Many technologies relied upon by modern society, such as portable electronics and renewable energy systems, require the use of rare-earth elements (REEs). The global demand for REEs is increasing rapidly, and new developments for their recovery from secondary sources have been sparked. Phosphogypsum (PG), the byproduct of phosphoric acid production, is considered a secondary source for REEs. This research builds upon previous studies investigating the hydrometallurgical recovery of REEs from PG via acid leaching. The current study put the emphasis on developing processes to recover consumed acid in the leaching process. Here we propose an innovative process that relies upon the addition of calcium sulfate anhydrite seeds to the leached solution. Anhydrite seeding results in the rejection of calcium sulfate from the leached solution and reduced calcium concentration. Because the REE leaching efficiency is controlled by the solubility limit of PG, which is correlated to the calcium concentration, the drop increases the potential of the solution to leach more REEs. Thus, the solution can be recycled and reused as the leachant in subsequent leaching steps. This novel process is a promising technique to recycle consumed acid, lowering the operating costs and improving the efficiency.