Recovery of Gold from Waste Jute Material - A Case Study
Recovery of gold from aurocyanide complex solutions by zinc precipitation requires a relatively clear solution for effective precipitation of the gold. Goldfields Ghana Limited (GGL), one of the companies in Ghana, which used zinc precipitation in its former treatment plant to recover gold from solution, clarified the gold pregnant solution by passing it through sand vats, which were lined with jute materials. The jute liners in the sand vats, intended to remove suspended solids from solution, were found to have adsorbed gold in the order of 2.27 g/t. These liners have been accumulated over the years as waste.
This paper investigates the feasibility of extracting the gold locked up in the waste jute material. Samples of the waste jute material were collected at uniform intervals from the surface of the waste dump, thermally oxidized to produce ash and leached with cyanide. Gold recovery from the jute ash into solution after 20 hours cyanidation was 97.92%. It was also established that favourable gold recovery was obtainable by leaching the jute ash mixed with the ore being treated at the plant. At GGL, where it is estimated that about 500 tonnes of the waste jute material has been accumulated over 118 years of operation of the zinc precipitation plant, about 1.1343 kg of gold can be leached into solution and recovered to increase the total gold recovered by the company. The implication is that in processing plants where this technology is applied, the waste jute accumulating over a period of time could be occasionally treated to recover its gold content as an additional income.
Ghana Mining Journal Vol. 9 2007: pp. 50-53