Rapid analysis of limestone and dolomite samples by pressed-pellet XRF technique

摘要

A pressed-peilet XRF method is developed for rapid analysis of limestone and dolomite samples. Finely powdered 4.5 g (-200 mesh) of limestone and dolomite is pressed on a boric acid base in a hydraulic press at a pressure of 20-25 tons to obtain an uniform disk of 40-mm diameter. This pellet is irradiated and fluorescence is measured on a Philips WD PW-2400 spectrometer using Rh end window X-ray tube. Eight international standard samples - three original standards, ECRM 782-1 (NIST), Jdo-1 (Japanese dolomite standard), Jls-1 (Japanese limestone standard) and five quartz mixed synthetic standards are used for calibration line. Two international standard samples - SRM 88b (dolomite) and SRM 1C (limestone) (both NIST) are analysed following the proposed method, and the results are quite in agreement with those of recommended values. The method, is routinely being used in Central Chemical Laboratory of Geological Survey of India for analysis of limestone and dolomite samples or any carbonate samples of these nature.