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Method for improving iron content and reducing sulfur content by direct reduction of carbon-containing pellets in rotary hearth furnace

A rotary hearth furnace, direct technology, used in furnaces, furnace types, fluidized bed furnaces, etc., can solve the problems of sulfur reduction, high sulfur content in products, addition of sulfur reducing agents, etc.

Inactive Publication Date: 2013-12-04
JIANGSU PROVINCE METALLURGICAL DESIGN INST
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  • Abstract
  • Description
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Problems solved by technology

[0002] When adopting carbon-containing briquette technology in coal-based direct reduction ironmaking technology, the grade and quality of direct reduced iron were considered, and sulfur reducing agents were not added to carbon-containing pellets. During industrial production and promotion, the sulfur content of the product The problem of too high has not been well resolved
[0003] In the prior art, there have been some studies on the behavior of sulfur in direct reduced iron, but due to the coexistence of metallized pellet gangue and iron, there is usually no good way to remove sulfur in the pellets, just It is hoped that the sulfur in carbon-containing pellets will volatilize naturally, or passively use low-sulfur ore and low-sulfur coal to reduce the adverse effects of sulfur on metallized pellets for steelmaking

Method used

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  • Method for improving iron content and reducing sulfur content by direct reduction of carbon-containing pellets in rotary hearth furnace
  • Method for improving iron content and reducing sulfur content by direct reduction of carbon-containing pellets in rotary hearth furnace
  • Method for improving iron content and reducing sulfur content by direct reduction of carbon-containing pellets in rotary hearth furnace

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specific Embodiment approach

[0011] The method for the direct reduction of carbon-containing pellet rotary hearth furnace of the present invention to raise iron and reduce sulfur, its preferred embodiment is:

[0012] Mix 64-84 parts by weight of iron oxide scale, 19-25 parts of semi-coke, 4-10 parts of limestone, and 9-11 parts of composite binder, press balls, dry, and spread in the rotary hearth furnace Internal reduction at 1200-1400 °C, the atmosphere in the rotary hearth furnace is a neutral atmosphere or a weakly reducing atmosphere, and the reduction time is 25-45 minutes;

[0013] After the reduction product is cooled, the metal particles are separated from the sulfur-rich gangue or slag by fine grinding and magnetic separation.

[0014] Said iron oxide scale: it is produced during forging and hot rolling of steel, with a particle size of ≤3mm.

[0015] In the semi-coke or semi-coking coal: fixed carbon ≥ 78% by weight, ash content ≤ 10% by weight, volatile matter ≤ 8% by weight, S ≤ 0.50% by we...

specific Embodiment

[0022] Schematic diagram of the method for direct reduction of iron, iron, and sulfur reduction in a carbon-containing pellet rotary hearth furnace—— figure 1 Among them, the raw materials include powdered iron oxide scale, semi-coke powder, powdered limestone particles, and the composite binder is composed of solid bentonite and PVA solution. The quality requirements of each raw material are: powdered iron oxide scale particle size ≤ 3mm; fixed carbon of blue charcoal powder ≥ 78wt%, ash content ≤ 10wt% volatile matter ≤ 8wt%, S ≤ 0.50wt%, particle size ≤ 2mm and particle content greater than 70wt% ; CaO ≥ 55wt% of limestone, SiO ≤ 3wt%, particle size ≤ 0.074mm and particle content greater than 70wt%; the solid bentonite content of the composite binder is 30wt%, and the PVA solution content is 70wt%, wherein the concentration of PVA is 5-7wt%. The operating points of the batching and mixing process: dry mix all solid powders on the mixer for 5 minutes according to the determi...

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Abstract

The invention discloses a method for improving iron content and reducing sulfur content by direct reduction of carbon-containing pellets in a rotary hearth furnace. The method comprises the following steps of: uniformly mixing 64-84wt% of iron oxide scale, 19-25wt% of semi-coke, 4-10wt% of lime stone and 10wt% of composite binder; after pelletizing and drying, reducing at 1200-1400 DEG C in the rotary hearth furnace, wherein the atmosphere in the rotary hearth furnace is a neutral atmosphere or a weak reducing atmosphere, and the reduction time is 25-45 min; cooling a reduced product and then finely milling and magnetically separating so that metal iron grains are separated from gangues or slag rich in sulfur; and finally, briquetting the collected iron grains. The method disclosed by the invention is simple in process and lower in energy consumption; more than 75% of sulfur in the carbon-containing pellets can be removed, the grade of the iron grains is about 90% and the sulfur reduction burden in a subsequent smelting process is relived.

Description

technical field [0001] The invention relates to a direct reduction technology for increasing iron and reducing sulfur, in particular to a method for directly reducing iron, increasing iron and reducing sulfur in a carbon-containing pellet rotary hearth furnace. Background technique [0002] When adopting carbon-containing briquette technology in coal-based direct reduction ironmaking technology, the grade and quality of direct reduced iron were considered, and sulfur reducing agents were not added to carbon-containing pellets. During industrial production and promotion, the sulfur content of the product The problem of too high has not been well resolved. [0003] In the prior art, there have been some studies on the behavior of sulfur in direct reduced iron, but due to the coexistence of metallized pellet gangue and iron, there is usually no good way to remove sulfur in the pellets, just It is hoped that the sulfur in carbon-containing pellets will volatilize naturally, or ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21B13/00
Inventor 吴道洪谢桦李胜利
Owner JIANGSU PROVINCE METALLURGICAL DESIGN INST
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