Original Article

Econ. Environ. Geol. 2018; 51(5): 429-438

Published online October 31, 2018

https://doi.org/10.9719/EEG.2018.51.5.429

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

Variations in Heavy Metal Analytical Results and Leaching Characteristics of Coal Ash Recycled Concretes according to Sample Crushing Methods

Jin Won Lee1, Seung-Hyun Choi1, Kangjoo Kim1* and Bo-Kyung Moon2

1Department of Environmental Engineering, Kunsan National University, Kunsan 54150, Korea
2Korea Western Power, Co., Ltd., Taean, Chungnam 32140, Korea

Correspondence to : kangjoo@kunsan.ac.kr

Received: August 14, 2018; Revised: October 3, 2018; Accepted: October 18, 2018

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

Since concrete is a hardened aggregates of various materials, it needs to be crushed for chemical analyses. However, the effect of sample crushing on the analytical results has not been precisely assessed till today. In this study, we prepared concrete test pieces using Portand cements and fly ashes as binding materials, and ponded ashes and sands as aggregates and analyzed the heavy metals of the test pieces using Standards for Fair Testing of Soil Contamination (SFTSC) and Wastes (SFTW). For this, each test piece was partially crushed at first and sieved for separation of grains of <0.15 mm, 0.15-0.5 mm, and 0.5-5 mm from the same crushed samples (Crushing Method I). Results of those samples using SFTSC showed a clear trend that analyzed heavy metal concentrations are higher in the finer fractions. Particularly, fractions with <0.15 mm indicated much higher concentrations than the theoretical ones, which were calculated based on the concentrations of individual materials and their mixing fractions. In contrast, the analytical results were generally comparable with the theoretical ones when the test pieces were totally pulverized such that all the crushed grains were <0.15 mm in size (Crushing Method II). These results are associated with the fact that cement materials and fly ashes, which are high in heavy metals relative to other materials, are enriched in the fine fractions. The analytical results using the SFTW derived very low concentrations in most of parameters and did not indicate the dependence of concentrations on the crushing methods due to using distilled water as leaching agent.

Keywords concrete, sample preparation, cement, coal ash, heavy metal analysis, Standard for Fair Testing of Soil Contamination

분쇄방법에 따른 석탄재 재활용 콘크리트의 중금속 분석결과 및 용출특성 변화

이진원1 ·최승현1 ·김강주1* ·문보경2

1군산대학교 환경공학과, 2한국서부발전(주)

요 약

Article

Original Article

Econ. Environ. Geol. 2018; 51(5): 429-438

Published online October 31, 2018 https://doi.org/10.9719/EEG.2018.51.5.429

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

Variations in Heavy Metal Analytical Results and Leaching Characteristics of Coal Ash Recycled Concretes according to Sample Crushing Methods

Jin Won Lee1, Seung-Hyun Choi1, Kangjoo Kim1* and Bo-Kyung Moon2

1Department of Environmental Engineering, Kunsan National University, Kunsan 54150, Korea
2Korea Western Power, Co., Ltd., Taean, Chungnam 32140, Korea

Correspondence to:kangjoo@kunsan.ac.kr

Received: August 14, 2018; Revised: October 3, 2018; Accepted: October 18, 2018

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

Since concrete is a hardened aggregates of various materials, it needs to be crushed for chemical analyses. However, the effect of sample crushing on the analytical results has not been precisely assessed till today. In this study, we prepared concrete test pieces using Portand cements and fly ashes as binding materials, and ponded ashes and sands as aggregates and analyzed the heavy metals of the test pieces using Standards for Fair Testing of Soil Contamination (SFTSC) and Wastes (SFTW). For this, each test piece was partially crushed at first and sieved for separation of grains of <0.15 mm, 0.15-0.5 mm, and 0.5-5 mm from the same crushed samples (Crushing Method I). Results of those samples using SFTSC showed a clear trend that analyzed heavy metal concentrations are higher in the finer fractions. Particularly, fractions with <0.15 mm indicated much higher concentrations than the theoretical ones, which were calculated based on the concentrations of individual materials and their mixing fractions. In contrast, the analytical results were generally comparable with the theoretical ones when the test pieces were totally pulverized such that all the crushed grains were <0.15 mm in size (Crushing Method II). These results are associated with the fact that cement materials and fly ashes, which are high in heavy metals relative to other materials, are enriched in the fine fractions. The analytical results using the SFTW derived very low concentrations in most of parameters and did not indicate the dependence of concentrations on the crushing methods due to using distilled water as leaching agent.

Keywords concrete, sample preparation, cement, coal ash, heavy metal analysis, Standard for Fair Testing of Soil Contamination

분쇄방법에 따른 석탄재 재활용 콘크리트의 중금속 분석결과 및 용출특성 변화

이진원1 ·최승현1 ·김강주1* ·문보경2

1군산대학교 환경공학과, 2한국서부발전(주)

Received: August 14, 2018; Revised: October 3, 2018; Accepted: October 18, 2018

요 약

    KSEEG
    Feb 29, 2024 Vol.57 No.1, pp. 1~91

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