Ce distribution, speciation and redox in Moroccan sedimentary phosphate ores

Phosphorus is a critical resource required for the production of agricultural fertilizers and is mainly produced from sedimentary phosphates rocks. These rocks usually contain rare earth elements, and potentially become a future REE reserves. Among the various REE, the cerium (Ce) shows relatively high concentration and variable negative anomaly indicative of the oxidation of Ce3+ into Ce4+ due to either microbial activity and/or different conditions (redox, pH, depth). Hence, in this proposal, we wish to characterize the in-situ distribution, speciation, and redox of Ce in phosphate rock from Morocco using a combination of μ-XRF, HR-XANES and HR-EXAFS to elucidate, i) the in-situ distribution and the concentration of Ce, ii) the Ce bearing minerals and the enrichment process, iii) the speciation of Ce (fixation mode, oxidation state). Results will guide the possible REE recovery, as well as to understand the geochemistry of enrichments to better assess the deposition conditions.