Ceramic contaminants in recycled glass cullet can result in inclusions in finished glass products. Ceramic inclusions can lead to eventual fracturing or breakage of the glass container, especially if the container is filled with a pressurized liquid like soda or beer. Providing a cullet supply free of ceramic contaminants is generally the responsibility of the materials recovery facility (MRF). Many MRFs physically remove ceramic contaminants from the cullet, either manually or with automated systems. An alternative to complete ceramic removal is to reduce the entire cullet supply to No.12 mesh or smaller. Called fine-sizing, this size reduction enables most ceramics to melt in the furnace. This Best Practice describes some prevalent technologies for fine-sizing cullet, and can be downloaded from the above-mentioned website.
