Laser Induced Breakdown Spectroscopy for Elemental Process Monitoring of Slurry Streams
The goal of this research program was to develop the method of laser-induced breakdown spectroscopy (LIBS) for applications in the phosphate industry. This would include rapid elemental analysis for P, Mg, Si and Fe in materials at various stages of phosphate mining and processing, using off-line, at-line and on-line measurement approaches. Several experimental systems were developed and evaluated. A research instrument with a high resolution spectrometer and gated, intensified CCD detector was used for initial fundamental studies. Several more compact instruments were then developed and optimized for measurements on powdered phosphate mineral samples. A final version of the compact instrument was field-evaluated. We conclude that, with careful preparation of standards, the method may prove useful for rapid laboratory measurements where accuracy and precision of »200% is acceptable. At-line quantitative analysis may be possible with some automated sampling and sample treatment (grinding and drying). Online quantitative chemical analysis in phosphate slurries does not appear to be practical at this time using LIBS.