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CN-122012865-A - Dephosphorization treatment method of converter

CN122012865ACN 122012865 ACN122012865 ACN 122012865ACN-122012865-A

Abstract

The application provides a dephosphorization treatment method of a converter, which comprises the steps of obtaining aluminum killed steel ladle residual molten steel and attached refining slag if the phosphorus content of molten steel at the end point of the converter is less than or equal to 0.005%, the end point temperature is greater than or equal to 1640 ℃ and the end point carbon content is less than or equal to 0.07%, pouring the aluminum killed steel ladle residual molten steel and the attached refining slag into a ladle to obtain refined hot slag, pouring the end point slag in the converter according to preset pouring amount, pouring the refined hot slag into the converter, purging the slag in the converter by adopting a nitrogen purging gun after the converter returns to 0 position, adjusting the bottom blowing mode of the converter into a strong stirring mode after the first preset time, and standing for a second preset time to carry out a tapping flow, so as to solve the problems that the current dephosphorization treatment method of the converter obviously increases the oxygen content in the molten steel and the iron oxide content in the slag, leads to increase the consumption of steel materials, the corrosion of the furnace lining, the alloy yield and the overoxidation of the molten steel is easy to be initiated, and the quality of the molten steel is affected.

Inventors

  • LIU ZHONGJIAN
  • Shang you

Assignees

  • 山东钢铁股份有限公司

Dates

Publication Date
20260512
Application Date
20260211

Claims (10)

  1. 1. A dephosphorization treatment method of a converter is characterized by comprising the following steps: If the phosphorus content of the molten steel at the end point of the converter exceeds a standard value less than or equal to 0.005%, the end point temperature is more than or equal to 1640 ℃ and the end point carbon content is less than or equal to 0.07%, obtaining residual molten steel and attached refining slag of the aluminum killed steel ladle, and pouring the residual molten steel and the attached refining slag into a ladle to obtain refined thermal slag; pouring out the terminal slag in the converter according to a preset deslagging amount; Pouring the refined hot slag into the converter, and blowing the slag in the converter by adopting a nitrogen blowing gun after the converter returns to the 0 position; And after the first preset time, adjusting the bottom blowing mode of the converter to a strong stirring mode, standing for the second preset time, and carrying out a tapping flow.
  2. 2. The dephosphorization treatment method of a converter according to claim 1, characterized in that the method further comprises: if the phosphorus content of the molten steel at the end point of the converter exceeds the standard value and is smaller than or equal to 0.005%, the end point temperature is larger than or equal to 1620 ℃ and the end point carbon content is smaller than or equal to 0.05%, obtaining the residual molten steel of the aluminum killed steel ladle and the attached refining slag, and pouring the residual molten steel and the attached refining slag into a ladle to obtain the refined hot slag.
  3. 3. The dephosphorization treatment method of a converter according to claim 1 or 2, wherein the basicity of the refined hot slag is greater than or equal to 4, and the Al 2 O 3 content of the refined hot slag is greater than or equal to 20%.
  4. 4. The dephosphorization treatment method of a converter according to claim 1, wherein the preset deslagging amount is within a range of one half to three quarters of the total slag amount of the terminal slag in the converter.
  5. 5. A dephosphorization treatment method of a converter according to claim 1, characterized in that the lance position of the nitrogen purging lance is located in the range of 1500mm to 1600 mm.
  6. 6. The dephosphorization treatment method of a converter according to claim 1, wherein the nitrogen pressure of the nitrogen purge gun is in the range of 0.85MPa to 0.95 MPa.
  7. 7. The dephosphorization treatment method of a converter according to claim 1, wherein the first preset time is in the range of 30s to 50 s.
  8. 8. The dephosphorization method of a converter according to claim 1, wherein the bottom blowing strength of the strong stirring mode is 5.54Nm 3 /(t.h).
  9. 9. The dephosphorization treatment method of a converter according to claim 1, wherein the second preset time is in a range of 1min to 2 min.
  10. 10. The dephosphorization method of a converter according to claim 1, wherein after the first preset time, the bottom blowing mode of the converter is adjusted to a strong stirring mode, and after the second preset time, the step of tapping is performed, comprising: after a first preset time, adjusting the bottom blowing mode of the converter to a strong stirring mode, standing for a second preset time, sampling from the converter, and determining the phosphorus content; and if the phosphorus content is within the phosphorus content qualified range, carrying out a tapping flow.

