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Method for producing granular iron by magnetically roasting and reducing low-quality limonite with rotary hearth furnace

A technology of magnetizing roasting and limonite, which is applied in the field of metallurgy to achieve the effects of low fuel consumption, short reduction time and fast reaction speed

Inactive Publication Date: 2012-09-05
CENT IRON & STEEL RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] As a new direct reduction ironmaking method, the rotary hearth furnace has the characteristics of low requirements on the quality of raw materials and fuels, fast smelting speed, and simple operation. However, the current rotary hearth furnace smelting needs to solve the problem of efficient utilization of high-temperature flue gas

Method used

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  • Method for producing granular iron by magnetically roasting and reducing low-quality limonite with rotary hearth furnace
  • Method for producing granular iron by magnetically roasting and reducing low-quality limonite with rotary hearth furnace

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] In Example 1, the chemical composition of limonite is as follows: TFe (full iron) 40.33%, FeO 0.64%, Fe 2 o 3 56.94%, SiO 2 16.20%, Al 2 o 3 4.01%, CaO 1.15%, MgO 0.48%, MnO 4.62%, Lol (burning loss) 15.96%.

[0028] A certain amount of limonite with the above chemical composition is reduced and roasted with flue gas from the rotary hearth furnace. The roasted ore is finely ground to below 30 mesh, and then enriched by magnetic separation to obtain the enriched ore. Then, based on the weight of the enriched ore after magnetic separation and enrichment, add about 25% of pitch coke as carbonaceous reducing agent, about 27% of quicklime and fluorite as composite additives and about 4% of The syrup is used as a binder and mixed evenly, pressed into pellets with a diameter of 10-40mm by a double-roller ball press, and dried at about 300°C for about 2 hours. Subsequently, the dried pellets are quickly reduced in a rotary hearth furnace, the reduction temperature is 1...

Embodiment 2

[0030] In Example 2, the chemical composition of limonite is as follows: TFe 46.60%, FeO 1.23%, Fe 2 o 3 65.2%, SiO 2 8.84%, Al 2 o 3 5.97%, CaO 1.29%, MgO 1.71%, MnO 0.89%, Lol (burning loss) 14.87%.

[0031] A certain amount of limonite with the above-mentioned chemical composition is reduced and roasted with the flue gas of the rotary hearth furnace. The ore is finely ground to below 30 mesh, and then enriched by magnetic separation to obtain enriched ore. Then, based on the weight of the enriched ore after magnetic separation and enrichment, add about 27% charcoal as carbonaceous reducing agent, about 15% quicklime and fluorite as composite additives and about 6% bitumen to the enriched ore Use as a binder and mix evenly, press it into pellets with a diameter of 10-40mm with a double-roller ball press, and dry at about 350°C for about 3 hours. Subsequently, the dried pellets are quickly reduced in a rotary hearth furnace, the reduction temperature is 1450°C, and th...

Embodiment 3

[0033]In Example 3, the chemical composition of limonite is as follows: TFe 42.83%, FeO 0.86%, Fe 2 o 3 60.23%, SiO 2 10.68%, Al 2 o 3 4.53%, CaO 0.79%, MgO 2.13%, MnO 1.56%, Lol 19.22%.

[0034] A certain amount of limonite with the above chemical composition is reduced and roasted with flue gas from the rotary hearth furnace. The ore is finely ground to below 30 mesh, and then enriched by magnetic separation to obtain enriched ore. Then, based on the weight of the enriched ore after magnetic separation and enrichment, add about 30% of anthracite as carbonaceous reducing agent, about 8% of quicklime and fluorite as composite additives and about 10% of syrup to the enriched ore Use asphalt as a binder and mix evenly, use a disc pelletizer to press into pellets with a diameter of 10-40mm, and dry at about 400°C for about 1 hour. Subsequently, the dried pellets are quickly reduced in a rotary hearth furnace, the reduction temperature is 1250°C, and the reduction time is ...

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Abstract

The invention provides a method for producing granular iron by magnetically roasting and reducing low-quality limonite with a rotary hearth furnace. The method comprises the following steps of: carrying out reduction roasting, fine grinding and magnetic concentration on limonite; adding carbonaceous reducing agents, compound additives and binders to concentrated ore after magnetic concentration and mixing the materials uniformly; then preparing pellets with pelleting equipment and drying the pellets; and carrying out quick reduction by adopting the rotary hearth furnace, and carrying out cooling, grinding and magnetic separation with a magnetic separator so as to obtain the granular iron, wherein the reducing agents for reduction roasting of limonite are flue gases generated by the rotary hearth furnace. The method has the advantages of high degree of automation, high reaction speed, high reduction efficiency, low smelting cost and the like.

Description

technical field [0001] The invention relates to the field of metallurgy, in particular to a method for producing granulated iron through direct reduction of low-quality limonite in a rotary hearth furnace. Background technique [0002] Limonite is mainly composed of limonite and a small amount of hematite and clay minerals, and its physical and chemical properties are unstable. Most of the limonite in nature is 2Fe 2 o 3 ·3H 2 O form exists, and its theoretical iron content is 59.8%. Because it contains a large amount of crystal water, about 8 to 15%, and its structure is soft, low density, large water content, and many pores, so new pores are left after the temperature rises and the crystal water is removed. The grade of limonite in my country is only about 40%, except for 2Fe 2 o 3 ·3H 2 In addition to O, it also contains a large amount of SiO 2 Gangue oxides are acidic iron ores. During the blast furnace smelting process, a large amount of fluxes such as limeston...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21B13/00
Inventor 高建军齐渊洪郭玉华严定鎏周和敏徐洪军
Owner CENT IRON & STEEL RES INST
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