Economic and Environmental Geology (자원환경지질)

The Korean Society of Economic and Environmental Geology (대한자원환경지질학회)
권호 표지
DOI QR코드

DOI QR Code

A Study for Recoverability of Iron Resource in Red Mud

레드머드 내 철 자원 회수 가능성 고찰

  • 김봉주 (한국원자력연구원, 방사성폐기물처분연구부) ;
  • 권장순 (한국원자력연구원, 방사성폐기물처분연구부) ;
  • 고용권 (한국원자력연구원, 방사성폐기물처분연구부) ;
  • 박천영 (조선대학교 에너지.자원공학과)
  • Received : 2020.03.15
  • Accepted : 2020.05.19
  • Published : 2020.06.28
Download PDF
⟨ Previous Next ⟩

Abstract

The red mud generated from bauxite during the Bayer alumina production process has been regarded as an industrial waste due to the high alkaline property and high content of Na. Despite of its environmental problem, various studies for recovery of the valuable resources from red mud has been also carried out because of high content (25.7 wt.% as Fe2O3 in this study) of iron in red mud. In order to recover the iron resource in the red mud, microwave heating experiments were performed with adding of activated carbon and elemental sulfur to the red mud. Through the microwave heating the powdered red mud mixtures converted to porous and vitrified solid aggregates. The vitrified aggregates produced by microwave heating are composed of goethite, zero valent iron (Fe0), pyrrhotite and pyrite. And then, the microwave heating samples were dissolved in the aqua regia solution, and Fe precipitates were obtained as a Fe-chlorides by adding of NaCl salt in the aqua regia solution. The Fe recovery rates in the Fe-chloride precipitates showed differences depending on the experimental mixture conditions, and Fe grades of the end products are 49.0 wt.%, 58.0 wt.% and 59.5 wt.% under mixture conditions of red mud, red mud + activated carbon, and red mud + activated carbon + elemental S, respectively. The Fe content of 56.0 wt.% is generally known as the grade value of Fe in a iron ore for iron production, and the Fe grades of microwave heating samples with adding activated carbon and elemental S in this study are higher than the grade value of 56.0 wt.%.

보오크사이트로부터 알루미나를 생산하는 Bayer 공정 부산물인 레드머드는 높은 pH와 나트륨(Na)의 함량으로 폐기물로 분류되어, 발생량을 줄이거나 재활용하는 공정의 개발은 환경적으로 중요한 이슈이다. 본 연구에서는 레드머드 내 다량 함유된 철(Fe)을 자원가치를 갖는 품위(56wt.%) 이상으로 향상시키고자 레드머드에 활성탄과 황을 혼합하여 마이크로웨이브 가열 시험을 수행하였다. 가열 소성과정에서 레드머드 혼합물 분말시료는 유리화된 다공성 구조의 결합체로 변화되었으며, X-선 회절분석을 통하여 산출물은 침철석, 영가철(Fe0, iron), 자류철석(Fe1-xS) 및 황철석(FeS2) 등으로 구성됨을 확인하였다. 가열 소성 결과물은 왕수분해를 통하여 Fe을 용해시키고, NaCl을 첨가하여 Fe을 침전 회수하였다. 레드머드 내 Fe의 회수는 시험 조건별로 상이하게 나타났으며, 단순히 레드머드를 마이크로웨이브 가열한 시료 내 Fe은 그 함량이 49.0wt.% 였다. 그러나, 활성탄을 첨가한 시료 및 활성탄과 황을 첨가한 레드머드 시료의 가열 소성 결과물 내 Fe의 함량은 각각 58.0wt.%, 59.5wt.% 로서 철 자원가치 품위인 56wt.%를 초과하였다.

