(1. 北京科技大学 土木与资源工程学院, 北京 100083；
2. 金属矿山高效开采与安全教育部重点实验室, 北京 100083)
摘 要: 采用“磁化焙烧-硫脲浸金-磁选-碱浸除杂”的金铁梯级提取法从焙烧氰化尾渣中浸出金，并制取铁精粉，通过物相转化、焙烧过程热力学计算和颗粒群结构分析，揭示铁精粉中杂质形成机理。结果表明：氰化尾渣添加8%焦粉于700 ℃下磁化焙烧60 min，焙烧样以硫脲法浸金，金浸出率达65.87%；浸金渣经磨矿磁选得到TFe品位为55.01%的初级铁精粉，再于90 ℃的10%NaOH溶液中碱浸8 h，可得TFe品位为62.22%、回收率为69.80%的合格铁精粉。物相转化和热力学计算表明，磁化焙烧过程中含铁矿物与Si、Ca、Al及重金属等杂质反应，生成铁橄榄石、钙铝榴石和铁钙辉石等新物相，与磁铁矿紧密共生，混入铁精粉中；微细粒磁铁矿存在严重磁团聚，石英等杂质会机械夹杂在磁团聚中，降低铁精粉质量。
关键字: 焙烧氰化尾渣；梯级提取；磁化焙烧；铁精粉；碱浸；物相转化；热力学计算
（1. School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. State Key Laboratory of High-Efficient Mining and Safety of Metal Mines, Ministry of Education, Beijing 100083, China）
Abstract:A cascading process, namely, magnetization roasting-thiourea leaching-magnetic separation-alkaline leaching, was developed to extract gold and prepare iron concentrates (ICs) from roasting cyanide tailing (RCT). The formation mechanisms of impurities in ICs were revealed by phase transformation, thermodynamics calculation and structure analysis. The results show that, after magnetization roasting of RCT by adding 8% coke powders at 700 ℃ for 60 min, Au extraction rate of 65.87% is achieved by thiourea leaching. Rough ICs with TFe grade of 55.01% are obtained by grinding and magnetic separation of leaching residue. By further leached in 10% NaOH solution, qualified ICs with TFe grade of 62.22% and recovery of 69.80% are prepared. The phase transformation and thermodynamics calculation reveal that fayalite, grossular and hedenbergite, tightly combing with magnetite, are generated by reacting iron oxides with Si, Al, Ca and heavy metals. Structural analysis exhibits that the impurity minerals are mechanically mixed into formed magnetic agglomerates, resulting in low quality of ICs.
Key words: roasting cyanide tailing; cascading recovery; magnetization roasting; iron concentrates; alkaline leaching; phase transformation; thermodynamics calculations
