Recovery Of Gold From Gold-Copper And Gold-Cobalt Cyanide Based Electroplating Solutions By Using An Electrogenerative Process

• Main Author: Aminuddin, Norazlina
• Format: Thesis
• Language: English
• Published: 2011
• Subjects: QD1-999 Chemistry
• Online Access: http://eprints.usm.my/40907/1/Norazlina_Bt_Aminuddin_24MS_HJ.pdf; http://eprints.usm.my/40907/

The recovery of gold from gold-copper and gold-cobalt cyanide based electroplating solutions using an electrogenerative process was carried out with a batch cell. The cathodes that had been used for this studied were porous graphite and reticulated vitreous carbon (RVC) while for anode was zinc foil. The influence of the presence of copper and cobalt metal ions toward gold deposition was studied by cyclic voltammetry. The recovery studies were carried out for 6 hours during which the gold in the bath solutions was determined by atomic absorption spectroscopy at regular intervals. The surface morphology and purity of the deposited gold were determined using scanning electron microscopy – energy dispersive X-ray spectrometry (SEM-EDX). More than 99% of gold was recovered after 6 h of operation using non-activated cathodes. It takes 3 h to recover more than 99 % of gold using activated cathodes. Activated RVC is a superior cathode material having the highest recovery rate compared to activated porous graphite, stainless steel and copper sheet. More gold is recovered when using a greater electrode surface area that is exposed to the catholyte solution. The results also show that at pH greater than 10 and with higher free cyanide concentration, copper will not be co-deposited with the gold.