The separation of gold and vanadium in carbonaceous gold ore by one-step roasting method

The separation of gold and vanadium in the refractory carbonaceous gold ore had been performed by one-step roasting method. The thermodynamic viability of the possible reactions in the process was analyzed based on thermodynamic data. And the effects of experimental parameters such as roasting temperature, roasting time and NaCl dosage on the recovery ratios of gold and vanadium were investigated. Under the optimal conditions of NaCl 10%, roasting temperature 800 degrees C, roasting time 4 h and air gas flow rate 1 L/min, the recovery ratios of gold and vanadium were 92% and 85.34%, respectively, realizing the effective separation of gold and vanadium. In addition, the reaction mechanism and phase transformation during the roasting process were revealed using SEM, EDS and XRD. Results demonstrated that it was beneficial to the chlorination reaction of gold in the presence of pyrite. In the low-temperature roasting, the chlorination reaction of gold was dominant in the roasting process. And in the high-temperature roasting, the chlorination reaction of gold and the sodium reaction of vanadium were dominant in the roasting process. (C) 2019 Published by Elsevier B.V.