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首页> 外文期刊>Environmental Science & Technology >Changes in Zinc Speciation with Mine Tailings Acidification in a Semiarid Weathering Environment
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Changes in Zinc Speciation with Mine Tailings Acidification in a Semiarid Weathering Environment

机译：半干旱风化环境下尾矿酸化锌形态的变化

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摘要

High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semiarid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the Klondyke State Superfund Site (AZ, USA), ranging in pH from 5.4 to 2.6, represent a weathering series, with acidification resulting from sulfide mineral oxidation, long-term Fe hydrolysis, and a concurrent decrease in total (6000 to 450 mg kg~l) and plant-available (590 to 75 mg kg-1) Zn due to leaching losses and changes in Zn speciation. Here, we used bulk and microfocused Zn K-edge X-ray absorption spectroscopy (XAS) data and a six-step sequential extraction procedure to determine tailings solid phase Zn speciation. Bulk sample spectra were fit by linear combination using three references: Zn-rich phyllosilicate (Zn_(0.8)talc), Zn sorbed to ferrihydrite (Zn_(adsFeOx)), and zinc sulfete (ZnSO_4•7H_2O). Analyses indicate that Zn sorbed in tetrahedral coordination to poorly crystalline Fe and Mn (oxyhydr)oxides decreases with acidification in the weathering sequence, whereas octahedral zinc in sulfate minerals and crystalline Fe oxides undergoes a relative accumulation. Microscale analyses identified hetaerolite (ZnMn_2O_4), hemimorphite (Za_4Si_2O_7(OH)_2•H_2O) and sphalerite (ZnS) as minor phases. Bulk and microfocused spectroscopy complement the chemical extraction results and highlight the importance of using a multimethod approach to interrogate complex tailings systems.
机译：矿山尾矿中高浓度的残留金属污染物可以通过风和水轻松运输，尤其是在采矿停止后数十年仍无植被的情况下，半干旱景观就是这种情况。了解污染物金属的形态和流动性，特别是在表面尾矿中，对于控制其植物毒性和重新植被受影响的部位至关重要。在先前的工作中，我们显示了Klondyke State Superfund Site（美国亚利桑那州）的表面尾矿样品的pH值范围为5.4至2.6，代表了风化系列，硫化物矿物氧化，长期铁水解和酸化导致酸化。由于浸出损失和锌形态的变化，锌总量减少（6000至450 mg kg-1），植物有效锌减少（590至75 mg kg-1）。在这里，我们使用块状和微聚焦的Zn K边缘X射线吸收光谱（XAS）数据以及六步顺序萃取程序来确定尾矿固相Zn形态。使用三个参考，通过线性组合拟合大块样品光谱：富锌层状硅酸盐（Zn_（0.8）滑石粉），吸附到三水铁矿上的锌（Zn_（adsFeOx））和硫化锌（ZnSO_4•7H_2O）。分析表明，在风化序列中，随着酸化作用的发生，四面体配体中吸附的锌吸附到结晶度较弱的Fe和Mn（羟基氧化物）氧化物时会减少，而硫酸盐矿物和结晶Fe氧化物中的八面体锌则相对积累。微观分析表明，杂沸石（ZnMn_2O_4），半晶石（Za_4Si_2O_7（OH）_2•H_2O）和闪锌矿（ZnS）为次要相。体相和微聚焦光谱对化学提取结果起到了补充作用，并突出了使用多方法方法对复杂尾矿系统进行讯问的重要性。

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  • 来源
    《Environmental Science & Technology》 |2011年第17期|p.7166-7172|共7页
  • 作者

    Sarah M. Hayes; Peggy A. ODay; Sam M. Webb; Raina M. Maier; Jon Chorover;

  • 作者单位

    Department of Soil, Water and Environmental Science, University of Arizona, Tucson, Arizona 85721, United States;

    School of Natural Sciences, University of California, Merced, California 95343, United States;

    Stanford Synchrotron Radiation Laboratory, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 69,Menlo Park, California 94025, United States;

    Department of Soil, Water and Environmental Science, University of Arizona, Tucson, Arizona 85721, United States;

    Department of Soil, Water and Environmental Science, University of Arizona, Tucson, Arizona 85721, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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  • 正文语种 eng
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