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A process for producing direct reduced iron from large-grained limonite and hematite ores

A process method and iron ore technology, applied in the direction of fluidized bed furnace, etc., can solve the problem of limited scale of reduced iron, and achieve the effects of saving investment costs, expanding production scale, and simple process methods

Inactive Publication Date: 2011-12-07
UNIV OF SCI & TECH BEIJING +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that the traditional reduction roasting-magnetic separation process is limited in the production of reduced iron with a fine particle size (-4mm), directly for large Reduced roasting of brown and hematite ores with particle size (–50mm)—weak magnetic separation to produce reduced iron, in order to improve roasting efficiency, save investment cost, save energy and reduce consumption

Method used

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  • A process for producing direct reduced iron from large-grained limonite and hematite ores
  • A process for producing direct reduced iron from large-grained limonite and hematite ores

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Embodiment 1

[0014] The total iron content of a limonite is 49.55%, and the main gangue mineral is quartz. 500g of raw ore is roughly crushed to 100% -50mm, adding reducing agent and flux, the amount of reducing agent is 30%; after mixing, reduce and roast at 1200°C for 120min; cool; grind at a concentration of about 60% to a particle size of -0.074mm 51%, magnetic separation at a magnetic field strength of 198.73kA / m. Obtain direct reduced iron with an iron grade of 90.2% and an iron recovery rate of 89.3%.

Embodiment 2

[0016] The raw material is a hematite ore containing 33.48% iron, and the main gangue mineral is quartz. 500g of raw ore is coarsely crushed to 100% -50mm, adding reducing agent and fluxing agent, the amount of reducing agent is 30%; after mixing, reducing and roasting at 1200°C for 240min; cooling; two-stage grinding, magnetic separation at both ends, magnetic field strength 198.73kA / m. Direct reduced iron with an iron grade of 89.3% and a recovery rate of 83.37% was obtained.

Embodiment 3

[0018] The total iron content of a limonite is 33.75%, and the main gangue mineral is quartz. 500g of raw ore is coarsely crushed to 100% -50mm, adding reducing agent and fluxing agent, the amount of reducing agent is 30%, and fluxing agent is 5%; after mixing, reduce and roast at 1200°C for 180min; cool; grind at a concentration of about 60%. Ore 30min to particle size -0.074mm accounted for 85%, magnetic separation at a magnetic field strength of 198.73kA / m. Obtain direct reduced iron with an iron grade of 89.92% and an iron recovery rate of 94.93%.

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Abstract

The invention belongs to the field of ferrous metallurgy and relates to a process method for producing reduced iron in a roasting shaft furnace by using a direct reduction roasting method, wherein used iron are iron ores which mainly exist in forms of limonite and hematite. The method is characterized in that roughly smashing raw ore till particle size is 100%(-50mm), and then fully mixing the pulverized ore with a tailor-made reducing agent and a fluxing agent in a proportion; carrying out direct reduction roasting in the roasting shaft furnace; and obtaining the directly reduced iron product with an iron grade of 90% and iron recovery of more than 80% by using an ore grinding magnetic method. In the process, the reduction temperature is 1100 DEG C-1250 DEG C, wherein the specific temperature is determined according to the property of the ore; the reduction time is 120-240 minutes; and according to the properties of different ores, different amounts of reducing agent and fluxing agent can be added in the process.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy and mineral processing, and relates to a process for producing direct reduced iron with large-grained limonite or hematite as the main raw material. This process method can use limonite and hematite ore with a particle size of -50mm to carry out direct reduction roasting, and under the action of reducing agent, the limonite and hematite in the iron ore can be reduced to metallic iron, and then the ore can be ground and weak magnetic separation to produce direct reduced iron. Background technique [0002] my country's iron ore resource reserves are seriously insufficient. Among the 57.671 billion tons of iron ore reserves that have been identified, the economic base reserves are only 16.686 billion tons, and there are many lean ores and few rich ores. The average grade of iron ore is only 33%. With the acceleration of my country's industrialization process, especially the rapid developmen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21B13/00
Inventor 孙体昌寇珏张继平张伟
Owner UNIV OF SCI & TECH BEIJING
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