A study on influence of precipitation condition on rounding of AUC particles

AUC 침전조건이 둥근 AUC 입자 제조에 미치는 영향

  • Published : 1998.06.01

Abstract

Mechanisms and conditions for rounding of AUC particles were examined during AUC precipitation. Rounding of AUC particle was possible only by external circulation using pump, not by internal circulation using agitator. The rate of AUC rounding $(dn_p/dt)$ was proporational to operation conditions such as magma density $(M_t:g-U/{\iota}l)$, turn over ratio $(T_o)$ and impeller tip velocity of pump (U); $ dn_p/dt{\propto}M_t{\cdot}T_o{\cdot}U^2$. The validity of this relationship was qualitatively confirmed by comparing the expermental results. Two rounding mechanisms were suggested. One is crack formation mechanism and the other etch-pit formation mechanism on the surface of AUC particle. It was found that the crack formation is more dominant at the initial stage and the etch-pit formation at the final stage of the AUC precipitation.

AUC 침전과정중 AUC 입차를 둥글게 제조하는 조건과 기구를 조사하였다. 둥근 AUC 제조는 교반기를 이용한 내부순환 시는 불가능했으나 펌프를 사용한 외부순환 시는 가능했다. 둥근 AUC 제조속도($dn_p$/dt)는 침전조건인 슬러리 밀도($M_t:U/l)$, 슬러리 회전율($T_o$:turn-over ratio), 임펠러 속도(U:Impelle tip velocity)에 비례하여 관계식을 $ dn_p/dt{\propto}M_t{\cdot}T_o{\cdot}U^2$로 표기할 수 있었으며, 이 속도식은 실험결과와 정성적으로 일치하였다. 그리고 두 개의 둥근 AUC 제조 기구가 제시되었는데, 하나는 균일형성기구이고 다른 하나는 etch-pit 형성기구이다. 전자는 AUC 침전과정에서 초기에 발생되고 후자는 침전과정 말기에 발생되는 것으로 확인되었다.

Keywords

References

  1. 원자력 진흥 종합계획 과학기술처
  2. Nuclear Technology v.18 S.G. Brandberg
  3. Nuclear Technology v.81 P.A. Haas
  4. Br. Nucl. Energy Soc. v.18 J.S. Wacklington;L.F. Raven;G. Thorpe
  5. 화학공업과 기술 v.9 no.5 김병구;장인순;황성태;박진호;김응호;박장진;최청송
  6. Ceramic powders, Material Science Monographs v.16 H. Assmann;W. Doerr
  7. Report Ser. v.221 H. Assmann;A. Bairiot
  8. Proceedings of the 2nd Korea-Japan Symposium on separation Technology I.S. Chang
  9. Trans. Am. Nucl. Soc. v.3 E. Brandau;W. Doerr
  10. J. Nucl. Mater v.99 Y.M. Pan;C.B. Ma;N.N. Hsu
  11. Chem. Eng. Sci. v.46 no.1 R. David;P. Marchal;J.P. Klein;J. Villermaux
  12. Powder Technology v.44 N.S. Tavare;M.B. Shah;J. Garside
  13. Chem. Eng. Sci. v.44 no.10 R. Zumstein;R.W. Rousseau
  14. Int. Chem. Eng. v.21 no.2 K. Toyokura;M Uchiyama;I. Hirasawa;M. Kawai
  15. Trans. IchemE v.60 A. Scrutton;P.A.M. Grootscholten;E.J. De Jong
  16. AlchE Journal v.28 no.5 P.A.M. Grootscholten;B.G.M. De Leer;E.J. DE Jong;C.J. Asselbergs
  17. Powder Technology v.49 W.J.B. Van Den Bergh;B. Scarlett
  18. AICHEJ v.20 T.W. Evans;G. Margolis;A.F. Sarofim
  19. Chem. Eng. Sci. v.47 no.12 B. Mazzarotta
  20. J. Nucl, Mater. v.153 C.S. Choi;J.H. Park;E.H. Kim;F.S. Shin;I.S. Chang
  21. Industrial crystallization v.81 M.A. Belyshev;A.A. Chernov