The invention relates to the technical field of
hydrometallurgy and resource recycling, and particularly discloses a method for recycling
vanadium pentoxide in
vanadium electrolyte and
vanadium pentoxide. The recycling method specifically comprises the following steps that S1,
electrolyte pretreatment is conducted, specifically, suspended impurities in waste
electrolyte are removed through a micro-
filtration membrane, then a
reducing agent is added, V < 5 + > is partially reduced into V < 4 + >, and V < 4 + > is obtained; the
molar ratio of V < 4 + > to V < 5 + > is controlled to be 1: (1-1.3); s2, controllable
crystallization: adding
polyethylene glycol-400 into the pretreatment liquid, heating to 70-85 DEG C, adding an
oxidizing agent, and reacting for 2 hours under the condition that the pH value is 2.5-3.5 to obtain reaction liquid; and S3,
solid-liquid separation and purification: cooling the reaction liquid to 25 DEG C, separating out V2O5 crystals, centrifuging, washing with dilute sulphuric acid, and carrying out
vacuum drying to obtain V2O5. According to the method, V2O5 crystals are directly and efficiently separated out under mild conditions by regulating and controlling the valence state of vanadium ions and structure-oriented
crystallization, so that the problems of high
pollution and low purity of a traditional process are solved, and a low-cost and sustainable waste liquid recycling scheme is provided for a vanadium battery industry chain.