The cyanidation of gold. III. Mechanistic details of the role of lead and sulfide ions

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

Hydrometallurgy Pub Date : 2025-10-08 DOI:10.1016/j.hydromet.2025.106584

M. Nicol

{"title":"The cyanidation of gold. III. Mechanistic details of the role of lead and sulfide ions","authors":"M. Nicol","doi":"10.1016/j.hydromet.2025.106584","DOIUrl":null,"url":null,"abstract":"<div><div>The role of lead ions in the cyanidation of gold has been extensively studied in this investigation. In addition to a speciation analysis using accepted thermodynamic data, the equilibrium potential for the deposition of lead under cyanidation conditions has been estimated. This has been used in conjunction with other electrochemical measurements to confirm that bulk lead metal is not deposited on a gold surface during cyanidation. The underpotential deposition of lead has been confirmed and it has been shown that an incomplete layer of lead is responsible for the increased rates in the presence of lead. The detrimental effect of high lead concentrations appears to be the result of the formation of a complete lead layer on the gold surface.</div><div>A less extensive study of the effect of sulfide ions on the rate of cyanidation has confirmed that low (micro-molar) concentrations of sulfide ions enhance the dissolution of gold in cyanide solutions but inhibit the rate of dissolution at high concentrations. The detrimental effect is associated with the anodic oxidation of gold and the formation of a passivating layer of Au<sub>2</sub>S is possibly responsible. There does not appear to be a significant effect of sulfide on the kinetics of the cathodic reduction of oxygen. A gold alloy containing 10 % silver is less susceptible to the inhibitory effect of sulfide ions.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"239 ","pages":"Article 106584"},"PeriodicalIF":4.8000,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Hydrometallurgy","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0304386X25001495","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"METALLURGY & METALLURGICAL ENGINEERING","Score":null,"Total":0}

引用次数: 0

Abstract

The role of lead ions in the cyanidation of gold has been extensively studied in this investigation. In addition to a speciation analysis using accepted thermodynamic data, the equilibrium potential for the deposition of lead under cyanidation conditions has been estimated. This has been used in conjunction with other electrochemical measurements to confirm that bulk lead metal is not deposited on a gold surface during cyanidation. The underpotential deposition of lead has been confirmed and it has been shown that an incomplete layer of lead is responsible for the increased rates in the presence of lead. The detrimental effect of high lead concentrations appears to be the result of the formation of a complete lead layer on the gold surface.

A less extensive study of the effect of sulfide ions on the rate of cyanidation has confirmed that low (micro-molar) concentrations of sulfide ions enhance the dissolution of gold in cyanide solutions but inhibit the rate of dissolution at high concentrations. The detrimental effect is associated with the anodic oxidation of gold and the formation of a passivating layer of Au₂S is possibly responsible. There does not appear to be a significant effect of sulfide on the kinetics of the cathodic reduction of oxygen. A gold alloy containing 10 % silver is less susceptible to the inhibitory effect of sulfide ions.

查看原文本刊更多论文

氰化金3。铅和硫化物离子作用的机理细节

本文对铅离子在金氰化反应中的作用进行了广泛的研究。除了利用公认的热力学数据进行形态分析外，还估计了氰化条件下铅沉积的平衡势。这已经与其他电化学测量一起使用，以确认在氰化过程中大块金属铅不会沉积在金表面。铅的欠电位沉积已经得到证实，并且已经表明，在铅存在的情况下，不完整的铅层是导致速率增加的原因。高铅浓度的有害影响似乎是在金表面形成完整铅层的结果。一项对硫化物离子对氰化速率影响的不太广泛的研究证实，低（微摩尔）浓度的硫化物离子促进了金在氰化物溶液中的溶解，但抑制了高浓度的溶解速率。这种不利影响与金的阳极氧化有关，而Au2S钝化层的形成可能是罪魁祸首。硫化物对氧的阴极还原动力学似乎没有显著的影响。含银10%的金合金对硫化物离子的抑制作用不太敏感。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

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.