The absorption of H-2 and CO from bubbles in a glass melt

Hydrogen and carbon monoxide bubbles in a glass melt are produced by reacti ons of carbon, iron and ferrous oxide impurities with oxygen or water vapou r. Their modelling in melting space joined with defect bubble analyses coul d help to identify the appropriate bubble defect source, however, mechanism s of bubble interactions with melts are not yet known. the experimental exa mination of bubbles initially containing 95 vol.% H-2 and 5 vol.% N-2 showe d a rapid absorption of hydrogen by the melt. The proposed mechanism of int eraction involved the controlling role of hydrogen and oxidizing components counter-diffusion in bubble surroundings and influence of chemical reactio n of hydrogen with the mentioned oxidizing melt components (O-2, sulphate i ons). The governing equations of this phenomenon were presented, as well as a simplified mechanism applying the value of hydrogen effective diffusion coefficient under given value of the redox state of glass. Using the result s of experimental observations, the temperature dependencies of the product of effective diffusion coefficient and solubility of hydrogen - necessary for the modelling of bubbles containing hydrogen - were determined in soda- lime-silica glass containing 0.5 wt.% SO3 ((DH2effLH2)-L-2/3 = exp (0.866-7 438/T)) and amber glass ((DH2effLH2)-L-2/3 = exp(0.946-9125/T)), where T is temperature in Kelvins.