Assessment and application of equilibrium slag–metal phosphorous partition for basic oxygen steelmaking

Abstract

The present work carried out an assessment of various methods for calculation of equilibrium slagmetal phosphorous partition for basic oxygen steelmaking in order to select the most acceptable procedure for estimation of the dephosphorisation capability of basic oxygen furnace (BOF) converters at Tata Steel. Equilibrium phosphorous partition was calculated by a thermodynamic approach proposed in the literature using the regular solution based quadratic formalism for slag, by semiempirical equations proposed by some investigators, as well as an optical basicity based correlation reported in literature. Turndown slag and metal composition and temperature data of a large number of BOF heats of LD-1 and LD-2 shops of Tata Steel, covering a period of several years, were employed for this purpose. Large discrepancies between the predictions of empirical correlations proposed by different investigators were found. On the basis of the assessment exercise, the correlation proposed by Turkdogan was accepted for further use and has been recommended for estimation of equilibrium slag-metal phosphorous partition for the BOF steelmaking at Tata Steel. The actual phosphorous partitions at the vessel turndown attained equilibrium only in few heats. Effectiveness of different bottom stirring systems adopted by Tata Steel over the years as well as that of post-stirring have been assessed on the basis of approach to equilibrium.

Retraction: Representation of Dephosphorization Ability for CaO–Containing Slags Based on the Ion and Molecule Coexistence Theory

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Many studies have been carried out to measure phosphorous distribution between various slags and hot metal since the 1940 s. 1,2,9) However, the measurement of phosphorous distribution between molten slag and hot metal is costly and difficult 11,12) in the operation. It is therefore very necessary to develop a reliable model for predicting phosphorous distribution between molten slag and hot metal.…”

“…It is therefore very necessary to develop a reliable model for predicting phosphorous distribution between molten slag and hot metal. Several attempts [9][10][11][12][13][14][15][16] have been made to treat slag-metal phosphorus equilibrium empirically and theoretically based on the concept of ionic or molecular constituents in the slags. However, these attempts are generally associated with artificial parameters, and most of the regressed parameters are valid only within certain limits of concentration.…”

Comparison of Thermo-electromagneto-hydrodynamic Multi-physical Fields in ESR Furnace with Vibrating and Traditional Electrodes

“…Vishwanathan and Melgaard 14) developed and analyzed the effect of the important operating parameters on hear transfer, two-phase fluid flow, and solidification. Szekeley 15,16) figured out a significant work in simulating the ESR process to solve the problem of heat transfer and fluid flow in the slag layer, molten pool and ingot. The work utilizes the standard turbulent model to resolve turbulent viscosity and turbulent thermal conductivity in the slag, and calculates the Maxwell equations to simulate the distribution of Lorenz force and the Joule heating in the slag.…”

Mathematical model of deoxidization with post stirring in a combined blowing converter

“…At the terminal of the smelting process, dissolved-oxygen in a molten pool of a converter is one of the causes that lead to the formation of internal oxide [1][2]. Therefore, how to decrease the dissolved oxygen content in the molten steel is indispensable for improving the production efficiency and for the steel cleanness at the converter smelting terminal [3][4]. To meet the requirements for smelting, the post stirring process, in which the inert gas is blown from the bottom of the converter after stopping blowing oxygen, is adopted for about a few minutes with the oxygen lance in the late stage of converter smelting [5][6].…”