金属矿山环境污染及整治对策

金属矿床开采 ,一方面是开发利用自然资源 ,另一方面由于对土水生态环境释放重金属和酸性废水而破坏自然环境。金属矿山环境污染源于金属硫化物特别是黄铁矿、磁黄铁矿的氧化分解。金属硫化物的氧化释放出重金属离子和SO4 2 -,黄铁矿、磁黄铁矿的氧化还释放出Fe2 +、Fe3+和H+,铁 (Fe2 +、Fe3+)的存在和pH值的降低大大加速金属硫化物的分解和重金属元素的沉淀。铁氧化细菌的活动可以提高或催化氧化反应的速度 ,加速重金属的水解和沉淀。铁作为普遍存在的元素 ,其地球化学行为影响着金属硫化物氧化的程度和速度 ;铁作为主要的次生沉淀矿物 ,其承载矿物主导其它重金属元素的沉淀。本文介绍了碱性物质中和、湿地处理系统、覆盖隔离技术等一系列已成功地运用于金属矿山环境污染整治的实用方法 ,并对一些前沿整治技术作了简要介绍

Metal deposit environmental pollution and its remediation

The exploitation of metal deposit is for the utilization of natural resources, but the exploitation produces heavy metal elements and acid mine drainage, which pollute soil-water ecosystem. Metal deposit environmental pollution originates from the oxidation and decomposition reaction of metal sulfides , particularly pyrite(FeS 2) and pyrrhotite (FeS).The oxidation of sulfides releases heavy metal ions and SO 4 2 , the oxidation of pyrite and pyrrhotite produces Fe 2+ ,Fe 3+ and H + in addition. Iron ions (Fe 2+ ,Fe 3+ ) production and pH value drop greatly accelerate the velocity of sulfides decomposition and of heavy metal ions precipitation. Bacterium activity can improve or catalyze the velocity of oxidation reaction ,accelerate hydrolysis and precipitation of heavy mental ions .Iron ,as a common element, its geochemical behavior affects the oxidation degree and velocity of sulfides; iron minerals ,as primary secondary minerals, their loading minerals dominate precipitation of other heavy metal elements. A series of remediation measures such as alkaline dosing treatment, wetland treatment system, capping and isolation measures have been successfully applied to control metal deposit environmental pollution .Finally , some advanced methods of treatments have been introduced.