Method developmento for elemental chemical characterization of slags, columbite and tantalite by spectrometric methods

Abstract

Brazil has 98.8% of niobium and 33.7% of tantalum reserves, holding a prominent position in the global market for these elements. Extraction occurs from columbite and tantalite minerals and the economically viable mines are often found associated with cassiterite (Sn content ore) in the northern Brazil, including states of Amazonas and Rondônia. These ores also contain rare earth elements, uranium, tungsten, titanium, silicon, and lead in their composition. Due to the commercial interest, the knowledge about chemical composition is imperative to define the commercial value. Spectroanalytical methods have been used to these purpose, however, sample preparation steps are still challenging since requires use of high volume of concentrate acid resulting in a high cost analysis. Due to this, the aim of this research project is the development of a simple method for the elemental chemical characterization of ores and sludge produced from columbite and tantalite residue. Applicability of laser-induced breakdown spectroscopy (LIBS) in the direct determination of Nb, Ta, Pb, and Sn in those sample will be evaluated. For trace and ultra-trace levels inorganic contaminants, methods like inductively coupled plasma optical emission spectrometry (ICP OES), inductively coupled plasma mass spectrometry (ICPMS), and wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) will be used. For this purpose, instrumental parameters will be optimized, and different calibration approaches will be assessed.