The Quality Of Mixed Cullet

About one million tons of glass cullet are used yearly by Italian glass makers for the production of coloured container glass, & it often is the main component of the batch. A description is given of cullet quality parameters that must be closely controlled by glass producers. Different inorganic contaminants are examined, which can cause the formation of stones in the final product. The parameters affetcing the redox state of the melt & its influence on the final glass colour are discussed, with particular reference to organic contaminants & the redox state of the cullet. The negative effects of heavy metals & halides on the quality of the final glass (for food containers) & waste gases are also discussed.