CRYSTALLIZATION CHARACTERISTICS OF IRON-CONTAINING SPODUMENE DIOPSIDEGLASSES

The crystallization characteristics of glasses based on a stoichiometr ic spodumene (LiAlSi2O6)-diopside (CaMgSi2O6) composition with additio n of Fe2O3 replacing Al2O3 are described. The effects of compositional variation due to the Al2O3/Fe2O3 replacement and thermal treatment on the nature, type and stability fields of crystallizing phases as well as the resulting microstructure are traced by DTA, X-ray diffraction (XRD) and scanning electron microscopy (SEM). In most cases, intense u niform bulk crystallization with fine-grained microstructure were achi eved on increase of iron oxide at the expense of alumina. The crystall izing phases, beta-eucryptite solid solution (ss), beta-spodumene ss, varieties of pyroxene solid solution of diopside, hedenbergite and aug ite nature are mostly formed together, in some cases, with alpha-quart z, lithium silicates, lithium ferrate (LiFeO2) and iron oxide. The typ e, stability and compatibility of the crystallized phases are discusse d in relation to the compositional variation of the glass and thermal treatment.