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Factors affecting platinum extraction from used reforming catalysts in iodine solutions at temperatures up to 95 °C

Zanjani, A ; Sharif University of Technology | 2009

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  1. Type of Document: Article
  2. DOI: 10.1016/j.hydromet.2009.02.001
  3. Publisher: 2009
  4. Abstract:
  5. Platinum extraction from the spent reforming catalysts in iodine-iodide solutions at temperatures from 25 to 95 °C was investigated. The reforming catalyst mostly consists of a porous gamma alumina support with metallic platinum finely dispersed on the walls of the nano-pores of the catalyst support. The effect of a variety of factors, including catalyst particle size, impeller agitation speed, reactant concentrations, liquid to solid mass ratio, temperature and the solution pH on the Pt extraction rate and recovery were investigated. It was found that the catalyst particle sizes less than 106 μm and impeller agitation speed higher than 700 rpm eliminated the effects of catalyst size and agitation level, respectively, on platinum leaching. The initial iodine-iodide concentrations and the liquid to solid ratio were mostly affecting the solution pH and the concentration of "active" iodine species, which in turn, affected the rate of Pt extraction. Higher acidities, generated by adding concentrated HCl, resulted in faster Pt extractions. Increasing the reaction temperature also produced faster platinum extraction kinetics. The "active" iodine species (HIO, I2(aq), and I3-) concentration decreased mostly due to conversion to "inactive" iodine-oxygen species and evaporation from the solution. © 2009 Elsevier B.V. All rights reserved
  6. Keywords:
  7. Platinum complex formation ; Platinum dissolution ; Reforming catalyst ; HIO ; Catalysis ; Catalyst supports ; Concentration (process) ; Dissolution ; Industrial chemicals ; Iodine ; Leaching ; Liquids ; Oxygen ; Particle size ; pH effects ; Platinum ; Reaction kinetics ; Platinum compounds
  8. Source: Hydrometallurgy ; Volume 97, Issue 1-2 , 2009 , Pages 119-125 ; 0304386X (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0304386X09000310