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The Effect of BaF2 Particle Size for Zirconium Recycling by Precipitation from Waste Acid and Ba2ZrF8 Vacuum Distillation Property

폐 산세 용액으로부터 공침 반응에 의한 지르코늄 회수 시 BaF2 입도 영향 및 Ba2ZrF8의 진공증류 특성

  • Choi, Jeong Hun (Graduate School of Department of Materials Science & Engineering, Chungnam National University) ;
  • Nersisyan, Hayk (RASOM, Chungnam National University) ;
  • Han, Seul Ki (Graduate School of Department of Materials Science & Engineering, Chungnam National University) ;
  • Kim, Young Min (Graduate School of Department of Materials Science & Engineering, Chungnam National University) ;
  • Park, Cheol-Ho (Kepco Nuclear Fuel(TSA)) ;
  • Kahng, Jong Won (Kepco Nuclear Fuel(TSA)) ;
  • Na, Ki Hyun (Kepco Nuclear Fuel(TSA)) ;
  • Kim, Jeong hun (Kepco Nuclear Fuel(NSA)) ;
  • Lee, Jong Hyeon (Graduate School of Department of Materials Science & Engineering, Chungnam National University)
  • Received : 2017.09.08
  • Accepted : 2017.11.06
  • Published : 2017.12.31

Abstract

Nuclear fuel cladding tube is fabricated by pilgering and annealing process. In order to remove impurity and oxygen layer on the surface, pickling process is carried out. When Zirconium(Zr) is dissolved and saturated in acid solution during the pickling process, all the waste acid including Zr is disposed. Therefore, $BaF_2$ is added into the waste acid to extract Zr and $Ba_2ZrF_8$ is subsequently formed. To recycle Zr by electrowinning process, $Ba_2ZrF_8$ is used as electrolyte, but it has high melting point ($1053^{\circ}C$). $ZrF_4$ should be added into $Ba_2ZrF_8$ to decrease the melting point. In this paper, it was investigated that $Ba_2ZrF_8$ was separated to $BaF_2$ and $ZrF_4$ by vacuum distillation. Firstly, $BaF_2$ with different particle size ($1{\mu}m$, $35{\mu}m$, $110{\mu}m$) was added into the waste acid and the respective precipitation property was estimated. $BaF_2$ obtained by vacuum distillation was shattered by ball-milling with different time. The precipitation efficiency was compared with $1{\mu}m$ of ${BaF_2}^{\prime}s$ one, which was not used as precipitation agent.

핵연료 피복관은 필거링 및 열처리 공정에 의해 제조되며, 핵연료 피복관 표면의 불순물 및 산화층을 제거하기 위해 산세 공정이 진행된다. 산세 공정 중 산세 용액으로 지르코늄이 용해되어 포화상태가 될 시 폐 산세 용액은 전량 폐기 되며 용액 내 지르코늄 또한 폐기된다. 그러므로 지르코늄을 재활용하기 위해 $BaF_2$를 폐 산세 용액에 첨가하여 공침 반응에 의해 $Ba_2ZrF_8$을 형성시켰다. 한편, 전해제련을 통해 Zr을 회수하기 위해서는 $Ba_2ZrF_8$을 전해질로 사용해야하지만, 용융점이 $1053^{\circ}C$로 높다. 따라서 $ZrF_4$를 첨가하여 용융점을 낮추어야한다. 본 연구에서는 $Ba_2ZrF_8$을 진공 증류를 통해 $BaF_2$$ZrF_4$로 분리하는 연구를 진행하였다. 먼저, $BaF_2$ 입자크기($1{\mu}m$, $35{\mu}m$, $110{\mu}m$)에 따른 침전 특성을 실험하였다. 그리고 진공 증류를 통해 수득된 $BaF_2$를 볼밀링을 통해 분쇄하였으며, 침전 공정을 거치지 않은 $BaF_2$와 침전 효율을 비교하였다.

Keywords

References

  1. Lee, J. E. et al., 2013 : A study of cleaning technology for zirconium scrap recycling in the nuclear industry, Clean Technol., 19(3), pp. 264-271. https://doi.org/10.7464/ksct.2013.19.3.264
  2. Cho, N. C., Lee, J. M., and Hong, S. I., 2011 : Processing of low tin Zr-1Nb-0.69Sn-0.11Fe alloy tubes and effect of final heat treatment on their mechanical and corrosion properties, Korean J. Met. Mater., 49(1), pp. 17-24. https://doi.org/10.3365/KJMM.2011.49.1.017
  3. Fennemann, W., Minzl, E., and Seidel, H., 1990 : Method of Regenerating ZrF4 Pickling Solutions, Patent US4937054.
  4. Anand Babu, C. et al., 1993 : Removal of fluoride from pickling waste with zirconium, Waste Management, 13(3), pp. 279-283. https://doi.org/10.1016/0956-053X(93)90052-X
  5. Stewart, T. and Jones, E. O., 1990 : Recycling and Treatment of Metal-Bearing Spent Acids, PNL 5294, Pacific Northwest Laboratory, Richland, Washington, pp. 153-161.
  6. Nersisyan, H. et al., 2017 : Two-step process of regeneration of acid(s) from $ZrF_4$ containing spent pickle liquor and recovery of zirconium metal, J. Nucl. Mater., 486, pp. 44-52. https://doi.org/10.1016/j.jnucmat.2017.01.017
  7. Han, S. K. et al., 2016 : Recovery of Zirconium from Spent Pickling Acid through Precipitation Using $BaF_2$ and Electrowinning in Fluoride Molten Salt, Korean J. Mater. Res. 26, pp. 681-687. https://doi.org/10.3740/MRSK.2016.26.12.681
  8. Grande, T., Aasland, S., and Julsrud, S., 1992 : Phase equilibria in the glass forming system $ZrF_4-BaF_2$, J. Non-Cryst. Solids, 140, pp. 69-72. https://doi.org/10.1016/S0022-3093(05)80743-4