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Polyvinyl alcohol (PVA) was added to prepare extraction resin, which was applied to separate heavy rare earth elements in Gd/Tb and Ho/Er system. The supports and extractant of extraction resin were styrene-divinyl benzene copolymer and bis (2-ethyl-hexyl) phosphinic acid (HEH[EHP]), respectively. Addition of PVA reduced the particle size of extraction resin up to 40%. Furthermore, addition of PVA brought more diluted effluent concentration, shorter effluent range and bigger resolution values during separation. This could be explained by the weakening of the bonding force between the rare earths and extraction resin, which could be ascribed to the nature of the interaction between the OH-group in PVA and the OH-group in extractants such as HEH[EHP]. Consequently, the optimum level of PVA addition and the concentration of effluent for Gd/Tb, Ho/Er separation were determined to be 1.5 wt% of PVA and 0.05 (for Gd/Tb separation) as well as, 0.4 (for Ho/Er separation) mol/ℓ HCl of effluent, respectively. At these conditions, the best separations were achieved as αGdTb=1.145, and αHoEr=0.615.
본 연구에서는 PVA를 이용하여 중희토류 원소분리용 추출수지를 합성하고, 합성된 추출수지를 이용하여 extraction chromatography법으로 Gd/Tb, Ho/Er 원소를 분리하고자 하였다. 합성 시 스틸렌-디비닐벤젠 공중합체에 추출제로 Bis(2-ethyl-hexyl)phosphinic acid(HEH[EHP])를 사용하였다. 현탁안정제인 PVA를 첨가한 추출수지의 입자크기는 PVA를 사용하지 않은 추출수지 보다 40% 이상 작아지는 것을 알 수 있었다. 또한 PVA를 첨가한 추출수지의 중희토류 분리실험 결과, PVA 첨가에 따라 용리액 농도가 더 낮아지고, 용출구간이 짧아지며 분리능이 향상되는 것을 확인할 수 있었다. 이는 PVA의 OH-그룹과 추출제의 OH-그룹과의 상호작용에 의하여 희토류 혼합용액과 추출제 사이의 결합력 변화 때문인 것으로 사료된다. 결과적으로, PVA를 첨가한 추출수지의 Gd/Tb, Ho/Er 원소 분리 시 PVA 1.5 wt% 첨가한 추출수지를 이용하고 용리액 농도를 각각 0.05(Gd/Tb), 0.4(Ho/Er) mol/ℓ로 유지시켰을 때 가장 높은 분리효율인 αGdTb=1.145, αHoEr=0.615를 얻을 수 있었다.
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- Publisher :The Korean Society of Mineral and Energy Resources Engineers
- Publisher(Ko) :한국자원공학회
- Journal Title :Journal of the Korean Society for Geosystem Engineering
- Journal Title(Ko) :한국지구시스템공학회지
- Volume : 42
- No :6
- Pages :595-602
Journal of the Korean Society of Mineral and Energy Resources Engineers
