Optimization of the synergy between reduction leaching of manganese anode slime and oxidation pretreatment of refractory gold ore by response surface methodology

A new process for extracting gold from refractory gold ore and manganese from manganese anode slime was developed by combining the oxidative pretreatment of refractory gold ore and reductive leaching of manganese anode slime. The response surface methodology was used to optimize the effects of time, temperature, and sulfuric acid concentration on the leaching efficiency of manganese. The manganese leaching efficiency was 91.64% under the conditions of two ore mass ratio of 1:0.5, sulfuric acid concentration of 1.25 mol/L, temperature of 85 °C, and leaching time of 2.5 h. The gold extraction efficiency from the pretreatment slag reached 90.30% and was higher than that of the untreated ore. The improvement of the gold-leaching efficiency is due to the destruction of pyrite and the decrease of gold ore size. Therefore, the synergistic effect between the leaching of manganese anode slime and the oxidative pretreatment of gold concentrate not only achieved the leaching of manganese, but also improved the leaching efficiency of gold.