Preliminary study on the efficiency of bioleaching process in gold extraction

Abstract

The term 'bioleaching' describes the solubilization of target metals from materials by microorganisms. The biooxidation agent used in this study was Acidithiobacillus ferrooxidans. The A. ferrooxidans metabolized iron and sulphur. Although cyanidation is frequently used to extract gold, it is not environmentally friendly. Thus, in order to extract gold economically while also being environmentally friendly, the bioleaching was implied. This study aimed to determine and characterize the composition of mineral in geological ore such as pyrite, arsenopyrite, magnetite, hematite, and quartz in gold ore using X-Ray diffraction (XRD) and Scanning Electron Microscopy (SEM)). The geological sample from Gua Musang were provided by Benua Sunda Cari Gali Sdn Bhd and treated by bioleaching to evaluate the yields of gold extraction. The provided sample was sieved to 32 um and sent to XRD analysis. The samples were placed in a liquid media with inoculum added, and the mixture was then cultured for 20 days at 30°C in a shaker incubator. After drying the samples at 100°C, the samples underwent complete digestion. Then, ICP-OES was used to analyze the gold yield concentrations. The bioxidation procedure led to an increase in gold concentrations from 0.33 ppm to 0.47-0.52 ppm. In addition, after bioleaching, arsenopyrite and iron levels in the samples decreased, which may have contributed to the increase in gold concentration. In conclusion, the biooxidation was effective in enhancing the gold extraction procedure through bioleaching.