LAUSR

Abstract According to Indonesian Standard SNI 15-7064-2004, Portland Composite Cement (PCC) or blended cement is defined as a hydraulic binder which consists of clinker, gypsum and one or more inorganic materials where their contents range from 6% to 35% of the total mass of PCC. However, some factories still have their clinker levels in PCC above 80%. Many factors are suspected to be the cause of this high clinker level problem in PCC, such as the quality of the raw meal mixture, the clinker combustion process, the quality of clinker and inorganic materials, and others. This paper presents the results of the study on high clinker content PCC produced by two different preheater configuration of Indonesian cement plants, SLC and SLCI. The analysis is based on the clinker microscopic examination, particle size distribution (PSD), and CFD process simulation of raw meal in the calciners. The results showed that high clinker content PCC were suspected to be closely related to PSD of raw meal, preheater configuration, and cooling speed of clinker when out of the kiln. Configuration of the preheater and speed of clinker cooling process can influence the uniformity of the pyroprocessing, which results in different residence time of the particles, clusterization of the belite phase as well as its distribution in the clinker.