Optimization of environmental factors affecting gold microbial bioleaching by indigenous bacteria in Zarshuran mineral ore

Zarshuran gold mine as the largest gold mine in Iran is located in Takab, West Azarbayjan. In this study, for the first time, the ability to isolate the gold element was examined by providing optimal conditions for the growth of natural microorganisms in Zarshuran gold ores and investigating the effect of different factors including pH, leaching time and the ratio of the ore volume to leachate.
The study was designed using the Taguchi method in three levels to evaluate the effect of each of the pH, leaching time and the ratio of the ore volume to leachate. The effect of each factor and the appropriate level for bioleaching refractory gold was investigated using the Qulitek-4 software.
The most effective factor was the ratio of the ore volume to leachate which was 17.20% and the least effective factor was the leaching time which was 7.84%. The level 3 was the most appropriate pH level which was assessed as 59.46%. The most appropriate level for the ratio of the ore volume to leachate was level 1, with the amount of 66.14% and a ratio of 1/1. The most appropriate level for the time was level 1, as well, with the amount of 56.78% and duration of 30 days.
Considering the three functional environmental factors, much gold can be separated from ore at an industrial scale without spending too much money.