Editors: | Kongoli F, Veiga MM, Anderson C |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2015 |
Pages: | 275 pages |
ISBN: | 978-1-987820-27-0 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
In the mining, ore, alluvial, and technogenic fields of the world, the microscopic and nanosized gold, a fraction of which is from 30 to 60% of the entire metal volume, is prevailed. Properties and behavior of the Au particles of such size differ from properties of big particles. It should be considered at developing novel technologies for the microscopic gold recovery. It was revealed that a significant decrease of the molten point is observed for the particles with size of 10 nm; for the particles with radius of 1 nm, the value of aˆ†T becomes very significant. A sharp increase of the diffusion coefficients takes place in the same range of sizes.
The model of the heating process for dispersed gold was developed using the Mathlab software. The time of heating and melting of such particles was calculated. It was determined that there is a variation of temperature along the droplets cross-section while heating the Au dispersed particles. This provides conditions for their movement inside the pores under the action of thermocapillary effect. Liquids, which do not wet the pores surface, such as gold, will be moved to the range of higher temperatures, that is to the surface, if the heat source is situated outside of heated body. Coagulation takes place along the path. As a result, the large Au drops (1 mm and more) were experimentally observed on the surface of the geological materials.
Keywords: dispersive gold, simulation, Mathlab