Cleaning of oil-contaminated solids

Abstract

The present invention relates to a method for treating of oil contaminated, metal-containing solids, in particular spent catalysts. The solids are cleaned with a dense phase gas and then metal is recovered from the cleaned solids.

1 . A method for treating of oil contaminated, metal-containing solids comprising a cleaning step wherein said oil is removed from said solids and a metal recovery step wherein metal is recovered from said cleaned solids, characterized in that said cleaning step comprises contacting said solids with a sub-critical dense phase gas. 
   
   
       2 . The method according to  claim 1  for treating of oil contaminated solids from oil refinery or petrochemical industry. 
   
   
       3 . The method according to  claim 1  characterized in that said solids are contacted with dense phase carbon dioxide. 
   
   
       4 . The method according to  claim 1  characterized in that detergents are added to said dense phase gas. 
   
   
       5 . The method according to  claim 1  characterized in that said cleaning step is performed at a pressure of at least 30 bar. 
   
   
       6 . The method according to  claim 1  characterized in that said cleanup step is performed at a temperature of at least 15° C. 
   
   
       7 . The method according to  claim 1  characterized in that a precious metal selected from the group consisting of palladium, nickel, silver, copper and vanadium is recovered from said cleaned solids. 
   
   
       8 . The method according to  claim 1  characterized in that prior to said cleaning step oil contaminated solids are stored under exclusion of air. 
   
   
       9 . The method according to  claim 8  characterized in that prior to said cleaning step said solids are handled under inert gas atmosphere. 
   
   
       10 . The method according to  claim 1  characterized in that said oil-contaminated solids are agitated during said cleaning step. 
   
   
       11 . The method according to  claim 2  wherein said oil contaminated solids are spent catalysts. 
   
   
       12 . The method according to  claim 5  characterized in that said cleaning step is performed at a pressure of at least 50 bar. 
   
   
       13 . The method according to  claim 5  characterized in that said cleaning step is performed at a pressure of at least 60 bar. 
   
   
       14 . The method according to  claim 6  characterized in that said cleanup step is performed at a temperature of at least 25° C. 
   
   
       15 . The method according to  claim 6  characterized in that said cleanup step is performed at a temperature of at least 40° C.