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 samples were quantitatively dissolved in less than 13 min. Titanium was determined by both spectrophotometry and inductively coupled plasma atomic emission spectrometry ICP-AES. Vanadium and iron were determined by ICP-AES. In several samples of ilmenites analyzed, the TiO2 concentration 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 spectrophotometric method, vanadium interference occurs only when the Ti/V concentration ratio is <4. In all samples analyzed this ratio was around 12, resulting in no interferences due to vanadium. Hence the ilmenite dissolution procedure using phosphoric acid was compatible with titanium quantification by both spectrophotometry and ICP-AES.