Welcome to the Glass Age

109 E rik M uijsenberg 7. Sustainable Glass Production with Carbon Reduction Sustainable glass recycling (UN Goal 11) Glass plays an important role in our society. Its usage in housing, transportation, communication, food storage, etc. is crucial to enjoying a high quality of life. To produce glass, we need raw materials and energy. We can reduce the need for materials by recycling more. Indeed a significant advantage of glass is that it can be endlessly recycled without loss in quality or purity although glass waste needs to be purified, cleaned, and color separated before use [1] [2]. Using more cullet for melting means not only considerable savings in raw materials costs and energy usage, but CO 2 emissions are also lower. Clean cullet needs to be reheated and homogenized; but melting reaction energy is not required and every 10% cullet addition reduces the energy consumption of glass melting by 2-3%. To melt soda lime glass from raw materials requires a theoretical energy of about 2.6 MJ/kg. As pure cullet, this is reduced to 1.9 MJ/kg. More importantly, re-melting cullet avoids CO 2 emissions from soda ash (Na 2 CO 3 ) and lime (CaCO 3 ) in the batch. Every metric ton of waste glass recycling saves about 315 kg of CO 2 that would be released manufacturing a new glass product [3]. However, the most common, efficient, end-fired container glass furnaces, melting with an average of 50% cullet, consume about 3.5 MJ/kg, due to additional heat losses through the furnace structure.