The objective of this study was to investigate thiourea leaching of gold present in the uranium tailings. Sulfuric acid treatment for raw material is important in order to dissolve uranium as well as to remove easily leachable metals. The acidic thiourea solution was proposed as a non-toxic possible alternative process route to cyanide in gold dissolution. The acidic system of thiourea-sodium sulfite was studied in the gold dissolution process. The presence of sodium sulfite can significantly reduce thiourea decomposition, accelerate the gold dissolution process, decrease the leaching time, and decrease the activation energy of gold dissolution. The activation energy for gold dissolution was evaluated. The activation energy solution with sodium sulfite is 7.62 kJ mol⁻¹ which is much lower than 9.32 kJ mol⁻¹ in the absence of sodium sulfite. Low activation energy confirms the surface reaction dissolution mechanism. This method demonstrates the possibility of extracting gold directly from low-grade ores without any physical or chemical pre-concentration method with a more environmentally friendly process.

Graphical Abstract

中文翻译：

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埃及中东部沙漠，Gabal El-Missikat，使用铀尾矿中的硫脲进行金浸出

这项研究的目的是调查硫尾矿中铀尾矿中金的浸出。原料的硫酸处理对于溶解铀以及去除易于浸出的金属很重要。有人建议将酸性硫脲溶液作为金溶解中氰化物的无毒可能替代工艺路线。在金溶解过程中研究了硫脲-亚硫酸钠的酸性体系。亚硫酸钠的存在可以显着减少硫脲的分解，加速金的溶解过程，减少浸出时间，并降低金溶解的活化能。评估了金溶解的活化能。亚硫酸钠的活化能溶液为7.62 kJ mol ^-1，远低于9.32 kJ mol在没有亚硫酸钠的情况下为^-1。低活化能证实了表面反应的溶解机理。该方法证明了可以从低品位矿石中直接提取金的可能性，而无需任何物理或化学预浓缩方法，并且工艺更加环保。

图形概要