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A method for producing low-sulfur steelmaking pig iron using a rotary hearth furnace

A steelmaking pig iron and rotary hearth furnace technology, applied in the field of coal-based direct reduction ironmaking, can solve the problems of increasing energy consumption and refractory material consumption, increasing the difficulty of process implementation, and increasing the melting point of slag system, so as to reduce energy consumption and reduce Production cost, effect of low melting temperature

Active Publication Date: 2016-01-20
LAIWU IRON & STEEL GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This process only relies on adding a large amount of limestone and dolomite to the ingredients for pearl iron desulfurization. The desulfurization capacity is limited, and the melting point of the slag system increases. The reduction melting temperature required in the rotary hearth furnace is as high as 1500 ° C, which not only greatly increases Reduce energy consumption and refractory material consumption, and also increase the difficulty of implementing the process

Method used

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  • A method for producing low-sulfur steelmaking pig iron using a rotary hearth furnace
  • A method for producing low-sulfur steelmaking pig iron using a rotary hearth furnace
  • A method for producing low-sulfur steelmaking pig iron using a rotary hearth furnace

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Effect test

Embodiment 1

[0029] 82 parts by weight of low-grade iron ore powder, 18 parts by weight of anthracite coal powder, 2 parts by weight of organic soybean powder binder, 24 parts by weight of limestone (51% CaO content), 4 parts by weight of fluorite, 8 parts by weight of soda, It is conveyed to the mixer through the belt and mixed, and the moisture content of the mixed material is adjusted to 8%. The mixed material is conveyed to the double-roller ball pressing machine through the belt to make carbon-containing pellets, the pressure is 15MPa, and the size of the pellets is 40×30×20mm pillow-shaped ellipsoid. After the raw balls are dried, they are spread on the bottom of the rotary hearth furnace in a single layer, and a layer of coke powder particles with a thickness of 10 to 15 mm is laid on the bottom of the furnace in advance, and the particle size is 3 mm. The temperature in the preheating section is 1150-1250°C, and the time is 5 minutes; the temperature in the reduction stage is 1250-...

Embodiment 2

[0035] 78.5 parts by weight of low-grade iron ore powder, 21.5 parts by weight of anthracite coal powder, 2 parts by weight of organic soybean flour binder, 22 parts by weight of limestone (51% CaO content), 2 parts by weight of fluorite, 6 parts by weight of soda, It is conveyed to the mixer through the belt for mixing, and the moisture content of the mixed material is adjusted to 12%. The mixed material is conveyed to the double-roller ball pressing machine through the belt to make carbon-containing pellets, the pressure is 15MPa, and the size of the pellets is 40×30×20mm pillow-shaped ellipsoid. Spread a layer of graphite powder particles with a thickness of 10-15 mm on the bottom of the furnace, with a particle size of 3 mm. After the green pellets are dried, spread them in a single layer on the graphite powder at the bottom of the rotary hearth furnace. At the same time, add 5% lumpy steel slag to the green pellets. The temperature in the preheating section is 1150-1250°C...

Embodiment 3

[0039]85 parts by weight of low-grade iron ore powder, 25 parts by weight of semi-coke, 4 parts by weight of organic dextrin binder, 15 parts by weight of limestone (with a CaO content of 51%), 6 parts by weight of fluorite, and 8 parts by weight of soda, It is conveyed to the mixer through the belt for mixing, and the moisture content of the mixed material is adjusted to 12%. The mixed material is conveyed to the double-roller ball pressing machine through the belt to make carbon-containing pellets, the pressure is 15MPa, and the size of the pellets is 40×30×20mm pillow-shaped ellipsoid. Spread a layer of graphite powder particles with a thickness of 15 mm on the bottom of the furnace, and the particle size is 5 mm. After the green pellets are dried, spread them in a single layer on the graphite powder at the bottom of the rotary hearth furnace. At the same time, add 10% lumpy steel slag to the green pellets. The temperature in the preheating section is 1150-1250°C for 10 min...

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Abstract

The invention relates to a method for producing low-sulfur pig iron for steel manufacture by using a rotary hearth furnace. The method uses low grade iron ore powder, a carbonaceous reducing agent, limestone, fluorite, soda and an organic binder as raw materials for pelletizing; the materials are subjected to preheating, reduction, melt-phase separation and cooling in the rotary hearth furnace to realize iron and slag separation; and the materials are discharged, subjected to secondary cooling, first screening, crushing, second screening and magnetic separation to achieve recovery of grate-layer material and separation of iron and slag, so as to obtain high-quality low-sulfur iron beads. The method provided by the invention achieve rapid reduction and melt-phase separation of carbon-containing pellet by adjusting the slag system, adding a sulfur fixing agent and optimizing temperature and air flow in the rotary hearth furnace, so as to obtain the lower-sulfur iron bead, which can be used as fine raw material for electric furnace or converter steelmaking. The method has the advanategs of low temperature for melt-phase separation and short time for high temperature maintenance, thereby reducing energy consumption.

Description

technical field [0001] The invention relates to the field of coal-based direct reduction ironmaking, in particular, the invention relates to a method for producing low-sulfur pig iron for steelmaking by using a rotary hearth furnace. Background technique [0002] Iron and steel metallurgy is a pillar industry of the national economy. In recent years, although China's iron and steel metallurgy technology has made great progress, the pressure of resource shortage has become a "bottleneck" for further development. Taking iron ore resources as an example, they are highly dependent on imports, and the degree of dependence on foreign countries has reached more than 50%. The safe supply of iron ore resources and the high price of imported iron ore have become the restrictive factors for the economic benefits of the steel industry. At present, high-quality iron ore resources are gradually scarce and prices remain high. my country's iron and steel enterprises have to use domestic and...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21B13/10C21B11/08
Inventor 曾晖薛庆国吴允王广王延平佘雪峰陈伟
Owner LAIWU IRON & STEEL GRP
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