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Thermal Analysis of Reactions in Soda–Lime Silicate Glass Batches Containing Melting Accelerants: I, One‐ and Two‐Component Systems
Author(s) -
Hong Kug Sun,
Speyer Robert F
Publication year - 1993
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1993.tb03647.x
Subject(s) - calcite , sodium silicate , dolomite , sodium carbonate , mineralogy , sodium sulfate , soda lime , thermal decomposition , chemical engineering , sodium , chemistry , silicate , materials science , inorganic chemistry , metallurgy , organic chemistry , engineering
To identify each glass melting reaction in a multicomponent system, one‐component and two‐component reaction processes were studied using DTA, TGA, and XRD. Two‐component mixtures were prepared by choosing pairs in the same ratio as in a commercial container glass batch composition (sand‐soda ash‐calcite‐dolomite‐feldspar). The presence of silica in the silica‐calcite system decreased the termination temperature of the decomposition of calcite, but did not alter the onset of decomposition. Similar behavior was found in the dolomite‐silica system. A double carbonate (Na 2 Ca(CO 3 ) 2 ) formed via solid‐state reaction in the calcite‐soda ash system, and metasilicate/disilicate phases were detected during the fusion process in the soda ash‐silica system. The effects of reaction accelerant additions in the soda ash‐silica system were investigated using 1 wt% additions of sodium sulfate, sodium nitrate, and sodium chloride. Sodium chloride was the most effective melting accelerant, lowering the termination temperature of CO 2 release by ∼80°C compared with the soda ash‐silica system with no additives. NaCl additions caused complete reaction and/or fusion of Na 2 CO 3 prior to its melting temperature. Sodium sulfate additions acted to suppress metasilicate/ disilicate formation by coating quartz grains and shifted consequent CO 2 release to higher temperature.