Iron-doped zircon: the mechanism of formation

Iron-doped zircon (zirconium silicate) has been prepared from silica, zirco nia and iron(II) sulphate heptahydrate using a mixture of sodium halides an d alkali metal nitrates as mineralisers to lower the temperature of reactio n. The formation of a silicon- and fluorine-containing glassy phase in the reaction vessel, together with evidence for a SiF3 breakdown product and th e analysis of solid phases formed at intermediate temperatures, implicate t he participation of a volatile silicon fluoride intermediate, probably SiF4 , in the formation of the iron-doped zircon. (C) 1999 Kluwer Academic Publi shers.