Research and application of enrichment methods for gold in refractory form found in pyrite and arsenopyrite minerals

Abstract

Gold occurs in diverse mineralogical associations, which significantly influence the choice of beneficiation methods. While cyanidation remains the primary technique for gold extraction, it is generally ineffective for refractory gold, where gold is finely disseminated within sulfide minerals such as pyrite and arsenopyrite. In such cases, flotation is widely employed as a pre-concentration method, followed by pyrometallurgical or hydrometallurgical processes to improve overall recovery. Refractory gold ores are often found in plants designed for conventional leaching, where they result in low recovery despite high gold grades. Process flowsheet modifications are therefore essential to recover gold inaccessible through standard cyanidation. This study focuses on the beneficiation of refractory gold ore from the Prevanly Region, part of ETI Bakir Co.’s Tereksay operation. Optical and scanning electron microscope analyses revealed no presence of native gold, indicating that gold occurs in sulfide phases. The gangue matrix primarily comprises quartz, muscovite, and dolomite. Initial bottle-roll leaching tests yielded low recoveries (20–25%), confirming the refractory nature of the ore. Subsequent flotation tests significantly improved recovery up to 95%, validating flotation as a suitable pretreatment. To enhance the concentrate grade, a Knelson concentrator was integrated into the circuit, effectively removing fine clay and silicate gangue. This addition contributed to producing a higher-grade gold concentrate by reducing impurities.