Ceramics-Silikáty 41 (3) 105-111 (1997)

 HIGH-TEMPERATURE REACTIONS OF SODIUM CHROMATE WITH SILICA

K. Marušková, J. Had, M. Maryška, L. Šanda, J. Hlaváč 

Reactions between sodium chromate and silica were studied on mixtures of silica sol with chromate solutions. After thermal exposure the conversion degree was determined by chemical analysis and gas chromatography. The reaction products were identified by X-ray diffraction and optical microscopy. The mixtures were found to react at temperatures above 900 °C in two stages: the ternary compound NaCrSi₂O₆ (kosmochlor) forms at lower temperatures and above 1050 °C decomposes to Cr₂O₃, Na₂Si₂O₅ and silica.

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