Mirco-level Insight into the Surface Tension -structure Relationship of Molten CaO-MgO-SiO2-FexO-P2O5 Slags

For comprehensive understanding and control of the properties of CaO -MgO-SiO2 FexO-P2O5 slags, thorough investigation of the surface tension -structure relationship is required. In this study, the structural behaviors of components were analyzed by Raman spectroscopy, and the transformation mechanism of surface tension as a function of composition was clarified. The results showed that with CaO/SiO2 increasing from 0.5 to 2.0, O(2-)resulted in the progressive breaking of bridging oxygen bonds in [SiO4]-and [PO4]tetrahedrons, and Ca2+ contributed to the stabilization of [Fead-tetrahedrons, thereby promoting the transformation from [FeO6]-octahedrons to [FeO4]-tetrahedrons. Although the network-forming ability of Fe3+ was enhanced, the overall no-bridging oxygen number still showed a gradual increase and thus the non-bridging oxygen bonds with higher unsatisfied energy in the surface layer led to an increase in surface tension. Nonetheless, the increasing P=O bonds effectively reduced surface tension due to its stable configuration in the range of CaO/SiO2 = 0.5-1.0, diminishing the increasing magnitude of surface tension. Furthermore, a strong linear relationship between surface tension and the logarithm of structural parameters was found. On this basis, a surface tension estimation equation applied to the CaO-MgO-SiO2-FexO-P2O5-based system was established in terms of the deconvolution results of the melt structures.

Automated summary

By analyzing the structural behaviors of components through Raman spectroscopy, this study clarified the transformation mechanism of surface tension in relation to composition changes in CaO-MgO-SiO2-FexO-P2O5 slags. It was found that an increase in CaO/SiO2 ratio led to more non-bridging oxygen bonds and higher surface tension, while an increase in P=O bonds effectively reduced surface tension. Ultimately, a surface tension estimation equation was established based on the deconvolution results of melt structures.