Interferences in the Determination of Titanium in Silicate Rocks and Venezuelan Laterites by Atomic Absorption Spectroscopy

A method to overcome the numerous interferences present for the determination of titanium in Venezuelan laterites and bauxites has been adopted. The technique is based on dissolving the sample in the HF-H₃BO₃ matrix. The advantages of using this system are discussed. After the sample is decomposed in this system, 1 part of 2000 ppm of Al, Si, and Fe in the same system is added to 9 parts of the decomposition solution. The atomic absorption determination is employed using the conventional standard curve method for the 364.3 nm line. A comparison of this method with x-ray fluorescence and colorimetry is given in search of one method for routine batch determinations. Interference studies of aluminium, silicon, and iron, the common major elements in Venezuelan laterites and bauxites, conclude that both aluminum and iron greatly affect the absorption signal for titanium. The proposed method, as well as x-ray fluorescence and colorimetry, was applied to standard reference rocks and a preliminary profile of Venezuelan laterites (ferrugineous bauxites).