Journal of the Korea institute for structural maintenance and inspection (한국구조물진단유지관리공학회 논문집)

Korea Institute for Structural Maintenance Inspection (한국구조물진단유지관리공학회)
권호 표지
DOI QR코드

DOI QR Code

Binding of the Hexavalent Chromium Ions in the Process of Cement Hydration

시멘트 수화에 따른 6가 크롬의 고정화 특성

  • Received : 2013.05.09
  • Accepted : 2013.07.24
  • Published : 2013.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

The hexavalent chromium (Cr(VI)) is well known as a hazardous ion, presumably inducing dermatic diseases and if serious cancer. The present study concerns the binding capacity of Cr(VI) ions in the cement powder and matrix for a quantitative technique of Cr(VI) ions in cement to influence human health. Both the water-soluble and acid-soluble Cr(VI) ions present in 3 types of ordinary Portland cement (OPC), pulverised fuel ash (PFA), ground granulated blast furnace slag (GGBS), and silica fume (SF) were measured using the spectrophotometer. As a result, it was found that the concentration of water-soluble Cr(VI) ion in cement ranged from 10.5 to 18.9mg/kg-cement, and in the additional materials a very low value of Cr(VI) ion was measured. Acid-soluble Cr(VI) ion was even higher than water-soluble Cr(VI) ion, ranging from 172.4 to 318.2mg/kg-cement. Nevertheless, the concentration of acid-soluble Cr(VI) ion is not proportional to addition of acid. It depends rather the variable pH of solvent involving cement paste. As enough cement hydration occurs, the binding capacity of Cr(VI) ion increases, inhibiting this ions from leaching out in the presence of hydration products such as ettringite or tri-calcium aluminate which bind Cr(VI) ion by ion-exchange.

시멘트 내 6가 크롬은 피부질환이나 암을 유발할 수 있는 유해한 인체에 유해한 이온으로 잘 알려져 있다. 본 연구에서는 사람에게 영향을 주는 시멘트 내 6가 크롬의 정량적 분석을 하고자 시멘트 및 시멘트 경화체 내 6가 크롬의 고정화에 대해 평가하였다. 국내에서 생산되는 일반 포틀랜드 시멘트 3종과 플라이애쉬, 고로슬래그 미분말, 실리카퓸을 사용하여 수용성 및 산가용성 6가 크롬을 분광광도법으로 측정하였다. 측정결과, 시멘트 내 수용성 6가 크롬의 농도는 10.5-18.9 mg/kg-cement 범위였으며 혼화재료 내 수용성 6가 크롬의 양은 매우 적게 측정되었다. 시멘트 내 산가용성 6가 크롬의 농도는 172.4-318.2 mg/kg-cement 범위로 측정되었으며 수용성 6가 크롬에 비해 증가하였다. 그러나 크롬의 pH에 의존적인 용해 특성에 따라 용매의 pH가 저감된다고 하여 산가용성 6가 크롬의 농도가 항상 크게 측정되지는 않았다. 시멘트 수화 후 수용성 6가 크롬은 2.0 mg/kg-cement 정도로 감소하였으며 이는 크롬산-에트링게이트 생성에 의한 결과임을 확인할 수 있었다.

Keywords

References

  1. Bravo, A., Cerulli, T., Dragoni, M., Magistri, M. and Padovani, D., "Determination of soluble chromates in cement and cementbased materials by ion chromatography", ZKG International, Vol. 58, 2005, pp.55-62.
  2. BS EN 196-10, "Methods of testing cement: Part 10 Determination of the water-soluble chromium(VI) content of cement", 2006.
  3. Directive 2003/53/EC, "Restrictions on the marketing and use of certain dangerous substances and preparations (nonylphenol, nonylphenol ethoxylate and cement)", 2003.
  4. Fontas, C., Queralt, I. and Hidalgo, M., "Novel and selective procedure for Cr(VI) determining by X-ray fluorescence analysis after membrane concentration", Spectrochimica Acta, Part B, Vol. 61, 2006, pp.407-413. https://doi.org/10.1016/j.sab.2006.02.011
  5. Fregert, S. and Gruvberger, B., "Factors decreasing the content of water-soluble chromate in cement", Acta Dermatologica Venereologica, Vol. 53, 1973, pp.267-270.
  6. Fregert, S., Gruvberger, B. and Sandahl, E., "Reduction of chromate in cement by iron sulfate", Contact Dermatitis, Vol. 5, 1979, pp.39-42. https://doi.org/10.1111/j.1600-0536.1979.tb05533.x
  7. Hills, L. and Johansen, V. C., Hexavalent chromium in cement manufacturing: literature review, 2007, PCA R&D Serial No. 2983.
  8. Jain, N. and Garg, M., "Effect of Cr(VI) on the hydration behavior of marble dust blended cement: solidification, leachability and XRD analysis", Construction and Building Materials, Vol 22, 2008, pp.1851-1856. https://doi.org/10.1016/j.conbuildmat.2007.04.022
  9. Kuehl, M., "It's all in the chemistry", World Cement, Vol. 9, 2006, pp.95-98.
  10. Magistri, M. and D'Arcangelo, M., "World cement research: Stannous sulfate", Mapei SPA, 2007.
  11. Magistri, M., Padovani, D. and Nicodemi, M., "A study on the release mechanism of soluble chrmates during the clinker hydration", In: The 6th Coloquia of Managers and Technicians of Cement Plants, Valencia, Spain, 2006.
  12. Ministry of environment, "Result of private and public joint research about heavy metals including cement", 2008.
  13. Potgieter, S. S., Panichev, N., Potgier, J. H. and Panicheva, S., "Determination of hexavalent chromium in South African cements and cement-related materials with electrothermal atomic absorption spectrometry", Cement and Concrete Research, Vol. 33, 2003, pp.1589-1593. https://doi.org/10.1016/S0008-8846(03)00132-7
  14. Trezza, M. A. and Ferraiuelo, M. F., "Hydration study of limestone blended cement in the presence of hazardous wastes containing Cr(VI)", Cement and Concrete Research, Vol. 33, 2003, pp.1039-1045. https://doi.org/10.1016/S0008-8846(03)00008-5
  15. Wang, S. and Vipulanandan, C., "Solidification/ stabilization of Cr(VI) with cement leachability and XRD analyses", Cement and Concrete Research, Vol. 30, 2000, pp.385-389. https://doi.org/10.1016/S0008-8846(99)00265-3
  16. Yamaguchi, O., Ida, M., Uchiyama, Y. and Hanehara, S., "A method for the determination of total Cr(VI) in cement", Journal of the European Ceramic Society, Vol. 26, 2006, pp.785-790. https://doi.org/10.1016/j.jeurceramsoc.2005.07.046