AN X-RAY-DIFFRACTION METHOD FOR SEMIQUANTITATIVE MINERALOGICAL ANALYSIS OF CHILEAN NITRATE ORE

Computer analysis of X-ray diffraction (XRD) data provides a simple me thod for determining the semiquantitative mineralogical composition of naturally occurring mixtures of saline minerals. The method herein de scribed was adapted from a computer program for the study of mixtures of naturally occurring clay minerals. The prog ram evaluates the relat ive intensities of selected diagnostic peaks for the minerals in a giv en mixture, and then calculates the relative concentrations of these m inerals. The method requires precise calibration of XRD data for the m inerals to be studied and selection of diffraction peaks that minimize inter-compound interferences. The calculated relative abundances are sufficiently accurate for direct comparison with bulk chemical analyse s of naturally occurring saline mineral 'assemblages.