Control method for preventing splash during refining ferrochromium alloy with argon oxygen

Abstract

The invention discloses a control method for preventing splash during refining ferrochromium alloy with argon oxygen. Based on infrared online detection of temperature difference between residue surface and molten iron in a furnace, the temperature the content of Cr2O3 in the residue is characterized by the temperature difference, the position of a top-blowing top gun and the mixing ration of argon (nitrogen) / oxygen of high-pressure argon (nitrogen) / oxygen mixture gas are controlled according to residue-molten iron temperature difference quantization interval to adjust the carbon-oxygen reaction speed and the content of Cr2O3 in the residue. Pressurized spraying agent or auxiliary material for improving the fluidity of the residue is added when the temperature difference is greater the maximum critical temperature difference or less than the minimum critical temperature difference to realize automatic control of splash prevention. In the method, splash control comes down to the control problem of residue sigma (Cr2O3) and carbon-oxygen reaction speed, the temperature and interval thereof between the residue and the molten iron are firstly utilized to represent the residue sigma (Cr2O3), residue foaming and drying extent, the problem of sigma (Cr2O3) measurement is simplified to residue-molten iron temperature difference measurement, and the problem that the content of Cr2O3 and carbon-oxygen reaction speed can not be measured is solved.

Description

technical field [0001] The invention relates to a production process for refining medium and low-carbon ferrochrome alloys with an AOD furnace, in particular to a control method for preventing splashing during argon-oxygen refining of ferrochrome alloys. Background technique [0002] Low-carbon ferrochromium alloy is an important raw material for smelting special steel and ultra-low carbon structural steel. The lower its carbon content and the higher its chromium content, the higher its economic value and use value. At present, the methods for smelting low-carbon ferrochrome alloys are mainly three-step method and "Perrin method". Carbon ferrochrome alloy is used as raw material to produce silicon chromium alloy, and then silicon chromium alloy is used as raw material to produce low carbon ferrochrome alloy, thereby obtaining low carbon ferrochrome alloy with carbon content (wt.%) lower than 0.5%. The disadvantage of this kind of method is that the process is long, the powe...

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Problems solved by technology

However, since the FeO content in the slag cannot be measured online, and the relationship between the FeO content and the gun position cannot be determined, this method is difficult to apply in practice.

[0015] In summary, the current research on spatter prevention is mainly concentrated in the production process of converter steelmaking (there is no literature and patent research on the method of preventing spatter in the production process of argon-oxygen refining ferrochrome alloy). In terms of causes and preventive measures, the incidence of splashing can be reduced by adjusting the loading system, optimizing the oxygen supply system and slagging system, etc.

However, the research on the spatter caused by the deviation of the molten iron composition, the change of the auxiliary material composition, the fluctuation of the oxygen (argon) flow rate, the position adjustment error of the top gun, and the imperfect process curve has not been in-depth, although the gas analysis method proposed in the literature is It provides a way to solve the slopping problem, but due to the poor real-time performance of the analysis, it is only used to analyze the cause of the slopping and after the event, and cannot realize automatic control, and the cost is high. When the furnace capacity is less than 20 tons, The cost of furnace gas analysis equipment will be much higher than that of smelting equipment, making it difficult for this method to be applied in engineering

However, due to the serious environmental interference of the smelting site and the different interference sources, the audio analysis method has low analysis accuracy and changes with the environment, which has great uncertainty. Moreover, when the signal is detected by this method, the splash has already Slight occurrence will bring practical difficulties to subsequent pressure spraying, let alone fundamentally control the occurrence of splashing

As for the method of adjusting the gun position according to the FeO content, there is currently no relevant technology for online detection of the FeO content in the slag (when smelting ferrochromium, Cr 2 o 3 cannot be measured online), so that this method cannot be used for online real-time control at this stage

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