Rare earth elementsRare Earth Element (REE) (REEs) are critical in numerous high-tech applications as the world moves toward sustainableSustainable and clean technologies. Various burgeoning sectors, including water treatment, medical science, and electrical engineering, increasingly rely on REE resources, with ~ 95% of global reserves associated with the minerals monaziteMonazite, bastnaesiteBastnaesite, and xenotimeXenotime. A critical step in processing these REE-bearing minerals is chemically cracking their structures to release REEs for extraction. Acid baking is one of the most widely utilized pretreatment techniques for breaking down mineral structures and producing intermediate compounds that can be effectively leached in subsequent steps. Efficient mineral decomposition varies across REE minerals due to their complex mineralogy, which often includes impuritiesImpurities like iron oxide-hydroxides (e.g., hematite, goethite, magnetite) and radioactive elements such as thorium and uranium, complicating the selectiveSelective extraction of REEs. Adjusting processing conditions to convert REEs into soluble compounds while maintaining impurities in an insoluble state is crucial for minimizing environmental, technical, and economic challenges in downstream processing. This paper aims to address impurity managementImpurity management in acid baking pretreatment techniques by examining the effect of process temperature on the selective extraction of REEs. By investigating the chemistry and extraction behavior of both REEs and impuritiesImpurities during acid baking, this work highlights opportunities for optimizing conditions, with particular emphasis on minimizing environmental impactEnvironmental impact, enhancing economic feasibility, and improving resource efficiency to advance REE recoveryREE recovery practices.