Composition and structural evolution of basalt melt during homogenization

During fabrication of basalt fiber, one critical procedure is the homogenization of melt, which typically lasts over 10 h at similar to 1500 degrees C. However, the changes in composition and structure of basalt melt during the homogenization process remain poorly understood. In this study, basalt melts were held at 1550 degrees C for various durations and then rapidly quenched to form basalt glasses, enabling analyses of their compositional and structural evolution. Compositions of glasses were analyzed using chemical titration, energy dispersive X-ray, and inductively coupled plasma optical emission spectrometry methods. The crystallization process was examined through differential scanning calorimetry analysis, while structural evolution was investigated via Raman and X-ray photoelectron spectroscopy O1s spectroscopy. The results showed that the primary composition change during homogenization was the valence transition from Fe3+ to Fe2+. The O2- produced with the valence transition gradually converted the Q3 units into the Q2 units. The homogenization process reached the stability of composition and structure after 8 h. A high proportion of Q2 units will align along the fiber axis, enhancing the melt spinnability and reinforcing the basalt fiber.