Gold recovery by way of extraction and adsorption from jeweller's residues

Abstract

The gold residues used in this study were obtained from jewellers in Diyarbakır. Thiourea method was applied in order to take the elemental gold from residues into solution medium. Firstly, the samples were roasted at 600°C for eliminating organic originated structures. After the roasting process, only 60% of starting amount of sample were remained. Secondly, the samples were ground up to-110 mesh and-130 mesh and gold analysis were done on this samples. A preliminary study which determined pH, temperature, the $Fe^{+3}$ and thiourea concentrations were reevaluated by changing solid/liquid ratios. Studies were carried out on samples of 110 mesh and 130 mesh. Solid/liquid ratios were examined. The most suitable extraction yield was found for the solid/liquid ratio of 1/1000 and all the gold was taken into solution. In this study, furthermore, the adsorption studies were done for the recovery of the extracted gold in thiourea solution using active carbon. The percent adsorptions were calculated from the data obtained. Then, adsorption isotherm was drawn it. It is seen that this isotherm obeyed to the Freundlich isotherm type.