Analysis of Dephosphorization Thermodynamics Based on the Melt Structure of CaO–SiO<sub>2</sub>–FeO–MgO System

To reduce the phosphorus content in steel, CaO–SiO2–FexO–MgO-based dephosphorization slag was designed to clarify microscopic reaction behavior of phosphorus. In present study, Raman spectra final were measured and deconvoluted. The spectral analysis showed that P5+ ions removed from liquid iron existed form Q0(P) Q1(P) groups. According result, phosphate capacity distribution ratio (LP*) redefined. results lgLP* proportional molar Q0(P)/Q1(P), indicating exerted a significant influence on LP* compared with Q1(P). As increases CaO/SiO2 0.15 1.25 FeO 7.2 21.9 mass% slag, gradually increased, whereas downward trend when increased 29.2 mass%. This because increase O2− generated by dissociations CaO, MgO continuously destroyed network structure formed more units, which compensated increasing Ca2+, Mg2+, Fe2+ cations stable Meanwhile, Q0(Si) units depolymerization further played role fixing Q0(P). However, due stronger polarization than Ca2+ easily deformed decomposed Fe2+. excessive diluted proportion made lose stability. reduced iron, rephosphorization phenomenon occurred, resulting decrease lgLP*.