Preparation of nano gold powder from acid leaching tail solution

According to the unique properties and many applications of nano gold powder, it was prepared from an acid leaching tail solution. The low value residual gold ions existed in acid leaching tail solution in Mouteh gold mine in Iran with fellow heavy metals as pollutants (Fe۲+, Cu۲+, and Zn۲+). Preparation of nano gold particles is achieved by two steps: First, by addition of ammonia as separation step and second by using the suitable reagents for precipitation and extraction step. Control conditions include pH, residence time, temperature, agitation, molar ratio of reducing agents to reagents. The optimum results show that nano gold powder was prepared by temperature of ۲۵۰ °C, urea to gold molar ratio of ۳:۱, and reduction time of ۲۰ min. Also, heat treatment improves dispersion of nano sized gold particles. The properties of gold nano powders were evaluated by SEM, A.A and UV-Vis spectroscopy methods and the size of particles were about ۸۰ to ۹۰ nm.

کلیدواژه ها:

Nano gold powder ، leaching tail ، urea ، Precipitation