Apatite is anOrganophosphorus mixture importantExtraction host mineral for rare earthRare Earth metalsMetal (REMs); however, it has received comparatively less attention than other REM-bearing minerals such as monazite, bastnasite, and xenotime. Herein, we present laboratory-scale results on REMs’ recovery from an apatite ore leached solutionSolution in nitric acid via solvent extractionSolvent extraction using an organophosphorusOrganophosphorus mixture extractant mixture. Key process parameters like the concentrations of H+ and NO3– ions in the aqueous phase and the extractant concentration in the organic phase were optimized to achieve maximum extractionExtraction of REMs. The results showed that increasing NO3– ions in the aqueous phase and extractant concentration in the organic phase enhanced REMs’ distribution into the organic phase. Conversely, higher proton concentration suppressed the extractionExtraction efficiency. Additionally, the composition ratio of the organophosphorus extractant mixture exhibited a notable influence on REMs’ extractionExtraction. The findings of this study will support the scale-up of the process for recovering high-purity REMs’ saltSalts.