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

•Thermal and chemical pretreatment methods improve the REE leaching characteristics of bituminous coal sources.•600oC Roasting with no chemicals decomposes organic matter, dehydroxalates clays, releases and breaks down some REE minerals.•Direct acid baking partially dehydroxalates clays, releases and breaks down liberated or partially liberated REE minerals.•Applying both roasting and acid baking decomposes organic matter, dehydroxalates clays, releases and breaks down REE minerals.•Roasting and acid baking combined provides nearly 80% recovery of light and heavy REEs from bituminous coal waste.