Simulation of the Heating of Microdispersed Gold and Silver Particles in Various Media

Abstract

The size distribution of gold and silver particles in ores of various types and technogenic formations has been studied using a scanning electron microscope. The Au particle sizes are found to be mainly in the range less than 1–2 μm. The Ag particle sizes are in the range less than 10 μm. For example, the main fraction of gold particles in copper–pyrite ore is 0.01–0.5 and 0.5–1.0 μm. The problem of heating an ensemble of dispersed gold and silver particles in various mineral media has been solved using numerical methods and the Matlab software package. A temperature gradient is shown to exist over the cross section of both solid and liquid dispersed metal particles in all media during the heating period. Consequently, Au and Ag droplets move in pores under the action of the thermocapillary effect. At a high gold and silver content, contact and subsequent merging of droplets (coagulation) is possible. At a low content, this is unlikely, as studies of silicate–carbonate ore have shown; this is confirmed experimentally.