Abstract:
As oxidized gold ores that are easier to process gradually deplete, the proportion of refractory arsenic-containing gold ores in global gold resources continues to rise. The simultaneous realization of "efficient dearsenication" and "gold liberation" has become one of the key challenges in the field of green metallurgy. Pressurized oxidation (POX) technology, relying on high-temperature and high-pressure wet environments, combines advantages such as fast reaction rates, effective arsenic solidification, and high gold recovery. It has demonstrated engineering potential in the pretreatment of some high-arsenic gold concentrates, achieving stable gold recovery rates of over 90 % and dearsenication efficiency exceeding 95 %. Based on the review of the mineralogical characteristics and arsenic occurrence states of arsenic-containing gold ores, this paper systematically summarized and compared experimental studies and industrial cases reported in recent years from four aspects: reaction mechanisms, thermodynamics and kinetics, process enhancement strategies, and arsenic fixation and environmental safety control. The results show that arsenopyrite and arsenical pyrite can be rapidly oxidized under conditions of 190 °C–230 °C, certain oxygen partial pressure, and acidity, where arsenic is converted from As(Ⅲ) to As(Ⅴ). Under suitable pH and
n(Fe)/
n(As) ranges, stable iron arsenate phases such as scorodite are preferentially formed, and the arsenic concentration in neutralization solutions can be reduced to milligram-per-liter levels. Segmented pressure strategies, increased slurry solid content, and optimized oxygen supply strategies help achieve near-autothermal operation, significantly reducing the consumption of external steam and fuel. The addition of solid arsenic carriers such as CaO and Fe
2O
3, along with the use of corrosion-resistant materials and structural optimization, can further improve arsenic residue leaching stability and extend the service life of equipment. Based on these findings, this paper discusses the applicability boundaries and advantages and limitations of POX in the clean pretreatment of arsenic-containing gold ores by considering energy consumption constraints and environmental emission requirements. Research demands related to digital twin simulation, intelligent process control, and arsenic residue resource utilization are proposed. The insights provided can offer theoretical support and technical references for process route selection, engineering scale-up design, and subsequent green transformation of high-arsenic refractory gold ores.