USE OF MULTIVARIATE AND NEUTRON-ACTIVATION ANALYSIS ON STUDYING ELEMENT INTERRELATIONSHIPS IN BRAZILIAN PHOSPHORITE

Methods to determine U, Th, and other constituent elements in mineral matrices through Instrumental Neutron Activation Analysis (INAA), have been widely utilized due to their capability to extract a large quant ity of information from small samples. In the present work, an experim ental methodology based on INAA associated to the cluster statistics t echnique was used to determine the uranium concentration and its corre lation with other elements present in the mineral phosphorites from th e northeast region of Brazil. Data for 22 elements including rare-eart h elements are presented. A good correlation between uranium and rare- earth elements is observed. For the transition metals, correlation wit h uranium was not noted.