| Abstract: | Interaction of metallic gold with (Na, K)Cl salt melts was investigated by the weight-loss method at 700–1000°C using silica glass ampoules. Interaction was not detected in hermetic evacuated ampoules over the whole temperature interval and even after the addition of 5 wt % Na2SO4 as a possible oxidizer to the salt. Gold solubility increased sharply in open ampoules, but this was accompanied by the evaporation of salt melt and, possibly, AuClx. The limiting gold solubility in the salt melt at 860°C was estimated as 1 wt % or 10000 ppm. The model of gold transport in a gas phase during magmatic degassing invokes shallow gold extraction by salt melt, melt evaporation, and removal of precipitated metallic particles by the gas phase. |
