Mineralogical characterization of REE mineralization in Norra Kärr alkaline complex, Sweden

Alkaline complexes comprise one of the most promising future sources for rare earth element supply. They are particularly enriched in heavy rare earth elements. However, the often complex and highly unusual mineralogy of REE-enriched ores from alkaline complexes pose particular challenges for beneficiation. A geometallurgical approach is required to quantify mineralogical and textural diversity and variability. Based on a geometallurgical model, a suitable approach to beneficiation can be developed. Scanning electron microscope (SEM)-based image analysis can be used to characterize ores as well as beneficiation products. A wide range of tangible mineralogical and textural parameters are constrained for every ore type, including mineral abundance, grain size, and liberation. SEM-based image analysis combined with a quantitative analysis of the chemical composition of the ore minerals is illustrated here for the case of the Norra Kärr alkaline complex, Sweden. Current research focuses on quantitative mineralogical and textural constraints for different lithological domains recognized in the HREE-Zrmineralized zones of the complex. Based on the results, a geometallurgical model will be developed that will be based on the processing characteristics of the different portions of the mineralized zones.