A STUDY ON THE RECOVERY OF TITANIUM FROM HYDROFLUORIC-ACID LEACH SOLUTION OF ILMENITE SAND

Pigment grade titanium dioxide (99.9% (wt.) TiO2 and 0.004% (wt.)Fe) was recovered from the hydrofluoric acid leach solution of ilmenite using the following steps: (1) precipitating out the Ti and Fe compounds from fluoride leach solution using sodium hydroxide solution; (2) oxidising Fe (II) to Fe(III) using HNO3 acid; (3) dissolving the solid mass in 7.5 M HCl; (4) extracting most of the Fe(III) by a two-stage methylisobutylketone (MIBK) extraction; (5) adjusting the pH of the aqueous phase to zero in order to extract titanium with di-2-ethylhexylphosphoric acid (D2EHPA) and leave siliceous materials in the aqueous phase; (6) stripping the organic phase with 0.5 M Na2CO3 solution to get a quantitative precipitation of metatitanic acid; and (7) filtration of the aqueous suspension of metatitanic acid, oven-drying and finally ignition at 1000-degrees-C. The overall recovery yield of TiO2 from the leach solution was greater than 92.5% (wt.). The MIBK, HCl and D2EHPA could be recovered and recycled.