P204-仲辛醇皂化萃取氰化尾渣酸浸液中铁的初步研究

采用P204-仲辛醇皂化萃取体系从金精矿氰化尾渣酸浸液中萃取分离铁, 初步研究其萃取机理, 并考察了萃取体系、P204浓度和料液初始pH值、含铁浓度及加入介质NaCl对Fe(Ⅲ)萃取的影响以及相比(O/A)、H₂SO₄浓度对Fe(Ⅲ)反萃的影响。实验结果表明：P204和仲辛醇对酸浸液中的Fe(Ⅲ)具有一定协同萃取效应, 仲辛醇作为萃取体系中的相转移试剂, 尤其能改善铁的反萃效率。同时, 采用氨水皂化后的萃取体系铁的提取率显著提高。P204、仲辛醇以及260^#溶剂油以1∶1∶2的体积比混合作为萃取体系, 在相比为2的条件下, 调整含铁10.18 g/L的原酸浸液的pH值接近2.0, 经过1级萃取, 萃余液中含铁低于0.25 g/L; 以25%(体积分数)的H₂SO₄反萃, 有机相中的铁基本被反萃完全。通过萃取和反萃, 铁离子溶液中杂质含量大大减少, 尤其是砷的含量。

Preliminary Study of Synergistic Extraction Iron from Acid Leaching Solution of Cyanidation Tailings with P204 and 2-octanol

The system of P204-2-octanol was used to extract Fe(Ⅲ) from the acid leaching solution of cyanidation tailings of gold concentrates. A preliminary study was made on the extraction mechanism. Investigations were carried out on the effects of the extraction system, P204 concentration, initial pH value of feed liquid, iron content and medium NaCl on Fe extraction rate as well as the effects of phase ratio(O/A) and H₂SO₄ concentration on Fe(Ⅲ) stripping. It was found that P204 and 2-octanol have a  certain synergistic extraction effect on extracting Fe(Ⅲ) from the acid leaching solution. As phase transfer reagent in the extraction system, 2-octanol could particularly improve the stripping efficiency. The extraction rate of iron could be greatly improved after the saponification of the extraction system with ammonia. Using the extraction system containing P204, 2-octanol and 260# solvent oil with a volume ratio of 1∶1∶2, and adjusting pH value of the original acid leaching solution with 10.18 g/L iron content to 2.0 at the O/A ratio of 2, after one-stage extraction, Fe³⁺ concentration in raffinate was less than 0.25 g/L. Fe³⁺ in the organic phase was mostly stripped using 25% (volume fraction) sulfuric acid. The contents of impurities, especially arsenic, in the solution were greatly reduced through the methods of extraction and stripping.