Visible and 'Invisible' Forms of Gold and Silver in the Crystallization Products of Melts in the Fe-S-Ag-Au System: Experimental Data

摘要

The forms of Au and Ag occurrence in the crystallization products of melts in the Fe-S-Ag-Au system depending on the proportions of Fe/S and Ag/Au have been studied at (Fe + S)/(Ag + Au) = 0.1. It is shown that the S-rich systems with S/Fe = 2 contain Au-Ag sulfides and Au-Ag alloys. The systems depleted in S with S/Fe = 1 contain only Au-Ag alloys. The results of XPS provide evidence for the sulfide and metallic components of Au and Ag among the crystallization products of melts in the system studied at S/Fe = 2 and a metallic component with S/Fe = 1. According to the data of electron microprobe analysis, the content of "invisible" forms of noble metals in pyrite and pyrrhotite is < 0.024 wt % for Au and <0.030 wt % for Ag; the contents of "invisible" Au and Ag in troilites are 0.040 +/- 0.013 wt % Au and 0.079 +/- 0.016 wt % Ag.