Computer modeling of satellite peak in tin profile of float glass

A one-dimensional finite difference computer model of the penetration of tin in float glass was used to investigate the mechanism of formation of the tin profile. It was found in the computer simulation that: (1) tin ions in the surface layer of the float glass are in motion after departing from the tin bath; (2) the tin ion motion is dependent on the thickness of the glass ribbon, and on the chemical component and temperature distribution in the atmosphere where the glass ribbon passes; (3) the tin profile with a satellite peak is formed while the glass ribbon passes in a region with an SO2 atmosphere and a certain temperature distribution. The mechanism of formation of the satellite peak proposed by T.J. Wang (Glass Technol. 38 (3) (1997) 104) has been verified by this computer simulation. The satellite peak will be formed in cases where: (1) an adequate amount of Sn2+ is oxidized to Sn4+, and (2) the Sn4+ is diffusing. The two conditions can be realized in a tin bath, and also in an annealing lehr with an SO2 atmosphere.