DETERMINATION OF TRACE AMOUNTS OF RARE-EARTH ELEMENTS BY NEUTRON-ACTIVATION ANALYSIS AFTER PRECONCENTRATION USING HYDRATED MAGNESIUM-OXIDE

A preconcentration method of 13 rare earth elements (REES) was studied for neutron activation ananlysis (NAA). Hydrated magnesium oxide was used as the preconcentration agent to absorb the REES ions from aqueou s solution onto the solid magnesium oxide, which was separated and ana lyzed. It was observed that the langmuir equation for isothermal adsor ption was well obeyed by the REES under the condition studied. The eff iciency of the preconcentration process using hydrated magnesium oxide was critically examined for each of REE and for mixture of REES by pr eparing a known volume of solution containing known amount of trace RE ES NAA was used to analyze REES recovered by the preconcentration proc ess. It was found that the REES recoveries were satisfactory and the p reconcentration process is reliable. There are several resort areas in Taiwan where local people are enjoying its hot spring water. It is ge nerally believed that the hot spring water spa would bring about some sorts of therapeutic functions. method developed above, was applied to analyze the trace amounts of REES in hot spring wale in Taiwan.