THE USE OF CEMENT CLINKER MICROSCOPY AS AN AID TO DETERMINE THE PERFORMANCE DIFFERENCES IN THE PRESENCE OF CHEMICAL ADDITIVES

摘要

This paper has been produced from an on-going investigation which shows the continued clear need for some level of advance clinker microscopy, if all the potentially negative characteristics that may occur in cement clinker production are to be correctly identified. XRF and QXRD Rietveld, while extremely useful tools for routine analysis picking up changes in chemical composition and constituent minerals, cannot identify the sort of detrimental features and situations described above. The more in depth form of 'whole' clinker microscopy described here is however, required to obtain all the important features and information which may be otherwise missed.In the one particular investigation highlighted, not only were recommendations provided which should lead to improved quality, but significant cost savings could also be realized. Additionally it seems possible that an improved clinker would also respond more positively to cement additives, although this has not yet been verified.It is well reported and confirmed in this paper that the relative performance of different clinkers in the presence of various chemical grinding aid additives cannot be determined by XRF and QXRD. However, the early findings of this microscopy-based investigation suggest some relationships do indeed appear to exist between the various clinkers' microstructure characteristics and their chemical additive performances. It appears clinkers with less than optimal quality characteristics such as those described above and as observed in the case study are often those associated with poor performance in the presence of the various additives under investigation. Clinkers with an 'optimal quality' appearance do not appear to show such poor chemical additive performances. However, this remains an on-going investigation without any as yet fully substantiated findings.It is important to understand if this general influence of atypical morphological clinker characteristics, due to various compositional and manufacturing related variables, on poor performance of chemical grinding aid additive can be developed. Do certain clinker characteristics, say under burning, only exhibit a poor additive performance with certain GA chemicals or are these across the board relationships.Further study in the next couple of years should provide confirmation, or not, of the observations made so far, which can then be used in the greater understanding of how and why certain clinkers perform well and others do not with a selection of different chemical additives. It remains necessary to determine why clinkers with less than optimal morphological characteristics perform poorly with chemical additives (and which ones) and why acceptable quality clinkers do not.