Facile and novel method for the recovery of gold from a calcined concentrate via copper–ammonia -thiourea system and activated carbon

IF 4.8 2区材料科学 Q1 METALLURGY & METALLURGICAL ENGINEERING

Hydrometallurgy Pub Date : 2024-01-08 DOI:10.1016/j.hydromet.2023.106260

Yue Lin , Yunlong Chen , Shuliang Chen , Xianzhi Hu , Futing Zi , Peng Yang

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引用次数: 0

Abstract

Cyanidation, as the primary method for gold extraction, poses significant risks to the environment and animals. Therefore, an eco-friendly, sustainable, and effective leaching approach has been devised for extracting gold from a gold concentrate after calcination, utilizing copper(II)-ammonia and thiourea. This research focuses primarily on optimizing leaching conditions, gold recovery from leach solution, and cyclic utilization of the leaching solution. Furthermore, we investigated the potential mechanisms behind the leaching and recovery processes using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and thermodynamic analysis. The leaching process exhibits a spontaneous reaction, and the mechanism for alkaline thiourea leaching of gold is as follows: (a) reduction of Cu(NH₃)₄²⁺ to Cu(TU)₄⁺, (b) oxidation of Au(0) to Au(TU)₂⁺ and (c) oxidation of Cu(TU)₄⁺ back to Cu(NH₃)₄²⁺, in the presence of oxygen, regenerating the catalyst. Under optimal leaching conditions, the proposed method achieves a gold extraction efficiency of approximately 86.6%, approaching that of cyanidation. The barren leach solution can be reused for subsequent leaching experiments, with consistent gold extraction efficiency and thiourea consumption. Therefore, this method presents a promising alternative to gold leaching via cyanidation.

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通过铜氨和硫脲体系从煅烧精矿中回收金的简便新方法

氰化法作为提炼黄金的主要方法，对环境和动物都有很大风险。因此，我们设计了一种环保、可持续和有效的浸出方法，利用铜（II）-氨和硫脲从煅烧后的金精矿中提取金。这项研究主要侧重于优化浸出条件、浸出液中金的回收以及浸出液的循环利用。此外，我们还利用扫描电子显微镜、能量色散 X 射线光谱、X 射线光电子能谱和热力学分析，研究了浸出和回收过程背后的潜在机制。浸出过程呈现内热反应，碱性硫脲浸金的机理如下：(a) Cu(NH3)42+ 还原成 Cu(TU)4+，(b) Au(0) 氧化成 Au(TU)2+，(c) Cu(TU)4+ 在氧气存在下氧化回 Cu(NH3)42+，催化剂再生。在最佳浸出条件下，拟议方法的金提取效率约为 86.6%，接近氰化法。贫瘠的浸出液可重复用于后续浸出实验，且金提取效率和硫脲消耗量保持一致。因此，该方法有望成为氰化法浸金的替代方法。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Hydrometallurgy 工程技术-冶金工程

CiteScore

9.50

自引率

6.40%

发文量

144

审稿时长

3.4 months

期刊介绍： Hydrometallurgy aims to compile studies on novel processes, process design, chemistry, modelling, control, economics and interfaces between unit operations, and to provide a forum for discussions on case histories and operational difficulties. Topics covered include: leaching of metal values by chemical reagents or bacterial action at ambient or elevated pressures and temperatures; separation of solids from leach liquors; removal of impurities and recovery of metal values by precipitation, ion exchange, solvent extraction, gaseous reduction, cementation, electro-winning and electro-refining; pre-treatment of ores by roasting or chemical treatments such as halogenation or reduction; recycling of reagents and treatment of effluents.