Clinker Formation and the Value of Microscopy

摘要

Evaluation of clinker using microscopy is a powerful technique that can help improve clinker production and cement quality. One can gather remarkable information about clinker history as well as provide information about cement performance. The key to using the microscope is understanding the process of clinker manufacture: how raw materials are transformed into clinker. The transformation involves both chemical and physical processes, as the material passes through the kiln system. To produce the desired calcium silicate phases of portland cement, specific raw materials are required. The burnability of the mixture of these materials is determined by chemical composition, mineralogy, and fineness. To convert the raw materials to the cement compounds, the ground feed goes through a series of clinkering reactions in the kiln system. Formation of the primary clinker phases (alite, belite, tricalcium aluminate, ferrite) during this time depends on the pyroprocessing conditions and material properties. At the same time in the kiln, clinker nodules are formed by agglomeration due to capillary forces of the liquid. The microscope is used to observe features such as clinker phase size, morphology, abundance, and distribution. These observations can not only provide information about the clinker production parameters, but can also offer clues to cement performance properties. Based on understanding of the process of clinker formation, interpretation of the microstructure can be used for quality control, troubleshooting, and to monitor process changes at the cement plant.