Blast furnace and converter for molten iron hearth large scale desulfurization or three eliminating simultaneously

Blast furnace and converter for molten iron hearth large scale desulfurization or three eliminating simultaneously

  • CN 1,718,762 A
  • Filed: 05/25/2005
  • Published: 01/11/2006
  • Est. Priority Date: 07/10/2004
  • Status: Active Application
First Claim
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1. A new hot metal pretreatment process for the operation of a blast furnace or other iron making furnaces, converters or other steel making furnaces by large desulphurization in front of a hot metal furnace or simultaneous dephosphorization and desilication liberation is provided, the existing blast furnace iron making is used for ensuring the smooth smelting, the qualified hot metal is produced, the slag is often required to have lower melting temperature, melting property temperature and viscosity, and certain high alkalinity is required to ensure the sufficient capability of removing the sulfur in the hot metal, the external desulphurization is not generally carried out, or the external desulphurization is carried out on the individual external iron or for lightening the desulphurization task of the next steel making process, and the method for the external desulphurization of the used hot metal comprises the following steps:

  • spreading desulfurizing agent in molten iron ditch, continuous adding plane flow method, eddy flow or mechanical or electromagnetic stirring or rotary drum rotation method, etc. adding desulfurizing agent into molten iron tank, shaking, mechanical or bubble stirring, bubble pump, spraying desulfurizing agent, inserting bell jar or refractory inserting rod into desulfurizing agent, feeding wire, pouring into tank, vacuum method, electrolysis method, etc.;

    the desulfurizer includes soda, NaOH, lime, dolomite, Ca (OH)2Limestone, charcoal, graphite, CaC2Calcium cyanamide, colemanite, fluorite, CaCl2

    Al2O3The traditional production of common steel uses a steel-making furnace as a unique refining container, and takes decarburization and heating as main targets, and simultaneously completes desilication, dephosphorization, desulfurization, deoxidation, impurity removal and alloying, and the simultaneous completion of so many high-temperature heterogeneous chemical reactions in the same container inherently contains many complex contradictions, such as;

    the high FeO slag in an oxidation environment is beneficial to dephosphorization, but is very unfavorable for desulfurization in a reducing atmosphere, and for example, rephosphorization occurs at a tapping target temperature-high temperature, steelmaking in a container is undoubtedly high in consumption and low in efficiency, and smelting is difficult to control to accurately reach a target, so the method needs to be divided into a plurality of process units such as molten iron three-removal (desulfurization, desiliconization and dephosphorization), decarburization, heating, deoxidation and inclusion control, alloying fine adjustment components and the like, particularly a large converter mainly used for producing ultra-clean steel is adopted at present, a special molten iron desulfurization station + converter desiliconization and dephosphorization process is adopted, the molten iron desulfurization station adopts a magnesium-blowing desulfurizer to desulfurize, desiliconization and dephosphorization are carried out in the converter, a refining converter slag is added with a slagging agent (promoting low-temperature slagging) to serve as a dephosphorizing agent of molten iron, and simultaneously bottom blowing is strengthened to enhance steel;

    the medium-small converter mainly for producing general purity steel adopts molten iron transportation and storage equipment as reactor, and at present, it adopts the processes of dephosphorization and desulfurization treatment, and the blast furnace must be operated with low silicon content, and the molten iron (Si)]Controlling the content below 0.4%, and using iron scale, sinter, concentrate and lime powder to make molten iron [ Si]in the tapping process]Less than 0.015 percent;

    the molten iron runner before the furnace is not dephosphorized, most of the molten iron runners are dephosphorized in a molten iron tank or a mixed iron furnace, sometimes, the molten iron tank is simultaneously desulfurized and dephosphorized, and a powder injection process is adopted to control CaO/O21.5-3.0 percent of solid/gas oxygen, less than or equal to 60 percent of solid/gas oxygen, and processed molten iron [ S%]、

    [P]The content should be less than 0.015% (deep desulfurization and phosphorus removal according to the steel grade), the invention is characterized in that the desulfurizer, the dephosphorizing agent, the desiliconizing agent or different compositions thereof are sprayed or scattered on the small well behind the front skimmer (also called sand mouth and slag bridge) of a blast furnace or a cupola furnace or other molten iron producing furnaces to continuously and fully expose the contained elements, or the sulfur in the molten iron is removed at low cost greatly,thereby effectively reducing the high-cost desulfurization load in the blast furnace or cupola furnace or other molten iron producing furnaces, realizing the operation of low slag alkalinity, low temperature and low slag ratio and low coke ratio, further improving and optimizing the furnace charge structure, and completely liberating blast furnaces and other iron making furnaces;

    or besides desulfurization, dephosphorization or desilication or extraction of vanadium or different combinations thereof in the molten iron of the vanadium-titanium ore are further carried out, so that the steel-making furnace can produce pure steel for greatly improving the performance and service life of the steel, and because the molten iron successfully realizes the total removal of three, the steel-making furnace is completely liberated for the purpose of trying to achieve for a long time originally for all steel-making furnaces including the converter;

    the steelmaking furnace has three decarburization and heating tasks only by using molten iron for decarburization;

    the less slag smelting is also the inevitable result after the three-step removal treatment;

    meanwhile, the high-speed converting of the steel furnace is facilitated;

    because the composition of the third molten iron is very stable, extremely favorable conditions are provided for the computer intelligent control of the steelmaking furnace, the accurate control of the converting terminal point and the direct tapping without turning down the furnace can be realized;

    the short blowing period and the reduced slag pouring times greatly reduce the erosion of the furnace lining, greatly improve the service life of the converter or other steel making furnaces, and in short, the large-scale desulfurization or the triple-removal in front of the blast furnace can completely liberate the operation of the blast furnace or other iron making furnaces, the converter or other steel making furnaces.

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