Abstract
Experimental and theoretical studies on the initial leaching rate of a spherical pellet of ZnO introduced in H2SO4 and H 2SO4- ZnSO4 solution have been conducted to discuss the characteristics of liquid-phase mass transfer for ZnO-H 2SO4 solution systems in an agitated vessel. The results obtained are as follows: 1) For the ZnO-H2SO4 systems, the leaching rate is proportional to the 0.6th power of the stirring rate. The leaching rate increases with the concentration of H2SO4 and H+. 2) For the ZnO-H2SO4-ZnSO4 systems, the leaching rate increases with the concentration of ZnSO4. At a high concentration of H+, the rate is independent of the concentration of H+. 3) The leaching process for these systems is controlled by the liquid-phase mass transfer rate. 4) For the ZnO-H 2SO4 and ZnO-H2SO4-ZnS04 systems, the rates calculated by a mass-transfer model based on a film theory that takes into account diffusion and electrical migration are in good agreement with the experimental values at a low concentration of H+. However, the calculated values are not consistent with the experimental values at high concentration. This disagreement might be caused by the effect of chemical reaction at the ZnO surface.
Original language | English |
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Pages (from-to) | 135-139 |
Number of pages | 5 |
Journal | Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals |
Volume | 71 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2007 Jan |
Keywords
- Acid solution
- Electrical migration
- Leaching, dissolution
- Mass transfer
- ZnO
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys
- Materials Chemistry