SILICA AND SODIUM CHLORIDE ASSISTED LEACHING OF CHALCOPYRITE

The study investigates the enhancement of chalcopyrite leaching through the addition of precipitated silica in conjunction with sodium chloride at moderate temperatures (65−90°C) in acidic media with ferric ions as the oxidant. The objective is to analyze the impact of silica on the leaching rates and mechanisms involved. Methodologically, the research incorporates solubility analysis, kinetic analysis using a shrinking sphere model, and scanning electron microscopy (SEM) to understand the leaching processes. Results indicate that the introduction of precipitated silica significantly improves copper dissolution rates compared to sodium chloride alone, with effects scaling with increased chloride concentration and temperature. The SEM analysis suggests that chloride and silica promote the precipitation of sulfur on silica particles' surfaces, preventing the blockage of chalcopyrite particles, thereby enhancing leaching kinetics. Additionally, sodium silicate and silica sand do not exhibit a similar positive influence. This study contributes to the ongoing exploration of additives in hydrometallurgical processes aimed at improving recovery efficiency from challenging copper sulfide ores.