Optimization and Modeling of the Ferric Ion Oxidation Method for a Resistant Gold Ore Using the Experiment Design Method

Zarshouran gold deposit is located 42 km north of Takab in NW Iran recognized as one of the most significant gold deposits in Iran. This ore has the gold grade of 2.4 gr/t which contains sulfide minerals such as pyrite and arsenopyrite. The gold recovery is less than 80% due to the association of gold in sulfide minerals. The aim of this research is to investigate the oxidation of sulfide minerals from the Zarshouran gold mine using the ferric-ionic acid system prior to the cyanidation process. Consequently, an experimental design was employed to investigate and optimize the key parameters affecting the oxidation of resistant ore by ferric ion including ferric ion concentration, pH, pulp solid percentage, temperature, and time. The results indicated that pH, iron sulfate concentration, pulp solid percentage, temperature, and time significantly influence gold recovery, respectively. Following oxidation with ferric ion and the cyanidation process under optimal conditions (iron sulfate concentration of 4 gr/t, temperature of 42 degrees Celsius, time of 6 h, pulp solid percentage of 15%, and pH of 1%), gold recovery improved from 41 to 67.85%.