METHOD OF EXTRACTING VANADIUM FROM VANADIUM SLAG WITH HIGH CONTENT OF CALCIUM AND PHOSPHORUS Russian patent published in 2021 - IPC C22B34/22 C22B7/04 C22B1/04 C22B3/04 

FIELD: chemical or physical processes.

SUBSTANCE: group of inventions relates to production of vanadium oxide, in particular to a method of extracting vanadium from vanadium slag with high content of calcium and phosphorus. Vanadium slag with high content of calcium and phosphorus containing from 9 to 25 % of V₂O₅, from 5 to 14 % of CaO and from 0.3 to 1.5 % of P is annealed with formation of clinker. After that, the first stage of clinker leaching is carried out using a mother solution at pH from 3.0 to 3.5. Solid and liquid phases are separated to produce first filtrate and first residue. First step of removing phosphorus is carried out with addition of an agent for removing phosphorus in form of polymer iron sulphate into first filtrate with separation of solid and liquid phases, and production of vanadium-containing liquid. Second leaching step is carried out with the first residue using a mother solution at pH from 1.3 to 2.0. Solid and liquid phases are separated to produce second filtrate and second residue. Second stage of phosphorus removal is performed by bringing pH of the second filtrate to an alkaline agent to 2.5–3.5. Solid and liquid phases are separated to obtain dephosphorized liquid. Third stage of leaching is carried out with the second residue using a mother solution at pH from 0.7 to 1.3. Solid and liquid phases are separated to produce third filtrate and final residue. Stages are repeated until vanadium residue content is reduced to less than 0.6 %.

EFFECT: method provides high degree of extraction of vanadium, simple and cheap process of time.

7 cl, 1 dwg