Method of recovering valuable metals from the vrds spent catalyst

Abstract

The present invention discloses method of recovering valuable metals, such as vanadium, molybdenum, nickel from the catalysts spent in the VRDS process for desulfurization of pertroleum. The method comprises leaching water-insoluble reactants after reacting the pre-treated waste crystals in solution of sodium hydroxide, maintaining the filtrate at pH 9.5 by adding sulfhuric acid or hydrochloric acid and then heating the filtrate, removing aluminium oxide from the soltuion, aerating the filtrate continously or priodically and agitating the filtrate below pH 1 at 80-100° C., thereby precipitating molybdenum oxide and vanadium oxide, and leaching and washing the precipitated molybdenum oxide and vanadium oxide.

1 . A method of recovering valuable matals from the waste catalysts in VRDS, comprising:
 pre-treating the waste catalysts for deoiling and desulfurization;   forming sodium aluminate, sodium vanadate and sodium molybdate as water-soluble reactants, and nickel oxide, cobalt oxide as water-insoluble reactants by reacting the pre-treated waste crystals in solution of sodium hydroxide at a temperature of 135˜160° C.; and   leaching the water-inslouble nickel oxide, cobalt oxide and impurities, thereby remaining the water-soluble sodium aluminate, sodium vanadate and sodium molybdate in the solution.   
     
     
         2 . A method according to  claim 1 , further comprising heating the filtrate containing the sodium aluminate, sodium vanadate and sodium molybdate so as to increase a temperature of the filtrate over a temerature of 80° C., and agitating the filtrate with adding hydrochloric acid or sulfhuric acid therein so as to maintain pH 9.5;
 forming aluminum oxide at the temperture over 110° C. with heat of the reaction; and   recovering the aluminum oxide by leaching.   
     
     
         3 . A method of recovering valuable matals from the waste catalysts in VRDS, comprising:
 forming a solution containing sodium vanadate and sodium molybdate bt treating the waste catalysts;   heating the solution with the solution maintained in pH 1.0˜−1.0; and   precipitating molybdenum oxide and vanadium oxide in the solution by aeration thereof.   
     
     
         4 . A method according to  claim 3  further comprising adding ammonia water to the solution in which molybdenum oxide and vanadium oxide are precipitated and thus agitating the mixtured solution so as to precipitate amonium metavanadate with ammonium molybdate remaining in the solution; and
 recovering and separating the crystals of the precipitated amonium metavanadate from the solution.