Experimental study of gold (III) ion electrochemical sorption/desorption regularities

Abstract

For the Republic of Kazakhstan as a country with developed mining and processing sectors, a topical issue is to develop the areas of knowledge aimed at improving and refining methods and technologies for comprehensive mineral processing including for the more complete extraction of precious metals. The necessity of these studies is determined by the high loss of precious metals during their processing and separation and the need to improve the process of their concentration. Advances in the field of carbon nanomaterials offer great prospects for improving existing technologies for the precious metal extraction from waste solutions and pulps. This paper covers the comprehensive studies into the influence of the solution flow rates, pH and the presence of ions of other metals on the extraction of gold on a carbon nanostructured material consisting of rice husk with its further regeneration and reuse. It was found that the highest gold (III) ion recovery is observed at pH ~ 2. The gold recovery efficiency was studied in the combined presence of copper, nickel and silver. The dependence of the electrochemical reduction sorption of gold on the flow rate of solutions was investigated. It was found that the optimal solution flow rate is 10 ml/min. The sorption capacity of a sorbent based on carbonized rice husk was calculated. The investigation of electrochemical sorption/desorption of gold (III) ions showed that the desorption process runs better in an acetone + water + NaOH mixture with a desorption degree of 96 %. This demonstrates the possibility of regenerating the electrode carbon material for reuse. The results obtained can be used to optimize the processes of extraction of precious metals from their solutions.