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Econ. Environ. Geol. 2021; 54(2): 299-308

Published online April 30, 2021

https://doi.org/10.9719/EEG.2021.54.2.299

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

Mineralogical and Geochemical Characteristics of the Precipitates in Acid Mine Drainage of the Heungjin-Taemaek Coal Mine

Ji-Hwan Shin, Ji-Yeon Park, Yeongkyoo Kim*

School of Earth System Sciences, Kyungpook National University, Daegu, 41566, Korea

Correspondence to : ygkim@knu.ac.kr

Received: March 25, 2021; Revised: April 25, 2021; Accepted: April 26, 2021

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided original work is properly cited.

Abstract

Fe(II) released from mining activities is precipitated as various Fe(III)-oxyhydroxides when exposed to an oxidizing environment including mine drainage. Ferrihydrite, one of the representative precipitated Fe(III) minerals, is easy to adsorb heavy metals and other pollutants due to the large specific surface area caused by very low crystallinity. Ferrihydrite is transformed to thermodynamically more stable goethite in the natural environment. Hence, information on the transformation of ferrihydrite to goethite and the related mobility of heavy metals in the acid mine drainage is important to predict the behaviors of those elements during ferrihydrite to goethite transition. The behaviors of heavy metals during the transformation of ferrihydrite to goethite were investigated for core samples collected from an AMD treatment system in the Heungjin-Taemaek coal mine by using X-ray diffraction (XRD), chemical analysis, and statistical analysis. XRD results showed that ferrihydrite gradually transformed to goethite from the top to the bottom of the core samples. Chemical analysis showed that the relative concentration of As was significantly high in the core samples compared with that in the drainage, indicating that As was likely to be adsorbed strongly on or coprecipitated with iron oxyhydroxide. Correlation analysis also indicated that As can be easily removed from mine drainage during iron mineral precipitation due to its high affinity to Fe. The concentration ratio of As, Cd, Co, Ni, and Zn to Fe generally decreased with depth in the core samples, suggesting that mineral transformation can increase those concentrations in the drainage. In contrast, the concentration ratio of Cr to Fe increased with depth, which can be explained by the chemical bond of iron oxide and chromate, and surface charge of ferrihydrite and goethite.

Keywords acid mine drainage, ferrihydrite, goethite, mineral transformation, heavy metal

흥진태맥 석탄광 산성광산배수 침전물의 광물학적 및 지구화학적 특성

신지환 · 박지연 · 김영규*

경북대학교 지구시스템과학부

요 약

광산 활동에서 비롯된 Fe(II)은 광산 배수를 따라 지표의 산화 환경에 노출되어 다양한 Fe(III)-산화수산화물로 침전된다. 대표적인 Fe(III) 침전 광물 중 하나인 페리하이드라이트는 결정도가 매우 낮아 비표면적이 크기 때문에, 중금속 및 다른 오염물질을 흡착하기에 용이하다. 페리하이드라이트는 자연 환경에서 열역학적으로 좀더 안정적인 침철석으로 전이된다. 페리하이드라이트에서 침철석으로 전이되는 동안 일어나는 중금속의 거동을 예측하기 위해서 산성광산배수에서 일어나는 페리하이드라이트에서 침철석으로의 전이와 이와 연관된 중금속의 유동성에 대한 정보는 중요하다. 광물 전이와 중금속 거동을 분석하기 위해 흥진태맥 석탄광의 산성광산배수 정화 시설의 코어 시료에 대하여 X-선 회절 분석(XRD), 화학 분석, 통계 분석이 시행되었다. XRD 결과는 페리하이드라이트가 코어 시료 상단에서 하단으로 점차 침철석으로 전이되었음을 보여주었다. 화학 분석 결과 코어시료에서 As의 상대적 농도는 배수에 비하여 매우 높아 As가 철옥시수산화물에 강하게 흡착 되었거나 공침되었을 가능성이 큼을 지시한다. 상관 분석 결과 또한 As와 Fe의 높은 친화도를 보여주어, 철광물이 침전하는 동안 As가 광산 배수에서 쉽게 제거될 수 있음을 나타냈다. 코어 시료에서 깊이가 깊어질수록 Fe에 대한 As, Cd, Co, Ni, Zn의 농도비는 대체로 감소하여, 광물전이 시 배수 내 이들의 농도를 증가시킬 수 있음을 나타냈다. 이와 반대로 Fe에 대한 Cr의 농도는 깊이가 증가할수록 증가하였는데 이 것은 chromate과 철광물과의 화학결합과 페리하이드라이트와 침철석의 표면 전하로 인한 것으로 생각된다.

