Study On Lime’s Microstructure Impacting Desulfuration In Steelmaking

Sulfur content is an important quality index for steel product, the toughness of steelmaterial would be greatly reduced because of sulfide existence. Lime is the main slaggingdesulfurization material whose physicochemical properties can affect slagging processdirectly. Currently, it is stricter for sulfur on important occasions.Based on the relationship between microstructure and lime activity, the effect oflime microscopic structure on desulfurization has been analyzed, which is of greatimportance to improve variety steel smelting in our country. The concrete content issummarized as follows:Firstly, The lime activity has been tested after limestone calcinations experiments,The results show that activity is gradually arising with the increase of temperature andtime. The activity of lime that is modificated by adding salt is higher than that of normallime. With the pressure rising, activity is increased then decreased. It comes up to437mLunder high pressure.Secondly, based on microstructure characterization of lime, the effect ofmicrostructure on ac has been studied. The analysis shows that activity is influenced bylime pore size and distribution. The lime activity is more than375mL when average porein600~1200nm.Finally, combined with microstructure and activity, on basis of desulfurizationexperiment, it found that desulfurization capacity can not depend on activity of limetotally. Desulfurization rate is influenced by lime pore size and distribution.Desulfurization rate increased with average pore diameter arising. However, Averagepore diameter oversize made desulfurization rate decrease instead. When600~1000nmpore accounts for the proportion of30%~50%and beyond1000nm pore accounts for theproportion of10%~35%，lime desulfurization rate is more than80%.