Semiempirical model for correction of matrix effects in on‐stream x‐ray fluorescence analysis

Abstract

A semiempirical non-linear model for the on-stream x-ray fluorescence analysis of slurries was developed, utilizing the intensities of fluorescent and scattered radiation. It is assumed that the slurry consists of liquid and solid parts. All components of the solids except the elements to be measured are considered to be a filling substance with an approximately constant absorption coefficient. The model permits the calculation of the elemental weight fractions in the solids without the need for the determination of the solid content in the slurry. The accuracy and reproducibility of the method are compared with those of existing multiple regression models. A non-linear expression for the determination of the solid content in the slurry using the intensity of scattered x-radiation is proposed and compared with some polynomial regression models. 1 Bp = BL + Cs (Bf -BL) + 1 CABj -Bf) [ a liquid phase of weight fraction 1 -C,. The weight = B L + CSB,

Direct chemical characterisation of clay suspensions by WD-XRF

“…In this particular case it was not necessary to use interelement coefficients, just as in cases reported in the literature,4 which indicate that the matrix effects are negligible in the X‐ray fluorescence analysis of a small number of elements within a narrow concentration range; the elements in Tables 8 and 9 are expressed as oxides because it is the normal state how they are in the analysed samples.…”

“…The results obtained show that there was no appreciable variation in the measurement with variations in solids content in the 66–69% range, this being the range in which clay slurries for ceramic tile manufacture may be assumed to lie. Although this finding might stem from the fact that only a small fraction of the suspension was analysed, as has been noted in the literature,4 it enables WD‐XRF measurements to be made under these variable conditions.…”

“…All the studied materials had a particle size distribution in which 90% of the particles were smaller than 40 µm. According to the literature,4, 5 this grain size is small enough for the particle size effect to be neglected in on‐stream X‐ray fluorescence analysis.…”

“…In a survey of literature, various studies are found that analysed different types of suspensions, such as coal minerals, using Compton radiation 2. In other papers, a method was put forward for suspension analysis by WD‐XRF using fluorescent, and coherent and incoherent radiation to calculate the suspension solids content and element concentrations 3, 4. Another study used total reflection X‐ray fluorescence spectrometry with an internal standard, in which particle size and solids content were taken into account 5.…”