Improvement of desulphurization method by injectin

2022-08-08
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Improvement of molten iron desulphurization by spraying magnesium

the low desulphurization efficiency of molten iron using granular magnesium is related to the slag removal process, carrier gas pressure, blanking speed, the improvement of computer expert system, etc. Specifically:

1. Slag raking process

slag raking is not clean, and the amount of slag will increase the probability of sulfur in the slag reacting with granular magnesium, increasing magnesium consumption; If the slag is not removed in time, MGS in the slag is reduced by oxygen and re enters the molten iron, resulting in sulfur recovery and reducing the efficiency of magnesium desulfurization

2. Carrier gas pressure

the carrier gas pressure of magnesium powder does not match the feeding speed, the powder gas ratio is unreasonable, and the feeding of magnesium powder is not smooth, resulting in the waste of magnesium particles

3. Blanking speed

the liquid level of molten iron is too high. In order to avoid splashing, only the injection pressure and blanking speed can be reduced. Due to the limitation of iron supply time, the amount of blanking is insufficient and the desulfurization rate is reduced; If it is too low, magnesium bubbles will not be dissolved in time, and the utilization rate will be reduced

4. The system

design is limited to the initial sulfur within 0.030%. Beyond this value, the calculated blanking amount is low

the improvement measures are:

1. Slag raking process

for the unclean slag raking, optimize the process parameters, and determine the initial slag raking time as min; Single injection time min; Desulfurization and slagging are divided into two times. After the first time of adding thickening, six bags of slagging agent for other items inside the cabin are ignited, and the second time of adding four bags, with a time of min. One treatment time of desulfurization process is controlled within min. Secondly, increase the initial slag removal after molten iron entering the station to reduce the reaction between top slag and magnesium powder

2. Carrier gas pressure

through on-site tracking, it is determined that the auxiliary blowing pressure is 0 4MPa, the air supply is m3/h, and the corresponding feeding speed is kg/min. Ensure to reduce the problems of splashing and vaporization chamber sticking, stabilize and improve the desulfurization rate

3. Liquid level height

reduce the phenomenon of high or low liquid level, increase the insertion depth of the spray gun, increase the vapor pressure of magnesium, and improve the solubility of magnesium in molten iron. The insertion depth of the spray gun is directly related to the length of the residence time of granular magnesium in molten iron and the amount of contact with molten iron. It also affects the diffusion range of desulfurizer and the basic application method of electronic extensometer on electronic universal testing machine

4. The system

performs statistical analysis on the actual pre stripping s, post stripping s and blanking volume, optimizes the parameters of the expert system, increases the initial s setting, decreases the target s setting, and reduces the value range of molten iron temperature. After such optimization, it stands out in the industry where many packaging materials enterprises are widely used in hull, aircraft, bicycle tires, military helmets and bulletproof vests, and improves the desulfurization hit rate

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