Metals recovery from spent supported catalyst

A method for recovering metals from a deoiled spent supported catalyst, wherein the catalyst comprises a Group VIB metal, a Group VIIIB metal, a Group VB metal and a catalyst support material, the method comprising:

• combining a deoiled spent supported catalyst comprising Group VIIIB, Group VIB, and Group VB metals with potassium carbonate to form a deoiled spent catalyst/potassium carbonate mixture;
• heating the deoiled spent supported catalyst/potassium carbonate mixture under oxidative conditions to reduce the levels of sulfur and carbon and to form a spent supported catalyst/potassium carbonate calcine comprising a water-soluble Group VIB metal compound, a water-soluble Group VB metal compound and a water-insoluble Group VIIIB metal compound;
• combining the spent supported catalyst/potassium carbonate calcine with water under slurry leach process conditions to form a spent supported catalyst/potassium carbonate calcine slurry and to leach the water-soluble Group VIB metal compound and the water-soluble Group VB metal compound from the spent supported catalyst/potassium carbonate calcine;
• separating and removing a filtrate and a solid residue from the spent supported catalyst/potassium carbonate calcine slurry, the filtrate comprising the water-soluble Group VIB metal compound and the water-soluble Group VB metal compound and the solid residue comprising the water-insoluble Group VIIIB metal compound;
• and
• recovering the water-soluble Group VIB metal compound and the water-soluble Group VB metal compound from the filtrate of the spent supported catalyst/potassium carbonate calcine slurry.