Dephosphorization method of high-phosphorous chromium-nickel pig iron

A technology of nickel pig iron and high phosphorus chromium is applied in the field of high phosphorus chromium nickel pig iron dephosphorization, which can solve the problems of short time, high cost and long time, and achieve the effects of short time, low cost and improved efficiency.

Inactive Publication Date: 2012-01-11
SHANXI TAIGANG STAINLESS STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the deficiencies of high cost and long time of the existing high-phosphorus chromium-nickel pig iron dephosphorization method, the present invention provides a low-cost, short-time high-phosphorus chromium-nickel pig iron dephosphorization method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] This embodiment is the following sequential steps:

[0025] I EAF preliminary desilication

[0026] Add 75.2t of high-phosphorus-chromium-nickel pig iron with the following weight percentages into the electric arc furnace for melting and preliminary desiliconization:

[0027] C: 4.0%; Si: 2.55%; Mn: 0.70%; P: 0.061%; S: 0.081%;

[0028] Cr: 3.00%; Ni: 4.45%; the rest is Fe and unavoidable impurities.

[0029] Add lime 3300kg in three batches, oxygen blowing volume 50Nm 3 / per minute, after 90 minutes of smelting, (C, Si, Mn are oxidized during the desiliconization process), the weight percentage of the composition of the molten iron before tapping the electric furnace is: C: 2.34%; Si: 0.09%; Mn: 0.20 %; P: 0.073%; S: 0.069%; Cr: 3.36%; Ni: 4.75%; the rest is Fe and unavoidable impurities.

[0030] The tapping temperature of the electric furnace is 1643°C.

[0031] II Remove the slag from the electric furnace and add it to the AOD furnace

[0032] After removing ...

Embodiment 2

[0042] This embodiment is the following sequential steps:

[0043] I EAF preliminary desilication

[0044] Add 75.4t of high-phosphorus chromium-nickel pig iron with the following weight percentages into the electric arc furnace for melting and preliminary desiliconization:

[0045] C: 4.0%; Si: 2.55%; Mn: 0.70%; P: 0.061%; S: 0.081%;

[0046] Cr: 3.00%; Ni: 4.8%; the rest is Fe and unavoidable impurities.

[0047] Add lime 3300kg in three batches, oxygen blowing volume 50Nm 3 / per minute, after 90 minutes of smelting, (C, Si, Mn are oxidized during the desiliconization process), the weight percentage of the composition of the molten iron before tapping the electric furnace is: C: 2.34%; Si: 0.05%; Mn: 0.25 %; P: 0.051%; S: 0.069%; Cr: 3.36%; Ni: 4.75%; the rest is Fe and unavoidable impurities.

[0048] The tapping temperature of the electric furnace is 1637°C.

[0049] II Remove the slag from the electric furnace and add it to the AOD furnace

[0050] After removing t...

Embodiment 3

[0060] This embodiment is the following sequential steps:

[0061] I EAF preliminary desilication

[0062] Add 74.4t of high-phosphorus-chromium-nickel pig iron with the following weight percentages into the electric arc furnace for melting and preliminary desiliconization:

[0063] C: 4.0%; Si: 2.45%; Mn: 0.70%; P: 0.061%; S: 0.081%;

[0064] Cr: 3.00%; Ni: 5.8%; the rest is Fe and unavoidable impurities.

[0065] Add lime 3300kg in three batches, oxygen blowing volume N50m 3 / per minute, after 90 minutes of smelting, (C, Si, Mn are oxidized during the desiliconization process), the weight percentage of the molten iron before tapping the electric furnace is: C: 2.58%; Si: 0.26%; Mn: 0.3 %; P: 0.098%; S: 0.067%; Cr: 3.32%; Ni: 6.23%; the rest is Fe and unavoidable impurities.

[0066] The tapping temperature of the electric furnace is 1643°C.

[0067] II Remove the slag from the electric furnace and add it to the AOD furnace

[0068] After removing the slag on the surface...

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PUM

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Abstract

The invention relates to a dephosphorization method of high-phosphorous chromium-nickel pig iron. The method comprises the following steps in order: I. EAF (electric arc furnace) preliminary desilication, adding the high-phosphorous chromium-nickel pig iron into an EAF for fusing so as to realize preliminary desilication, with silicon in the desiliconized molten iron up to 0.05-1.0% by weight; II. removing electric furnace slag and blending the molten iron into an AOD (argon oxygen decarburization) furnace or converter, with the molten iron at a temperature of 1400-1550DEG C; III. dephosphorization, adding 6-45kg/ton steel of lime and 1-34kg/ton steel of fluorite into the blended molten iron, leaving the alkalinity R being 1-5, blowing a mixed gas of oxygen and nitrogen that are in a ratio of 2:1-5:1, when the gas allocation amounts to 0.5-3Nm<3>/ton steel. min. and the content of molten steel P is less than or equal to 0.04%, removing oxidized slag, thus obtaining low-phosphorous molten iron. In another method, a ladle and molten iron dephosphorization pretreatment is conducted after removing electric furnace slag following EAF preliminary desilication in step I. The dephosphorization method of high-phosphorous chromium-nickel pig iron in the invention is characterized by low cost and short time. The dephosphorization process is shortened to 6-10min, thus enhancing the dephosphorization efficiency.

Description

technical field [0001] The invention relates to a method for dephosphorizing high-phosphorus chromium-nickel pig iron, specifically a method for dephosphorizing chromium-nickel pig iron with a phosphorus content of 0.06%-0.12%. Background technique [0002] High-phosphorus chromium-nickel pig iron has wide resources and low price, and can be directly used in the production of stainless steel. However, high-phosphorus chromium-nickel pig iron contains high silicon, phosphorus and carbon, which limits the amount of high-phosphorus chromium-nickel pig iron. [0003] The existing dephosphorization method generally uses electric furnace oxidation dephosphorization. In the mode of all-cold smelting, the temperature required to melt pig iron is relatively high, while the dephosphorization temperature requires that the temperature of molten steel should not be too high. The two conflict, and temperature control becomes dephosphorization. The restrictive conditions of phosphorus; at ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C1/02C21C1/04
Inventor 王鹏刘明生闫建新
Owner SHANXI TAIGANG STAINLESS STEEL CO LTD
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