Thermodynamic Analysis of Mineral Phase Composition of Steel Slag System

In order to transform the crystalline form of Ca2SiO4 (C2S) in phosphorus-containing slag from monoclinic β-polycrystalline square γ-polycrystalline, a volume expansion about 11% was generated, which caused undergo self-powdering. The CaO-SiO2-Al2O3-MgO-MnO-P2O5-FeO system analyzed using FactSage7.1 thermodynamic software, and effects different P2O5, FeO basicity on mineral phase composition were range 1300~1700 °C. It shown that all have an effect phases. When mass fraction P2O5 lower than 0.25%, it had less transformation C2S structure. content higher favorable generation low-melting-point substances, but reacted with silicate phase, making P5+ solidly soluble C2S, inhibiting β-C2S γ-C2S hindering self-powdering slag. ranged 20% 28%, as increased, decreased 33.3% 25.9%, while temperature at completely dissolved into liquid 1600 °C 1500 complete melting decreased. low facilitates high-phosphorus slag, temperatures below 1450 °C, increase basicity, proportion first increased then With 1.8; highest accounting for 33.7%; exceeding is conducive removal phosphorus achieving