This presentation shows the advantages of re-melting post-consumer glass, but also the potential risks of using contaminated cullet in the raw material batch of glass furnaces (e.g. container glass furnaces). As an example of potential advantages; increasing the cullet% in the batch of an efficient end-port fired regenerative container glass furnace from 65-75% decreased the specific energy consumption from 3.95MJ/kj molten glass to 3.8 MJ/kg and reduced the direct CO2 emissions with 31 grams per kg glass. Additional, lower indirect CO2 emissions can be taken into account, since less primary raw materials have to be applied, saving fossil energy in raw material synthesis (e.g. synthetic soda production). Waste glass has to be sorted and prepared in dedicated cullet recycling (treatment) plants (CTP) to meet the strict quality standards often expressed in maximum mass fraction of ceramics, stones, china, metal and colour mismatches that can still be accepted. But, also the presence of organic components (fats, oils, sugar, food residues) has to be controlled to avoid production or glass colour problems.
