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Method for molten iron pretreatment desulfurization by using LF furnace

A molten iron pretreatment and molten iron technology, which is applied in the field of molten iron pretreatment, can solve the problems of large iron loss, inability to achieve precise temperature control of molten iron composition monitoring, and increase equipment investment. Effect

Inactive Publication Date: 2021-07-09
SHIJIAZHUANG IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the above three processes all carry out pretreatment and desulfurization of molten iron in iron ladle or iron tank. In addition to the need to increase equipment investment, the physical and chemical indicators of the desulfurizer are strictly required, and are also limited by factors such as iron ladle volume and headroom, and cannot achieve temperature Accurate control and monitoring of molten iron composition in the process, in addition, during the injection and stirring process, the iron loss is relatively large

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Embodiment 1: The method of utilizing LF furnace for pretreatment and desulfurization of molten iron adopts the following specific processes.

[0025] (1) Sampling and analysis of temperature measurement of molten iron in ironmaking production, temperature 1412°C, sulfur 0.052%, transported to the slag removal station through the ladle, and then use the slag removal machine to remove the top slag in the iron ladle.

[0026] (2) At the same time, put the desulfurization slag agent into the ladle prepared in advance on the ladle car of the LF furnace, and connect the bottom blowing system to the bottom blowing pipeline of the ladle; the desulfurization slag agent is 350kg of lime, 120kg of fluorite, binary Alkalinity R=5.2.

[0027] (3) After the slag scraper removes the slag from the top of the ladle, open the bottom blowing system, blow the vent brick at the bottom of the ladle into nitrogen, the gas flow rate is 270NL / min, use the crane to pour the molten iron in the l...

Embodiment 2

[0029] Embodiment 2: The method for pretreatment and desulfurization of molten iron using an LF furnace adopts the following specific processes.

[0030] (1) Sampling and analysis of temperature measurement of molten iron in ironmaking production, temperature 1425°C, sulfur 0.068%, transported to the slag removal station through ladles, and then use the slag removal machine to remove the top slag in the iron ladle.

[0031] (2) At the same time, put the desulfurization slag agent into the ladle prepared in advance on the ladle car of the LF furnace, and connect the bottom blowing system to the bottom blowing pipeline of the ladle; the desulfurization slag agent is 400kg of lime, 110kg of fluorite, binary Alkalinity R=6.1.

[0032] (3) After the slag scraper removes the slag from the top of the ladle, open the bottom blowing system, and the ventilating brick at the bottom of the ladle is blown into carbon dioxide, and the gas flow rate is 223NL / min; use the crane to pour the mo...

Embodiment 3

[0034] Embodiment 3: The method for pretreatment and desulfurization of molten iron using an LF furnace adopts the following specific processes.

[0035] (1) Sampling and analysis of temperature measurement of molten iron in ironmaking production, temperature 1481°C, sulfur 0.092%, transported to the slag removal station through the ladle, and then use the slag removal machine to remove the top slag in the iron ladle.

[0036] (2) At the same time, put the desulfurization slag agent into the ladle prepared in advance on the ladle car of the LF furnace, and connect the bottom blowing system to the bottom blowing pipeline of the ladle; the desulfurization slag agent is 400kg of lime, 130kg of fluorite, binary Alkalinity R=3.0.

[0037] (3) After the slag scraper removes the slag from the top of the ladle, open the bottom blowing system, and argon gas is introduced into the blowing brick at the bottom of the ladle, with a gas flow rate of 286NL / min. After completion, turn down the...

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PUM

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Abstract

The invention discloses a method for molten iron pretreatment desulfurization by using an LF furnace. The method comprises the following steps: transporting a ladle to a slagging-off position, and removing top slag in the ladle; adding a desulfurization slag agent in a ladle of the LF furnace; blowing gas from the bottom of the ladle, and pouring molten iron in the ladle in the ladle; adding a foaming agent in the ladle for foaming slag, and blowing the gas from the bottom for stirring; after bottom blowing is performed by a period of time, measuring the temperature for sampling; if component sulfur meets the steel smelting process requirements of a converter, closing the gas blown from the bottom of the LF furnace, and removing the top slag in the ladle; if the component sulfur does not meet the steel smelting process requirements of the converter, removing the slag, and adding the desulfurization slag agent again for power transmission stirring desulfurization until the component sulfur in the molten iron meets the steel smelting process requirements of the converter, then closing the gas blown from the bottom of the LF furnace, and removing the top slag in the ladle; and after the top slag in the ladle is removed, feeding the molten iron in an iron mixer or the converter, and adding the molten iron with qualified components for smelting. The method has the characteristic of low use investment cost.

Description

technical field [0001] The invention relates to a method for pretreatment of molten iron, in particular to a method for pretreatment and desulfurization of molten iron using an LF furnace. Background technique [0002] Sulfur exists in the form of sulfide inclusions in steel, which has adverse effects on the plasticity, toughness, welding performance, thickness direction performance, fatigue performance and corrosion resistance of steel. Sulfur exists in steel in the form of iron sulfide (FeS), and FeS and Fe form a low melting point (985°C) compound. The hot-working temperature of steel is generally above 1150-1200°C, so when the steel is hot-worked, the workpiece cracks due to the premature melting of the FeS compound. This phenomenon is called "hot embrittlement". The higher the sulfur content, the more serious the hot embrittlement phenomenon, so the sulfur content in the steel must be controlled. [0003] In view of the hazards of sulfur, low-sulfur steel has high add...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C1/02C21C7/064C21C7/072
CPCC21C1/025C21C7/064C21C7/072
Inventor 赵晓磊丁志军杨锋功高鹏杨华峰李世琪范师师岳占陈国卫广运王成杰黄鑫秦影李慧
Owner SHIJIAZHUANG IRON & STEEL