As global demand for sustainable energy storage increases, lithium iron phosphate (LFP) cathodes have attracted growing attention due to their high safety, long cycle life, and reliance on relatively abundant raw materials. To support sustainable and scalable LFP production, it is essential to understand the full supply chain from mining to battery-grade precursor preparation. This review examines the extraction, beneficiation, processing, and purification of phosphorus, iron, and lithium ores, tracing their conversion into purified iron (≥99 wt.%) and phosphoric acid (≥85 wt.%) suitable for battery applications. Particular attention is given to purification technologies, the process parameters that control material quality and impurity content, and methods capable of reaching impurity removal efficiencies as high as 99.9–100%. In addition, the review discusses different production routes for key iron-based precursors, including iron phosphate (FePO₄) and iron sulfate (FeSO₄). While battery recycling offers strong potential for material recovery, further optimization of ore extraction and refining remains necessary to improve process efficiency and reduce environmental impact. Overall, these insights provide guidance for future development of sustainable, efficient, and large-scale LFP cathode production to support the global energy transition.