Method of preparing high-hematite self-fluxing pellets by adding limestone through usage of rotary kiln process

A technology of limestone and pellets, applied in the field of metallurgy, can solve the problems of high compressive strength, ring formation of rotary kiln at preheating and roasting temperature, low expansion index, etc., and achieves the promotion of energy saving, emission reduction, production cost reduction, and good metallurgical performance. Effect

Inactive Publication Date: 2019-02-01
BAOSTEEL ZHANJIANG IRON & STEEL CO LTD
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  • Abstract
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Problems solved by technology

[0007] The purpose of the present invention is to provide a method for preparing high-hematite self-fluxing pellets by adding limestone using the rotary kiln process. By adding an appropriate amount of magnetite, the decomposition and heat absorption of limestone and the high preheating and roasting temperature of hematite pellets can be solved. It is easy to cause ring formation in the rotary kiln, and the problems that coal ash mainly composed of silicon and aluminum enters the pellets from the internal coal blending, so as to obtain self-melting with less harmful impurities, high compressive strength, low expansion index, and good reducibility sex pellets

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  • Method of preparing high-hematite self-fluxing pellets by adding limestone through usage of rotary kiln process

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Embodiment 1

[0033] A method for preparing high hematite self-fluxing pellets by adding limestone using a rotary kiln process, comprising the following steps:

[0034] (1) Raw material pretreatment: magnetite and hematite are processed to the required particle size by grinding, and the raw material pretreatment can be dry or wet grinding, wherein the content of TFe in magnetite is 62.0%-71.0%, SiO 2 The content of limestone is 0.5%-4.5%, and the content of particles below 44μm after pretreatment is ≥60%; at the same time, the limestone is crushed from massive to granular, and then further ground into powder, of which the CaO content is ≥52.0%, and the pretreatment is below 44μm The particle content of ≥70%;

[0035] (2) High-pressure roller mill: separate or mix magnetite, hematite and limestone with the required particle size and then carry out high-pressure roller-milling. Specific surface area≥1500cm 2 / g, wherein the raw material weight parts are respectively: 30 parts of magnetite,...

Embodiment 2

[0042] A method for preparing high hematite self-fluxing pellets by adding limestone using a rotary kiln process, comprising the following steps:

[0043] (1) Raw material pretreatment: magnetite and hematite are processed to the required particle size by grinding. The raw material pretreatment can be dry or wet grinding. The content of TFe in magnetite is 62.0%-71.0%. SiO 2 The content of limestone is 0.5%-4.5%, and the content of particles below 44μm after pretreatment is ≥60%; at the same time, the limestone is crushed from massive to granular, and then further ground into powder, of which the CaO content is ≥52.0%, and the pretreatment is below 44μm The particle content of ≥70%;

[0044](2) High-pressure roller mill: separate or mix magnetite, hematite and limestone with the required particle size and then carry out high-pressure roller-milling. Specific surface area≥1500cm 2 / g, wherein the raw material weight parts are respectively: 15 parts of magnetite, 70 parts of ...

Embodiment 3

[0051] The invention has been successfully applied to Baosteel Zhanjiang iron and steel pellet production line. The production line uses the rotary kiln process to add limestone to prepare high hematite self-fluxing pellets. The product has less harmful impurities, high compressive strength, low expansion index and good reducibility. , with an annual production capacity of 4.5-5 million tons, see Table 1 for details.

[0052] Table 1 Composition and performance of high hematite self-fluxing pellets produced from June to September 2018

[0053]

[0054] It can be seen from Table 1 that the self-fluxing pellets produced by the patented method of the invention have few harmful impurities, high compressive strength, low expansion index and good reducibility.

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Abstract

The invention relates to a method of preparing high-hematite self-fluxing pellet by adding limestone through usage of a rotary kiln process, and belongs to the technical field of metallurgy. The method specifically comprises the following steps of raw material pretreatment, high-pressure roller grinding, pelletizing, drying, preheating, roasting, cooling and screening; a proper amount of magnetiteis added, so that the problems that heat absorption is carried out when the limestone is decomposed, ring is easily caused due to a preheating roasting temperature of hematite pellet is high and coalash which mainly composed of silicon and aluminum brought by inner coal blending enters the interior of the pellet are solved, and the self-fluxing pellet which is less in harmful impurities, high incompressive strength, low in expansion index and good in reducibility is obtained.

Description

technical field [0001] The invention relates to a method for preparing high hematite self-fluxing pellets by adding limestone through a rotary kiln process, and belongs to the technical field of metallurgy. Background technique [0002] The pelletizing method is the most widely used agglomeration method for fine-grained iron-containing raw materials in domestic and foreign iron and steel enterprises. It is divided into acidic pellets and alkaline pellets according to whether a flux is added. Generally, the alkaline pellets have an alkalinity of 0.8-1.2 times. The agglomerates are called self-fluxing pellets. [0003] The pyrometallurgical properties of self-fluxing pellets are better than those of acid pellets, and they are suitable for blast furnace smelting with a high proportion or even global pellets. Replacing sinter with self-fluxing pellets can significantly improve the furnace grade, reduce energy consumption, and reduce pollutant emissions, thereby promoting energy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B1/216C22B1/20C22B1/243
CPCC22B1/20C22B1/216C22B1/243
Inventor 易陆杰梁利生蒋林海唐世明谢云江
Owner BAOSTEEL ZHANJIANG IRON & STEEL CO LTD
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