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首页> 外文会议>Annual national meeting American Society for Surface Mining and Reclamation >HYDRAULIC CONDUCTIVITY OF ASH MIXTURES AND METAL RELEASE UPON LEACHING
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HYDRAULIC CONDUCTIVITY OF ASH MIXTURES AND METAL RELEASE UPON LEACHING

机译：灰色混合物的液压导电性和浸出时的金属释放

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Generation of electricity by coal-fired power plants produces large quantities of bottom ash and fly ash. New power plants commonly use fluidized bed combustion (FBC) boilers, which create ashes with high neutralization potential (NP). These ashes, due to their alkaline nature, are often used in surface mine reclamation projects to neutralize acidity and reduce hydraulic conductivity of disturbed overburden materials. Conventional fly ashes from older power plants exhibit a range of pH and NP, with some ashes having neutral or acidic pH and low NP values. This study measured the hydraulic conductivity and leachate quality of various mixtures of three fly ashes: 1) a fly ash with low NP (LNP ash) and two FBC ashes (FBC1 and FBC2). Results indicate that water will flow through these materials at a moderate rate (about 10~(-4) cm/sec), but compaction with machinery and with pressure from overlying fill materials may decrease these hydraulic conductivity rates by an order of magnitude. Several trace elements were found at high levels in the leachates of some ash mixtures after sulfuric acid leaching. LNP fly ash leachates had high arsenic and selenium concentrations. Amending LNP conventional ash with FBC ashes reduced arsenic concentrations but not selenium contents. Lead, cadmium, and barium concentrations in fly ash leachates were not high enough to cause water pollution problems. Manganese was released from LNP ash at a constant level, FBC 1 ash did not release manganese, while FBC2 ash released manganese only after the NP had been exhausted by 60 pore volumes of sulfuric acid leaching.
机译：通过燃煤发电厂产生电力产生大量的底灰和粉煤灰。新型发电厂常用流化床燃烧（FBC）锅炉，用高中和电位（NP）产生灰烬。由于它们的碱性性质，这些灰烬通常用于表面矿井填海工程中，以中和酸度并降低干扰覆盖物材料的液压导电性。较老发电厂的常规飞灰表现出一系列pH和NP，具有中性或酸性pH和低NP值。本研究测量了三次飞灰的各种混合物的液压导电和渗滤液质量：1）具有低NP（LNP灰分）和两个FBC灰（FBC1和FBC2）的粉煤灰。结果表明，水将以适度的速率（约10〜（-4）cm / sec）流过这些材料，但是用机械压实和来自覆盖填充材料的压力可以通过幅度降低这些液压导电率。在硫酸浸出后，在一些灰分混合物的浸出物中发现了几种微量元素。 LNP粉煤灰渗滤液具有高砷和硒浓度。用FBC灰烬修改LNP常规灰分，降低砷浓度，但不是硒含量。粉煤灰渗滤液中的铅，镉和钡浓度不足以引起水污染问题。 FBC 1 Ash在恒定水平下从LNP灰释放出锰，而FBC2灰分释放锰才释放锰，仅在NP被耗尽60孔体积的硫酸浸出后。

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