THERMAL-DECOMPOSITION OF BI2STE2 TETRADYMITE

The oxidative thermal decomposition of natural tetradymite (Bi2STe2) h as been studied by thermal techniques and by X-ray diffraction, infrar ed spectroscopy and scanning electron microscopy. Oxidation occurs exo thermically at comparatively low temperatures, whereas desulfatization takes place endothermically at higher temperatures. A scheme for the overall reaction is proposed. The exothermic process occurs at lower t emperature for material of smaller particle size.