employed Poly (oxythylene)-9-nonlphenyl ether (PONPE-9) to recycle gold(III) ion by pH-switching process via cloud point extraction. Its phase separation behavior under different experimental conditions was evaluated (Wongwailikhit et al., 2003). The results indicated that recoveries of greater than 63% of gold were obtained (Wongwailikhit et al., 2003). Urbanski et al. (2000) investigated the kinetics of gold electrowinning from acidic thiourea solutions containing alcohol admixture which was obtained by gold elution from activated carbon in the processing of gold-bearing raw materials as depending on temperature, cur- rent intensity and type of the cathode material. The results found that 96%–100% of gold could be recovered under suitable condi- tions, as well as, the current efficiencies and energy consumption in the experimental conditions were in the range of 0.5%–1% and less than 15 kW h kg−1 of gold, respectively, using platinum mesh cathode (Urbanski et al., 2000).