Application of Raman spectroscopy to the flotation process of fluorite

摘要

Exact knowledge of the content of the various components in a flotation system is critical in both product analysis and process control. In the present work, FT-Raman spectroscopy was successfully applied to an industrial fluorite flotation system for quantification of calcium fluoride (CaF_2). In a first step, an artificial model system consisting of CaF_2, barium sulphate and silica was set up to test feasibility of FT-Raman spectroscopy and to generate a calibration curve. An empirical model was developed, which incorporates effects of particle size on Raman shift and peak area, so that a CaF_2 quantification is feasible independent of particle size. Conversely, the empirical model provides information about the approximate particle size in the analysed sample. A cross-validation using X-ray fluorescence spectroscopy showed excellent quantification of CaF_2 in seven industrial fluorite samples with CaF_2 weight fraction in a range from 7 % to 98 % with absolute deviations of less than 5 %. In a first laboratory batch-flotation experiment, the CaF_2 content of the froth product could be quantified successfully providing additional information about the approximate median particle size of the concentrate, making FT-Raman spectroscopy superior to commonly applied X-ray fluorescence spectroscopy.