With the ongoing departure from coal-fired power plants and decreasing demand for pig iron in mature markets, the availability of blast furnace slags and fly ashes is expected to decrease. At the level of cement production, extended use of calcined clays and limestone as SCM are the only approaches applicable at large enough scale. ![]() These include re-usable structures with extended service life or concretes with reduced cement contents 3, 6. At the level of concrete structures and concrete applications, several approaches can bring considerable CO 2 savings. Nevertheless, the cement industry needs to drastically reduce its emissions and at the same time satisfy the increasing cement demand of the global economy 5. For the clinker production, further energy efficiency improvements would have only a minor effect as the energy consumption approaches the lowest theoretical value and is often driven by additional objectives such as alternative fuels usage rate. Almost all suitable Supplementary Cementitious Materials (SCMs) available are already used in cement and concrete production. As summarized in 1, both these approaches have already reached their potentials in mature economics. Hence, focus of researchers as well as of cement producers has been on lowering the clinker content in cements and on improving the efficiency of clinker production. Most of the concrete’s emissions result from production of the main cement component, the clinker. Even though concrete has low specific CO 2 emissions below 150 kg CO2,eq/ton concrete 1, its abundance makes it responsible for 5–8% of man-made CO 2 emissions 1, 2, 3, 4. Already now, concrete is the second most used substance by mass after water. Global urbanization and economic development increase demand for new buildings and infrastructure and hence for concrete. The carbonated fines have specific CO 2 savings more than 30% higher than the simple clinker replacement by limestone. Upon full carbonation, gels with pozzolanic properties form in the fines irrespective of the conditions tested. It is shown that all CO 2 originally released by limestone calcination during clinker production can be sequestered by the full carbonation of the fines within a short time. ![]() The CO 2 sequestration and the reactivity of the obtained carbonated recycled fines is experimentally demonstrated for lab as well as industrial materials for different mineralization conditions. A Carbon Capture and Utilization (CCU) approach based on mineralization of fines derived from concrete appears to be a viable alternative to reduce these emissions. ![]() Reduction of CO 2 emissions associated with cement production is challenging in view of the increasing cement demand and the fact that major part of the emissions originates from the main raw material used - limestone - which can be only to extremely low amount substituted.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |