Research and production practice of a synergistic process for gold recovery from arsenic-sulfur-bearing ores via strong alkali pretreatment, cyanidation, and flotation

This paper presents a synergistic process for arsenic-sulfur-bearing gold ores, which includes "strong alkali pretreatment−cyanide leaching−cyanidation tailings flotation". A highly alkaline environment with pH ≥ 12 was created using liquid caustic soda, combined with high-pressure oxygen to enhance oxidation. This process helps dissolve the passive films of low-valent sulfates, arsenite, and polysulfide on the surface of arsenic sulfide minerals, exposing the gold particles and thus improving the gold leaching rate. Simultaneously, more exposed surfaces of the arsenic sulfide minerals in the cyanidation tailings lead to an increased gold recovery rate through flotation. This process has been successfully applied in mineral processing practice, resulting in a 9.12 percentage point increase in overall gold recovery compared to the original process, providing a reference for the efficient recovery of similarly complex arsenic-sulfur-bearing gold ores.