SPECTROPHOTOMETRIC AND INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION SPECTROMETRIC DETERMINATION OF TITANIUM IN ILMENITES AFTER RAPID DISSOLUTION WITH PHOSPHORIC-ACID

The use of 85% phosphoric acid in borosilicate conical flasks for the dissolution of ilmenites at 230 +/- 10 degrees C is reported. The samp les were quantitatively dissolved in less than 13 min. Titanium was de termined by both spectrophotometry and inductively coupled plasma atom ic emission spectrometry ICP-AES. Vanadium and iron were determined by ICP-AES. In several samples of ilmenites analyzed, the TiO2 concentra tion was in the range 10.6-57.5% and those of FeO and V2O5 were in the ranges 31.6-51.4% and 0.39-1.32%, respectively. In the spectrophotome tric method, vanadium interference occurs only when the Ti/V concentra tion ratio is <4. In all samples analyzed this ratio was around 12, re sulting in no interferences due to vanadium. Hence the ilmenite dissol ution procedure using phosphoric acid was compatible with titanium qua ntification by both spectrophotometry and ICP-AES.