Исследование биотехнологической переработки сульфидной золотосодержащей руды

Abstract

In this research, we set out to search for methods that can be used in biotechnological processing of sulphide carbonaceous refractory gold-containing ores with a view of subsequent gold extraction. The mesophilic strain of the Acidithiobacillus ferrooxidans bacterium, which exhibits sustained activity over prolonged periods (12 months), has been isolated and adapted. The activity of this strain is shown to vary from 1,4 to 2,8 g/l of oxidised iron per hour. In the process of heap bacterial oxidation, a significant decrease in the refractoriness of sulphide ores is observed. Under the conditions of ore crushing to a particle size of 2 mm, the oxidation degree of arsenopyrite and pyrite is determined to reach the values of 89-93% and 50-56%, respectively. Thus, ores containing 0,9-1,5 g/t of gold appear to be appropriate for processing, since the gold recovery reaches 65-75% after heap bioleaching (HB). The obtained results are confirmed by semi-industrial tests. The proposed technology of heap bacterial oxidation permits the preparation of sulphide refractory gold-containing ores for subsequent gold extraction based on the bacterial leaching technology (BL), which leads to a significant increase in the extraction of gold. Under this process, sulphide minerals are transformed into natural oxidised forms with a minimal anthropogenic impact on the environment.