CALCULATIONS OF INTERACTIONS OF GAS-BUBBLES WITH GLASS LIQUIDS CONTAINING SULFATES

The behaviour of bubbles in commercial sulphate containing glasses is usually controlled by the diffusion of gases in the liquid glass; howe ver, the bubble surface reaction of sulphate layer formation or decomp osition can control the mass transfer of the SO2 and O-2 at the highes t concentrations of both gases in bubbles. The equations describing th is mass transfer were numerically solved to reveal the typical feature s of size and composition development of bubbles in the soda-lime-sili ca liquid glass. Layer formation on the bubble surface was accompanied by bubble shrinkage. According to the model, the extent of the bubble size reduction and the sulphate layer thickness grow as the initial a mount of SO2 and O-2 in the bubble increases, as the volume ratio betw een the SO2 and O-2 approaches the stoichiometry (2:1) and as temperat ure decreases. The development of the SO2 and O-2 concentrations in th e bubble shows the largest terminal SO2/O-2 ratios if the initial SO2/ O-2 ratio is greater than 2, if the initial state of the glass is redu ced and if the glass is slowly cooled. The results have importance for the mathematical modelling of the refining process in glass melting a nd for the identification of bubble sources in a furnace, using result s of bubble composition analyses. (C) 1998 Published by Elsevier Scien ce B.V. All rights reserved.