New imaging technique reveals hidden chemistry in cement production
Researchers have demonstrated that high-temperature X-ray imaging can predict cement quality in real time by tracking how raw materials transform inside kilns. The finding could help cement manufacturers reduce waste and improve consistency—critical for an industry responsible for 8% of global CO2 emissions and facing mounting pressure to cut costs and carbon footprints.
Originaltitel: Phase evolution and burnability of cement raw meal
<p>The use of high-temperature X-ray diffraction (HT-XRD) to study the mass transfer of raw meal constituents towards forming clinker phases and the occurrence of free lime (calcium oxide), also known as burnability, was assessed. A measuring strategy with temperature ranging from 1000°C to 1450°C was developed and compared with a conventional burnability method. The free lime determined by the methods showed that HT-XRD produced good results for the evaluation of burnability. In addition, HT-XRD revealed the formation of intermediate phases, providing insight into early reactions in a cement kiln. The particle size of quartz was found to affect crystal expansion of the phase at a high temperature, subsequently affecting the formation of silica polymorphs. The different raw meals used in this study also indicate that the formation of different silica polymorphs affects the formation of C<sub>2</sub>S. The lack of knowledge regarding the influence of β-quartz on the reduction of free lime is highlighted.</p>