Metals recovery from spent catalyst

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

• heating a deoiled spent catalyst comprising a Group VIB metal, a Group VIIIB metal, and a Group VB metal under oxidative conditions at a first pre-selected temperature for a first time sufficient to reduce the levels of sulfur and carbon to less than pre-selected amounts and to form a calcined spent catalyst;
• combining the calcined spent catalyst comprising Group VIII, Group VIB, and Group VB metal compounds with potassium carbonate to form a calcined spent catalyst/potassium carbonate mixture;
• heating the calcined spent catalyst/potassium carbonate mixture at a second pre-selected temperature and for a second pre-selected time under gas flow conditions to form a potassium carbonate calcine;
• contacting the potassium carbonate calcine with water to form a potassium carbonate calcine slurry at a temperature and for a time sufficient to leach a soluble Group VIB metal compound and a soluble Group VB metal compound from the potassium carbonate calcine;
• separating and removing a filtrate and a solid residue from the potassium carbonate calcine slurry, the filtrate comprising the soluble Group VIB metal compound and the soluble Group VB metal compound and the solid residue comprising an insoluble Group VIIIB metal compound;
• and
• recovering the soluble Group VIB metal compound and the soluble Group VB metal compound from the potassium carbonate calcine slurry filtrate.

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

• combining the spent catalyst comprising Group VIII, Group VIB, and Group VB metal compounds with potassium carbonate to form a spent catalyst/potassium carbonate mixture;
• heating the spent catalyst/potassium carbonate mixture under oxidative conditions at a pre-selected temperature for a time sufficient to reduce the levels of sulfur and carbon to less than pre-selected amounts and to form a potassium carbonate calcine;
• contacting the potassium carbonate calcine with water to form a potassium carbonate calcine slurry at a temperature and for a time sufficient to leach a soluble Group VIB metal compound and a soluble Group VB metal compound from the potassium carbonate calcine;
• separating and removing a filtrate and a solid residue from the potassium carbonate calcine slurry, the filtrate comprising the soluble Group VIB metal compound and the soluble Group VB metal compound and the solid residue comprising an insoluble Group VIIIB metal compound;
• and
• recovering the soluble Group VIB metal compound and the soluble Group VB metal compound from the potassium carbonate calcine slurry filtrate.