DETERMINATION OF RARE-EARTH ELEMENTS IN TAIWAN MONAZITE BY CHEMICAL NEUTRON-ACTIVATION ANALYSIS

Taiwan monazite is a unique mineral obtained from the heavy sand found in the river floor of Tzuo-suei river and En-suei river. Both rivers are flowing parallel with separated narrow area into the sea at southw estern coast of Taiwan. The characteristic of monazite is that it cont ains considerable rare earth elements (REEs). REEs are considered very useful elements in the local industries and scientific researches suc h as ceramic, semiconductors, and glass optics. In this study, chemica l neutron activation analysis (CNAA) was used to determine the content s of REEs in Taiwan monazite. A few milligram of monazite was digested in the microwave oven for 25 minutes with mixed acid (conc. HNO3 and HClO4). REEs were preconcentrated by hydrated magnesium oxide and CNAA was performed.