Melting behavior of sulfur-bearing silicate–phosphate glass batches

Abstract

The main purpose of the research was to explain the differences between nominal and actual chemical compositions of silicate-phosphate glasses in the SiO2-P2O5-K2O-MgO-SO3 system. The actual compositions of the materials were determined with X-ray fluorescence (XRF) analyses. Changes in the chemical composition were explained by examining the melting processes for selected glass batches with differential scanning calorimetry-thermogravimetry-related gas analysis by mass spectrometry (DSC-TG-EGA (MS)) and high-temperature X-ray diffraction (HT-XRD). It was found that changes in the chemical composition of the sulfur-bearing glasses were associated with the release of gaseous products. The main gases released during thermal decomposition of the selected glass batch were water vapor, carbon dioxide, carbon monoxide, and ammonia. Since these glasses have potential for use as glassy fertilizers, there is no doubt that the present study is important from an environmental point of view.