难处理金矿预氧化过程中载金包裹体的相变与重构研究进展

    Recent Advances for Phase Transformation and Reconstruction of Gold-bearing Inclusions during the Pre-oxidation of Refractory Gold Ores

    • 摘要: 这是一篇矿业工程领域的论文。在“双碳”和难处理金矿资源“压舱石”背景下,预氧化是难处理金矿高效提金的有效预处理方法。有效破坏微细浸染金包裹体,消除或避免有害物质对金的钝化、劫金或二次包裹作用,是决定难处理金矿中金回收率高低的关键和瓶颈问题。明晰预氧化过程中载金物质的相变重构演化规律,对定向破坏载金包裹体和高效浸金至关重要。本文概述了难处理金矿的典型特征与现有预氧化技术,总结了焙烧氧化、热压氧化、生物氧化、化学氧化及其他预氧化过程中载金包裹体的相变重构研究进展。结果表明,载金硫化物通过预氧化主要转变为铁(砷)氧化物和硫(砷)酸盐,受氧化温度、气氛或含氧量、酸碱环境、氧化还原电位、菌种特性等多因素耦合作用,也可能转变为单质硫、氧化硫、硫代硫酸盐、黄钾铁矾和臭葱石等次生产物,黄钾铁矾、氧化铁和硫酸钙等是导致金二次包裹的主要固相物质。低温低压中性热压氧化,高效嗜热嗜碱耐砷菌种驯化、多因素耦合下的细菌氧化过程强化,绿色高效氧化剂筛选、基于多场耦合的化学氧化等预氧化工艺开发与微观机制仍需系统深入研究。矿石特性、预氧化过程反应、载金物质相变重构与金回收率之间的耦合关系及调控是未来难处理金矿绿色高效预氧化领域的研究热点与难点。

       

      Abstract: This is an article in the field of mining engineering. Under the background of "double carbon" and "ballast stone" of refractory gold ore resources, pre-oxidation is an effective pretreatment method for efficient gold extraction from refractory gold ores. Destroying the finely impregnated gold inclusions, and eliminating or avoiding the passivation, robbing or secondary wrapping of gold by harmful substances, are the key and bottleneck problems to determine the gold recovery rate in refractory gold ores. Understanding the phase transformation and reconstruction evolution of gold-bearing minerals during pre-oxidation process is critical for inclusions destruction directly and gold leaching. In this article, the typical characteristics of refractory gold ores and existing pre-oxidation techniques were outlined, and the research advances in phase transformation and reconstruction of gold-bearing inclusions in roasting oxidation, hot-press oxidation, biological oxidation, chemical oxidation and other pre-oxidation processes were summarized. The result shows that the gold-bearing sulfides are mainly transformed into Fe oxides (or As oxides) and sulfate (or arsenate) by pre-oxidation. However, due to the coupling effect of multiple factors such as oxidation temperature, atmosphere or oxygen concentration, pH value, redox potential, Bacterial characteristics, etc., sulfides may also be converted into elemental sulfur, sulfur oxide, thiosulfate, jarosite and scorodite. In addition, jarosite, iron oxide and calcium sulfate are the main solid matters leading to the secondary package of gold. Pre-oxidation process and microscopic mechanisms, such as neutral thermobaric oxidation with low temperature and pressure, bacteria domestication with thermophilic, alkalophilic and arsenic-resistant properties, process enhancement of bacterial oxidation under multi-factor coupling, green and efficient oxidant screening, and chemical oxidation based on multi-field coupling, etc., still need to be deeply researched. The coupling relationship and regulation among ore characteristics, process reaction of pre-oxidation, phase transformation and reconstruction of gold-bearing materials and gold recovery rate are the research hotspots and difficulties in the green and efficient pre-oxidation field for refractory gold ores in the future.

       

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