Thermodynamics of the xanthoconite-proustite and pyrostilpnite-pyrargyrite phase transition as determined by abrasive stripping voltammetry

✍ Scribed by Birgit Lange; Fritz Scholz; Hans-Joachim Bautsch; Ferdinand Damaschun; Gert Wappler

• Publisher: Springer-Verlag
• Year: 1993
• Tongue: English
• Weight: 621 KB
• Volume: 19
• Category: Article
• ISSN: 0342-1791
• DOI: 10.1007/bf00203189

✦ Synopsis

The electrochemical reduction of xanthoconite, proustite, pyrostilpnite, and pyrargyrite was studied by abrasive stripping voltammetry, a technique which is based upon a preliminary mechanical transfer of trace amounts of the mineral onto the surface of a paraffin impregnated graphite electrode. Because the electrochemical reduction proceeds near to reversibility and is very similar for each pair of minerals, the peak potentials in differential pulse voltammetry can be used to calculate the standard enthalpy of phase transformation of xanthoconite to proustite and of pyrostilpnite to pyrargyrite: o _ A T H(xanth~proust) --35.46_ 14.15 kJ/mol and 0 AT H(pyrostilp~pyrarg)-38.85-[-6.60 k J/tool. These values are not accessible otherwise until now.