Study On The Optimization Of Hot Metal Desulphurization By Mg-injection Process Through Water Model Experiment

On the base of water model experiment and numerical simulation, optimizations of structure parameter of lance and technics parameter have been investigated according to the condition of Mg-injection desulphurization in 100t pig iron ladle in some steel mill. After main factors influencing on magnesium consumption coefficient were analysed, Some regression equations were made from actual smelting data. Magnesium desulphurization kinetics model was built according to the condition of the actual magnesium desulphurization on the base of thermodynamics and kinetics analysis.The industrial experimental results showed that magnesium consumption coefficient decreased 13.6% (from 1.591KgMg/KgS to 1.375KgMg/KgS when desulphurization value was ≥0.016%) after bellmouth height-705mm, inclination of lance-11 ° , carrier gas flow rate-35Nm~3/h and lance level-2150mm were adopted in industrial production.In industrial production, lots of factors affect magnesium consumption coefficient ,not only structure parameter of lance and technics parameter, also molten iron fore-and-aft component. It was found that magnesium consumption coefficient depended on Mg-injection value and desulphurization quantity obviously after statistics analysis. Magnesium consumption coefficient was less than 2KgMg/KgS when desulphurization quantity is above 0.005% and it increased sharply when it under 0.005%.Magnesium desulphurization kinetics model was analyzed in theory. The results showed that desulphurization rate was apparently influenced by lance level while it was not obviously influenced by inclination of lance and bellmouth height; desulphurization rate was becoming slow if carrier gas flow was too low (Q=25Nm~3/h) and was not obviously influenced if carrier gas flow was over some value.