Investigation of Relationship Between Residence Time Distribution and Size Distribution of Solid Particles in Tank Leaching Modelling

Document Type : Research - Paper

Authors

1 Ph.D student, Dept. of Mining & Metallurgical Engineering, Yazd University, Yazd, Iran

2 Assistant Professor, Dept. of Mining & Metallurgical Engineering, Yazd University, Yazd, Iran

3 Assistant Professor, Dept. of Mining Engineering, Tarbiat Modares University, Tehran, Iran

4 Associate Professor, Dept. of Mining & Metallurgical Engineering, Yazd University, Yazd, Iran

Abstract

While many studies have confirmed the effect of particle size distribution on the residence time in a reactor, the most employed models of continuous tank leaching process consider the residence time and particle size distributions as independent variables. In minerals processing field, no systematic study has been conducted on this issue yet. In this research, the relationship between the particles size and their residence time in a mixing tank has been studied. An empirical method for the determination of the residence time distribution function based on the inflow particles size distribution has been proposed. The relationship between the average size of one size fraction of particles and its residence time was obtained by mean residence time and parameter  (an empirical coefficient). Results showed that increasing the particle sizes resulted in a 50% increase in the mean residence time while  decreased from 0.95 to 0.3. Using the evaluated values of  the residence time distribution function of the inflow stream was determined. Including this function in the segregated flow model, the effect of the variations of the  value on the leaching performance was evaluated. Results showed that smaller values of  resulted in higher conversion value.

Keywords

References

  1. Levenspiel, O. (1999). “Chemical reaction engineering”. Industrial & Engineering Chemistry Research.
  2. Crundwell, F. (1995). “Progress in the mathematical modelling of leaching reactors”. Hydrometallurgy, 39(1-3): 321-335.
  3. Dixon, D. G. (1995). “Improved methods for the design of multistage leaching systems”. Hydrometallurgy, 39(1): 337-351.
  4. Kotsiopoulos, A., Hansford, G. S., and Rawatlal, R. (2008). “An approach of segregation in modeling continuous flow tank bioleach systems”. AIChE journal, 54(6): 1592-1599.
  5. Gao, Y., Fernando, J., and Marianthi, G. I. (2012). “A review of the Residence Time Distribution (RTD) application in solid unit operation”. Powder Technology, 228: 416-423.
  6. Vignes, A. (2013). “Extractive metallurgy 3. Process operations and routs”. John Willy & Sons.
  7. Crundwell, F., Preez, N. D., and Lloyd, J. M. (2013). “Dynamics of particle-size distributions in continuous leaching reactors and autoclaves”. Hydrometallurgy, 133: 44-50.
  8. Oldeshue, J. Y. (1969). “Suspending solids and dispersing gases in mixing vessels”. Industrial & Engineering Chemistry, 61.
  9. Kuwata, M., and Martin, S. T. (2012). “Particle size distributions following condensational growth in continuous flow aerosol reactors as derived from residence time distributions: Theoretical development and application to secondary organic aerosol”. Aerosol Science and Technology, 46(8): 937-949.
  10. Dull, M., Ozcoban, H., and Leopold, C. (2018). “Analysis of the powder behavior and the residence time distribution within a production scale rotary tablet press”. European Journal of Pharmaceutical Sciences, 125: 205-214.
  11. Murphy, T. (2002). “Residence time distribution of solid particles in CSTR”. McGill University Libraries.
  12. Baldi, J. R., and Sharma, R. N. (1978). “Continuous removal of a solid suspension from stirred tanks”. Proceedings of International Symposium on Mixing, Mons (France), 1-B5.
  13. Tojo, K., and Miyanami, K. (1982). “Solids suspension in mixing tanks”. Industrial& Engineering Chemistry Fundamentals, 21: 214-220.
  14. Sheoran, M., Chandra, A., Bhunia, H., Bajpai, P. K., and Pant, H. J. (2018). “Residence time distribution studies using radiotracers in chemical industry-A review”. Chemical Engineering Communications, 205(6): 739-758.
  15. Fogler, H. S. (2006). “Distributions of residence times for chemical reactors”. Elements of Chemical Reaction Engineering, 4.

Files

History

  • Receive Date: 14 July 2020
  • Revise Date: 14 February 2021
  • Accept Date: 14 February 2021

Share

How to cite

Statistics