X-ray analytical system

A method is given for the on-line analysis of slurries using x-ray fluorescence which allows for corrections due to variations in slurry particle size and for interference from other elements present. The mixture is exposed to a heterochromatic beam of primary x rays that includes wavelengths capable of exciting x ray re-emissions from the mixture at (a) a wavelength characteristic of the element of interest, (b) a soft wavelength different from any wavelength characteristic of the element, and (c) a hard wavelength different from any wavelength characteristic of the element. The intensities of the respective x ray emissions at each of the three wavelengths are measured, and the apparent concentration of the element indicated by the intensity of the re-emission at wavelength (a) is corrected for the influence of the matrix as determined by the intensities at wavelengths (b) and (c)