废弃矿井水质演化生物地球化学机制及有价元素资源化利用综述

Biogeochemical mechanisms behind water quality evolution and valuable element reutilization of abandoned mine drainage: A review

  • 摘要:
    背景 废弃矿井水不仅是矿区主要污染源,也是战略性关键金属与地下空间利用的重要载体。我国矿山水污染呈现南方重于北方的空间格局,这是由气候条件、地质背景与采矿历史共同决定的。
    进展 基于环境地球化学前沿视角,系统评述酸性矿山废水(AMD)的形成演化机制及污染阻控−资源回收−能源协同利用技术。废弃矿井闭坑后水质呈现明显的阶段性特征:初期由无机水岩反应主导的重金属浓度高峰,中期微生物驱动的自净化过程,至长期融入区域地下水系统后的动态平衡状态。通过剖析黄铁矿氧化的动力学过程,指出嗜中性微生物在酸化初期的启动作用是控制酸性矿山废水释放速率的关键环节。通过阐明污染物在岩溶−水复杂介质中的源汇演变规律,揭示了碳酸盐岩缓冲作用诱导次生矿物沉淀−老化过程对重金属吸附−解吸的非线性控制机制。
    展望 基于上述阶段性演化特征的认知,有价资源回收技术的路径选择需求与水质阶段深度耦合:闭坑初期宜采用电化学活化石灰石系统实现靶向金属回收,闭坑中期可通过硫酸浸出工艺转化富集态沉淀渣中的有价元素,至闭坑长期则需针对不同水质特征构建分类处理与调蓄利用体系。研究成果可为构建废弃矿井水污染治理与有价元素资源化利用新范式提供科学依据与技术路径。

     

    Abstract:
    Background  Abandoned mine drainage, also known as acidic mine drainage (AMD), represents a major pollution source in mining areas while also serving as an important carrier of strategic critical metals and underground space utilization. In China, water pollution stemming from coal mining is more severe in the south than in the north. This spatial pattern is jointly shaped by climatic conditions, geological settings, and mining history.
    Advances  From the perspective of the environmental geochemical frontier, this study presents a systematic review of AMD formation and evolution mechanisms, as well as technologies for water pollution prevention and control, resource recovery, and collaborative energy utilization. The water quality of an abandoned mine undergoes a distinct three-stage evolutionary process: (1) heavy metal concentration peaking in the initial stage, predominantly governed by inorganic water-rock interactions; (2) microbially driven self-purification in the medium term; and (3) dynamic equilibrium after mixing with the regional groundwater system in the long term. Analysis of the kinetic process of pyrite oxidation indicates that the initiation of initial acidification by neutrophilic microbes plays a key role in controlling the AMD release rate. Furthermore, the source-sink evolution pattern of contaminants in complex karst-water media is elucidated, revealing that the adsorption and desorption of heavy metals are subjected to the nonlinear control of secondary minerals’ precipitation and aging induced by the buffering effect of carbonate rocks.
    Prospects  Given the evolutionary characteristics of mine water quality in different stages after the mine abandonment, it is necessary to select technologies for valuable resource recovery by deeply coupling the evolutionary stages. Specifically, in the initial stage, an electrochemically activated limestone system should be employed for targeted metal recovery; in the medium term, valuable elements in element-enriched precipitated slags can be converted using sulfuric acid leaching, and in the long term, a class-based treatment and regulation system should be established based on distinct water quality characteristics. The results of this study will provide a scientifically robust basis and a technical pathway for developing a new paradigm of water pollution treatment and valuable element reutilization for abandoned mines.

     

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