Assessing rare earth elements in Indian coal ash using Westcott formalism in NAA and leaching studies

Abstract

This study employs Westcott formalism coupled with the internal monostandard approach in k₀-NAA to assess Rare Earth Elements (REEs) in Indian coal ash samples. This method mitigates neutron flux perturbations during irradiation and enables in situ detector efficiency calibration for quantitative analysis. Deviations in thermal capture cross-sections for non-1/v nuclides in REEs were addressed using the Westcott g(T_n)-factor obtained from the ENDF/B-VIII.0 data. REEs content in Indian coal ash was found to be 350–500 mg kg⁻¹, aligning with global standards. Leaching feasibility for medium-lived REEs with hydrochloric acid was demonstrated, supporting effective recovery. These findings suggest Indian coal ash as a potential secondary resource for REEs amid global supply challenges.