In situ X-ray diffraction studies on the production process of rhenium

Rhenium powder is industrially produced in a two-step reaction by reducing NH4ReO4 with hydrogen at 623 and 1173 K. In this study, both steps of the production process have been investigated via in situ X-ray powder diffraction. Up to 550 K no reaction with hydrogen can be observed. Between 550 K and 623 K poorly crystalline rhenium is formed. Crystallinity is increased during the second step at 1173 K. Annealing under hydrogen or nitrogen provides a comparable product in respect to the examined crystal and real structure parameters independent of the gas atmosphere.

Automated summary

In this study, the production process of rhenium powder was investigated using in situ X-ray powder diffraction. The reaction between rhenium and hydrogen was found to be absent below 550 K, while crystallinity increased at 1173 K. Annealing under hydrogen or nitrogen resulted in comparable products.