Patent ID: 7157063
Filing Date: 2007-01-02
Classification: C01G,C22B,Y02P

Abstract:
1. A process for recovering vanadium from a vanadium-containing sodium chromate solution obtained from the fusion of a chromium ore with alkali, which comprises the steps of: (a). adjusting the pH of the sodium chromate solution to 12–13 by addition of sodium hydroxide and adding calcium oxide, calcium hydroxide, calcium dichromate or calcium chromate to the sodium chromate solution to precipitate calcium hydroxyvanadate (Ca (b) separating the calcium hydroxyvanadate precipitate from the solution, (c) mixing the calcium hydroxyvanadate precipitate with water in an amount of from 1.5 to 10 times the dry weight of the calcium hydroxyvanadate precipitate and (d) separating the calcium carbonate from the solution formed in step (c), (e) acidifying the solution remaining after the separation of calcium carbonate in step (d) with chromic acid or with a mixture of sodium dichromate/chromic acid (sodium polychromate), to a pH below 4 at a temperature of at least 80° C. to precipitate vanadium pentoxide, and finally (f) separating the precipitated vanadium pentoxide V