X-RAY-FLUORESCENCE ANALYSIS OF FERROALLOYS - DEVELOPMENT OF METHODS FOR THE PREPARATION OF TEST AND CALIBRATION SAMPLES

Methods were developed with a view to evaluating various sample prepar ation systems for use with X-ray fluorescence techniques in order to d etermine the major and minor components of ferroalloys, which are used as alloy-forming elements in steel making. The methods were compared in terms of simplicity and rapidity and these parameters were assessed in relation to the accuracy and precision of the results. The samples were prepared in three formats: metal samples, by dilution with iron and remelting in an induction furnace; pellets, by direct compaction o f the ground material, and beads, by alkaline melting of the pre-oxidi zed sample. The tests used to optimize these methods were conducted wi th commercial ferroalloys, previously characterized by employing wet c hemical and spectroscopic methods. Reproducibility and precision studi es were conducted on samples obtained using each of the three sample p reparation systems. The precisions (relative standard deviations) of m ajor element determinations were <0.8, <1.0 and <0.5% and those for mi nor elements were <5, <5 and <3% for metal samples, pellets and beads, respectively. The accuracy of the methods was checked by analysing re ference materials of each type of ferroalloy.