| Solid State Synthesis of Willemite, Zn2Si04 :
Role of Precursors |
AMITAVA MAJUMDAR AND DIBYENDU GANGULI
Pages : 93-97
DOI : 10.1080/0371750X.1991.10804499 |
| Abstract |
| Three ptecursors of equivalent oxide composition 2ZnO.Si02, namely,
(i) a colloidal gel prepared from zinc nitrate tetra+ hexahydrate
(partially crystallized) and a colloidal silica sol, (ii) a colloidal gel
(amorphous) prepared from zinc chloride n-hydrate and the same
colloidal silica sol, and (iii) a mechanical mixture of quartz and
ZnO, have been used for examining their relative reactivities in the
fo~mation of willemite, Zn2Si04• The samples were heat-treated at
temperatures in the range 1000°C-1400°C and for soaking periods of
less than 1 hr to 80 hours. X-ray analyses showed the nitrate-derived
gel to be the most reactive, followed by the chloride-derived gel; the
crystalline oxide mixture showed sluggish reaction. Attempts have
been made to explain this difference in reactivity in terms of the
thermal behaviour of the precursors below l000°C. |
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