주요어 산성광산배수, 페리하이드라이트, 침철석, 광물 전이, 중금속

Article

Research Paper

Econ. Environ. Geol. 2021; 54(2): 299-308

Published online April 30, 2021 https://doi.org/10.9719/EEG.2021.54.2.299

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

Mineralogical and Geochemical Characteristics of the Precipitates in Acid Mine Drainage of the Heungjin-Taemaek Coal Mine

Ji-Hwan Shin, Ji-Yeon Park, Yeongkyoo Kim*

School of Earth System Sciences, Kyungpook National University, Daegu, 41566, Korea

Correspondence to:ygkim@knu.ac.kr

Received: March 25, 2021; Revised: April 25, 2021; Accepted: April 26, 2021

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided original work is properly cited.

Abstract

Fe(II) released from mining activities is precipitated as various Fe(III)-oxyhydroxides when exposed to an oxidizing environment including mine drainage. Ferrihydrite, one of the representative precipitated Fe(III) minerals, is easy to adsorb heavy metals and other pollutants due to the large specific surface area caused by very low crystallinity. Ferrihydrite is transformed to thermodynamically more stable goethite in the natural environment. Hence, information on the transformation of ferrihydrite to goethite and the related mobility of heavy metals in the acid mine drainage is important to predict the behaviors of those elements during ferrihydrite to goethite transition. The behaviors of heavy metals during the transformation of ferrihydrite to goethite were investigated for core samples collected from an AMD treatment system in the Heungjin-Taemaek coal mine by using X-ray diffraction (XRD), chemical analysis, and statistical analysis. XRD results showed that ferrihydrite gradually transformed to goethite from the top to the bottom of the core samples. Chemical analysis showed that the relative concentration of As was significantly high in the core samples compared with that in the drainage, indicating that As was likely to be adsorbed strongly on or coprecipitated with iron oxyhydroxide. Correlation analysis also indicated that As can be easily removed from mine drainage during iron mineral precipitation due to its high affinity to Fe. The concentration ratio of As, Cd, Co, Ni, and Zn to Fe generally decreased with depth in the core samples, suggesting that mineral transformation can increase those concentrations in the drainage. In contrast, the concentration ratio of Cr to Fe increased with depth, which can be explained by the chemical bond of iron oxide and chromate, and surface charge of ferrihydrite and goethite.

Keywords acid mine drainage, ferrihydrite, goethite, mineral transformation, heavy metal

