화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
Journal of the Korean Industrial and Engineering Chemistry, Vol.6, No.5, 882-891, October, 1995
Export Citation
개미산 탈질에 의한 모의폐액내 Zr 및 Mo 분리제거 연구(II)
Removal of Zr and Mo from the simulated Radwaste solution by Denitration with Formic Acid(Ⅱ)
이일희, 황두성, 김광욱, 신영준, 유재형
초록
본 연구는 개미산에 의한 탈질시 다량 발생되는 배기체의 처리 효율을 증진시키기 위한 탈질장치의 개선 및 고액분리시 고려되어야 할 침전물의 여과특성에 중점을 두어 수행하였다. 실험계로는 회분식, 반회분식 및 교반동반 반회분식을 각각 선정하여, 전 연구[1]에서 설정된 최적의 탈질조건, 즉 [HCOOH]/[HNO3]=1.5, 2.5시간, 90℃에서 배기체의 발생속도, 침전물의 여과특성 그리고 각 원소의 침전거동을 고찰하였다. 배기체의 발생속도는 회분식의 경우 반응시작 10∼15분 사이 약 0.68ℓ/min로 급격히 증가되었다가, 약 20분 후에는 0.05ℓ/min 이하로 감소하는데 반하여, 반회분식 또는 교반동반 반회분식의 경우는 약 50분 동안 0.06ℓ/min 이하로 거의 일정하게 유지되어, 반회분식이 양호한 것으로 나타났다. 여과특성에서는 회분식의 평균 여과 비저항(average filtration specific resistance)이 1.2×1011m/Kg, 반회분식이∼1012m/Kg으로 회분식이 우수한 것으로 나타났다. 또한 Zr 및 Mo의 침전 제거율에서는 실험계와 무관하게 Zr은 99%이상이었으며, Mo는 회분식에서 약 86% 정도로 다소 유리하나, 기타계와 거의 비슷한 수준이었다. 2성분계(Zr-Mo) 및 다성분계에서 형성된 각 침전물의 특성은 실험계 변화에 무관하게, 2성분계에서는 ZrMo2O7(OH)2(H2O)2의 결정물이었으며, 다성분계에서는 모두 무정형 (amorphous)으로 나타났다.
This study was performed in order to improve the denitration system for the effective treatment of off-gas evolved rapidly during denigration with formic acid, and to examine the filterability of slurry formed in denitration, which is a major parameter to be set up in the denigration process. Experiment system was selected the batch, semi-batch and semi-batch with mixing system, respectively. The off-gas evolution rate, the filterability of slurry, and the precipitation fractions of each element were considered with the changes of the system at the optimum condition, namely [HCOOH]/[HNO3]=1.5, 2.5hr and 90℃ of denigration, established previous study[1]. The gas evolution rate for the batch was about 0.68ℓ/min during 10∼20 minutes of denitration, while it decreased rapidly below 0.05ℓ/min after 20 minutes. As for the semi-batch and the semi-batch with mixing system, the rates were less than 0.06ℓ/min during 50 minutes. It is found that the systems of semi-batch type are most favorable in terms of off-gas evolution. The average filtration specific resistance for the batch and the semi-batch system were 1.2×1011m/Kg and ∼ 1012m/Kg, respectively. The batch system Is quite favorable in view of filterability of slurry. The precipitation fractions of Zr and Mo for the batch system were over 99% and 86%, respectively, but those of Zr and Mo with denitration system were not significant. Also, regardless of denitration system, the form of precipitate formed during denitration at two-component(Zr-Mo) and at multi-component system were crystal of ZrMo2O7(OH)2(H2O)2 and amorphous, respectively.
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