, Volume 55, Issue 4, pp 37–40 | Cite as

Leaching platinum-group metals in a sulfuric acid/chloride solution

  • M. H. H. Mahmoud
Research Summary Precious Metals: Aqueous


A leaching process was established based on the ability of platinum-group metals to form stable chloro-complexes in acidic chloride solutions. Industrial catalyst losses were examined for the recovery of platinum, palladium, and rhodium by leaching with a mixture of sulfuric acid and sodium chloride to avoid using aqua regia or autoclave conditions. Extraction of platinum and rhodium in 60% H2SO4 at 135°C steadily increased with increasing NaCl concentrations reaching 95% and 85%, respectively, at 0.1 M NaCl after two hours. By comparison, palladium was dissolved more quickly but also reached 85% under the same conditions. Extraction of each metal increased with temperatures up to 125°C but plateaued at higher temperatures. Similar behavior was observed with increasing H2SO4 concentrations up to 60%. More than 99% extraction of each metal was obtained after ten hours using 0.1 M NaCl and 60% H2SO4 at 125°C.


Palladium Rhodium Platinum Group Metal Acidic Chloride Solution Unwashed Sample 
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Copyright information

© TMS 2003

Authors and Affiliations

  • M. H. H. Mahmoud
    • 1
  1. 1.the Extractive Metallurgy DepartmentCentral Metallurgical R&D InstituteCairoEgypt

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