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含砷金矿加压氧化脱砷预处理技术研究进展

Research progress on pressurized oxidation dearsenication pretreatment process for arsenic-containing gold ores

  • 摘要: 随着易处理氧化型金矿资源逐渐枯竭,难处理含砷金矿在全球黄金资源中所占比例不断提高,其“高效脱砷”与“金解离”的协同实现已成为绿色冶金领域的关键难题之一。加压氧化(POX)技术依托高温高压湿法环境,兼具反应速率快、砷固化效果好、金回收率高等优点,已在部分高砷金精矿预处理中显示出金回收率可稳定在90 %以上、砷去除率超过95 %的工程潜力。在梳理含砷金矿矿物学特征及砷赋存状态的基础上,从反应机理、热力学与动力学行为、工艺强化路径及砷固定与环境安全控制4个方面,对近年来公开报道的试验研究和工业实例进行了系统归纳与比较。结果表明,毒砂和含砷黄铁矿在190 ℃~230 ℃、一定氧分压和酸度条件下可实现快速氧化,砷由As(Ⅲ)向As(Ⅴ)转化后,在适宜的pH和n(Fe)/n(As)条件下,优先生成臭葱石等稳定铁砷酸盐,相应条件下中和液中砷质量浓度可降至毫克每升量级;分段加压、提高矿浆固含量与优化供氧策略有助于实现近自热运行,显著降低外加蒸汽和燃料消耗;添加CaO、Fe2O3等固砷载体及采用耐蚀材料与结构优化,可进一步改善砷渣浸出稳定性并延长设备服役寿命。在此基础上,结合能耗约束和环境排放要求,讨论了POX在含砷金矿清洁预处理中的适用边界与优势局限,提出了面向数字孪生模拟、过程智能控制及固砷渣资源化利用等方面的研究需求,相关认识可为高砷难处理金矿的工艺路线筛选、工程放大设计及后续绿色化改造提供理论支撑和技术参考。

     

    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 Fe2O3, 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.

     

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