Recovery of rhenium from a spent catalyst

Claim 1

A PROCESS FOR THE RECOVERY OF RHENIUM FROM A MOLYBDENUM-CONTAINING ALUM SOLUTION RESULTING FROM THE DIGESTION OF A SPENT PLATIUM-RHENIUM CATALYST IN CONCENTRATED SULFURIC ACID, WITH A PLATINUM-CONTAINING RESIDUE HAVING BEEN SEPARATED BY FILTRATION WHICH COMPRISES A. CHANGING SAID ALUM SOLUTION DOWNWARDLY THROUGH A FIRST CONTACTOR COLUMN WITH AN AMINE SOLUTION CHARGED UPWARDLY THERETHROUGH AT CONDITIONS TO MAINTAIN AN AMINE/RHENIUM MOLE RATIO OF FROM ABOUT 1.4 TO ABOUT 1.8 IN THE LOWER OF SAID COLUMN AND EXTRACTING SUBSTANTIALLY ALL OF THE RHENIUM IN SAID ALUM SOLUTION, B. CHANGING THE RESULTING RHENIUM-CONTAINING AMINE SOLUTION UPWARDLY THROUGH A SECOND CONTCTOR COLUMN IN CONTACT WITH AN ALUM SOLUTION CHARGED DOWNWARDLY THERETHROUGH AND CONTAINING SUFFICIENT ADDED RHENIUM TO MAINTAIN AN AMINE/RHENIUM MOLE RATIO IN THE UPPER PORTION OF SAID COLUMN OF FROM ABOUT 0.1 TO ABOUT 1.2, AND STRIPPING SUBSTANTIALLY ALL OF THE MOLYBUDEUM FROM SAID RHENIUMCONTAINING AMINE SOLUTION, AND EXTRACTING A MAJOR PORTION OF THE RHENIUM CONTAINED IN SAID ALUM SOLUTION; C. CHARGING THE RESULTING MOLYBDENUM-CONTAINING ALUM SOLUTION DOWNWARDLY THROUGH THE FIRST CONTACTOR COLUMN IN ADMIXTURE WITH THE FIRST MENTIONED ALUM SOLUTION CHARGED THERETO, AND SEPARATING AND RECOVERING THE MOLYBDENUM-FREE RHENIUM-CONTAINING AMINE SOLUTION; D. DISCHARGING A PORTION OF THE MOLYBDENUM-CONTAINING ALUM SOLUTION PASSING DOWNWARDLY THROUGH SAID FIRST CONTRACTOR COLUMN, AND CHARGING THE REMAINING PORTION DOWNWARDLY THROUGH A THIRD CONTRACTOR COLUMN IN CONTACT WITH AN AMINE SOLUTION CHARGED UPWARDLY THERETHROUGH, EXTRACTING SUBSTANTIALLY ALL OF THE MOLYBDENUM CONTAINED IN SAID ALUM SOLUTION, AND CHARGING THE RESULTING ALUM SOLUTION AND ADDED RHENIUM DOWNWARDLY THROUGH SAID SECOND CONTRACTOR COLUMN IN ACCORDANCE WITH STEP (A), AND CHARGING THE RESULTING AMINE SOLUTION UPWARDLY THROUGH THE SECOND CONTACT COLUMN IN ACCORDANCE WITH STEP (A).