Comprehensive Recovery of Phosphorus and Vanadium from a Low-Grade Phosphorus–Vanadium Ore in Xinjiang, China

To address the marked differences in the host phases of phosphorus and vanadium, severe ore sliming, and the difficulty of synergistic recovery from the low-grade phosphorus–vanadium-associated ore in Mazharweina, Xinjiang, process mineralogical analysis, phosphorus flotation condition tests, and acid leaching-solvent extraction tests were conducted to investigate phosphorus and vanadium recovery from this ore. The results showed that the P2O5 and V2O5 grades of the raw ore were 16.71% and 0.798%, respectively. Phosphorus occurred mainly in collophane, whereas vanadium did not form independent minerals and was mainly dispersed in carriers such as mica, argillaceous silicates, and colloidal limonite. P2O5 and V2O5 showed no obvious natural enrichment in any particle-size fraction, and effective separation of P and V could not be achieved by particle-size classification. Therefore, a pre-desliming-direct phosphorus flotation process was adopted. Under the conditions of a grinding fineness of 80% passing −74 μm and an EM-C2 dosage of 1400 g/t, closed-circuit flotation comprising one roughing, one scavenging, and three cleaning stages produced a phosphate concentrate with a P2O5 grade of 28.32% and a recovery of 59.50%, while the P2O5 grade of the tailings decreased to 1.52%. Vanadium was mainly enriched in the slime and dephosphorization tailings. At a liquid-to-solid ratio of 8:1, an H2SO4 mass concentration of 250 g/L, and a leaching time of 8 h, the V2O5 leaching rate from the slime was 77.83%. After N235 extraction, Na2CO3 stripping, vanadium precipitation, and calcination of the leachate, a vanadium product with a V2O5 purity of 98.42% was obtained, with an overall recovery from the raw ore of 63.83%. The results demonstrate the feasibility of combining phosphorus flotation with hydrometallurgical treatment of the slime and dephosphorization tailings for the comprehensive recovery of phosphorus and vanadium from this complex phosphorus–vanadium ore.