydrated molten iron-smelting sludge, a magnesium-containing additive and a binding agent are mixed according to a mass percentage of 88-95%:1-8%:2.5-5.5%:0.7-1.5%. When the raw materials are uniformly mixed, moisture of the mixed raw materials is controlled to be 4-9%. A wet-grinding process is carried out for 2-9 min, and then a finished product of the high-reducibility pellet is obtained successively through a pelletizing process, a drying process, a pre-heating process and a roasting process after the wet-grinding process finished. The high-reducibility pellet is not less than 60% in TFe, is 1.0-3.0% in MgO content and is 0.8-1.4 in a ratio of CaO to SiO2. By means of the method, not only are problems, such as high temperature during pre-heating and roasting process, a long time and a low strength of the finished product of the high-reducibility pellet and the like, during preparation of an oxidizing pellet by the hematite concentrate are solved effectively, but also the pellet is significantly enhanced in reducing performance, thereby achieving energy conservation and emission reduction during iron smelting.

Description

Technical field [0001] The invention relates to a technology for agglomeration of iron-making raw material pellets, in particular to a high-reducibility pellet and a preparation method thereof. Background technique [0002] With the increasingly serious energy and environmental issues, energy conservation, emission reduction and low-carbon development have become key issues for the transformation of the development mode of the steel industry and the survival and development of enterprises. In order to reduce energy consumption and pollutant emissions in ironmaking production, the production of high-quality iron-containing raw materials is an important research direction. Pellet has the characteristics of good strength, uniform particle size, regular shape, and high iron grade. It can play a role in improving the technical and economic indicators of ironmaking and reducing the cost of pig iron in smelting. However, the pellets currently used in ironmaking production are mainly ac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B1/244
CPCC22B1/244
Inventor 熊林毛晓明李建沈红标彭新
Owner BAOSHAN IRON & STEEL CO LTD
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