کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9632615 | 462125 | 2005 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Leaching of metallic silver with aqueous ozone
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Leaching of metallic silver with aqueous ozone Leaching of metallic silver with aqueous ozone](/preview/png/9632615.png)
چکیده انگلیسی
The recycling of silver from metallic scraps can be performed through O3 leaching at an ambient temperature and low (â¼0.1 M) H2SO4 concentration. The main by-product is O2, which can be recycled to the O3 generation or used as leaching agent in a pretreatment step. The stoichiometry and the effects of the stirring speed, ozone and acid concentration and temperature on the leaching of silver were investigated. Silver dissolved as Ag2+(aq) in the range 10â3-1 M H2SO4, but for pH â¥4, insoluble Ag2O2 was the main reaction product. Kinetics appeared to be controlled by mass transfer of O3(aq) to the solid-liquid interface, showing first order dependency with respect to [O3]aq and PO3. Specific rates were only slightly dependent on the temperature in the interval 10-50 °C, but decreased at 60 °C due to the fall in O3 solubility. The mass transfer coefficients showed an average activation energy of 17 kJ/mol. No significant effect of [H2SO4] on mass transfer coefficients was observed for 10â2-1 M. Leaching rate gradually diminished for pH >2, as a consequence of the influence of the [H+] in the transport control.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Hydrometallurgy - Volume 76, Issues 3â4, March 2005, Pages 225-232
Journal: Hydrometallurgy - Volume 76, Issues 3â4, March 2005, Pages 225-232
نویسندگان
J. Viñals, E. Juan, A. Roca, M. Cruells, J. Casado,