The Quality Of Mixed Cullet (In Italian)

About one million tonnes of glass cullet are used each year by Italian glass manufacturers in the production of coloured glass containers, and often it 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 affecting the redox state of the melt and its influence on the final glass colour are discussed, with particular reference to organic contaminants and the redox state of the cullet. The negative effects of heavy metals and halides on the quality of the final glass (for food containers) and waste gases are also discussed.