Process for direct and selective recovery of vanadium values from aqueous solutions thereof

Claim 1

A PROCESS FOR SELECTIVELY RECOVERING HIGHLY PURE VANADIUM VALUES AT HIGH YIELD FROM IRON, PHOSPHORUS AND ALUMINUM CONTAMINATED AQUEOUS VANADIUM CONTAINING SOLUTIONS COMPRISING: (1) PROVIDING AN AQUEOUS IRON, PHOSPHORUS AND ALUMINUM CONTAMINATED STARTING SOLUTION CONTAINING QUADRIVALENT VANADIUM VALUES, (2) ADJUSTING THE PH OF SAID SOLUTION TO ABOUT 0.0$0.1, (3) HEATING SAID SOLUTION AND MAINTAINING ITS TEMPERATURE AT ABOUT 25 TO 80*C., WHILE (4) OXIDIZING SAID QUADRIVALENT VANADIUM VALUES TO THE PENTAVALENT STATE WITH AN OXIDIZING AGENT, WHILE MAINTAINING THE PH OF SAID SOLUTION BELOW ABOUT 0.1, THEREBY CAUSING PRECIPITATION OF APPROXIMATELY 80 WEIGHT PERCENT OF THE VANADIUM VALUES IN SAID SOLUTION AS HYDRATED VANADIUM OXIDES, THEN (5) ADJUSTING THE PH OF SAID AQUEOUS SOLUTION TO BE WITHIN THE RANGE OF FROM ABOUT 0.3 TO 1.0 BY THE ADDITION OF AT LEAST ON REAGENT SELECTED FROM THE GROUP CONSISTING OF AMMONIUM HYDROXIDE AND AMMONIA, THEREBY CAUSING FURTHER SELECTIVE PRECIPITATION THE REMAINING VANADIUM VALUES IN SAID SOLUTION AS AMMONIUM POLYANADATES, (6) DIGESTING SAID AQUEOUS SOLUTION CONTAINING THE PRECIPITATES FOR ABOUT ONE HOUR AT A TEMPERATURE RANGING FROM ABOUT 25 TO 80*C., AND (7) SEPARATING SAID PRECIPITATES FROM THE SOLUTION BY FILTRATION.