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Convertor tapping washing fining furnace fast desulfurization method

A technology for tapping slag and refining furnace, which is applied to the rapid refining and desulfurization of converter slag washing and refining furnace slag making under weak oxidation conditions, and the field of converter steelmaking, which can solve the problems of rising steelmaking cost, inability to desulfurize, and blockage of nozzles. , to achieve the effect of low production cost, good desulfurization effect and rapid desulfurization

Inactive Publication Date: 2008-08-06
HANSTEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Generally, the traditional refining process adopted by LF furnace (refining furnace) is: adding aluminum to molten steel and slag for strong deoxidation to produce white slag desulfurization. This traditional technology mainly has the following disadvantages: (1) Due to the high price of aluminum, the cost of steelmaking increases. High; (2) The protection casting requirements for continuous casting are strict, and if the protection pouring is not good, it is easy to cause blockage of the nozzle and lead to co-casting; (3) The refining time required for white slag production is long. The pouring time of continuous casting is about 20 minutes or even faster. Under such a short refining time, the general LF furnace can hardly desulfurize

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Example 1: The composition of the pre-slag is by weight: CaO 52, Al 2 o 3 41. CaF 2 7. SiO2 2 8. Fe 2 o 3 1.2, H 2 O 0.4.

[0014] Converter tapping 30t molten steel, the sulfur content of converter tapping is 0.036%, add 100kg pre-melted slag and 90kg lime to the ladle before tapping, and add Si, Mn alloy and 15kg Add silicon aluminum barium, then add 200kg of pre-melted slag, tap 3 / 4~4 / 5 and add slag blocking ball (cone) to ensure good slag blocking effect, and control the amount of slag below 3Kg / t. After refining, add 120kg of pre-melted slag, 90kg of lime, 60kg of calcium carbide, and 90Kg of ferrosilicon powder. After 3 minutes of melting the slag, the color of the slag turns yellowish white, but the slag is relatively thin. Add 60kg of lime and continue melting the slag for 2 minutes. After the slag is finished, the viscosity of the slag is suitable, and the flow rate of the bottom blowing gas is adjusted to 15m 3 / h, stirred for 3 minutes, and the sul...

Embodiment 2

[0016] The composition of the pre-slag is by weight: CaO 46, Al 2 o 3 38. CaF 2 5. SiO2 2 6. Fe 2 o 3 1.5, H 2 O 0.3.

[0017] 30t molten steel is tapped from the converter, and the sulfur content of the tapped steel is 0.032%. Before tapping, 70kg of pre-melted slag and 150kg of lime are added to the ladle. When tapping 1 / 5-1 / 4, add Si, Mn alloy and 10kg Add silicon aluminum barium, then add 140kg of pre-melted slag, tap 3 / 4~4 / 5 and add slag blocking ball (cone) to ensure good slag blocking effect, and control the amount of slag below 3Kg / t. After refining, add 150kg of pre-melted slag, 90kg of lime, 120kg of calcium carbide, and 90Kg of ferrosilicon powder. After 4 minutes of melting the slag, add 30kg of ferrosilicon powder because the color of the slag is dark green. After 3 minutes of melting the slag, the color turns yellowish white. Adjust the bottom blowing air flow rate to 15m 3 / h, stirred for 3 minutes, and the sulfur content of the steel was 0.006%.

Embodiment 3

[0018] Example Three: The composition of the pre-slag is by weight: CaO 49, Al 2 o 3 45. CaF 2 6. SiO2 2 7. Fe 2 o 3 1.H 2 O 0.2.

[0019] Converter tapping 30t molten steel, converter tapping sulfur content is 0.035%, add 120kg pre-melted slag and 120kg lime to the ladle before tapping, add Si, Mn alloy and 15kg in sequence when tapping 1 / 5-1 / 4 Silicon aluminum barium, then add 240kg of pre-melted slag, tap 3 / 4~4 / 5 and add slag blocking ball (cone) to ensure good slag blocking effect, and control the amount of slag below 3Kg / t. After refining, add 90kg of pre-melted slag, 120kg of lime, 90kg of calcium carbide, and 60Kg of ferrosilicon powder. After 5 minutes of slag melting, the color turns yellow and white. Adjust the flow rate of the bottom blowing gas to 15m 3 / h, stirred for 2 minutes, and the sulfur content of the steel was 0.010%.

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Abstract

The invention relates to a method for rapidly desulfurizing a slag washing and refining furnace for converter tapping, which belongs to the steelmaking technical field and is used to solve the problem that the converter tapping is rapidly refined and desulfurized. The method comprises two steps of steel ladles slag-washing and LF refining and is characterized in that pre-melted slag and white lime 3-5Kg / t are added according to the ratio of 7-12Kg / t in the step of the steel ladles slag-washing, the pre-melted slag is added according to the ratio of 3-5Kg / t in the step of LF refining, and fluxing medium is added according to the following ratio: lime 3-5Kg / t, calcium carbide 2-4Kg / t and ferrosilicon powder 2-4Kg / t, the components of the pre-melted slag is combined according to following weight units: CaO 46-52, Al2O3 38-45, CaF2 5-7, SiO2<=10, Fe2O3 <=2, H2O<= 0.5, and the pre-melted slag melting point <=1350DEG C. The invention can increase the rear furnace slug washing of a high converter under the condition that aluminum is added to deoxidize in refining and refining slag is rapidly produced under the weak oxidation condition, and the requirements for producing low sulphur steel are satisfied.

Description

technical field [0001] The invention relates to a converter steelmaking technology, in particular to a rapid refining and desulfurization method for washing converter slag and mixing refining furnace slag under weak oxidation conditions, belonging to the technical field of metallurgy and steelmaking. Background technique [0002] In recent years, with the rapid development of the steel industry and the continuous improvement of steel quality, high-quality steel has increasingly strict requirements on the S content in steel, and general high-quality steel requires that the sulfur content be below 0.015%. Due to the dwindling of high-quality ore resources, the S content in molten iron is on the rise, and the desulfurization capacity of the converter smelting process is limited. Therefore, the desulfurization technology outside the furnace is the key technology for iron and steel enterprises to smelt high-quality steel and low-sulfur steel. Generally, the traditional refining p...

Claims

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Application Information

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IPC IPC(8): C21C7/064
Inventor 闫晓平胡志刚苑卫科朱怀星朱占文翟晓毅安君辉赵晓雷李庆胜
Owner HANSTEEL
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