EARTHポスター発表（Poster：EARTH）

[PE1-034] Reductive adsorption of gold on magnetite particles in hydrochloric acid solution

○JuMi OH¹, KyoungKeun YOO¹, Richard Diaz Alorro² (1. Korea Maritime and Ocean University, 2. Curtin University)

キーワード：gold, reductive adsorption, magnetite, HCl solution

In this study, the recovery of gold ion from hydrochloric acid solution containing gold was performed using magnetite as adsorption media, which could be achieved by electrochemical reduction of gold ion.
The synthesis solution was prepared by adding 0.1g magnetite to 50cm³ hydrochloric acid solution containing 0.05mol/m³ of Au and 10cm³ of NaCl. The effect of pH (2-12), reaction time (3-72hr), initial gold concentration (20-200mg/L) and other impurities (Ni, Cu, Pb) gold adsorption on magnetite particle was investigated.
The gold uptake was about 20% at pH 2-6 and about 40% at pH 8-10, but decreased significantly above pH 10. The sorption of gold ion increased with reaction time. Also, the sorption of gold ion increased proportionally with increasing gold concentration. In order to investigate the possibility of selective recovery of gold in the case of containing other impurities, simulated solution considering leaching of waste PCB with Ni, Cu and Pb was prepared. When gold and other metals have the same concentration, the recovery of other metal ions was less than 3% while gold ion was recovered more than 50%. When the concentrations of other metals are higher than that of gold, the selective recovery of gold was somewhat reduced. The scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDX) analyses showed the presence of Au on the magnetite (Fe₃O₄) surface.
In conclusion, 50% gold adsorption was achieved under the following conditions: 0.05mol/m³ Au, 0.1g magnetite powder, 72hr, 25°C, 250rpm.