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Control method for enabling resulfurization amount of low-sulfur molten iron to be lower than 10ppm in smelting process of converter

A converter smelting, low-sulfur molten iron technology, applied in the manufacture of converters, etc., can solve the problems of affecting stability, restricting the development of low-sulfur steel types, and large fluctuations in sulfur content, so as to prevent sulfur return, ensure fluctuation range, and process flow simple effect

Inactive Publication Date: 2012-02-01
广东北科科技发展有限公司 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the serious phenomenon of sulfur return in the converter smelting process, the amount of sulfur return is as high as 30ppm or even higher, resulting in large fluctuations in the sulfur content in the molten steel at the end of the converter. It is necessary to increase the tapping temperature and add a large amount of synthetic slag to the ladle for desulfurization. The sulfur content of molten steel affects the stability of the operation after smelting in the converter and limits the development of low-sulfur steel grades

Method used

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  • Control method for enabling resulfurization amount of low-sulfur molten iron to be lower than 10ppm in smelting process of converter

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Weigh 90kg / t of total smelting slag according to the amount of molten iron per ton, including 50kg / t of lime, 20kg / t of lightly burned dolomite, 13kg / t of magnesium balls, 5kg / t of miscellaneous ash, and 5kg / t of returned ore. 2kg / t spare. In order to ensure the sulfur content of the final molten steel, the sulfur content in the lime and light-burned dolomite is ≤0.006%, the sulfur content in the magnesium balls is ≤0.003%, and the sulfur content in the returned ore is ≤0.025%.

[0019] Then proceed as follows:

[0020] (1) Desulfurization pretreatment of molten iron is carried out using traditional techniques, but the sulfur content in the molten iron must be ensured to be less than or equal to 40ppm, and then the molten iron slag shall be removed to make the temperature of the molten iron > 1250°C.

[0021] (2) Add 90kg / t total smelting slag that has been weighed per ton of molten iron into the converter. , magnesium balls and ashes are added to the converter, that ...

Embodiment 2

[0039] Compared with Example 1, this example differs only in the content of total smelting slag. The amount of molten iron per ton in this embodiment weighs 95kg / t of total smelting slag material, of which lime is 50kg / t, lightly burned dolomite is 25kg / t, magnesium balls are 13kg / t, miscellaneous ash is 5kg / t, and The ore is 2kg / t.

Embodiment 3

[0041] Compared with implementation 1 and 2, this embodiment differs only in the content of total smelting slag. In this embodiment, 100kg / t of total smelting slag is weighed according to the amount of molten iron per ton, of which lime is 55kg / t, lightly burned dolomite is 25kg / t, magnesium balls are 13kg / t, miscellaneous ash is 5kg / t, and The ore is 2kg / t.

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Abstract

The invention discloses a control method for enabling the resulfurization amount of low-sulfur molten iron to be lower than 10ppm in the smelting process of a converter, which is characterized by mainly comprising the following steps of: (1) performing desulfurization pretreatment on the molten iron to enable the sulfur content in the molten iron to be not more than 40ppm, and then completely skimming molten iron slag to enable the temperature of the molten iron to be more than 1250 DEG C; (2) adding smelting total slag charge mixed by lime, light-burned dolomite, return fines, magnesium pellets and miscellaneous ash into the molten iron in the converter according to the proportion of 90-100kg / t; (3) controlling the bottom blowing strength to be 0.02m<3> / min. t at 5 minutes before converter blowing, and then switching the bottom blowing strength to 0.03 m<3> / min. t; and (4) controlling the end point temperature of the converter to be 1650-1680 DEG C after the converter blowing is completed, wherein the end point alkalinity of converter slag is 4.2-4.5, and the content of the iron oxide in the slag is controlled to be below 20%. Through the invention, the process flow is very simple, and the resulfurization amount in the smelting process of the converter can be effectively reduced.

Description

technical field [0001] The invention relates to a smelting control method, in particular to a control method in which the sulfur return amount of low-sulfur molten iron is lower than 10 ppm during the converter smelting process. Background technique [0002] Converter sulfur return is mainly due to the fact that when the desulfurized low-sulfur molten iron is blowing in the converter, due to the high sulfur content in the added slagging materials, molten iron residue and scrap steel, part of the sulfur returns to the molten steel, resulting in high sulfur at the end of converter blowing. on the initial sulfur. Producers attach great importance to hot metal desulfurization and molten steel desulfurization, often neglecting the control of sulfur return. In fact, the control of converter sulfur return is a very critical link in the production of low-sulfur, ultra-low-sulfur and other high-quality, high-value-added steels. It is directly related to production costs and whether ...

Claims

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Application Information

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IPC IPC(8): C21C5/28C21C1/02C21C7/064
Inventor 李晶姚永宽刘德祥耿建林阿不力克木亚森余健李翔姚国伟吴国平姚迪
Owner 广东北科科技发展有限公司