With modern X-ray instruments, precision is generally satisfactory for the analysis of MgO, Al2O3, SiO2, CaO, and Fe2O3 in finished and raw-mix cements and other similar materials. Accuracy, that is, agreement between cheraicaland X-ray values, quite frequently is much worse than precision. Some typical examples illustrating this point are reviewed.
In the soft region, generally, it has not been possible to assign the cause of iuaccuracy to interelement effects. The hypothesis is formulated that in the soft region this problem could be due to mineralogical differences and inhomogeneity on a micro scale. Theoretical calculations support the plausibility of this argument.
To improve accuracy, present techniques have been based on type standardization, acid digestion fusion using a high flux-to-sample ratio, etc. In general, these methods have certain basic limitations. In order to retain useful intensities and lineto- background ratios for the soft region, 8 new fusion technique has been developed. The experimental data based on this method of reducing micro-inhomogeneity and eliminating minaralogical differences indicate improvements in accuracy. In the case of finished cements the improvements in accuracy have been quite modest. With rawmix cements, startling improvements have been obtained for the analysis of SiO2 and CaO.