GOLD ACCUMULATION ON ARSENOPYRITE

Abstract

We experimentally investigated the process of gold precipitation on arsenopyrite - its kinetics and temperature dependence, S/As ratio and grain size. To clarify the role of arsenic, we studied its precipitation in the pyrite-arsenopyrite-lollingite series. The work was done in autoclaves with 0.001N to 0.0001N NaAuCl at 20° to 150° C. The data may help to explain certain trends of gold accumulation in natural deposits. Its preferential accumulation in arsenopyrite, particularly in pyrite-arsenopyrite aggregates, could reflect the kinetics of this process and the more active role of arsenopyrite as a gold precipitor. The established effect of arsenic on the accumulation of gold agrees well with the high degree of correlation between these elements in various gold ore associations, particularly in ore veinlet-disseminated sulfide ores in siliceous-carbonaceous rocks.