Significant of Gold Mineralogical Study for The Chemical Separation of Weathered Ore in Malaysia

Abstract

This paper provides a mineralogical study on the gold ore sample obtained from a local gold mine in Malaysia that underwent the lateritisation process. The mineralogical characteristic of the secondary gold was investigated using the optical microscope study. Then, the presence of other minerals was identified by X-ray fluorescence, X-ray diffraction and scanning electron microscope / energy dispersive X-ray. X-ray mapping was also employed for the determination of the elemental distribution in the gold ore samples. From the optical microscopy and SEM/EDX study, the gold grain was found embedded in the quartz and also was spotted interlocked in iron oxide and arsenopyrite as well within size from sub-microscopic (1<μm) to microscopic (≤10μm) with a flaky type of surface morphology as well as the presence of element of Si, O and Fe. XRD shows the mineral phases of quartz, muscovite and magnetite. In XRM, the gold was also found disseminated on the silicate minerals surface like quartz (SiO2), chlorite ((Mg5Al)(AlSi3)O10(OH)8) and clay minerals, as also confirmed by the chemical composition presents in the XRF analysis. Hence, from this mineralogical studies, the characteristic of the gold is unsuitable to be processed by physical separation as the submicroscopic gold will tend to be lost during processing and a sustainable processing method such as non-cyanide leaching can be proposed to overcome the problem.