The fusion bead method is an effective sample preparation technique for accurate analysis of a
wide variety of powder samples by XRF spectrometry such as ores, rocks and refractory
materials since it eliminates heterogeneity effects associated with grain size and mineralogical
composition. In order to obtain highly accurate results, it is necessary to provide a constant
flux-to-sample ratio (flux ratio) in each preparation of a given sample type. Even if weighing is
performed precisely, variation in flux ratio may occur owing to loss on ignition (LOI) or gain on
ignition (GOI) of the sample, evaporation of the flux or decomposition of oxidizing agents during
fusion. These influences introduce analytical errors in the fused bead method by altering the
flux ratio and x-ray absorption properties of the matrix.

Prior attempts to correct these sources of variation based on flux weight and sample weight and
to correct for LOI/GOI were applied in the calibration equation for ore analysis via the fusion
method (ISO9516-1: 2003(E)), but the application of these corrections is limited and inflexible.
We have established a unique, easy-to-use, universal fusion bead correction method for the
empirical calibration method with matrix correction for fusion bead analysis. The advanced
correction equation has been derived from a theoretical intensity equation based on the principle
of X-ray absorption characteristics. The equation consists of alpha coefficients computed by a
fundamental parameter (FP) method. The software computing alpha coefficients is capable of
Copyright ©JCPDS-International Centre for Diffraction Data 2012 ISSN 1097-0002 242
calculating the coefficients for weight ratios of flux : sample, bead : sample and oxidizing agent :
sample, as well as matrix correction coefficients to account for the influence of coexisting
elements in fused bead samples. It is also possible to calculate coefficients for the composition
of a fused bead when the weight after fusion exceeds 100% of the starting weight owing to GOI
from oxidation of elements in reduced states during fusion. Thus, the correction method can be
used to correct LOI/GOI, flux evaporation and variations in flux ratio due to inaccuracies in
weighing the sample and fusion reagents. We have demonstrated that the method accurately
corrects for such effects in the analysis of iron ore and copper concentrate using the fusion

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ICDD V55_28 Strategy of Fusion Bead Correction in XRF Analysis of Powders