The Quality Of Mixed Cullet

About one million tons of glass cullet are used yearly by the Italian glassworks for the production of coloured container glass, and it often is the main component of the batch. A description is given of a 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 affecting the redox state of the melt and its influences on the final glass colour are discussed, with particular reference to organic contaminents and the redox state of the cullet. The negative effects of heavy metals and halids on the quality of the final glass (for food containers) and waste gases are also discussed.