An acid baking approach to enhance heavy rare earth recovery from bituminous coal-based sources

The recovery of rare earth elements (REEs) from secondary resources, particularly coal-based materials, has recently received attention due to supply and demand imbalance. Research reported date indicates that a high REE can be realized when treating bituminous coal sources using strong acid solutions approximately100 g/L or higher. This study introduces an approach enhance the total (TREE), especially for heavy (HREEs), these at significantly lower concentrations. Based on presence minerals like monazite xenotime, detailed investigation was undertaken quantify three pre-leach treatment methods, i.e., 1) roasting, 2) direct baking, 3) baking after roasting. Roasting tests 600 °C revealed light REEs (LREEs) enhanced while HREEs remained relatively unaffected. LREE HREE values 38.3% 21.3%, respectively, were achieved 50 (0.5 M) sulfuric solution 5% solid concentration temperature 75 2 h. Comparatively, 250 provided substantial increases in approximately 49.4% 53.0%, equivalent dosage. Recoveries maximized 77.0% 79.6% HREE, by roasting followed baking. Similar results obtained second source. Due correlations between Al values, performed kaolinite illite, which prominent clay within source coals. These experiments improvements likely result dehydroxylation clays subsequent release decomposition REE-bearing such as monazite, xenotime zircon.