Cement Energy Environment

40 Further, energy requirements are cut significantly as activation takes place at temperatures below 900 °C instead of 1,450 °C. Accordingly, assuming a 50 % substitution rate, total CO 2 savings of up to 40 % can be achieved. Activated clay usage is already economically attractive under current market conditions. And with foreseeable decreasing availability of many substitution materials Another trend in the context of sustainability is the grinding technology with an increasing demand for high fineness cements and cements with several constituents, of which all are ground to individual particle size distributions. This trend resembles to a large extent the target of an improved overall environmental foot print of respective tailor made cements. Main drivers are clinker factor reduction without compromising quality, an increasing demand for high-performance cements and cements with special features. In many aspects, ball mills, high pressure grinding systems and vertical roller mills as standard grinding technologies in the cement industry come to their limits if applied to such cements. Hence, thyssenkrupp has expanded its grinding systems portfolio by an agitated polysius ® Booster Mill – High Fineness Cement Grinding for clinker and rising costs of CO 2 emissions this will even improve in the future. In many regions, limestone is in short supply and clinker has to be imported at high costs. A current driving force in Europe is the legislation to shut down coal fired power plants in the medium term, which will lead to the disappearance of fly ash from the market (Figure 3). Figure 3:The polysius ® activated clay process facilitates the production of activated clay as substitution materials for clinker. It is based on calciner technology and facilitates high quality products. bead mill system. This mill consists of a cylindrical vessel in which a rotor generates a bead motion which induces an intense shear force and impact on the particles. The resulting energy density is 10-20 times higher than in a ball mill and entails a respective compact equipment design (Figure 4).