( 1. 云南大学 化学与材料工程学院, 昆明 650091;
2. 北京大学 化学与分子工程学院,北京 100871;
3. 昆明贵金属研究所,昆明 650221)
摘 要: 以TBP为萃取剂, 用新型的柱状萃取装置对水相中加入与Au(I)等摩尔CTAB(十六烷基三甲基溴化铵)的低浓度氰化金溶液进行了萃取研究, 考察了水相中添加CTAB、 有机相TBP的体积、 盐析剂NaCl浓度等对TBP萃取Au(I) 性能的影响以及载金有机相中金的反萃取。 结果表明: 在水相中添加CTAB后, TBP对低浓度金的萃取性能大幅度提高; 50 L含金浓度约为10 mg/L的氰化金溶液经3级萃取试验后, 金的萃取率大于95%, 萃余相浓度小于0.5×10-6。 用硫氰化钾对含金浓度约为3 g/L的载金有机相进行了反萃取研究, 当KSCN浓度大于3mol/L时, 对金的反萃率大于93%。
关键字: 萃取柱; KAu(CN)2; 十六烷基三甲基溴化铵; 磷酸三丁脂; 硫氰化钾
( 1. College of Chemistry and Material,
Yunnan University, Kunming 650091, China;
2. College of Chemistry and Molecular Engineering,
Peking University, Beijing 100871, China;
3. Institute of Precious Metals, Kunming 6500221, China)
Abstract: The solvent extraction of trace gold(I) in alkaline cyanide solution by CTAB/TBP system was investigated using a new kind of extraction equipment. Various parameters, such as the effect of addition of CTAB aqueous phase, the quantity of TBP, the concentration of NaCl were studied. The results demonstrate that the addition of CTAB in aqueous phase can enhance the gold (I) extraction rate of TBP sharply. Though it has little effect on the gold (I) extraction percentage, the concentration of NaCl and the quantity of TBP can reduce the degree of emulsification. The extraction of 50 L alkaline cyanide solutions in three extraction columns shows that the extraction percentage is more than 95%, and the gold mass concentration of raffinate is less than 0.5×10-6 in the all extraction process. Gold (I) stripping from gold loaded organic phase by KSCN was also studied. About 93% gold (I) in organic phase could be stripped into aqueous phase when the concentration of KSCN reached 3 mol/L.
Key words: extraction column; KAu(CN)2; cetyltrimethylammonium bromide; tributyl phosphate; KSCN