DIBK-based solvent extraction and quantification of U, Th, Zr and REEs in beach sand samples using ICP-OES

A simple and efficient solvent extraction method using di-isobutyl ketone (DIBK) in hydrochloric acid medium has been used for the separation of iron (Fe) in beach sand samples originating from beach placer deposits for the determination of economically important elements like uranium (U), thorium (Th), zirconium (Zr) and rare earth elements (REE). Quartz being the main constituent of beach sand samples, a notable and variable concentration of ilmenite, leucoxene, garnet, sillimanite, rutile, monazite and zircon are commonly found in the beach sand deposits. The presence of high amount of iron present in the beach sand samples causes spectral interferences in the analysis of rare earth elements and actinides (Th and U) using inductively coupled plasma optical emission spectrometry (ICP-OES). The present study establishes a reliable approach for Fe removal through DIBK extraction, thereby minimizing analytical interferences. The extraction parameters were optimized for achieving over 95% removal of Fe in a single extraction using DIBK. The method was validated through spiking experiments and comparison with established standardized separation techniques, showing excellent agreement with reported values. Application of the procedure to beach sand samples from two Indian deposits enabled accurate determination of U, Th, Zr, and REEs. The method offers a precise, sensitive, and reproducible analytical tool for trace element determination in Fe-rich matrices.