Critical Assessment of P2O5 Activity Coefficients in CaO-based Slags during Dephosphorization Process of Iron-based Melts

Abstract

According to the experimental results of hot metal dephosphorization by CaO-based slags at a commercial-scale hot metal pretreatment station, activity a P 2 O 5 of P 2 O 5 in the CaO-based slags has been determined using the calculated comprehensive mass action concentration N Fe t O of iron oxides by the ion and molecule coexistence theory (IMCT) for representing the reaction ability of Fe t O, i.e., activity of a Fe t O . The collected ten models from the literature for predicting activity coefficient c P 2 O 5 of P 2 O 5 in CaO-based slags have been evaluated based on the determined activity a P 2 O 5 of P 2 O 5 by the IMCT as the criterion. The collected ten models of activity coefficient c P 2 O 5 of P 2 O 5 in CaO-based slags can be described in the form of a linear function as log c P 2 O 5 y ¼ c 0 þ c 1 x, in which independent variable x represents the chemical composition of slags, intercept c 0 including the constant term depicts temperature effect and other unmentioned or acquiescent thermodynamic factors, and slope c 1 is regressed by the experimental results. Thus, a general approach for obtaining good prediction results of activity a P 2 O 5 of P 2 O 5 in CaO-based slags is proposed by revising the constant term in intercept c 0 for the collected ten models. The better models with an ideal revising possibility or flexibility in the collected ten models have been selected and recommended.

The Effect of Sulfur Concentration in the Metal on the Mass Transfer of Phosphorus in Bloated Metal Droplets

“…Workers at Swinburne University in Australia have developed an overall BOF model considering the behavior of bloated droplets. Some recent studies on dephosphorization kinetics and phosphorus partition between liquid iron and oxidizing slag have been carried out by Manning et al, Assis et al, and Yang et al More recently, reviewing published phosphorus partition equations, Drain et al developed a new phosphorus partition correlation based on industrial data, which can be used in basic oxygen steelmaking conditions. Several very interesting investigations, on the emulsification behavior due to material exchange between liquid metal and molten oxide, have been conducted by Assis et al and Spooner et al using high temperature confocal scanning laser microscopy and micro X‐ray computer tomography (XCT).…”

Application Preparation of High‐Performance Iron‐Based Powder Metallurgy Sintered Materials in Sports Industry

“…The Archimedes drainage method is used to detect the density ρ of each sample, and the surface is treated with wax to improve the accuracy of the test. Use BSM-200.4 electronic analytical balance to measure the quality [11]. Calculate the sample density according to formula ( (10), where m 1 is the mass of the sample in air (g), m 2 is the mass (g) after sealing wax, m 3 is the suspended mass in water (g), and ρ w is the density of water ðg/cm 3 Þ. ρ wax Is the density of paraffin wax ðg/cm 3 Þ.…”

“…The porosity of the sintered matrix is the key parameter of the infiltration amount in the subsequent copper infiltration process. After the density of the sintered matrix is measured, the matrix porosity ε can be calculated according to formula (11) [12]. ρ 0 is the theoretical density of the sintered matrix ðg/cm 3 Þ, and ρ is the measured density of the sintered matrix ðg/cm 3 Þ.…”

Effect of various components on the distribution of phosphorus in CaO–FeO–MgO–SiO2–MnO–TiO2–V2O5–P2O5 slag based on IMCT

“…The reaction capacity or activity of the component in the slag is characterized by the mass action concentration of the component (N i ), which is defined as the mole fraction under the equilibrium condition of the slag system. Based on the IMCT, Yang et al [17][18][19][20][21][22][23][24] had successfully developed a thermodynamic model for predicting L P between molten steel and CaO-SiO 2 -MgO-FeO-Fe 2 O 3 -MnO-Al 2 O 3 -P 2 O 5 slags during top-bottom combined blown converter steelmaking process, and a thermodynamic model for predicting the phosphate capacity of CaO-SiO 2 -MgO-FeO-Fe 2 O 3 -MnO-Al 2 O 3 -P 2 O 5 slags at the steelmaking endpoint during an 80-ton top-bottom combined blown converter steelmaking process, simultaneously proposed the coupling relationships between dephosphorization and desulphurization abilities or potentials for CaO-FeO-Fe 2 O 3 -Al 2 O 3 -P 2 O 5 slags over a large variation range of slag oxidization ability during the secondary refining process of molten steel. The aforementioned models can be valid for predicting dephosphorization ability of CaO-based slags between hot metal and molten steel, respectively.…”