Ceramics-Silikáty 35, (3) 211 - 223 (1991)

The mass balance of gaseous reaction products (CO₂, H₂O and gaseous forms of boric acid) escaped during the process of heating of the pressed Eutal glass batch in the range of 25 - 800 °C a) in the stream of N₂ and b) in the stream of natural gas combustion products of the approximate composition as 70 vol. % N₂, 20 vol. % H₂O, 10 vol. % CO₂ was determined. The termogravimetry, atomic emission spectrometry, DTA and X-ray diffraction techniques were used in this investigation. This paper is focused on determination of the boric oxide mass decrease in the pre-heated batch as a temperature function that is due to reactive vaporization in the presence of water vapour. The total relative loss of boric oxide from the pressed batch with an initial content of B₂O₃ equal to 6.8 % is about 14.5 % when the batch is pre-heated in the stream of combustion products whereas reheating the batch in the nitrogen stream results in a loss of 6.8 % . The value of the B2O3 loss depends consequently upon the content of structural water in the batch components, as well as upon the water in the natural gas.