Directional conversion and removal of complex phosphorus compounds from acidic leaching solution containing vanadium

Deep phosphorus removal from acidic leaching solution containing vanadium is a challenging problem due to the formation of complex phosphorus compounds. This problem can be possibly solved by proposed hydrogen peroxide coupled with iron-aluminum mixed salts, in which complex phosphorus compounds can be directionally converted and removed. Under the optimal conditions (the mole ratio of Fe/Al/P at 1.25:0.40:1.00, initial pH value at 5.00, reaction time for 1 h, reaction temperature at 70 degrees C, the mole ratio of H2O2/P of 20:1), the phosphorus removal efficiency and vanadium loss rate were 99.29 % and 5.96 %, respectively. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy were used for characterization analyses of phosphorus in the removal products. Results indicated that hydroxyl radicals (center dot OH) made the directional conversion of complex phosphate radicals to PO43-. Complex phosphorus compounds were eventually removed in the form of PO43-. An efficient phosphorus removal progress was obtained. The concentration of residual phosphorus in solution was only 3.7 mg/L, and the mole ratio of vanadium to phosphorus in solution changed from 18 to 2353.