Comparative thermodynamic analysis of gold dissolution in four organic carboxylic acid-catalyzed thiosulfate systems using Eh–pH and species distribution diagrams

IF 3.7 2区材料科学 Q1 METALLURGY & METALLURGICAL ENGINEERING

Journal of Central South University Pub Date : 2024-06-24 DOI:10.1007/s11771-024-5572-0

Jun-nan Chen, Feng Xie, Wei Wang, Yun-long Bai

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Abstract

The non-ammonia thiosulfate leaching system is considered to be an attractive and eco-friendly route for gold leaching without the usage of cyanide or ammonia. In this paper, the role of four organic carboxylic acids, named oxalic acid (Ox), malic acid (Mal), citric acid (Cit), and tartaric acid (Tart) in copper-thiosulfate system has been studied comparatively. Based on the available thermodynamic data, a series of E_h–pH and species distribution diagrams for copper-Ox/Mal/Cit/Tart-thiosulfate system under various conditions have been constructed from thermodynamic calculation. The results show that thiosulfate is the only effective complexing agent for aurous ions, while the organic carboxylic acids work as a copper ligand. The copper-Mal/Cit/Tart-thiosulfate system exhibits potential advantages over the traditional copper-ammonia-thiosulfate system, such as wider pH range and lower thiosulfate consumption. The calculation also indicates the redox potentials of Cu(II)/Cu(I) for the leaching systems are in the subsequence of E⁰[Cu(Ox)₂²⁻/Cu(S₂O₃)₃⁵⁻] >E⁰[Cu(NH₃)₄²⁺/Cu(S₂O₃)₃⁵⁻] >E⁰[Cu₂(Mal)₂H₋₂²⁻/Cu(S₂O₃)₃⁵⁻] ≈E⁰[Cu₂(Cit)₂H₋₂⁴⁻/Cu(S₂O₃)₃⁵⁻] > E⁰[Cu(Tart)₂H₋₄⁶⁻/Cu(S₂O₃)₃⁵⁻]. Increasing thiosulfate concentration leads to a sharp decline in the content of copper-Ox/Mal/Cit/Tart complex, and the stability of the formed cupric complex follows the descending order of tartaric acid>citric acid>malic acid>oxalic acid.

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利用 Eh-pH 和物种分布图对金在四种有机羧酸催化的硫代硫酸盐体系中的溶解进行热力学比较分析

不使用氰化物或氨的非氨硫代硫酸浸出系统被认为是一种具有吸引力且环保的金浸出方法。本文比较研究了草酸（Ox）、苹果酸（Mal）、柠檬酸（Cit）和酒石酸（Tart）这四种有机羧酸在硫代硫酸铜体系中的作用。根据现有的热力学数据，通过热力学计算构建了一系列不同条件下硫代硫酸铜-Ox/苹果酸/柠檬酸/酒石酸体系的 Eh-pH 和物种分布图。结果表明，硫代硫酸盐是唯一有效的含金离子络合剂，而有机羧酸则可作为铜配体。与传统的铜-氨-硫代硫酸体系相比，铜-氨-硫代硫酸体系具有更宽的 pH 值范围和更低的硫代硫酸消耗量等潜在优势。计算还表明，浸出体系中 Cu(II)/Cu(I) 的氧化还原电位在 E0[Cu(Ox)22-/Cu(S2O3)35-] >；E0[Cu(NH3)42+/Cu(S2O3)35−] >E0[Cu2(Mal)2H−22−/Cu(S2O3)35−] ≈E0[Cu2(Cit)2H−24−/Cu(S2O3)35−] > E0[Cu(Tart)2H−46−/Cu(S2O3)35−].硫代硫酸浓度的增加导致铜-氧化物/苹果酸/柠檬酸/酒石酸络合物的含量急剧下降，形成的铜络合物的稳定性从高到低依次为酒石酸>柠檬酸>苹果酸>草酸。

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

Journal of Central South University METALLURGY & METALLURGICAL ENGINEERING-

CiteScore

6.10

自引率

6.80%

发文量

242

审稿时长

2-4 weeks

期刊介绍： Focuses on the latest research achievements in mining and metallurgy Coverage spans across materials science and engineering, metallurgical science and engineering, mineral processing, geology and mining, chemical engineering, and mechanical, electronic and information engineering