A recycling process for waste coloured glass based on the property of glass phase separation. The soda-lime-silica glass with heavy metal ions such as Cr ions was re-melted withB2O3 and the glass thus obtained heat-treated and leached by hot acid solution. All the alkali and heavy metal ions were successfully removed from the glass and nearly pure Si02 was obtained. The decoloration mechanism was investigated. The glass structural change with composition and heat treatment was measured by 11B and 27A1NMR spectra. The valence and site of the Cr ions in the glasses before and after the heat and acid treatments were investigated by leaching rate, ESR and UV/VIS spectra. It was found that the process of removing the heavy metal ions from the waste coloured glass is related to the composition and heat treatment dependent structural change of the glass.
