Ex parte KETCHAM et al. - Page 8

                Appeal No. 1997-0448                                                                                                     
                Application No. 08/327,980                                                                                               

                        Vertes discloses roasting a molybdenite concentrate, pressure oxidizing roasted concentrate                      

                which consists predominantly of molybdenum oxide, of which the majority is in the form of molybdenum                     

                trioxide, at a temperature from about 150EC to about 350EC and a partial pressure of oxygen of at                        

                least about 100 psi whereby suboxides of molybdenum are converted to molybdenum trioxide and                             

                contaminating metal molybdites and sub-molybdate compounds thereof are converted to aqueous acid                         
                soluble molybdate compounds.   The resultant slurry is filtered to separate the solids, i.e.,11                                                                                      

                predominantly molybdenum trioxide and insoluble gangue contaminants.   Thereafter, the filtered solids12                                         

                are solubilized with aqueous ammonium hydroxide solution and filtered to separate or “leach out”                         
                soluble ammonium molybdate compounds from residual solid contaminants.   The resultant filtrate is13                                     

                crystallized and calcined to produce ammonium gas which is recycled back to aqueous ammonium                             
                hydroxide, thereby yielding high purity molybdenum trioxide.   Alternatively, the filtered solids can be14                                                     

                solubilized with an aqueous alkali metal hydroxide solution (instead of solubilized with aqueous                         
                ammonium hydroxide solution) to form the corresponding soluble alkali metal molybdate compound.             15           

                        11See Vertes, col. 3, line 7 - col. 4, line 50.                                                                  
                        12See Vertes, col. 4, lines 51-57.                                                                               
                        13See Vertes, col. 4, line 57 - col. 5, line 3.                                                                  
                        14See Vertes, col. 5, lines 4-24.                                                                                
                        15See Vertes, col. 5, lines 25-30 and col. 6, lines 5-14.                                                        
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