Noble Metal Speciations in Hydrothermal Sulphides

A significant part of the primary gold reserves in world is contained sulphide ores, many types which are refractory processing. The deposits ores will be main potential source production future. and silver can associated with micro- nano-sized inclusions Au Ag minerals as well isomorphous, adsorbed other species noble metals (NM) not thoroughly investigated. For gold-bearing Urals, distribution forms NM were studied base metal sulphides by laser ablation-inductively coupled plasma mass spectrometry neutron activation analysis. Composition arsenopyrite As-pyrite, proper identified using electron probe microanalysis. ratio various invisible gold—which includes nanoparticles chemically bound gold—in discussed. Observations also performed on about 120 synthetic crystals NM-doped sphalerite greenockite. In VMS increasing metamorphism, CAu CAg major (sphalerite, chalcopyrite, pyrite) generally decrease. portion decreases —from ~65–85% to ~35–60% total Au. As a result recrystallisation enlarged passes into visible state native gold, Au-Ag tellurides sulphides. usually <30% bulk