Method for preventing resulfurization of molten iron after desulfurization treatment

A technology of molten iron and desulfurization slag, which is applied in steel manufacturing process, furnace, lighting and heating equipment, etc. It can solve the problems of desulfurization slag floating and separation of molten iron, etc., and achieve the effect of increasing productivity and reducing manufacturing cost

Inactive Publication Date: 2019-05-07
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0013] That is, no technology has been proposed to promote the floating and separation of fine desulfurization slag suspended in molten iron after desulfurization treatment, and to prevent resulfurization of molten iron after desulfurization treatment.

Method used

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  • Method for preventing resulfurization of molten iron after desulfurization treatment
  • Method for preventing resulfurization of molten iron after desulfurization treatment
  • Method for preventing resulfurization of molten iron after desulfurization treatment

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Embodiment

[0078] When smelting low-sulfur steel with a sulfur concentration specification of 0.0024% by mass or less for steel products in the order of desulfurization treatment and dephosphorization treatment, the following tests were carried out: the conventional smelting method and the present smelting method with 150 charges each. Invented the smelting method and compared the sulfur concentration in molten iron at the end of the dephosphorization treatment in the next step. If there is a difference in the sulfur concentration in the molten iron at the end of the dephosphorization treatment, this is caused by the difference in the amount of sulfur returned.

[0079] Here, the conventional smelting method refers to a smelting method in which desulfurization treatment is performed using a CaO-based desulfurizer in a mechanically agitated desulfurization device, and the desulfurization slag covering the molten iron bath surface is removed without performing the desulfurization slag float...

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Abstract

In processes for manufacturing molten steel from molten pig iron by performing, on desulfurized molten pig iron, a subsequent step of decarburization refining, etc., the present invention prevents resulfurization arising from microscopic desulfurization slag suspended in the molten pig iron or desulfurization slag adhering to the side walls of the processing vessel that is generated during desulfurization of the molten pig iron. This method for preventing resulfurization of molten pig iron after desulfurization: performs desulfurization of molten pig iron inside a processing vessel using a mechanical stirring desulfurization apparatus; then blows inert gas into the molten pig iron from gas-jetting holes (6) set in the impeller (4) of the mechanical stirring desulfurization apparatus and stirs the molten pig iron (3); floats the desulfurization slag suspended in the molten pig iron and / or desulfurization slag adhering to the inner walls of the processing vessel up to the surface of the molten pig iron by said stirring; discharges the floating desulfurization slag from the processing vessel; and subsequently conveys the molten pig iron inside the processing vessel to the next step.

Description

technical field [0001] The present invention relates to the prevention of residues generated during the desulfurization treatment of molten iron and suspended in molten iron after treatment in the process of smelting molten steel from molten iron such as decarburization refining in the next step after desulfurization treatment. A method for re-sulfurization caused by desulfurization slag in the treatment vessel. Background technique [0002] In recent years, the ratio of ultra-low-sulfur and / or ultra-low-phosphorus steel grades has increased due to the increasing demand for high-purity and high-functionalization of steel materials. Under such circumstances, in the steelmaking process, there is a need for a technology for melting ultra-low-sulfur and / or ultra-low-phosphorus steel grades without causing an increase in cost, an increase in the amount of slag generated, and the like. [0003] In the case of smelting low-sulfur steel, ultra-low-sulfur steel, etc., desulfurizatio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C1/02
CPCC21C1/02C21C1/06C21C2300/08F27D27/00F27D2027/002
Inventor 中井由枝内田祐一菊池直树市川彰铃木纪彦锅岛祐树
Owner JFE STEEL CORP
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