gold sulfate is a moderately water and acid soluble sulfate compound of the chemical formula AuSO4 or more correctly Au2(SO4)2. It is a common source for a range of industrial applications and may be used to support the manufacturing processes of solar cells, batteries and other sulfide-related devices.
In geological settings of magmatic-hydrothermal, porphyry-epithermal and metamorphic (orogenic and intrusion related) gold deposits, the capacity of fluids to transport and precipitate gold is a crucial factor in the economic concentration and distribution of the metal across lithosphere. The capacity of fluids to transport gold depends on the temperature (T), pressure (P), pH, and redox potential (fO2) that they generate and evolve during ore deposition. In particular, the presence of S-3S3-, a major trisulfur ion, has long been regarded as one of the primary carriers of gold in hydrothermal fluids (1-4).
S-3S3- synthesis is highly sensitive to small changes in T, P, fO2, and S content during the evolution of a fluid: Cooling of a typical porphyry fluid carrying 10 ppm Au by only 50 degC, from 600 degC to 550 degC (7), will precipitate 90% of its dissolved Au through the breakdown of S-3S3- and its Au(HS)S-3Au(HS)S3- species, as shown in Fig. 2A.
These findings have important consequences for the exploration of gold and metal-rich ores. They evoke a number of enigmatic features in gold geochemistry, such as large variations in Au concentrations within ores and pronounced anomalies in the Au-to-Cu, Zn-Ag, and Pb-Au ratios of ores and veins that are associated with high-grade epithermal mineral veins (1-4, 5-6, 7). Moreover, the selective affinity of S-3S3- for Au, and possibly other sulfur-loving metals and metalloids, can explain why some high-grade orogenic gold deposits, such as Carlin, have distinct signatures.
