Рrecipitation of platinum group metals (Rh, Ru, Pd, so-called MPG) from the melt essentially affects the reliability of installations for vitrification of high-level liquid radioactive waste (HLW). To date, it is difficult to find an approach which allows simultaneous recovery of all three metals. The aim of our work was to select a sorbent that would provide simultaneous up to complete recovery of given metals. The following inorganic materials were tested as sorbents – yellow blood salt (YBS).and hexacyanoferrates of iron, aluminum, copper and nickel. The degree of metal recovery was studied is influenced by the temperature and concentration of nitric acid. Only palladium was completely recovered using YBS. At the same time, specially prepared iron hexacyanoferrate (HCF-Fe) under optimal experimental conditions recovers almost all Pd and more than 95% and 90% of Rh and Ru, respectively. The behavior of fission products, including the main dose-forming components of HLW (Cs, Sr) and Mo, U, Ag, REE) in the course of MPG recovery was studied. The experiments were carried using both multicomponent model solutions and real raffinates. Options for further management of the recovered metals have been worked out. Thus, the proposed method of metal recovery seems promising for the development of a technology for the removal of MPG from nitric HLW during the reprocessing of the spent nuclear fuel (SNF) before vitrification. The recovered metals can be probably used in various technological processes. Also, this method can provide the MPG recovery from low-concentration tail solutions.
본 연구는 살균 소독제로 오존을 이용하고. 살균효과를 극대화 할 수 있는 방식으로 마이크로버블 장치에 오존을 공급하여 배양액 재처리 기술을 위한 오존 마이크로버블의 살균효과를 구명하고자 실시하였으며 결과를 요약하면 다음과 같다. 마이크로버블 장치의 성능에서 압력 3.5kgf·cm−2에서 평균입경은 27.42μm로 측정되었고 마이크로버블의 발생량은 당 평균 12만개로 나타났으며, 적정 오존 발생량은 3g·h−1일 때 오존농도는 2ppm, 배출 오존농도는 0.06ppm에 도달하는 것으로 나타났다. 병원균 살균효과는 오존수의 경우 FO, PC 와 CG 모두 오존농도 0.5ppm, 처리시간 30초만으로도 현저한 감소를 보였다. FO는 오존농도 0.5ppm, 처리시간 60초 이내에서 멸균되었고, PC는 오존농도 2.0ppm, 처리시간 30초 이내에서 멸균되었으나, CG의 경우 2.0ppm 이상의 오존수를 처리하여야 할 것으로 판단되었다. 오존가스의 경우 처리시간 120초 이내에서 현저한 감소를 보였으며, FO와 PC는 처리시간 180초 이내에서 멸균되었고, CG의 경우 180초 이상 오존가스를 처리하여야 할 것으로 판단되었다.