Recovery Of Gold From Chloride Containing Solution Using Electrogenerative Method
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Date
2017-12
Authors
Roslan, Nurul Ashikin
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Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
The electrogenerative system that was developed as an alternative method to the electrochemical recovery of gold from chloride solution is presented. In this process, a chemical reaction takes place spontaneously since it does not require any external supply of energy. A static batch cell operating in electrogenerative mode is used in gold recovery from chloride solutions. In this present work, a gold chloride solution was used to replace cyanide solution due to its toxicity. Gold chloride solution is also a suitable alternative lixiviants which has stimulated new developments in extraction technology combined with environmental concern. Two types of electrodes were used which are three-dimensional cathode materials namely reticulated vitreous carbon (RVC) and porous graphite (PG), and two-dimensional cathode stainless steel plates coupled with a zinc anode. This system showed > 90% of gold being recovered within 3h operation. Activated RVC served as the best
cathode material having the highest recovery rate with > 90% of gold being recovered in 1 h operation but in acidic condition (pH 3.00 ± 0.11). An electrogenerative flow-through cell with activated cathodes was developed too. The performance of the cell was evaluated with initial gold concentration of 50, 100, 250 and 500 mg L-1 and different types of cathode materials. The result revealed > 99% of gold was recovered within 2 h in acidic solution, an optimum flow rate of 50 mL min-1 and deoxygenated state. The suitable number of flow cells used in the system was investigated and it was discovered that a single flow cell system is more effective compared to the two flow cells system in series. Besides, flow-through cell system also was applied to recover gold from an E-waste solution. More than 99% gold in 100 mg L–1 of initial gold chloride concentration was recovered within 2h of operation.
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Keywords
Recovery of gold from chloride containing solution , using electrogenerative method