Globally, continuous R & D efforts are being made to recuperate precious metals from wastes in order to conserve the natural resources as well as minimize environmental pollution. Keeping in view of the above, a process has been developed to recover gold from industrial effluent using hydrometallurgical route. Initially, the effluent was pre-treated using precipitation and solvent extraction techniques to remove impurities, i.e., iron and copper as value added products. Iron was removed up to 99.99% at pH ~ 3.5. Further, copper was extracted using 10% LIX 84IC maintaining phase ratio 1/1 in mixing time of 15 min and equilibrium (eq.). pH 2.2. Selective adsorption of gold was carried out using ionenaustauscher-II and resulted in 99% gold adsorption between pH 7 and 8 in contact time of 30 min. Experimental results obtained for the adsorption of gold was found to follow second order reaction and fitted well with the Freundlich isotherm. Gold from the loaded resin was eluted using a mixture of hydrochloric acid and thiourea. From the pure gold solution, metal could be produced using cementation/charcoal adsorption followed by heat treatment, respectively.

中文翻译：

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从工业废水中选择性回收金、铜和铁作为可销售产品的新方法

在全球范围内，正在不断进行研发工作，以从废物中回收贵金属，以保护自然资源并最大程度地减少环境污染。鉴于上述情况，已开发出一种使用湿法冶金路线从工业废水中回收金的工艺。最初，流出物使用沉淀和溶剂萃取技术进行预处理以去除杂质，即作为增值产品的铁和铜。在 pH ~ 3.5 时，铁的去除率高达 99.99%。此外，在 15 分钟的混合时间和平衡（当量）中，使用 10% LIX 84IC 保持相比 1/1 提取铜。pH 值 2.2。使用 ionenaustauscher-II 进行金的选择性吸附，在 30 分钟的接触时间内在 pH 7 和 8 之间产生 99% 的金吸附。发现获得的金吸附实验结果遵循二级反应并与 Freundlich 等温线吻合。使用盐酸和硫脲的混合物从负载的树脂中洗脱金。从纯金溶液中，可以分别使用胶结/木炭吸附和热处理来生产金属。