Haney E B, Haney R L, Hossner L R, White G N
Railroad Commission of Texas, Surface Mining and Reclamation Division, P.O. Box 12967 Austin, TX 78711-2967, USA.
J Environ Qual. 2006 Apr 26;35(3):871-9. doi: 10.2134/jeq2005.0187. Print 2006 May-Jun.
Siderite (FeCO3) is commonly found in coal overburden and, when present, can cause interference in the determination of neutralization potential (NP). Under acidic testing conditions, FeCO3 reacts to neutralize acid, which contributes to the NP. However, continued weathering of FeCO3 (oxidation of Fe2+ and hydrolysis of Fe3+) produces a neutral to slightly acidic solution. The effects of hydrogen peroxide (H2O2), potassium permanganate (KMnO4), and O2 on the laboratory measurement of NP of siderite samples taken from overburden were examined. All oxidation treatments lowered the NP values of the siderite samples as compared with the standard USEPA method. However, oxidation with H2O2 produced variable results depending on the amount of H2O2 added. Neutralization potential values obtained after oxidation treatments were highly correlated with Mn concentration. Reaction products (i.e., 2-line ferrihydrite) of siderite samples with H2O2 and KMnO4 were not representative of natural siderite weathering. Oxidation with O2 produced the lowest NP values for siderite samples. The reaction products produced by oxidation with O2 most closely represent those intermediate products formed when siderite is exposed to atmospheric weathering conditions. Oxidation with O2 also proved to be the most reproducible method for accurately assessing NP when siderite is present in overburden samples.
菱铁矿（FeCO₃）常见于煤矸石中，一旦存在，会对中和潜力（NP）的测定产生干扰。在酸性测试条件下，FeCO₃会发生反应中和酸，这对NP有贡献。然而，FeCO₃的持续风化（Fe²⁺氧化和Fe³⁺水解）会产生中性至微酸性溶液。研究了过氧化氢（H₂O₂）、高锰酸钾（KMnO₄）和氧气对取自煤矸石的菱铁矿样品NP实验室测定的影响。与美国环境保护局（USEPA）标准方法相比，所有氧化处理均降低了菱铁矿样品的NP值。然而，用H₂O₂氧化会因添加的H₂O₂量不同而产生不同结果。氧化处理后获得的中和潜力值与锰浓度高度相关。菱铁矿样品与H₂O₂和KMnO₄反应的产物（即二线水铁矿）并非自然菱铁矿风化的典型产物。用氧气氧化时，菱铁矿样品的NP值最低。用氧气氧化产生的反应产物最接近菱铁矿暴露于大气风化条件下形成的中间产物。当煤矸石样品中存在菱铁矿时，用氧气氧化也被证明是准确评估NP最具可重复性的方法。
Zotero 插件