Method of recovering vanadium from leach liquors

Claim 1

A PROCESS FOR THE PRODUCTION OF VANADIUM OXIDE FROM A SULPHURIC ACID SOLUTION CONTAINING PENTAVALENT VANADIUM AND DISSOLVED PHOSPHROUS IMPURITIES WHICH COMPRISES ADDING LIME TO PH 8.0 SEPARTING THE PRECIPITATE AND TO SAID PRECIPITATE ADDING AQUEOUS SULPHURIC ACID TO A PH 1.0-1.2, SEPARATING THE RESULTING SOLUTION FROM THE RESIDUE, INCORPORATING ALKALI METAL CARBONATE WITH THE SOLUTION TO A FINAL PH OF ABOUT 7.5, SEPARATING THE VANADIUM-BEARING SOLUTION FROM THE PRECIPITATE, ADDING SULPHURIC ACID TO A PH 1.0-2.0, THEN HEATING AND AGITATING THE SOLUTION AT 90*C. TO 95*C. TO PRECIPITATE RED CAKE, SEPARATING THE RED CAKE AND HEATING THE SAME TO FUSION TO YIELD BLACK CAKE CONTAINING AT LEAST 85 PERCENT BY WEIGHT VANADIUM OXIDE, NOT HIGHER THAN 0.01 PERCENT P205 AND NOT HIGHER THAN 0.01 PERCENT SULPHUR.