Method for re-extracting vanadium from vanadium containing byproduct of ferric vanadate

The invention relates to a method for re-extracting vanadium from a vanadium containing byproduct of ferric vanadate. The method comprises the following steps: (1) mixing ferric vanadate and coarse vanadium slag according to a mass ratio of (0.3 to 1.5) to 100; (2) adding sodium carbonate into the mixed powder to extract vanadium; (3) adding polyferric sulfate into supernatant after vanadium extracting to obtain ferric vanadate and reusing ferric vanadate to the step (1). The coarse vanadium slag generated by a converter has a higher temperature, ferric vanadate generated in a sodium-treatmentvanadium extracting process contains 15 to 40wt.% of moisture, ferric vanadate contains impurities of silicon, aluminum and the like, and suction filtration is not easy to perform; self heat of the coarse vanadium slag is utilized to dry ferric vanadate, and ferric vanadate and the coarse vanadium slag are mixed; thus, not only is the thermal energy utilization rate improved and is a mixed effectbetween ferric vanadate a