The reuse of recycled cullet in the production of new glass containers lies above 60%. The cullet ratio depends on the glass colour, the level of impurities, and on availability. As a side effect of cullet waste management, the occurrence o f metallic and ceramic impurities cannot be avoided. Quality criteria for recycled cullet must comprise these impurities as potential sources of quality defects in the product. The potential of ceramics to generate glass defects contributes to a large extent to economic and technological restrictions for the overall amount of recycled cullet. The impurities in recycled cullet are distinguished by their potential to impair glass quality. In recycling cullet, emphasis must be laid on safe separation of the most critical species. It is the objective of this work to generate a basis which allows to identify the most critical ESP species, and to assess their effect on glass quality.
