Spectrochemical Detection and Monitoring of Rare Earth Elements during Extraction from Coal/Coal Byproducts (Topic 17d)

Separation and concentration of rare earth elements (REEs) from coal and coal (mining and combustion) byproducts is a growing technology. DOE’s interest is evidenced by the establishment of several programs in REE recovery during recent years. In order to achieve industrial scale and reliability, process control and process development need analytical tools that can provide rapid and accurate feedback on elemental concentrations at various process stages. The current analytical chemistry methods employed, such as ICP-MS, while sensitive and accurate, are time consuming (requiring sample preparation) and expensive. The aim of the proposed research is to develop a laser-induced breakdown spectroscopy (LIBS) instrument that pushes the bounds of performance of current portable hardware and LIBS methodologies in order to monitor REE recovery processes from the very high concentration product to the very low concentration feedstock. LIBS is a technique that lends itself well to the detection of atomic composition to ppm levels. The method is applicable to nearly any material make-up or phase, and conducive to generation of low cost small, portable, and continuous process monitoring systems. Specifically, LIBS is capable of monitoring all of the most important REEs; Y, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb as well as important matrix elements (e.g. Al, Ca, Fe, Si, P, Ti, V). PSI will use its strong expertise in both the development of cost-effective, high recovery chemical methods for REE extraction, and in the development of optical sensor technologies and systems, to rapidly measure REE content of solid and solution samples within minutes, and with very little sample preparation. Phase I will perform an optimization of the proposed enhanced LIBS methodology via the design, construction, and exercise of a laboratory prototype instrument. This Phase will also quantify the ability of the technique to monitor different REEs, at different points in the REE enrichment process, in different sample morphologies/phases, and for benchtop hardware versus the portable spectroscopic hardware envisioned for an affordable at-line diagnostic instrument. Rare earth elements (REEs) are a valuable commodity for many industries. Methods for extraction and concentration of these materials from coal, coal ash, and coal mining byproducts are developing technologies for obtaining these materials from inexpensive feedstocks. The proposed sensor technology will enable optimized physical and chemical processes with higher efficiencies, increased REE yields, and higher REE concentration final products. Additional applications include: crude oil source fingerprinting by metals analysis, coal / ash content monitoring in slag and combustion particulates, recycling of electronic, magnetic, and nuclear waste, residual metals monitoring in catalytic processes (pharma), and process monitoring in the steel, glass, mining, magnet, lighting element and catalytic converter industries.