Method for refining vanadium pentoxide from vanadium liquid

The invention relates to a method for refining vanadium pentoxide from vanadium liquid, the vanadium liquid comprises sodium vanadium liquid or calcified vanadium liquid, and the method comprises the following steps: a, carrying out vanadium precipitation on the vanadium liquid by using ammonium salt vanadium precipitation or hydrolysis vanadium precipitation to obtain ammonium polyvanadate or red cakes; b, beating ammonium polyvanadate or the red cake with ammonium bicarbonate and/or ammonium carbonate for re-dissolution, and carrying out solid-liquid separation to obtain an ammonium metavanadate solution; c, cooling and crystallizing the ammonium metavanadate solution to obtain ammonium metavanadate crystals and post-crystallization liquid; d, adding ammonium bicarbonate and/or ammonium carbonate into the crystallized liquid, and returning to the step b; and e, calcining the ammonium metavanadate crystal to obtain vanadium pentoxide. The used stock solution is the vanadium solution, the range of the vanadiu