The enrichment of the low-grade-phosphate ore of the Tozeur-Nefta deposit was investigated using scrubbing-attrition, ball grinding and anionic/cationic reverse flotation in order to separate phosphate-rich particles from their gangue. The choice of the beneficiation process was based on the petrographic, mineralogical and chemical analyses. The petrographic and mineralogical studies have revealed the abundance of phosphatic (carbonate-fluorapatite-CFA) particles) coupled with carbonates (calcite, dolomite,) and silicates (quartz, illite, kaolonite) that constitute the (endo/exo) gangue of these ores. Chemical analysis has demonstrated that the raw phosphate sample contains low amounts of P₂O₅ (12.0%) and MgO (4.9%) and high amounts of CaO (40.7%) and SiO₂ (20.5%). Microscopic observation/counting has shown that the release mesh occurs in the 71–315 μm size. Scrubbing-attrition, grinding and reverse flotation methods were applied to the +71μm fraction. Scrubbing-attrition tests of the 71–315 μm fraction have helped to improve the P₂O₅ grade to 15.5%. Ball-grinding tests were used to reduce the coarse fraction +315 μm. Grounded materials were sieved to 71–315 μm and combined with the scrubbed fraction in the flotation feed. Reverse-flotation tests of the phosphate-rich fraction (71–315 μm) have helped to improve the P₂O₅ grade to 27.1%, with a recovery rate of 92.4%.

Because of the increase in demand for phosphate products with the depletion of phosphate reserves in the world, more attention is paid to the low-grade phosphate ores (13% P₂O₅) and the generated tailings. The present work consists of a detailed study of the low-grade phosphate ore (12.01% P₂O₅) of the Tozeur-Nefta deposit. It aims at elaborating the appropriate beneficiation process to improve the content of P₂O₅. The petrographic study has revealed the abundance of phosphatic (carbonate-fluorapatite-CFA) particles (sub-rounded pellets, ooliths, bone debris) coupled with carbonates (calcite, dolomite, ankerite) and silicates (quartz, illite, kaolonite) that make the (endo/exo) gangue of these ores. The microscopic observation/counting has shown that the phosphate-rich fraction (release mesh) occurs in the 71–315 μm size. Chemical analysis has demonstrated that the raw phosphate sample contains low amounts of P₂O₅ (12.01%) and MgO (4.95%) and high amounts of CaO (40.75%) and SiO₂ (20.5%). Sizing, scrubbing-attrition, grinding and froth flotation methods were applied to the +71 μm fraction in order to separate phosphate-rich particles from their gangue. Scrubbing-attrition tests of the 71–315 μm fraction has helped to improve the P₂O₅ grade to 15.53%. Ball-grinding tests were used to reduce the coarse fraction +315 μm. Grounded materials were sieved to 71–315 μm and combined altogether with the scrubbed fraction to the flotation feed. Reverse-flotation tests of the phosphate-rich fraction (71–315 μm) have helped to improve the P₂O₅ grade to 27.13%, with a recovery rate of 92.38%.