Gold extraction via cyanide leaching using alkaline-based empty fruit bunch activated carbon

Abstract

This research is carried out to extend the knowledge on the modernized method of modifying the physical and structural properties of empty fruit bunches (EFB), a low-cost, highly accessible and abundant agricultural waste in Malaysia, for gold adsorption process. To complete this aim, EFB was modified by using an alkaline-based chemical to improve the surface area, porosity volume and surface chemistry of sorbents. The structure of the empty fruit bunch is characterized by using characterization techniques such as Thermogravimetric analysis (TGA) and Energy-Dispersive X-ray spectroscopy. The gold solution was prepared by mixing gold with a sodium cyanide solution to undergo a leaching process for 24 hours. The solution was then used for the adsorption experiment. The performance of the alkaline-based EFB-AC to separate gold from the cyanide leaching solution was further studied on the effect of contact time, pH and agitation rate. The gold adsorption capacity achieved by the alkaline-based EFB-AC was measured by calculating the difference between the initial and final gold concentrations using Atomic Absorption Spectrometry (AAS). The maximum gold adsorption capacity findings of contact time, pH, and agitation rate were found to be 2.5 hours, pH of 10 and 60 rpm, respectively. This study reveals that the alkaline-based EFB-AC has the potential to extract gold as an alternative activated carbon in the gold adsorption process.