Keywords

References

  1. Borra, C.R., Pontikes, Y., Binnemans, K. and Gerven, T.V. (2015) Leaching of rare earths from bauxite residue (red mud). Mineral Engineering, v.76, p.20-27. https://doi.org/10.1016/j.mineng.2015.01.005
  2. Brunori, C., Cremisini, C., Massanisso, P., Pinto, V. and Torricelli, L. (2005) Reuse of a treated red mud bauxite waste: studies on environmental compatibility. Hournal Hazardous materials, v.117, p.55-63. https://doi.org/10.1016/j.jhazmat.2004.09.010
  3. Ghosh, I., Guha, S., Balasubramaniam, R. and Kumar, A.V.R. (2011) Leaching of metals from fresh and sintered red mud. Journal of Hazardous Materials, v.185, p.662-668.
  4. Grafe, M., Power, G. and Klauber, C. (2011) Bauxite residue issues: III. Alkalinity and associated chemistry. Hydrometallurgy, v.108, p.60-79. https://doi.org/10.1016/j.hydromet.2011.02.004
  5. Ishizaki, K., Stir, M., Gozzo, F., Catala-Civera, J.M., Vaucher, S. and Nicula, R. (2012) Magnetic microwave heating of magnetiite-carbon black mixtures. Materials Chemistry and Physics, v.134, p.1007-1012. https://doi.org/10.1016/j.matchemphys.2012.03.104
  6. Kasliwal, P. and Sai, P.S.T. (1999) Enrichment of titanium dioxide in red mud: a kinetic study. Hydrometallurgy, v.53, p.73-87. https://doi.org/10.1016/S0304-386X(99)00034-1
  7. Kim, E.J. and Batchelor, B. (2009) Synthesis and characterization of pyrite($FeS_2$) using microwave irradiation. materials Research Bulletin, v.44, p.1553-1558. https://doi.org/10.1016/j.materresbull.2009.02.006
  8. Klauber, C., Grafe, M. and Power, G. (2011) Bauxite residue issues: II. options for residue utilization. Hydrometallurgy, v.108, p.11-32. https://doi.org/10.1016/j.hydromet.2011.02.007
  9. Li, G., Liu, M., Rao, M., Jiang, T., Zhuang, J. and Zhang, Y. (2014) Stepwise extraction of valuable components from red mud based on reductive roasting with sodium salts. Journal of Hazardous Materials, v.280, p.774-780. https://doi.org/10.1016/j.jhazmat.2014.09.005
  10. Lim, K.H. and Shon B.H. (2015) Study on recovery of heavy metals from red mud by using the ultrasonic waves. Journal of the Korea Academia-Industrial Cooperation Society, v.16, p.906-913. https://doi.org/10.5762/KAIS.2015.16.1.906
  11. Liu, W., Yang, J. and Xiao, B. (2009) Review on treatment and utilization of bauxite residues in China. International Journal of Mineral processing, v.93, p.220-231. https://doi.org/10.1016/j.minpro.2009.08.005
  12. Lu, T., Pickles, C.A. and Kelebk, S. (2007), Microwave heating behaviour of a gibbsite type bauxite ore, In; Bekguleryuz, M.O., Paray, F., Wells, M.(eds), processings of Symposium on light metals in Transport Applications, metSoc(CIM), Toronto, Ont. Canada, pp. 421-449.
  13. Pickles, C.A., Mouris, J. and Hutcheon, R.M. (2005) High-temperature dielectric properties of goethite from 400 to 3000 MHz. Journal of Materials Research, v.20, p.18-29. https://doi.org/10.1557/JMR.2005.0012
  14. Samouhos, M., Taxiarchou, M., Tsakiridis, P.E. and Potiriadis, K. (2013) Greek "red mud" residue: a study of microwave reductive roasting followed by magnetic separation for a metallic iron recovery process. Journal of Hazardous materials, v.254, p.193-205. https://doi.org/10.1016/j.jhazmat.2013.03.059
  15. Samouhos, M., Taxiarxhou, M., Hutcheon, R. and Devlin, E. (2012) Microwave reductin of a nickeliferous laterite ore. Minerals Engineering, v.34, p.19-29. https://doi.org/10.1016/j.mineng.2012.04.005
  16. Smith, P. (2009) The processing of high silica bauxites-review of existing and potential processes. Hydrometallurgy, v.98, p.162-176. https://doi.org/10.1016/j.hydromet.2009.04.015
  17. Standish, N. and Worner, H. (1990) Microwave application in the reducrion of metal oxide with carbon. International Microwave Power Institute, v.25, p.177-180.
  18. Standish, N. and Worner, H. (1990) Microwave application in the reduction of metal oxide with carbon. International Microwave Power Institute, v.25, p.177-180.
  19. Xenidis, A., Zografidis, C., Kotsis, I. and Boufounos, D. (2009) Reductive roasting and magnetics separation of greek bauxite residue for its utilization in iron ore industry. Light metals v.2009, p.63-67.
  20. Zhong, L., Zhang, Y. and Zhang, Y. (2009) Extraction of alumina and sodium oxide from red mud by a mild hydro-chemical process. Journal of Hazardous Materials, v.172, p.1629-1634. https://doi.org/10.1016/j.jhazmat.2009.08.036
  21. Zhu, D.Q., Chun, T.J., Pan, J. and HE, Z. (2012) Recovery of iron from high-iron red mud by reduction roasting with adding sodium salt, Journal of Iron and Steel Research. International, v.19, p.1-5.