United States Geological Survey (USGS)

Sourcing sufficient quantities of precursor chemicals at the appropriate purity can be a major challenge for scaling up production of advanced materials containing critical and/or strategic elements (many of which are imported). The USGS Minerals Program has been applying several innovative technologies for in-situ quantification of the amounts and forms of critical and/or strategic metals in potential domestic sources including historic ores, unconventional mineral deposits, and various types of solid and liquid waste streams.

A team of researchers in the USGS Minerals Program is improving and expanding the available methods for direct quantification of hexavalent chromium [Cr(VI)] in solids using innovative techniques. Synchrotron-based X-ray absorption spectroscopy (XAS) is currently the best available technique for direct quantification of Cr(VI) in solids at trace (ppm) levels and in phases lacking long-range atomic order. The USGS group has developed semi-automated peak-fitting methods to overcome user bias in this approach to quantifying Cr(VI).