Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT) (방사성폐기물학회지)

Korean Radioactive Waste Society (한국방사성폐기물학회)
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An Electrochemical Reduction of TiO2 Pellet in Molten Calcium Chloride

CaCl2 용융염에서 TiO2 펠렛의 전기화학적 환원반응 특성

  • Received : 2012.05.05
  • Accepted : 2012.06.20
  • Published : 2012.06.30
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Abstract

A porous $TiO_2$ pellet was electrochemically converted to the metallic titanium by using a $CaCl_2$ molten salt system at $850^{\circ}C$. Ni-$TiO_2$ and graphite electrodes were used as cathode and anode, respectively. The electrochemical behaviour of $TiO_2$ pellet was determined by a constant voltage control electrolysis. Various reaction intermediates such as $CaTiO_3$, $Ti_2O$ and $Ti_6O$ were observed by XRD analysis during electrolysis of the pellet. Once $TiO_2$ pellet was converted to a porous metallic structure, the porous structure disappeared by sintering and shrinking with increasing the reaction time at high temperature.

본 연구에서는 $850^{\circ}C$의 $CaCl_2$ 용융염계에서 전해환원공정을 통해 $TiO_2$로부터 금속티타늄을 제조하였다. Ni-$TiO_2$ 조합전극을 환원전극으로 그라파이트를 산화전극으로 사용하였으며, 셀전위를 제어하면서 $TiO_2$의 전해환원 특성을 관찰하였다. XRD 분석을 통해 $TiO_2$가 $CaTiO_3$, $Ti_2O$, $Ti_6O$와 같은 다양한 반응 중간생성물을 거쳐 Ti 스폰지로 환원되는 것이 밝혀졌다. 또한 SEM 분석을 통해 $TiO_2$ 전해환원 반응동안 펠렛의 바깥표면부터 환원반응이 시작되어 펠렛중심으로 진행이 되는 것이 확인되었다. 전해환원 반응도중 환원된 티타늄금속은 초기에는 다공성 스폰지 구조를 보이나 고온에서 반응이 진행됨에 따라 점차 소결에 의해 수축되어 다공성 구조가 사라지는 현상을 보였다.

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References

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