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A technology of iron ore shaft furnace-rotary kiln direct reduction to produce iron powder

A rotary kiln, iron ore technology, applied in furnaces, rotary drum furnaces, furnace components, etc., can solve the problems of low pellet strength and metal recovery rate, shorten the reduction time, increase production, and reduce pulverization. Effect

Active Publication Date: 2016-04-13
GANSU JIU STEEL GRP HONGXING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the problem of low pellet strength and low metal recovery rate in the direct reduction of refractory low-grade iron ore, the present invention provides an iron ore shaft furnace-rotary kiln direct reduction process for producing iron powder

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  • A technology of iron ore shaft furnace-rotary kiln direct reduction to produce iron powder

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Embodiment 1

[0030] An iron ore shaft furnace-rotary kiln direct reduction process for producing iron powder, comprising the following process steps:

[0031] (1) Dry grinding and pelletizing of iron ore: After the ore is ground to a particle size of -200 mesh and accounts for more than 80%, it is enriched by magnetic separation to obtain a coarse concentrate powder with an iron grade of 36.1%. The obtained coarse concentrate powder is mixed with The bentonite is mixed according to the mass ratio of 100:1, then moistened, ground and pelletized to obtain pellets with a particle size of 8-16mm;

[0032] (2) Drying pre-consolidation and oxidative roasting of pellets: Pellets are added from the top of the shaft furnace, and in the drying zone of the shaft furnace, the pellets are dried at a temperature of 200-300°C for 15 minutes and then flow down to the Shaft furnace preheating roasting zone and soaking zone. In the preheating roasting zone and soaking zone, the pellets are fully heated, oxi...

Embodiment 2

[0040] The difference between embodiment 2 and embodiment 1 is:

[0041] In step (1), the iron grade of the coarse concentrate powder obtained after magnetic separation and enrichment is 37.8%, and the obtained coarse concentrate powder and bentonite are mixed in a mass ratio of 100:2 and then moistened and pelletized;

[0042] In step (2), in the drying zone of the shaft furnace, the pellets are dried at a temperature of 250-350°C for 12 minutes and then flow down to the preheating roasting zone and soaking zone of the shaft furnace by their own gravity. In the preheating roasting zone and soaking zone, The time for controlling the oxidation and roasting of the pellets is 50 minutes;

[0043] In step (3), the oxidized pellets and the dried granulated coal are mixed in a mass ratio of 100:40 and then added to the rotary kiln for reduction. The reduction temperature of the pellets is controlled at 1080-1120°C and the time is 90 minutes;

[0044] In step (5), after weak magneti...

Embodiment 3

[0046] The difference between embodiment 3 and embodiment 1 is:

[0047] In step (1), the iron grade of the coarse concentrate powder obtained after magnetic separation and enrichment is 42.3%, and the obtained coarse concentrate powder and bentonite are mixed in a mass ratio of 100:3 and then moistened and pelletized;

[0048] In step (2), in the drying zone of the shaft furnace, the pellets are dried at a temperature of 300-400°C for 10 minutes and then flow down to the preheating roasting zone and soaking zone of the shaft furnace by their own gravity. In the preheating roasting zone and soaking zone, The time for controlling the oxidation and roasting of the pellets is 45 minutes;

[0049] In step (3), the oxidized pellets and the dried granulated coal are mixed in a mass ratio of 100:50 and then added to the rotary kiln for reduction. The reduction temperature of the pellets is controlled at 1110-1150°C and the time is 60 minutes;

[0050] In step (5), after weak magneti...

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Abstract

The invention provides an iron ore shaft furnace-rotary kiln direct reduction process for producing iron powder, which includes the following process steps: (1) after the iron ore is ground, it is enriched by magnetic separation, and the obtained rough concentrate powder is mixed with bentonite Afterwards, carry out grinding and pelletizing to obtain pellets; (2) Pellets are added from the top of the shaft furnace, and the pellets are fully heated, oxidized and consolidated in the shaft furnace; (3) Oxidized pellets Mix it with granular coal and add it to the rotary kiln for reduction; (4) Put the reduced pellets into the waste heat recovery device, so that the pellets and air can perform indirect heat exchange; (5) The materials discharged from the waste heat recovery device are magnetically The metallized iron powder with a metallization rate of more than 85% and an iron grade of more than 80% can be obtained. The invention solves the problems of low pellet strength and easy generation of liquid phase in the direct reduction of refractory low-grade iron ore, improves the reduction temperature of the pellets in the reduction roasting rotary kiln, shortens the reduction time, and reduces the number of pellets. powdering phenomenon.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and mineral engineering, and relates to an iron ore shaft furnace-rotary kiln direct reduction process for producing iron powder. Background technique [0002] With the depletion of domestic high-grade rich ore and easy-to-separate ore resources, the development and utilization of difficult-to-separate low-grade ore has become the focus of iron and steel enterprises. In the aspect of direct reduction of refractory low-grade iron ore, since the grain size distribution of iron ore crystals is generally between 5 and 20 μm, iron minerals are mostly symbiotic with gangues, with a high degree of dispersion and complicated intercalation. In order to make effective use of this kind of iron ore, a lot of research work has been carried out at home and abroad, mainly based on the research on the mineral composition, phase and distribution characteristics of magnetite, using traditional strong magnetic se...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21B13/08C22B1/02F27D17/00B03C1/00
Inventor 王明华权芳民雷鹏飞展仁礼鲁逢霖张志刚寇明月付涛
Owner GANSU JIU STEEL GRP HONGXING IRON & STEEL CO LTD
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