Description

Dephosphorization treatment method of converter Technical Field The application relates to the technical field of steelmaking processes, in particular to a dephosphorization treatment method of a converter. Background Dephosphorization is a critical task in the converter steelmaking production process, and directly relates to the quality of molten steel and whether the production requirements of different steel grades can be met. Particularly for the production of low-phosphorus steel, the control requirement on the phosphorus content in molten steel is very strict. However, in the actual production link, because of the fluctuation condition of the molten iron components, the slag forming operation is difficult to reach an ideal state, deviation occurs in temperature control, or the process operation is influenced by various factors such as improper places, and the like, the phenomenon that the phosphorus content of molten steel is higher than the target requirement at the end point of blowing, namely the phosphorus content at the end point is high, often occurs. In order to cope with the problem of high phosphorus at the converting end of the converter, it is a common practice to perform a "make-up" operation. Specifically, after the end point phosphorus height is found, secondary oxygen supply is carried out on the converter, and slag forming materials such as lime, ore and the like are added into the converter in a supplementary mode. The secondary oxygen supply provides a stronger oxidation environment, and the supplementary slag-forming material is utilized to further promote the dephosphorization reaction, so that the purpose of reducing the phosphorus content in the molten steel is achieved. Although the 'blowing-up' treatment method can reduce the phosphorus content of molten steel to a certain extent, a plurality of obvious defects exist. On the one hand, the "blowback" operation can significantly increase the oxygen content in the molten steel as well as the iron oxide content in the slag. The method can greatly increase the consumption of steel materials, improve the production cost, aggravate the corrosion of a furnace lining and shorten the service life of the converter. Meanwhile, the excessively high oxygen content can reduce the alloy yield, and can easily cause peroxidation of molten steel, so that adverse effects on the quality of the molten steel, such as reduction of performance indexes of toughness, plasticity and the like of the steel, are generated. On the other hand, when the terminal carbon is low, the treatment difficulty is extremely high by adopting a 'supplementary blowing' method, and the phenomenon that the molten steel components exceed the standard is easy to occur, so that the normal production and the stability of the molten steel quality are further influenced. Disclosure of Invention The application provides a dephosphorization treatment method of a converter, which aims to solve the technical problems that the existing dephosphorization treatment method of the converter obviously increases the oxygen content in molten steel and the iron oxide content in slag, so that the consumption of steel materials is increased, the corrosion of a furnace lining is aggravated, the alloy yield is reduced, the peroxidation of the molten steel is easily caused, the quality of the molten steel is influenced, the treatment difficulty is high when the terminal carbon is low, and the phenomenon of exceeding standard of components is easily caused. The application provides a dephosphorization treatment method of a converter, which comprises the following steps: If the phosphorus content of the molten steel at the end point of the converter exceeds a standard value less than or equal to 0.005%, the end point temperature is more than or equal to 1640 ℃ and the end point carbon content is less than or equal to 0.07%, obtaining residual molten steel and attached refining slag of the aluminum killed steel ladle, and pouring the residual molten steel and the attached refining slag into a ladle to obtain refined thermal slag; pouring out the terminal slag in the converter according to a preset deslagging amount; Pouring the refined hot slag into the converter, and blowing the slag in the converter by adopting a nitrogen blowing gun after the converter returns to the 0 position; And after the first preset time, adjusting the bottom blowing mode of the converter to a strong stirring mode, standing for the second preset time, and carrying out a tapping flow. In some embodiments, the method further comprises: if the phosphorus content of the molten steel at the end point of the converter exceeds the standard value and is smaller than or equal to 0.005%, the end point temperature is larger than or equal to 1620 ℃ and the end point carbon content is smaller than or equal to 0.05%, obtaining the residual molten steel of the aluminum killed steel ladle and the attached refining slag, and pouring the residu