Estimation and Analysis of Excess Oxygen Input into Ladle During Liquid Steel Tapping

Abstract

Carryover of oxidising slag from primary steelmaking furnace during tapping affects the quality of liquid steel in several ways. Secondary steelmaking practices, such as deoxidation, desulphurization, vacuum degassing as well as inclusion control in liquid steel bath, are greatly influenced by the amount and characteristic of carryover slag. Both, slag volume as well as ferro alloy consumption increases due to the presence of carryover slag during ladle refining treatment. Carryover of furnace slag in ladle during tapping cannot be avoided and results in consumption of excess electrical energy. Thus, control of carry over slag mainly during tapping is essential by suitably modifying the operational practice. In the present investigation, slag carry over during liquid steel tapping operation is quantified for the processed data obtained from an integrated steel plant based on material balance and equilibrium thermodynamic study. Some of the relevant operational factors related to slag, deoxidation, temperature and solutes (C, S and N) are identified and correlated with the amount of slag carry over. Though, the slag carry over during tapping operation is gravity dependent draining phenomena, scope for controlling the same is identified & discussed in the present study.