Effect of P₂O₅ addition on enrichment behaviour of phosphorus in CaO–SiO₂–FeO–P₂O₅ slag

Abstract

The CaO-SiO 2 -FeO-P 2 O 5 slag was measured by Raman spectra, and the changes in the structure and behaviour of phosphorus were analysed under different slag components. The results proved that phosphorus exists in two enrichment behaviours in the slag, which can be judged according to the mole fractions of Q 1 (Si), Q 2 (Si), and Q 3 (Si). When the content of P 2 O 5 increases from 4.5% to 8.5%, the Q 0 (P) intensity changes most significantly. Since the Fe-O bond energy (390.4 kJ mol −1 ) is weaker than the P-O (410 kJ mol −1 ) bond energy, the silicon-oxygen network structure will show a behaviour change of depolymerization first and then polymerization. XRD analysis shows that with the increase of P 2 O 5 content, different calcium silicate phases are added and decreased in the slag, and the content of a small amount of calcium ferrite phase changes, Si x O z− y bonds or separates from each other, which is consistent with the change law of Raman analysis.

Effect of highly oxidizing converter dephosphorization slag on dephosphorization behaviour of molten steel

“…The analysis results show that the converter dephosphorization slag samples all contain 3CaO•P 2 O 5 , 2CaO•SiO 2 , MgFe 2 O 4 , Fe 3 O 4, and FeO mineralogical phases. It can be seen from Figure 7 (a) that the phase composition of converter dephosphorization slag is concentrated in the diffraction angle range of 30°-65° [21], and the diffraction peak at about 35°gradually increases with the increase of basicity. It can be seen from Figure 7(b)-(e) that the main components in this area are 3CaO•P 2 O 5 and 2CaO•SiO 2 , indicating that with the increase of basicity, phosphorus in the form of 2CaO•SiO 2 -3CaO•P 2 O 5 in slag gradually increases.…”

Ionic analysis of the effect of temperature on dephosphorization capacity of silicate slags

“…Zhou et al [9] found that phosphorus existed in two enrichment behaviours in the slag and was considered to exist in the network structure of silicon-oxygen groups with different degrees of polymerization. Under the combined action of FeO and P 2 O 5 , the silicon-oxygen groups depolymerized first and then polymerized with increasing P 2 O 5 , which is caused by the fact that the Fe–O bond energy is weaker than the P–O bond energy.…”