This paper presents the results of laboratory scale experiments aimed
at verifying the effect of chemical composition and processing conditi
ons on the solubility, mineral composition and morphology of a glass c
omposed mainly of SiO2, P2O5 MgO and CaO. The results indicate that, b
y controlling the cooling rate of melts with adequate composition, gla
ss spheres of sub-micro-metric size can be produced as a consequence o
f liquid-liquid phase separation. The SiO2 rich glass spheres with con
trollable size can be separated from the continuous glass phase by dis
solution of the latter with a weak acid followed by centrifugation.