Fast chemical imaging of refractories at macroscopic scale using Laser-Induced Breakdown Spectroscopy (LIBS)

Laser-Induced Breakdown Spectroscopy (LIBS) is growingly used for fast analysis of solid materials in various industrial applications including recycling/sorting, environment, mining industry, metallurgy, pharmaceutics, ... With this technique, a single high-energy laser pulse is focused on the surface of the target to vaporize the material and transform the vapor into a hot plasma that is analyzed spectroscopically. Emission lines from the chemical species in the laser-induced plasma (ions, atoms and molecules) are then used to get the chemical composition of the probed area, which is determined by the laser spot size. Chemical imaging with LIBS is performed based on the hyperspectral dataset that can be acquired in minutes by scanning the laser spot over the sample surface. Our project aimed at developing a LIBS system with imaging capability and assessing its application to refractories and raw materials. Preliminary results show interesting insights into the use of LIBS for fast chemical imaging at macroscopic scale (50 to 500 µm pixel resolution, up to 100 x 200 mm area size) of a variety of materials with excellent detectability, especially for light and alkali elements. LIBS appears as an efficient technique for screening large areas or sample sets. In addition, color images of plasma-induced luminescence can be acquired in parallel with LIBS analysis without extra analytical time, which provides additional information for material characterization.

The European Regional Development Fund (ERDF) and Wallonia region are gratefully acknowledged for their financial support to this research project: MATSUB (IMAWA Portfolio)