화학공학소재연구정보센터
Journal of the Korean Industrial and Engineering Chemistry, Vol.8, No.1, 99-107, February, 1997
우라늄 정광의 용해/정제 및 핵연료 분말 가공공정에서 발생된 폐액의 처리에 관한 연구
A Study on Treatment of Wastes from the Uranium Ore Dissolution/purification and Nuclear Fuel Powder Fabrication
초록
핵연료분말 변환공정 중 우라늄 정광의 용해/정제 및 가공공정에서 발생하는 폐액의 처리에 대한 연구가 수행되었다. 우라늄 정광의 용해/정제공정에서 발생된 폐액은 pH 1 이하의 강산성으로 AUC 분말 제조공정에서 발생된 폐액 중의 우라늄을 ADU 형태로 회수한 후 발생된 2차 여액 속의 미세 ADU 입자 용해를 위해 사용된다. 2차 여액 속의 미세 ADU 입자들의 용해를 위해 용해/정제 공정의 폐액을 사용해서 pH 4로 전처리한 후, lime을 이용하여 pH 9.2로 30분 정도 반응시킬 경우 여액 중의 우라늄 농도를 3ppm 이하로 처리할 수 있었다. 가공 폐액은 미세 oil droplet들이 emulsion 형태로 발생하며, 약 300ppm의 우라늄 농도를 나타내었다. 먼저, emulsion을 파괴시키는 방법은 질산을 가하여 급속가열시키는 것이 효과적이었다. Emulsion 파괴 후 1mole NaOH를 가하여 Na2U2O2형태로 우라늄을 회수하였으며, pH11.5에서 최적 처리조건을 나타내었으나 최종 여액 중의 우라늄 농도는 5ppm을 나타냈다. 여액 중의 우라늄 농도를 최소화하기 위해 lime으로 처리하는 방법이 연구되었으며, 가공폐액을 직접 lime 처리하기 위해 4N 질산으로 emulsion을 파괴 시킨 후, pH 1.6에서 lime을 1.5g/100m1로 반응시킬 경우 여액 중의 우라늄 농도를 1ppm까지 낮출 수 있었다. 한편, 경수로형 분말 제조공정 중 우라늄 회수공정에서 발생된 폐액 중의 미량 우라늄은 NaOH를 가하여 우라늄을 침전시킨 결과, Na·U·F·NH4 등이 흔합된 침전물이 얻어졌으며, 여과후 상등액에서는 우라늄은 감지할 수 없었다.
This study Provides the treatment methods of liquid wastes from the dissolution/purification process of nuclear fuel raw material and the fabrication process of nuclear fuel powder. One of the treatment methods is to process liquid waste from uranium raw material dissolution/purification process. This waste, of the strong acid, can be reused to dissolve the fine ADU particles in filtrate which is ADU waste of pH 8.0 converted from AUC waste after recovery of uranium. To dissolve the fine ADU particles, ADU filtrate was pretreated to pH 4.0 with the dissolution/purification waste, and then mixed with the lime to pH 9.2 and aged for 30 minutes. From this processing, uranium content of the filtrate was decreased to below 3ppm. The waste from fuel powder fabrication is emulsified solution dispersed with fine oil droplets. This emulsion was destroyed effectively by adding and mixing the nitric acid with rapid heating at the same time. After this processing, Na2U2O7 compound is produced by addition of NaOH. Optimum condition of this processing was shown at pH 11.5, and uranium content of the filtrate was analyzed to 5ppm. To remove the trace of uranium in the filtrate, lime should be added. Otherwise, 4N nitric acid was used to destroy the emulsion directly, and then lime was added to this waste. Uranium content of the treated filtrate was below 1 ppm. In addition to these wastes, the trace of uranium in filtrate after recovery of uranium from the AUC waste which is produced during PWR power preparation, is treated with NaOH to takeup fluorine(F) in the waste because florine is valuable and toxic material. In the finally treated waste, uranium was not detected.
  1. Chang IS, "Comparison of the Conversion Processes," KAERI/AR-206/83, 한국에너지연구소 (1983)
  2. Chang IS, "Development of Wolsung-Type Nuclear Fuels Technology," KAERI/RR-588/86, 한국에너지연구소 (1986)
  3. Annual Report of Energy Resources of Australia Limited (1988)
  4. Charles DH, Archie ER, "Uranium Production Technology," D. Van Nostrand Company, Ing., Princeton (1959)
  5. Alfredson PG, "Development of Process for Pilot Plant Production of Purified Uranyl Nitrate Solution," AAEC/E-344 (1975)
  6. LoTeh C, "Handbook of Solvent Extraction," John Wiley & Sons, New York (1983)
  7. Kennedy J, "Radiometric Studies with Phosphorus-32 Labelled TBP; part 2, Acid-Alkali Hydrolysis," AARE-CE/R-1284
  8. 장인순, "AUC 제조 및 그의 액체 폐기물 처리에 관한 연구," KAERI/RR-240/80, 한국에너지연구소 (1980)
  9. Serne RJ, Peterson SR, Gee GW, "Laboratory Measurements of Contaminant Attenuation of Uranium Mill Tailings Leachates by Sediments and Clay Liners," NUREG/CR-3124 (1983)
  10. Shepherd TA, Cherry JA, "Contaminant Migration in Seepage from Uranium Tailings Impoundments; An Overview," 3rd Symposium on Uranium Mill Tailing Management, Nov. 23-24 (1980)
  11. Lissant KJ, "Making and Breaking Emulsions," Emulsions and Emulsion Technology, Part 1, chap. 2, Marcel Dekker, Inc., New York (1974)
  12. Monson LT, Stinzel RW, "Colloid Chemistry," Reinhold, New York (1931)
  13. Riddick TM, "The Control of Colloid Stability Through Zeta Potential," Livingston, Wynne-wood, Pa. (1981)
  14. Dokazoguz HZ, Muller HM, Environ. Sci. Technol., 8, 1014 (1974)