Laboratory glass melting experiments were made to study the effect of glass redox on selenium retention. Initially, it was found that as expected, selenium retention decreases as glass redox ratio increases. But, unexpectedly, selenium retention then levels off and reaches a minimum upon further increases in glass redox, before once again increasing for very high redox ratios of more than 0.60. Selenium concentrations in the furnace atmosphere at different locations in a commercial float glass furnace were also measured as an indicator of selenium volatility at different stages of glass melting. A study of the effect of glass redox ratio on the spectral absorption of the major selenium containing colouring centres in float glass was also made.