흥진태맥 석탄광 산성광산배수 침전물의 광물학적 및 지구화학적 특성

신지환 · 박지연 · 김영규*

경북대학교 지구시스템과학부

Received: March 25, 2021; Revised: April 25, 2021; Accepted: April 26, 2021

요 약

광산 활동에서 비롯된 Fe(II)은 광산 배수를 따라 지표의 산화 환경에 노출되어 다양한 Fe(III)-산화수산화물로 침전된다. 대표적인 Fe(III) 침전 광물 중 하나인 페리하이드라이트는 결정도가 매우 낮아 비표면적이 크기 때문에, 중금속 및 다른 오염물질을 흡착하기에 용이하다. 페리하이드라이트는 자연 환경에서 열역학적으로 좀더 안정적인 침철석으로 전이된다. 페리하이드라이트에서 침철석으로 전이되는 동안 일어나는 중금속의 거동을 예측하기 위해서 산성광산배수에서 일어나는 페리하이드라이트에서 침철석으로의 전이와 이와 연관된 중금속의 유동성에 대한 정보는 중요하다. 광물 전이와 중금속 거동을 분석하기 위해 흥진태맥 석탄광의 산성광산배수 정화 시설의 코어 시료에 대하여 X-선 회절 분석(XRD), 화학 분석, 통계 분석이 시행되었다. XRD 결과는 페리하이드라이트가 코어 시료 상단에서 하단으로 점차 침철석으로 전이되었음을 보여주었다. 화학 분석 결과 코어시료에서 As의 상대적 농도는 배수에 비하여 매우 높아 As가 철옥시수산화물에 강하게 흡착 되었거나 공침되었을 가능성이 큼을 지시한다. 상관 분석 결과 또한 As와 Fe의 높은 친화도를 보여주어, 철광물이 침전하는 동안 As가 광산 배수에서 쉽게 제거될 수 있음을 나타냈다. 코어 시료에서 깊이가 깊어질수록 Fe에 대한 As, Cd, Co, Ni, Zn의 농도비는 대체로 감소하여, 광물전이 시 배수 내 이들의 농도를 증가시킬 수 있음을 나타냈다. 이와 반대로 Fe에 대한 Cr의 농도는 깊이가 증가할수록 증가하였는데 이 것은 chromate과 철광물과의 화학결합과 페리하이드라이트와 침철석의 표면 전하로 인한 것으로 생각된다.

주요어 산성광산배수, 페리하이드라이트, 침철석, 광물 전이, 중금속

    Fig 1.

    Figure 1.Passive treatment system for acid mine drainage from the Heungjin-Taemaek coal mine and the sampling points (A, B, C).
    Economic and Environmental Geology 2021; 54: 299-308https://doi.org/10.9719/EEG.2021.54.2.299

    Fig 2.

    Figure 2.XRD patterns of samples from sediment cores with different depths from the two sampling points. f: feldspars fh: ferrihydrite, gt: goethite, k: kaolinite, m: mica, q: quartz.
    Economic and Environmental Geology 2021; 54: 299-308https://doi.org/10.9719/EEG.2021.54.2.299

    Fig 3.

    Figure 3.The wt% of Fe2O3 at different depths for two core samples.
    Economic and Environmental Geology 2021; 54: 299-308https://doi.org/10.9719/EEG.2021.54.2.299

    Fig 4.

    Figure 4.The concentrations of As and heavy metals at different depths for two core samples.
    Economic and Environmental Geology 2021; 54: 299-308https://doi.org/10.9719/EEG.2021.54.2.299

    Fig 5.

    Figure 5.The concentration ratio of As and heavy metal and iron at different depths for two core samples.
    Economic and Environmental Geology 2021; 54: 299-308https://doi.org/10.9719/EEG.2021.54.2.299

    Table 1 . Field data measured in the oxidation ponds of the Heungjin-Taemaek mine’s treatment system.

    PointTemperature
     (°C)
    pHEh
    (mV)
    EC
    (mS/cm)
    A166.622880.85
    B15.86.562920.85
    C15.76.53450.92

    Eh: redox potential, EC: electrical conductivity..


    Table 2 . Concentration of elements in the mine drainage from the three points studied.

    PointCaNaMgSiFeSO4ClAsCoNiZn
    mg/kgμg/kg
    A18733.727.36.990.023921.323.9420.315.768.8
    B19334.528.27.020.034061.403.4620.017.769.2
    C19434.528.37.110.024101.423.3220.217.169.8

    Table 3 . Pearson’s correlation coefficients between concentration of iron and other metals.

    AsCdCoCrCuNiPbZn
    Fe.819**.507.612-.652*.103.506.157.541

    ** significant at 0.01 level, * significant at 0.05 level..


    KSEEG
    Jun 30, 2024 Vol.57 No.3, pp. 281~352

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