Optimalisasi pH pada Pelindian Emas dari Batuan Sinabar dengan Larutan Klorida-Hipoklorit

Abstract

Gold leaching with chloride-hypochlorite solution has the potential to be a promising alternative for environmentally friendly gold extraction, replacing cyanidation and amalgamation methods that are harmful to the environment and health. This study aims to study the effect of pH on the gold leaching process, especially from cinnabar rocks originating from Buru Island, Maluku Islands. The stages carried out in the study include preparation and characterization of rock samples, determination of total gold content in rocks, and leaching with chloride-hypochlorite solution. Initial rock characterization was carried out using Scanning Electron Microscope - Energy Dispersive X-ray (SEM-EDX) and X-ray diffraction (XRD) to determine the elemental composition and types of minerals in the rocks. The measurement of gold content was done using an atomic absorption spectrophotometer (AAS). The effect of the pH of the initial chloride-hypochlorite solution was studied through pH variations in the range of 3-7. The increase in leached gold occurred along with the decrease in the initial pH of the chloride-hypochlorite solution to pH 4. The optimum gold percentage of 43.25% was obtained under leaching conditions of 0.19 M NaOCl, 200 g/L NaCl, S/L ratio of 1:20 for 5 hours with an initial pH of the chloride-hypochlorite solution of 4.